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Archive for the ‘Delphi’ Category

Using Delphi to fight the Corona Pandemic

April 26, 2020 Leave a comment

I just published an article on Idera’s Community website, focusing on how Delphi and Object Pascal plays a key role in fighting the Corona Pandemic.

My focus this time is on DIPS AS, a Norwegian corporation that produces a wide range of software solutions for hospitals, medical facilities and special care units. They were amoung the first companies in Norway to provide a Covid-19 module through their FastTrak application, which is completely written in Delphi.

Click the link to read the article (or just click the preview image below): https://community.idera.com/developer-tools/b/blog/posts/delphi-in-healthcare-fighting-the-corona-pandemic

pdd

 

Vector Containers For Delphi and FPC

April 11, 2020 Leave a comment

Edit: Version 1.0.1 has been released, with a ton of powerful features. Read about it here and grab your fork: https://jonlennartaasenden.wordpress.com/2020/04/13/qtx-framework-for-delphi-and-fpc-is-available-on-bitbucket/


If you have been looking at C++ and envied them their std::vector classes, wanting the same for Delphi or being able to access untyped memory using a typed-view (basically turning a buffer into an array of <T>) then I have some good news for you!

Vector containers, unified storage model and typed views are just some of the highlights of my vector-library. I did an article on the subject at the Embarcadero community website, so head over and read up on how you can enjoy these features in your Delphi application!

I also added FreePascal support, so that the library can be used with TMS Web Framework.

vectors

Head over to the Embarcadero Community website to read the full article

C/C++ porting, QTX and general status

March 15, 2020 2 comments

C is a language that I used to play around with a lot back in the Amiga days. I think the last time I used a C compiler to write a library must have been in 1992 or something like that? I held on to my Amiga 1200 for as long as i could – but having fallen completely in love with Pascal, I eventually switched to x86 and went down the Turbo Pascal road.

Lately however, C++ developers have been asking for their own Developer group on Facebook. I run several groups on Facebook in the so-called “developer” family. So you have Delphi Developer, FPC Developer, Node.JS Developer and now – C++Builder developer. The groups more or less tend to themselves, and the node.js and FPC groups are presently being seeded (meaning, that the member count is being grown for a period).

The C++Builder group however, is having the same activity level as the Delphi group almost, thanks to some really good developers that post links, tips and help solve questions. I was also fortunate enough to have David Millington come on the Admin team. David is leading the C++Builder project, so his insight  and knowledge of both language and product is exemplary. Just like Jim McKeeth, he is a wonderful resource for the community and chime in with answers to tricky questions whenever he has time to spare.

Getting back in the saddle

Having working some 30 years with Pascal and Object Pascal, 25 of those years in Delphi, C/C++ is never far away. I have an article on the subject that i’ve written for the Idera Community website, so I wont dig too deep into that here — but needless to say, Rad Studio consists of two languages: Object Pascal and C/C++, so no matter how much you love either language, the other is never far away.

So I figured it was time for this old dog to learn some new tricks! I have always said that it’s wise to learn a language immediately below and above your comfort zone. So if Delphi is your favorite language, then C/C++ is below you (meaning: more low level and complex). Above you are languages like JavaScript and C#. Learning JavaScript makes strategic sense (or use DWScript to compile Pascal to JavaScript like I do).

When I started out, the immediate language below Object Pascal was never C, but assembler. So for the longest time I turned to assembler whenever I needed a speed boost; graphics manipulation and processing pixels is especially a field where assembly makes all the difference.

But since C++Builder is indeed an integral part of Rad Studio, and Object Pascal and C/C++ so intimately connected (they have evolved side by side), why not enjoy both assembly and C right?

So I decided to jump back into the saddle and see what I could make of it.

C/C++ is not as hard as you think

intf

I’m having a ball writing C/C++, and just like Delphi – you can start where you are.

While I’m not going to rehash the article I have already prepared for the Idera Community pages here, I do want to encourage people to give it a proper try. I have always said that if you know an archetypal language, you can easily pick up other languages, because the archetypal languages will benefit you for a lifetime. This has to do with archetypal languages operating according to how computers really work; as opposed to optimistic languages (a term from the DB work, optimistic locking), also called contextual languages, like C#, Java, JavaScript etc. are based on how human beings would like things to be.

So I now had a chance to put my money where my mouth is.

When I left C back in the early 90s, I never bothered with OOP. I mean, I used C purely for shared libraries anyways, while the actual programs were done in Pascal or a hybrid language called Blitz Basic. The latter compiled to razor sharp machine code, and you could use inline assembly – which I used a lot back then (very few programmers on those machines went without assembler, it was almost given that you could use 68k in some capacity).

Without ruining the article about to be published, I had a great time with C++Builder. It took a few hours to get my bearings, but since both the VCL and FMX frameworks are there – you can approach C/C++ just like you would Object Pascal. So it’s a matter of getting an overview really.

Needless to say, I’ll be porting  a fair share of my libraries to C/C++ when I have time (those that makes sense under that paradigme). It’s always good to push yourself and there are plenty of subtle differences that I found useful.

Quartex Media Desktop

When I last wrote about QTX we were nearing the completion of the FileSystem and Task Management service. The prototype had all its file-handling directly in the core service  (or server) which worked just fine — but it was linked to the Smart Pascal RTL. It has taken time to write a new RTL + a full multi-user, platform independent service stack and desktop (phew!) but we are seeing progress!

desktop

The QTX Baseline backend services is now largely done

The filesystem service is now largely done! There are a few synchronous calls I want to get rid of, but thankfully my framework has both async and sync variations of all file procedures – so that is now finished.

To make that clearer: first I have to wrap and implement the functionality for the RTL. Once they are in the RTL, I can use those functions to build the service functions. So yeah, it’s been extremely elaborate — but thankfully it’s also become a rich, well organized codebase (both the RTL and the Quartex Media Desktop codebases) – so I think we are ready to get cracking on the core!

The core is still operating with the older API. So our next step is to remove that from the core and instead delegate calls to the filesystem to our new service. So the core will simply be reduced to a post-office or traffic officer if you like. Messages come in from the desktops, and the core delegates the messages to whatever service is in charge of them.

But, this also means that both the core and the desktop must use the new and fancy messages. And this is where I did something very clever.

While I was writing the service, I also write a client class to test (obviously). And the way the core works — means that the same client that the core use to talk to the services — can be used by the desktop as well.

So our work in the desktop to get file-access and drives running again, is to wrap the client in our TQTXDevice ancestor class. The desktop NEVER accesses the API directly. All it knows about are these device drivers (or object instances). Which is  how we solve things like DropBox and Google Drive support. The desktop wont have the faintest clue that its using Dropbox, or copying files between a local disk and Google Drive for example — because it only communicates with these device classes.

Recursive stuff

One thing that sucked about node.js function for deleting a folder, is that it’s recursive parameter doesn’t work on Windows or OS X. So I had to implement a full recursive deletefolder routine manually. Not a big thing, but slightly more painful than expected under asynchronous execution. Thankfully, Object Pascal allows for inline defined procedures, so I didn’t have to isolate it in a separate class.

Here is some of the code, a tiny spec compared to the full shabam, but it gives you an idea of what life is like under async conditions:

unit service.file.core;

interface

{.$DEFINE DEBUG}

const
  CNT_PREFS_DEFAULTPORT     = 1883;
  CNT_PREFS_FILENAME        = 'QTXTaskManager.preferences.ini';
  CNT_PREFS_DBNAME          = 'taskdata.db';

  CNT_ZCONFIG_SERVICE_NAME  = 'TaskManager';

uses
  qtx.sysutils,
  qtx.json,
  qtx.db,
  qtx.logfile,
  qtx.orm,
  qtx.time,

  qtx.node.os,
  qtx.node.sqlite3,
  qtx.node.zconfig,
  qtx.node.cluster,

  qtx.node.core,
  qtx.node.filesystem,
  qtx.node.filewalker,
  qtx.fileapi.core,

  qtx.network.service,
  qtx.network.udp,

  qtx.inifile,
  qtx.node.inifile,

  NodeJS.child_process,

  ragnarok.types,
  ragnarok.Server,
  ragnarok.messages.base,
  ragnarok.messages.factory,
  ragnarok.messages.network,

  service.base,
  service.dispatcher,
  service.file.messages;

type

  TQTXTaskServiceFactory = class(TMessageFactory)
  protected
    procedure RegisterIntrinsic; override;
  end;

  TQTXFileWriteCB = procedure (TagValue: variant; Error: Exception);
  TQTXFileStateCB = procedure (TagValue: variant; Error: Exception);

  TQTXUnRegisterLocalDeviceCB = procedure (TagValue: variant; DiskName: string; Error: Exception);
  TQTXRegisterLocalDeviceCB = procedure (TagValue: variant; LocalPath: string; Error: Exception);
  TQTXFindDeviceCB = procedure (TagValue: variant; Device: JDeviceInfo; Error: Exception);
  TQTXGetDisksCB = procedure (TagValue: variant; Devices: JDeviceList; Error: Exception);

  TQTXGetFileInfoCB = procedure (TagValue: variant; LocalName: string; Info: JStats; Error: Exception);
  TQTXGetTranslatePathCB = procedure (TagValue: variant; Original, Translated: string; Error: Exception);

  TQTXCheckDevicePathCB = procedure (TagValue: variant; PathName: string; Error: Exception);

  TQTXServerExecuteCB = procedure (TagValue: variant; Data: string; Error: Exception);

  TQTXTaskService = class(TRagnarokService)
  private
    FPrefs:     TQTXIniFile;
    FLog:       TQTXLogEmitter;
    FDatabase:  TSQLite3Database;

    FZConfig:   TQTXZConfigClient;
    FRegHandle: TQTXDispatchHandle;
    FRegCount:  integer;

    procedure   HandleGetDevices(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
    procedure   HandleGetDeviceByName(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
    procedure   HandleCreateLocalDevice(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
    procedure   HandleDestroyDevice(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
    procedure   HandleFileRead(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
    procedure   HandleFileReadPartial(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
    procedure   HandleGetFileInfo(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
    procedure   HandleFileDelete(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);

    procedure   HandleFileWrite(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
    procedure   HandleFileWritePartial(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
    procedure   HandleFileRename(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
    procedure   HandleGetDir(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);

    procedure   HandleMkDir(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
    procedure   HandleRmDir(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);

    procedure   ExecuteExternalJS(Params: array of string;
      TagValue: variant; const CB: TQTXServerExecuteCB);

    procedure   SendError(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage; Message: string);

  protected
    function    GetFactory: TMessageFactory; override;
    procedure   SetupPreferences(const CB: TRagnarokServiceCB);
    procedure   SetupLogfile(LogFileName: string;const CB: TRagnarokServiceCB);
    procedure   SetupDatabase(const CB: TRagnarokServiceCB);

    procedure   ValidateLocalDiskName(TagValue: variant; Username, DeviceName: string; CB: TQTXCheckDevicePathCB);
    procedure   RegisterLocalDevice(TagValue: variant; Username, DiskName: string; CB: TQTXRegisterLocalDeviceCB);
    procedure   UnRegisterLocalDevice(TagValue: variant; UserName, DiskName:string; CB: TQTXUnRegisterLocalDeviceCB);

    procedure   GetDevicesForUser(TagValue: variant; UserName: string; CB: TQTXGetDisksCB);
    procedure   FindDeviceByName(TagValue: variant; UserName, DiskName: string; CB: TQTXFindDeviceCB);
    procedure   FindDeviceByType(TagValue: variant; UserName: string; &Type: JDeviceType; CB: TQTXGetDisksCB);

    procedure   GetTranslatedPathFor(TagValue: variant; Username, FullPath: string; CB: TQTXGetTranslatePathCB);

    procedure   GetFileInfo(TagValue: variant; UserName: string; FullPath: string; CB: TQTXGetFileInfoCB);

    procedure   SetupTaskTable(const TagValue: variant; const CB: TRagnarokServiceCB);
    procedure   SetupOperationsTable(const TagValue: variant; const CB: TRagnarokServiceCB);
    procedure   SetupDeviceTable(const TagValue: variant; const CB: TRagnarokServiceCB);

    procedure   AfterServerStarted; override;
    procedure   BeforeServerStopped; override;
    procedure   Dispatch(Socket: TNJWebSocketSocket; Message: TQTXBaseMessage); override;

  public
    property    Preferences: TQTXIniFile read FPrefs;
    property    Database: TSQLite3Database read FDatabase;

    procedure   SetupService(const CB: TRagnarokServiceCB);

    constructor Create; override;
    destructor  Destroy; override;
  end;


implementation

//#############################################################################
// TQTXFileenticationFactory
//#############################################################################

procedure TQTXTaskServiceFactory.RegisterIntrinsic;
begin
  writeln("Registering task interface");
  &Register(TQTXFileGetDeviceListRequest);
  &Register(TQTXFileGetDeviceByNameRequest);
  &Register(TQTXFileCreateLocalDeviceRequest);
  &Register(TQTXFileDestroyDeviceRequest);
  &Register(TQTXFileReadPartialRequest);
  &Register(TQTXFileReadRequest);
  &Register(TQTXFileWritePartialRequest);
  &Register(TQTXFileWriteRequest);
  &Register(TQTXFileDeleteRequest);
  &Register(TQTXFileRenameRequest);
  &Register(TQTXFileInfoRequest);
  &Register(TQTXFileDirRequest);
  &Register(TQTXMkDirRequest);
  &Register(TQTXRmDirRequest);
  &Register(TQTXFileRenameRequest);
  &Register(TQTXFileDirRequest);
end;

//#############################################################################
// TQTXTaskService
//#############################################################################

constructor TQTXTaskService.Create;
begin
  inherited Create;
  FPrefs := TQTXIniFile.Create();
  FLog := TQTXLogEmitter.Create();
  FDatabase := TSQLite3Database.Create(nil);

  FZConfig := TQTXZConfigClient.Create();
  FZConfig.Port := 2292;

  self.OnUserSignedOff := procedure (Sender: TObject; Username: string)
  begin
    WriteToLogF("We got a service signal! User [%s] has signed off completely", [Username]);
  end;

  MessageDispatch.RegisterMessage(TQTXFileGetDeviceListRequest, @HandleGetDevices);
  MessageDispatch.RegisterMessage(TQTXFileGetDeviceByNameRequest, @HandleGetDeviceByName);
  MessageDispatch.RegisterMessage(TQTXFileCreateLocalDeviceRequest, @HandleCreateLocalDevice);
  MessageDispatch.RegisterMessage(TQTXFileDestroyDeviceRequest, @HandleDestroyDevice);

  MessageDispatch.RegisterMessage(TQTXFileReadRequest, @HandleFileRead);
  MessageDispatch.RegisterMessage(TQTXFileReadPartialRequest, @HandleFileReadPartial);

  MessageDispatch.RegisterMessage(TQTXFileWriteRequest, @HandleFileWrite);
  MessageDispatch.RegisterMessage(TQTXFileWritePartialRequest, @HandleFileWritePartial);

  MessageDispatch.RegisterMessage(TQTXFileInfoRequest, @HandleGetFileInfo);
  MessageDispatch.RegisterMessage(TQTXFileDeleteRequest, @HandleFileDelete);

  MessageDispatch.RegisterMessage(TQTXMkDirRequest, @HandleMkDir);
  MessageDispatch.RegisterMessage(TQTXRmDirRequest, @HandleRmDir);
  MessageDispatch.RegisterMessage(TQTXFileRenameRequest, @HandleFileRename);

  MessageDispatch.RegisterMessage(TQTXFileDirRequest, @HandleGetDir);
end;

destructor TQTXTaskService.Destroy;
begin
  // decouple logger from our instance
  self.logging := nil;

  // Release prefs + log
  FPrefs.free;
  FLog.free;
  FZConfig.free;
  inherited;
end;

procedure TQTXTaskService.SendError(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage; Message: string);
begin
  var reply := TQTXErrorMessage.Create(request.ticket);
  try
    reply.Code := CNT_MESSAGE_CODE_ERROR;
    reply.Routing.TagValue := Request.Routing.TagValue;
    reply.Response := Message;

    if Socket.ReadyState = rsOpen then
    begin
      try
        Socket.Send( reply.Serialize() );
      except
        on e: exception do
        WriteToLog(e.message);
      end;
    end else
      WriteToLog("Failed to dispatch error, socket is closed error");
  finally
    reply.free;
  end;
end;

procedure TQTXTaskService.ExecuteExternalJS(Params: array of string;
  TagValue: variant; const CB: TQTXServerExecuteCB);
begin
  var LTask: JChildProcess;

  var lOpts := TVariant.CreateObject();
  lOpts.shell := false;
  lOpts.detached := true;

  Params.insert(0, '--no-warnings');

  // Spawn a new process, this creates a new shell interface
  try
    LTask := child_process().spawn('node', Params, lOpts );
  except
    on e: exception do
    begin
      if assigned(CB) then
        CB(TagValue, e.message, e);
      exit;
    end;
  end;

  // Map general errors on process level
  LTask.on('error', procedure (error: variant)
  begin
    {$IFDEF DEBUG}
    writeln("error->" + error.toString());
    {$ENDIF}
    WriteToLog(error.toString());

    if assigned(CB) then
      CB(TagValue, "", nil);
  end);

  // map stdout so we capture the output
  LTask.stdout.on('data', procedure (data: variant)
  begin
    if assigned(CB) then
      CB(TagValue, data.toString(), nil);
  end);

  // map stderr so we can capture exception messages
  LTask.stderr.on('data', procedure (error:variant)
  begin
    {$IFDEF DEBUG}
    writeln("stdErr->" + error.toString());
    {$ENDIF}

    if assigned(CB) then
      CB(TagValue, "", nil);

    WriteToLog(error.toString());
  end);
end;

function TQTXTaskService.GetFactory: TMessageFactory;
begin
  result := TQTXTaskServiceFactory.Create();
end;

procedure TQTXTaskService.SetupService(const CB: TRagnarokServiceCB);
begin
  SetupPreferences( procedure (Error: Exception)
  begin
    // No logfile yet setup (!)
    if Error  nil then
    begin
      WriteToLog("Preferences setup: Failed!");
      WriteToLog(error.message);
      raise error;
    end else
    WriteToLog("Preferences setup: OK");

    // logfile-name is always relative to the executable
    var LLogFileName := TQTXNodeFileUtils.IncludeTrailingPathDelimiter( TQTXNodeFileUtils.GetCurrentDirectory );
    LLogFileName += FPrefs.ReadString('log', 'logfile', 'log.txt');

    // Port is defined in the ancestor, so we assigns it here
    Port := FPrefs.ReadInteger('networking', 'port', CNT_PREFS_DEFAULTPORT);

    SetupLogfile(LLogFileName, procedure (Error: Exception)
    begin
      if Error  nil then
      begin
        WriteToLog("Logfile setup: Failed!");
        WriteToLog(error.message);
        raise error;
      end else
      WriteToLog("Logfile setup: OK");

      SetupDatabase( procedure (Error: Exception)
      begin
        if Error  nil then
        begin
          WriteToLog("Database setup: Failed!");
          WriteToLog(error.message);
          if assigned(CB) then
            CB(Error)
          else
            raise Error;
        end else
        WriteToLog("Database setup: OK");

        if assigned(CB) then
          CB(nil);
      end);

    end);
  end);
end;

procedure TQTXTaskService.SetupPreferences(const CB: TRagnarokServiceCB);
begin
  var lBasePath := TQTXNodeFileUtils.GetCurrentDirectory;
  var LPrefsFile := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(LBasePath) + CNT_PREFS_FILENAME;

  if TQTXNodeFileUtils.FileExists(LPrefsFile) then
  begin
    FPrefs.LoadFromFile(nil, LPrefsFile, procedure (TagValue: variant; Error: Exception)
    begin
      if Error  nil then
      begin
        if assigned(CB) then
          CB(Error)
        else
          raise Error;
        exit;
      end;

      if assigned(CB) then
        CB(nil);
    end);

  end else
  begin
    var LError := Exception.Create('Could not locate preferences file: ' + LPrefsFile);
    WriteToLog(LError.message);
    if assigned(CB) then
      CB(LError)
    else
      raise LError;
  end;
end;

procedure TQTXTaskService.SetupLogfile(LogFileName: string;const CB: TRagnarokServiceCB);
begin
  // Attempt to open logfile
  // Note: Log-object error options is set to throw exceptions
  try
    FLog.Open(LogFileName);
  except
    on e: exception do
    begin
      if assigned(CB) then
      begin
        CB(e);
        exit;
      end else
      begin
        writeln(e.message);
        raise;
      end;
    end;
  end;

  // We inherit from TQTXLogObject, which means we can pipe
  // all errors etc directly using built-in functions. So here
  // we simply glue our instance to the log-file, and its all good
  self.Logging := FLog as IQTXLogClient;

  if assigned(CB) then
    CB(nil);
end;

procedure TQTXTaskService.FindDeviceByType(TagValue: variant; UserName: string; &Type: JDeviceType; CB: TQTXGetDisksCB);
begin
  UserName := username.trim().ToLower();
  if Username.length < 1 then
  begin
    WriteToLog("Failed to lookup disk, username was invalid error");
    var lError := EException.Create("Failed to lookup devices, invalid username");
    if assigned(CB) then
      CB(TagValue, nil, lError)
    else
      raise lError;
    exit;
  end;

  GetDevicesForUser(TagValue, Username,
  procedure (TagValue: variant; Devices: JDeviceList; Error: Exception)
  begin
    if Error  nil then
    begin
      if assigned(CB) then
        CB(TagValue, nil, Error)
      else
        raise Error;
      exit;
    end;

    var x := 0;
    while x < Devices.dlDrives.Count do
    begin
      if Devices.dlDrives[x].&Type  &Type then
      begin
        Devices.dlDrives.delete(x, 1);
        continue;
      end;
      inc(x);
    end;

    if assigned(CB) then
      CB(TagValue, Devices, nil);
  end);
end;

procedure TQTXTaskService.FindDeviceByName(TagValue: variant; Username, DiskName: string; CB: TQTXFindDeviceCB);
begin
  UserName := username.trim().ToLower();
  if Username.length < 1 then
  begin
    var lLogText := "Failed to lookup device, username was invalid error";
    WriteToLog(lLogText);
    var lError := EException.Create(lLogText);
    if assigned(CB) then
      CB(TagValue, nil, lError)
    else
      raise lError;
    exit;
  end;

  DiskName := DiskName.trim();
  if DiskName.length < 1 then
  begin
    var lLogText := "Failed to lookup device, disk-name was invalid error";
    WriteToLog(lLogText);
    var lError := EException.Create(lLogText);
    if assigned(CB) then
      CB(TagValue, nil, lError)
    else
      raise lError;
    exit;
  end;

  GetDevicesForUser(TagValue, Username,
  procedure (TagValue: variant; Devices: JDeviceList; Error: Exception)
  begin
    if Error  nil then
    begin
      if assigned(CB) then
        CB(TagValue, nil, Error)
      else
        raise Error;
      exit;
    end;

    DiskName := DiskName.trim().ToLower();
    var lDiskInfo: JDeviceInfo := nil;


    for var disk in Devices.dlDrives do
    begin
      if disk.Name.ToLower() = DiskName then
      begin
        lDiskInfo := disk;
        break;
      end;
    end;

    if assigned(CB) then
      CB(TagValue, lDiskInfo, nil);
  end);
end;

procedure TQTXTaskService.GetTranslatedPathFor(TagValue: variant; Username, FullPath: string; CB: TQTXGetTranslatePathCB);
begin
  var lParser := TQTXPathParser.Create();
  try
    var lInfo: TQTXPathData;
    if lparser.Parse(FullPath, lInfo) then
    begin
      // Locate the device for the path belonging to the user
      FindDeviceByName(TagValue, UserName, lInfo.MountPart,
      procedure (TagValue: variant; Device: JDeviceInfo; Error: Exception)
      begin
        if Error  nil then
        begin
          if assigned(CB) then
            CB(TagValue, FullPath, '', Error)
          else
            raise Error;
          exit;
        end;

        if Device.&Type  dtLocal then
        begin
          var lError := EException.CreateFmt('Failed to translate path, device [%s] is not local error', [Device.Name]);
          if assigned(CB) then
            CB(TagValue, FullPath, '', Error)
          else
            raise Error;
          exit;
        end;

        // We want the path + filename, so we can append that to
        // the actual localized filesystem
        var lExtract := FullPath;
        delete(lExtract, 1, lInfo.MountPart.Length + 1);

        // Construct complete storage location
        var lFullPath := TQTXNodeFileUtils.GetCurrentDirectory();
        lFullPath := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(lFullPath) + 'userdevices';
        lFullPath := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(lFullPath) + Device.location.trim();
        lFullPath := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(lFullPath) + lExtract;

        // Return translated path
        if assigned(CB) then
          CB(TagValue, FullPath, lFullPath, nil);

      end);
    end else
    begin
      var lErr := EException.CreateFmt("Invalid path [%s] error", [FullPath]);
      if assigned(CB) then
        CB(TagValue, FullPath, '', lErr)
      else
        raise lErr;
    end;
  finally
    lParser.free;
  end;
end;

procedure TQTXTaskService.GetFileInfo(TagValue: variant; UserName, FullPath: string; CB: TQTXGetFileInfoCB);
begin
  var lParser := TQTXPathParser.Create();
  try
    var lInfo: TQTXPathData;
    if lparser.Parse(FullPath, lInfo) then
    begin
      // Locate the device for the path belonging to the user
      FindDeviceByName(TagValue, UserName, lInfo.MountPart,
      procedure (TagValue: variant; Device: JDeviceInfo; Error: Exception)
      begin
        if Error  nil then
        begin
          if assigned(CB) then
            CB(TagValue, '', nil, Error)
          else
            raise Error;
          exit;
        end;

        case Device.&Type of
        dtLocal:
          begin
            // We want the path + filename, so we can append that to
            // the actual localized filesystem
            var lExtract := FullPath;
            delete(lExtract, 1, lInfo.MountPart.Length + 1);

            // Construct complete storage location
            var lFullPath := TQTXNodeFileUtils.GetCurrentDirectory();
            lFullPath := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(lFullPath) + 'userdevices';
            lFullPath := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(lFullPath) + Device.location.trim();
            lFullPath := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(lFullPath) + lExtract;

            // Call the underlying OS to get the file statistics
            NodeJsFsAPI().lStat(lFullPath,
            procedure (Error: JError; Stats: JStats)
            begin
              if Error  nil then
              begin
                var lError := EException.Create(Error.message);
                if assigned(CB) then
                  CB(TagValue, lFullPath, nil, lError)
                else
                  raise lError;
                exit;
              end;

              // And deliver
              if assigned(CB) then
                CB(TagValue, lFullPath, Stats, nil);
            end);
          end;
        dtDropbox, dtGoogle, dtMsDrive:
          begin
            var lError := EException.Create("Cloud bindings not activated error");
            if assigned(CB) then
              CB(TagValue, '', nil, lError)
          end;
        end;
      end);
    end else
    begin
      var lErr := EException.CreateFmt("Invalid path [%s] error", [FullPath]);
      if assigned(CB) then
        CB(TagValue, '', nil, lErr)
      else
        raise lErr;
    end;
  finally
    lParser.free;
  end;
end;

procedure TQTXTaskService.GetDevicesForUser(TagValue: variant; Username: string; CB: TQTXGetDisksCB);
begin
  UserName := username.trim().ToLower();
  if Username.length < 1 then
  begin
    WriteToLog("Failed to lookup devices, username was invalid error");
    var lError := EException.Create("Failed to lookup devices, invalid username");
    if assigned(CB) then
      CB(TagValue, nil, lError)
    else
      raise lError;
    exit;
  end;

  var lTransaction: TQTXReadTransaction;
  if not TSQLite3Database(DataBase).CreateReadTransaction(lTransaction) then
  begin
    var lErr := EException.Create("Failed to create read-transaction error");
    if assigned(cb) then
      CB(TagValue, nil, lErr)
    else
      raise lErr;
    exit;
  end;

  var lQuery := TSQLite3ReadTransaction(lTransaction);
  lQuery.SQL := "select * from devices where owner=?";
  lQuery.Parameters.AddValueOnly(Username);

  lQuery.Execute(
  procedure (Sender: TObject; Error: Exception)
  begin
    if Error  nil then
    begin
      if assigned(CB) then
        CB(TagValue, nil, Error)
      else
        raise Error;
      exit;
    end;

    var lDisks := new JDeviceList();
    lDisks.dlUser := UserName;

    for var x := 0 to lQuery.datarows.length-1 do
    begin
      var lInfo := new JDeviceInfo();
      lInfo.Name := lQuery.datarows[x]["name"];
      lInfo.&Type := JDeviceType( lQuery.datarows[x]["type"] );
      lInfo.owner := lQuery.datarows[x]["owner"];
      lInfo.location := lQuery.datarows[x]["location"];
      lInfo.APIKey := lQuery.datarows[x]["apikey"];
      lInfo.APISecret := lQuery.datarows[x]["apisecret"];
      lInfo.APIPassword := lQuery.datarows[x]["apipassword"];
      lInfo.APIUser := lQuery.datarows[x]["apiuser"];
      lDisks.dlDrives.add(lInfo);
    end;

    try
      if assigned(CB) then
        CB(TagValue, lDisks, nil);
    finally
      lQuery.free;
    end;
  end);
end;

procedure TQTXTaskService.ValidateLocalDiskName(TagValue: variant; Username, DeviceName: string; CB: TQTXCheckDevicePathCB);
begin
  var Filename := 'disk.' + username + '.' + DeviceName + '.' + ord(JDeviceType.dtLocal).ToString();

  var LBasePath := TQTXNodeFileUtils.GetCurrentDirectory();
  LBasePath := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(LBasePath) + 'userdevices';

  // Make sure the device folder is there
  if not TQTXNodeFileUtils.DirectoryExists(LBasePath) then
  begin
    var lError := EException.CreateFmt("Directory not found: %s", [lBasePath]);
    if assigned(CB) then
      CB(TagValue, '', lError)
    else
      raise lError;
    exit;
  end;

  lBasePath := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(LBasePath) + Filename;

  if TQTXNodeFileUtils.DirectoryExists(LBasePath) then
  begin
    var lError := EException.CreateFmt("Path already exist error [%s]", [lBasePath]);
    if assigned(CB) then
      CB(TagValue, '', lError)
    else
      raise lError;
    exit;
  end;

  // OK, folder is not created yet, so its good to go
  if assigned(CB) then
    CB(TagValue, Filename, nil);
end;

procedure TQTXTaskService.UnRegisterLocalDevice(TagValue: variant; UserName, DiskName: string; CB: TQTXUnRegisterLocalDeviceCB);
begin
  WriteToLogF("Removing local device [%s] for user [%s] ", [DiskName, Username]);

  // Check username string
  UserName := username.trim().ToLower();
  if Username.length < 1 then
  begin
    WriteToLog("Failed to unregister device, username was invalid error");
    var lError := EException.Create("Failed to register device, invalid username");
    if assigned(CB) then
      CB(TagValue, DiskName, lError)
    else
      raise lError;
    exit;
  end;

  // Check diskname string
  DiskName := DiskName.trim().ToLower();
  if DiskName.length < 1 then
  begin
    WriteToLog("Failed to unregister device, disk-name was invalid error");
    var lError := EException.Create("Failed to register device, invalid disk-name");
    if assigned(CB) then
      CB(TagValue, DiskName, lError)
    else
      raise lError;
    exit;
  end;

  FindDeviceByName(TagValue, Username, DiskName,
  procedure (TagValue: variant; Device: JDeviceInfo; Error: Exception)
  begin
    // Did the search fail?
    if Error  nil then
    begin
      WriteToLog(Error.message);
      if assigned(CB) then
        CB(TagValue, DiskName, Error)
      else
        raise Error;
      exit;
    end;

    // Make sure the device is local
    if Device.&Type  dtLocal then
    begin
      var lError := EException.CreateFmt('Failed to translate path, device [%s] is not local error', [Device.Name]);
      if assigned(CB) then
        CB(TagValue, DiskName, Error)
      else
        raise Error;
      exit;
    end;

    // Delete record from database
    var lWriter: TQTXWriteTransaction;
    if FDatabase.CreateWriteTransaction(lWriter) then
    begin
      lWriter.SQL := "delete from profiles where user = ? and name = ?;";
      lWriter.Parameters.AddValueOnly(Username);
      lWriter.Parameters.AddValueOnly(DiskName);

      lWriter.Execute(
      procedure (Sender: TObject; Error: Exception)
      begin
        try

          if Error  nil then
          begin
            if assigned(CB) then
              CB(TagValue, DiskName, Error)
            else
              raise Error;
            exit;
          end;

          // Construct complete storage location
          var lFullPath := TQTXNodeFileUtils.GetCurrentDirectory();
          lFullPath := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(lFullPath) + 'userdevices';
          lFullPath := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(lFullPath) + Device.location.trim();

          // Now delete the disk-drive directory
          TQTXNodeFileUtils.DeleteDirectory(nil, lFullPath,
          procedure (TagValue: variant; Path: string; Error: Exception)
          begin
            if assigned(CB) then
              CB(TagValue, DiskName, Error)
          end);

        finally
          lWriter.free;
          lWriter := nil;
        end;
      end);
    end;
  end);
end;

procedure TQTXTaskService.RegisterLocalDevice(TagValue: variant; Username, DiskName: string; CB: TQTXRegisterLocalDeviceCB);
begin
  WriteToLogF("Adding local device [%s] for user [%s] ", [DiskName, Username]);

  UserName := username.trim().ToLower();
  if Username.length < 1 then
  begin
    WriteToLog("Failed to register device, username was invalid error");
    var lError := EException.Create("Failed to register device, invalid username");
    if assigned(CB) then
      CB(TagValue, '', lError)
    else
      raise lError;
    exit;
  end;

  DiskName := DiskName.trim().ToLower();
  if DiskName.length < 1 then
  begin
    WriteToLog("Failed to register device, disk-name was invalid error");
    var lError := EException.Create("Failed to register device, invalid disk-name");
    if assigned(CB) then
      CB(TagValue, '', lError)
    else
      raise lError;
    exit;
  end;

  FindDeviceByName(TagValue, Username, DiskName,
  procedure (TagValue: variant; Device: JDeviceInfo; Error: Exception)
  begin
    // Did the search fail?
    if Error  nil then
    begin
      WriteToLog(Error.message);
      if assigned(CB) then
        CB(TagValue, '', Error)
      else
        raise Error;
      exit;
    end;

    // Does a device that match already exist?
    if Device  nil then
    begin
      var lError := EException.CreateFmt("Failed to create device [%s], device already exists", [DiskName]);
      if assigned(CB) then
        CB(TagValue, '', lError)
      else
        raise lError;
      exit;
    end;

    //  make sure the device-folder does not exist, so we can create it
    ValidateLocalDiskName(TagValue, Username, DiskName,
    procedure (TagValue: variant; PathName: string; Error: Exception)
    begin
      if Error  nil then
      begin
        if assigned(CB) then
          CB(TagValue, '', Error)
        else
          raise Error;
        exit;
      end;

      // ValidateLocalDiskName only returns the valid directory-name,
      // not a full path -- so we need to build up the full targetpath
      var lFullPath := TQTXNodeFileUtils.GetCurrentDirectory();
      lFullPath := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(lFullPath) + 'userdevices';
      lFullPath := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(lFullPath) + PathName;

      TQTXNodeFileUtils.CreateDirectory(nil, lFullPath,
      procedure (TagValue: variant; Path: string; Error: exception)
      begin
        if Error  nil then
        begin
          var lError := EException.CreateFmt("Failed to create device [%s] with path: %s", [DiskName, lFullPath]);
          if assigned(CB) then
            CB(TagValue, PathName, lError)
          else
            raise lError;
          exit;
        end;

        FDatabase.Execute(
          #'insert into devices (type, owner, name, location)
            values(?, ?, ?, ?);',
            [ord(JDeviceType.dtLocal), UserName, Diskname, PathName] ,
        procedure (Sender: TObject; Error: Exception)
        begin
          if Error  nil then
          begin
            WriteToLog(Error.message);
            if assigned(CB) then
              CB(TagValue, PathName, Error)
            else
              raise Error;
            exit;
          end;

          WriteToLogF("Device [%s] added to database user [%s]", [DiskName, UserName]);
          if assigned(CB) then
            CB(TagValue, PathName, nil);
        end);

      end);



    end);
  end);
end;

procedure TQTXTaskService.SetupDeviceTable(const TagValue: variant; const CB: TRagnarokServiceCB);
begin

  FDatabase.Execute(
    #'
      create table if not exists devices
          (
            id integer primary key AUTOINCREMENT,
            type        integer,
            owner       text,
            name        text,
            location    text,
            apikey      text,
            apisecret   text,
            apipassword text,
            apiuser     text
          );
          ', [],
    procedure (Sender: TObject; Error: Exception)
    begin
      if Error  nil then
      begin
        WriteToLog(Error.message);
        if assigned(CB) then
          CB(Error)
        else
          raise Error;
        exit;
      end else
      if assigned(CB) then
        CB(nil);
    end);
end;

procedure TQTXTaskService.SetupTaskTable(const TagValue: variant; const CB: TRagnarokServiceCB);
begin

  FDatabase.Execute(
    #'
      create table if not exists tasks
          (
            id integer primary key AUTOINCREMENT,
            state     integer,
            username  text,
            created   real
          );
          ', [],
    procedure (Sender: TObject; Error: Exception)
    begin
      if Error  nil then
      begin
        WriteToLog(Error.message);
        if assigned(CB) then
          CB(Error)
        else
          raise Error;
        exit;
      end else
      if assigned(CB) then
        CB(nil);
    end);
end;


procedure TQTXTaskService.SetupOperationsTable(const TagValue: variant; const CB: TRagnarokServiceCB);
begin
  FDatabase.Execute(
    #'
      create table if not exists operations
          (
            id integer primary key AUTOINCREMENT,
            username text,
            taskid integer,
            name text,
            filename text
          );
          ', [],
    procedure (Sender: TObject; Error: Exception)
    begin
      if Error  nil then
      begin
        WriteToLog(Error.message);
        if assigned(CB) then
          CB(Error)
        else
          raise Error;
        exit;
      end else
      if assigned(CB) then
        CB(nil);
    end);
end;

procedure TQTXTaskService.SetupDatabase(const CB: TRagnarokServiceCB);
begin
  // Try to read database-path from preferences file
  var LDbFileToOpen := FPrefs.ReadString("database", "database_name", "");

  // Trim away spaces, check if there is a filename
  LDbFileToOpen := LDbFileToOpen.trim();
  if LDbFileToOpen.length < 1 then
  begin
    // No filename? Fall back on pre-defined file in CWD
    var LBasePath := TQTXNodeFileUtils.GetCurrentDirectory();
    LDbFileToOpen := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(LBasePath) + CNT_PREFS_DBNAME;
  end;

  FDatabase.AccessMode := TSQLite3AccessMode.sqaReadWriteCreate;
  FDatabase.Open(LDbFileToOpen,
    procedure (Sender: TObject; Error: Exception)
    begin
      if Error  nil then
      begin
        WriteToLog(Error.message);
        if assigned(CB) then
          CB(Error)
        else
          raise Error;
        exit;
      end;

      WriteToLog("Initializing task table");
      SetupTaskTable(nil, procedure (Error: exception)
      begin
        if Error  nil then
        begin
          WriteToLog("Tasks initialized: **failed");
          WriteToLog(error.message);
          if assigned(CB) then
            CB(Error)
          else
            raise Error;
          exit;
        end else
        writeToLog("Tasks initialized: OK");

        WriteToLog("Initializing operations table");
        SetupOperationsTable(nil, procedure (Error: exception)
        begin
          if Error  nil then
          begin
            WriteToLog("Operations initialized: **failed");
            WriteToLog(error.message);
            if assigned(CB) then
              CB(Error);
            exit;
          end else
          writeToLog("Operations initialized: OK");

          WriteToLog("Initializing device table");
          SetupDeviceTable(nil, procedure (Error: exception)
          begin
            if Error  nil then
            begin
              WriteToLog("Device-table initialized: **failed");
              WriteToLog(error.message);
              if assigned(CB) then
                CB(Error);
              exit;
            end else
            writeToLog("Device-table initialized: OK");

            if assigned(CB) then
              CB(nil);
          end);
        end);
      end);
    end);
end;


procedure TQTXTaskService.HandleFileRead(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
begin
  var lRequest := TQTXFileReadRequest(request);
  var lUserName := lRequest.UserName;
  var lFileName := lRequest.FileName;

  // Check filename length
  if lFileName.length  0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  lTemp := './';
  if pos(lTemp, lFileName) > 0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  GetFileInfo(lRequest, lUserName, lFileName,
  procedure (TagValue: variant; LocalFile: string; Info: JStats; Error: Exception)
  begin
    if Error  nil then
    begin
      WriteToLog(Error.message);
      SendError(Socket, Request, Error.Message);
      exit;
    end;

    var lOptions: TReadFileOptions;
    lOptions.encoding := 'binary';

    NodeJsFsAPI().readFile(LocalFile, lOptions,
    procedure (Error: JError; Data: JNodeBuffer)
    begin
      if Error  nil then
      begin
        WriteToLog(Error.message);
        SendError(Socket, Request, Error.Message);
        exit;
      end;

      var lResponse := TQTXFileReadResponse.Create(Request.Ticket);
      lResponse.UserName := lUserName;
      lResponse.Routing.TagValue := request.routing.tagValue;
      lResponse.FileName := lFileName;
      lResponse.Code := CNT_MESSAGE_CODE_OK;
      lResponse.Response := CNT_MESSAGE_TEXT_OK;

      // Convert filedata in one pass
      try
        var lConvert := TDataTypeConverter.Create();
        try
          lResponse.Attachment.AppendBytes( lConvert.TypedArrayToBytes(Data) );
        finally
          lConvert.free;
        end;
      except
        on e: exception do
        begin
          WriteToLog(e.message);
          SendError(Socket, Request, e.Message);
          exit;
        end;
      end;

      try
        Socket.Send( lResponse.Serialize() );
      except
        on e: exception do
          WriteToLog(e.message);
      end;
    end);
  end);
end;

procedure TQTXTaskService.HandleFileReadPartial(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
begin
  var lRequest := TQTXFileReadPartialRequest(request);
  var lUserName := lRequest.UserName;
  var lFileName := lRequest.FileName;
  var lStart := lRequest.Offset;
  var lSize := lRequest.Size;

  // Check filename length
  if lFileName.length  0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  lTemp := './';
  if pos(lTemp, lFileName) > 0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  if lSize < 1 then
  begin
    SendError(Socket, Request, "Read failed, invalid size error");
    exit;
  end;

  if lStart < 0 then
  begin
    SendError(Socket, Request, "Read failed, invalid offset error");
    exit;
  end;

  GetFileInfo(lRequest, lUserName, lFileName,
  procedure (TagValue: variant; LocalFile: string; Info: JStats; Error: Exception)
  begin
    if Error  nil then
    begin
      WriteToLog(Error.message);
      SendError(Socket, Request, Error.Message);
      exit;
    end;

    if lStart > Info.size then
    begin
      SendError(Socket, Request, "Read failed, offset beyond filesize error");
      exit;
    end;

    NodeJsFsAPI().open(LocalFile, "r",
    procedure (Error: JError; Fd: THandle)
    begin
      if error  nil then
      begin
        WriteToLog(Error.message);
        SendError(Socket, Request, Error.Message);
        exit;
      end;

      var Data = new JNodeBuffer(lSize);
      NodeJsFsAPI().read(Fd, Data, 0, lSize, lStart,
      procedure (Error: JError; BytesRead: integer; buffer: JNodeBuffer)
      begin
        if Error  nil then
        begin
          NodeJsFsAPI().closeSync(Fd);
          WriteToLog(Error.message);
          SendError(Socket, Request, Error.Message);
          exit;
        end;

        // Close the file-handle and return data
        NodeJsFsAPI().close(Fd, procedure (Error: JError)
        begin
          var lResponse := TQTXFileReadPartialResponse.Create(Request.Ticket);
          lResponse.UserName := lUserName;
          lResponse.Routing.TagValue := request.routing.tagValue;
          lResponse.FileName := lFileName;
          lResponse.Code := CNT_MESSAGE_CODE_OK;
          lResponse.Response := CNT_MESSAGE_TEXT_OK;

          // Only encode data if read
          if BytesRead > 0 then
          begin
            // Convert filedata in one pass
            try
              var lConvert := TDataTypeConverter.Create();
              try
                lResponse.Attachment.AppendBytes( lConvert.TypedArrayToBytes(buffer) );
              finally
                lConvert.free;
              end;
            except
              on e: exception do
              begin
                WriteToLog(e.message);
                SendError(Socket, Request, e.Message);
                exit;
              end;
            end;
          end;

          try
            Socket.Send( lResponse.Serialize() );
          except
            on e: exception do
              WriteToLog(e.message);
          end;

        end);
      end);
    end);
  end);
end;

procedure TQTXTaskService.HandleFileWrite(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
begin
  var lRequest  := TQTXFileWriteRequest(request);
  var lFileName := lRequest.FileName.trim();
  var lUserName := lRequest.UserName.trim();

  var FullPath  := lFileName;

  // Check filename length
  if lFileName.length  0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  lTemp := './';
  if pos(lTemp, lFileName) > 0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  var lParser := TQTXPathParser.Create();
  try
    var lInfo: TQTXPathData;
    if lparser.Parse(FullPath, lInfo) then
    begin
      // Locate the device for the path belonging to the user
      FindDeviceByName(nil, lUserName, lInfo.MountPart,
      procedure (TagValue: variant; Device: JDeviceInfo; Error: Exception)
      begin
        if Error  nil then
        begin
          WriteToLog(Error.Message);
          SendError(Socket, Request, Error.Message);
          exit;
        end;

        case Device.&Type of
        dtLocal:
          begin
            // We want the path + filename, so we can append that to
            // the actual localized filesystem
            var lExtract := FullPath;
            delete(lExtract, 1, lInfo.MountPart.Length + 1);

            // Construct complete storage location
            var lFullPath := TQTXNodeFileUtils.GetCurrentDirectory();
            lFullPath := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(lFullPath) + 'userdevices';
            lFullPath := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(lFullPath) + Device.location.trim();
            lFullPath := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(lFullPath) + lExtract;

            // Extract data to be appended, if any
            // note: null bytes should be allowed, it should just create the file
            var lBytes: array of UInt8;
            if lRequest.attachment.Size > 0 then
              lBytes := lRequest.Attachment.ToBytes();

            // Write the data to the file
            NodeJsFsAPI().writeFile(lFullPath, lBytes,
            procedure (Error: JError)
            begin
              if Error  nil then
              begin
                WriteToLog(Error.Message);
                SendError(Socket, Request, Error.Message);
                exit;
              end;

              // Setup response object
              var lResponse := TQTXFileWriteResponse.Create(lRequest.Ticket);
              lResponse.UserName := lUserName;
              lResponse.FileName := lFileName;
              lResponse.Code := CNT_MESSAGE_CODE_OK;
              lResponse.Response := CNT_MESSAGE_TEXT_OK;

              // Send success response
              try
                Socket.Send( lResponse.Serialize() );
              except
                on e: exception do
                  WriteToLog(e.message);
              end;

            end);

          end;
        dtDropbox, dtGoogle, dtMsDrive:
          begin
            var lErrorText := Format("Clound bindings not active error [%s]", [lRequest.FileName]);
            WriteToLog(lErrorText);
            SendError(Socket, Request, lErrorText);
          end;
        end;
      end);
    end else
    begin
      SendError(Socket, Request, format("Invalid path [%s] error", [FullPath]));
    end;
  finally
    lParser.free;
  end;
end;

procedure TQTXTaskService.HandleFileWritePartial(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
begin
  var lRequest  := TQTXFileWritePartialRequest(request);
  var lFileName  := lRequest.FileName.trim();
  var lUserName := lRequest.UserName.trim();
  var lFileOffset := lRequest.Offset;

  // Check filename length
  if lFileName.length  0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  lTemp := './';
  if pos(lTemp, lFileName) > 0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  var FullPath := lFileName;

  var lParser := TQTXPathParser.Create();
  try
    var lInfo: TQTXPathData;
    if lparser.Parse(FullPath, lInfo) then
    begin
      // Locate the device for the path belonging to the user
      FindDeviceByName(nil, lUserName, lInfo.MountPart,
      procedure (TagValue: variant; Device: JDeviceInfo; Error: Exception)
      begin
        if Error  nil then
        begin
          WriteToLog(Error.Message);
          SendError(Socket, Request, Error.Message);
          exit;
        end;

        case Device.&Type of
        dtLocal:
          begin
            // We want the path + filename, so we can append that to
            // the actual localized filesystem
            var lExtract := FullPath;
            delete(lExtract, 1, lInfo.MountPart.Length + 1);

            // Construct complete storage location
            var lFullPath := TQTXNodeFileUtils.GetCurrentDirectory();
            lFullPath := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(lFullPath) + 'userdevices';
            lFullPath := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(lFullPath) + Device.location.trim();
            lFullPath := TQTXNodeFileUtils.IncludeTrailingPathDelimiter(lFullPath) + lExtract;

            // Extract data to be appended, if any
            // note: null bytes should be allowed, it should just create the file
            var lBytes: array of UInt8;
            if lRequest.attachment.Size > 0 then
              lBytes := lRequest.Attachment.ToBytes();

            var lAccess := TQTXNodeFile.Create();
            lAccess.Open(lFullPath, TQTXNodeFileMode.nfWrite,
            procedure (Error: Exception)
            begin
              if Error  nil then
              begin
                WriteToLog(Error.Message);
                SendError(Socket, Request, Error.Message);
                exit;
              end;

              lAccess.Write(lBytes, lFileOffset,
              procedure (Error: Exception)
              begin
                if Error  nil then
                begin
                  WriteToLog(Error.Message);
                  SendError(Socket, Request, Error.Message);
                  exit;
                end;

                // Setup response object
                var lResponse := TQTXFileWriteResponse.Create(lRequest.Ticket);
                lResponse.UserName := lUserName;
                lResponse.FileName := lFileName;
                lResponse.Code := CNT_MESSAGE_CODE_OK;
                lResponse.Response := CNT_MESSAGE_TEXT_OK;

                // Send success response
                try
                  Socket.Send( lResponse.Serialize() );
                except
                  on e: exception do
                    WriteToLog(e.message);
                end;

              end);
            end);
          end;
        dtDropbox, dtGoogle, dtMsDrive:
          begin
            var lErrorText := Format("Clound bindings not active error [%s]", [lRequest.FileName]);
            WriteToLog(lErrorText);
            SendError(Socket, Request, lErrorText);
          end;
        end;
      end);
    end else
    begin
      SendError(Socket, Request, format("Invalid path [%s] error", [FullPath]));
    end;
  finally
    lParser.free;
  end;
end;

procedure TQTXTaskService.HandleRmDir(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
begin
  var lRequest := TQTXRmDirRequest(request);
  var lUserName := lRequest.UserName.trim();
  var lDirPath := lRequest.DirPath.trim();

  if lDirPath.length  0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  lTemp := './';
  if pos(lTemp, lDirPath) > 0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  var lParser := TQTXPathParser.Create();
  try
    var lInfo: TQTXPathData;
    if lParser.Parse(lDirPath, lInfo) then
    begin
      GetTranslatedPathFor(nil, lUserName, lDirPath,
      procedure (TagValue: variant; Original, Translated: string; Error: Exception)
      begin
        if Error  nil then
        begin
          WriteToLog(Error.message);
          SendError(Socket, Request, Error.Message);
          exit;
        end;

        if not TQTXNodeFileUtils.DirectoryExists(Translated) then
        begin
          WriteToLogF("RmDir Failed, directory [%s] does not exist", [Translated]);
          SendError(Socket, Request, Format("RmDir failed, directory [%s] does not exist", [Original]));
          exit;
        end;

        TQTXNodeFileUtils.DeleteDirectory(nil, Translated,
        procedure (TagValue: variant; Path: string; Error: Exception)
        begin
          if error  nil then
          begin
            WriteToLog(Error.message);
            SendError(Socket, Request, Error.Message);
            exit;
          end;

          // Setup response object
          var lResponse := TQTXRmDirResponse.Create(lRequest.Ticket);
          lResponse.UserName := lUserName;
          lResponse.DirPath := lDirPath;
          lResponse.Code := CNT_MESSAGE_CODE_OK;
          lResponse.Response := CNT_MESSAGE_TEXT_OK;
          lResponse.Routing.TagValue := lRequest.Routing.TagValue;

          // Send success response
          try
            Socket.Send( lResponse.Serialize() );
          except
            on e: exception do
              WriteToLog(e.message);
          end;
        end);
      end);
    end else
    begin
      var lText := format("RmDir failed, invalid path [%s] error", [lDirPath]);
      WriteToLog(lText);
      SendError(Socket, Request, lText);
    end;
  finally
    lParser.free;
  end;
end;

procedure TQTXTaskService.HandleMkDir(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
begin
  var lRequest := TQTXMkDirRequest(request);
  var lUserName := lRequest.UserName.trim();
  var lDirPath := lRequest.DirPath.trim();

  if lDirPath.length  0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  lTemp := './';
  if pos(lTemp, lDirPath) > 0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  var lParser := TQTXPathParser.Create();
  try
    var lInfo: TQTXPathData;
    if lparser.Parse(lDirPath, lInfo) then
    begin
      GetTranslatedPathFor(nil, lUserName, lDirPath,
      procedure (TagValue: variant; Original, Translated: string; Error: Exception)
      begin
        if Error  nil then
        begin
          WriteToLog(Error.message);
          SendError(Socket, Request, Error.Message);
          exit;
        end;

        TQTXNodeFileUtils.DirectoryExists(nil, Translated,
        procedure (TagValue: variant; Path: string; Error: Exception)
        begin
          if Error  nil then
          begin
            WriteToLogF("MkDir Failed, directory [%s] already exists", [Translated]);
            SendError(Socket, Request, Format("MkDir Failed, directory [%s] already exists", [Original]));
            exit;
          end;

          TQTXNodeFileUtils.CreateDirectory(nil, Translated,
          procedure (TagValue: variant; Path: string; Error: Exception)
          begin
            if Error  nil then
            begin
              WriteToLogF("MkDir Failed, directory [%s] could not be created", [Original]);
              SendError(Socket, Request, Format("MkDir Failed, directory [%s] could not be created", [Translated]));
              exit;
            end;

            // Setup response object
            var lResponse := TQTXMkDirResponse.Create(lRequest.Ticket);
            lResponse.UserName := lUserName;
            lResponse.DirPath := lDirPath;
            lResponse.Code := CNT_MESSAGE_CODE_OK;
            lResponse.Response := CNT_MESSAGE_TEXT_OK;
            lResponse.Routing.TagValue := lRequest.Routing.TagValue;

            // Send success response
            try
              Socket.Send( lResponse.Serialize() );
            except
              on e: exception do
                WriteToLog(e.message);
            end;

          end);
        end);
      end);

    end else
    begin
      var lText := format("MkDir Failed, invalid path [%s] error", [lDirPath]);
      WriteToLog(lText);
      SendError(Socket, Request, lText);
    end;
  finally
    lParser.free;
  end;
end;

procedure TQTXTaskService.HandleFileDelete(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
begin
  var lRequest := TQTXFileDeleteRequest(Request);
  var lUserName := lRequest.UserName.trim();
  var lFileName := lRequest.FileName.trim();

  if lFileName.length  0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  lTemp := './';
  if pos(lTemp, lFileName) > 0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  GetFileInfo(lRequest, lUserName, lFileName,
  procedure (TagValue: variant; LocalFile: string; Info: JStats; Error: Exception)
  begin
    if Error  nil then
    begin
      WriteToLog(Error.message);
      SendError(Socket, Request, Error.Message);
      exit;
    end;

    if not Info.isFile then
    begin
      SendError(Socket, Request, "Filesystem object is not a file error");
      exit;
    end;

    NodeJsFsAPI().unlink(LocalFile,
    procedure (Error: JError)
    begin
      if Error  nil then
      begin
        WriteToLog(Error.message);
        SendError(Socket, Request, Error.message);
        exit;
      end;

      var lResponse := new TQTXFileDeleteResponse(lRequest.Ticket);
      lResponse.Routing.TagValue := request.Routing.TagValue;
      lResponse.UserName := lUserName;
      lResponse.FileName := lFileName;
      lResponse.Code := CNT_MESSAGE_CODE_OK;
      lResponse.Response := CNT_MESSAGE_TEXT_OK;

      try
        Socket.Send( lResponse.Serialize() );
      except
        on e: exception do
          WriteToLog(e.message);
      end;
    end);
  end);
end;

procedure TQTXTaskService.HandleFileRename(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
begin
  var lRequest := TQTXFileRenameRequest(Request);
  var lUserName := lRequest.UserName.trim();
  var lFileName := lRequest.FileName.trim();
  var lNewName := lRequest.NewName.trim();

  // Check filename length
  if lFileName.length < 1 then
  begin
    SendError(Socket, Request, Format("Invalid or empty from-filename [%s] error", [lFileName]) );
    exit;
  end;

  // check newname length
  if lNewName.length  0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  if pos(lTemp, lNewName) > 0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  lTemp := './';
  if pos(lTemp, lFileName) > 0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  if pos(lTemp, lNewName) > 0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;


  GetFileInfo(lRequest, lUserName, lFileName,
  procedure (TagValue: variant; LocalFile: string; Info: JStats; Error: Exception)
  begin
    if Error  nil then
    begin
      WriteToLog(Error.message);
      SendError(Socket, Request, Error.Message);
      exit;
    end;

    if not Info.isFile then
    begin
      SendError(Socket, Request, "Filesystem object is not a file error");
      exit;
    end;

    GetTranslatedPathFor(nil, lUsername, lNewName,
    procedure (TagValue: variant; Original, Translated: string; Error: Exception)
    begin
      if Error  nil then
      begin
        WriteToLog(Error.message);
        SendError(Socket, Request, Error.Message);
        exit;
      end;

      NodeJsFsAPI().rename(LocalFile, Translated,
      procedure (Error: JError)
      begin
        if Error  nil then
        begin
          WriteToLog(Error.message);
          SendError(Socket, Request, Error.message);
          exit;
        end;

        var lResponse := new TQTXFileRenameResponse(lRequest.Ticket);
        lResponse.Routing.TagValue := request.Routing.TagValue;
        lResponse.UserName := lUserName;
        lResponse.FileName := lFileName;
        lResponse.Code := CNT_MESSAGE_CODE_OK;
        lResponse.Response := CNT_MESSAGE_TEXT_OK;

        try
          Socket.Send( lResponse.Serialize() );
        except
          on e: exception do
            WriteToLog(e.message);
        end;
      end);

    end);

  end);
end;

procedure TQTXTaskService.HandleGetDir(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
begin
  var lRequest := TQTXFileDirRequest(Request);
  var lUserName := lRequest.UserName.trim();
  var lPath := lRequest.Path.trim();

  // prevent path escape attempts
  var lTemp := "../";
  if pos(lTemp, lPath) > 0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  lTemp := './';
  if pos(lTemp, lPath) > 0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  GetTranslatedPathFor(nil, lUserName, lPath,
  procedure (TagValue: variant; Original, Translated: string; Error: Exception)
  begin
    if Error  nil then
    begin
      WriteToLog(Error.message);
      SendError(Socket, Request, Error.Message);
      exit;
    end;

    //writeln("Translated path is:" + Translated);

    if not TQTXNodeFileUtils.DirectoryExists(Translated) then
    begin
      WriteToLogF("GetDir Failed, directory [%s] does not exist", [Translated]);
      SendError(Socket, Request, Format("GetDir failed, directory [%s] does not exist", [Original]));
      exit;
    end;

    var lWalker := TQTXFileWalker.Create();
    lWalker.Examine(Translated, procedure (Sender: TQTXFileWalker; Error: EException)
    begin
      if Error  nil then
      begin
        WriteToLogF("GetDir Failed: %s", [Error.Message]);
        SendError(Socket, Request, Format("GetDir failed: %s", [Error.Message]));
        exit;
      end;

      // Get the directory data, swap out the path
      // record with the original [amiga] style path
      var lData := Sender.ExtractList();
      lData.dlPath := Original;

      var lResponse := new TQTXFileDirResponse(lRequest.Ticket);
      lResponse.Routing.TagValue := request.Routing.TagValue;
      lResponse.UserName := lUserName;
      lResponse.Path := lPath;
      lResponse.Assign( lData );

      try
        Socket.Send( lResponse.Serialize() );
      except
        on e: exception do
          WriteToLog(e.message);
      end;

      // release instance in 100ms
      TQTXDispatch.execute(procedure ()
      begin
        try
          lWalker.free
        except
          on e: exception do
          begin
            WriteToLogF("Failed to release file-walker instance: %s", [e.message]);
          end;
        end;
      end, 100);
    end);
  end);
end;

procedure TQTXTaskService.HandleGetFileInfo(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
begin
  var lRequest := TQTXFileInfoRequest(Request);
  var lUserName := lRequest.UserName.trim();
  var lFileName := lRequest.FileName.trim();

  // prevent path escape attempts
  var lTemp := "../";
  if pos(lTemp, lFileName) > 0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  lTemp := './';
  if pos(lTemp, lFileName) > 0 then
  begin
    SendError(Socket, Request, Format("Unsupported path sequence [%s] detected error", [lTemp]) );
    exit;
  end;

  GetFileInfo(lRequest, lUserName, lFileName,
  procedure (TagValue: variant; LocalFile: string; Info: JStats; Error: Exception)
  begin
    if Error  nil then
    begin
      WriteToLog(Error.message);
      SendError(Socket, Request, Error.Message);
      exit;
    end;

    // Collect the data
    var lData := new JFileItem();
    lData.diFileName := lFileName;
    lData.diFileType := if Info.isFile then JFileItemType.wtFile else JFileItemType.wtFolder;
    lData.diFileSize := Info.size;
    lData.diFileMode := IntToStr(Info.mode);
    lData.diCreated  := TDateUtils.FromJsDate( Info.cTime );
    lData.diModified := TDateUtils.FromJsDate( Info.mTime );

    var lResponse := new TQTXFileInfoResponse(lRequest.Ticket);
    lResponse.Routing.TagValue := request.Routing.TagValue;
    lResponse.UserName := lUserName;
    lResponse.FileName := lFileName;
    lResponse.Assign(lData);

    try
      Socket.Send( lResponse.Serialize() );
    except
      on e: exception do
        WriteToLog(e.message);
    end;
  end);
end;

procedure TQTXTaskService.HandleDestroyDevice(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
begin
  var lMessage := TQTXFileDestroyDeviceRequest(request);

  // This will also destroy any files + unregister the device in the
  // database table for the service -- do not mess with this!
  UnRegisterLocalDevice(nil, lMessage.Username, lMessage.DeviceName,
  procedure (TagValue: variant; LocalPath: string; Error: Exception)
  begin
    if Error  nil then
    begin
      WriteToLog(Error.Message);
      SendError(Socket, Request, Error.Message);
      exit;
    end;

    var lResponse := TQTXFileDestroyDeviceResponse.Create(request.ticket);
    lResponse.UserName := lMessage.UserName;
    lResponse.DeviceName := lMessage.DeviceName;
    lResponse.Routing.TagValue := Request.Routing.TagValue;
    lResponse.Code := CNT_MESSAGE_CODE_OK;
    lResponse.Response := CNT_MESSAGE_TEXT_OK;

    try
      Socket.Send( lResponse.Serialize() );
    except
      on e: exception do
      begin
        WriteToLog(e.message);
      end;
    end;
  end);
end;

procedure TQTXTaskService.HandleCreateLocalDevice(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
begin
  var lMessage := TQTXFileCreateLocalDeviceRequest(request);

  // Attempt to register.
  // NOTE: This will automatically create a matching folder
  //       under $cwd/userdevices/[calculated_name_of_device]

  RegisterLocalDevice(nil, lMessage.Username, lMessage.DeviceName,
  procedure (TagValue: variant; LocalPath: string; Error: Exception)
  begin
    if Error  nil then
    begin
      WriteToLog(Error.Message);
      SendError(Socket, Request, Error.Message);
      exit;
    end;

    FindDeviceByName(nil, lMessage.Username, lMessage.DeviceName,
    procedure (TagValue: variant; Device: JDeviceInfo; Error: Exception)
    begin
      if Error  nil then
      begin
        WriteToLog(Error.Message);
        SendError(Socket, Request, Error.Message);
        exit;
      end;

      var lResponse := TQTXFileCreateLocalDeviceResponse.Create(request.ticket);
      lResponse.UserName := lMessage.UserName;
      lResponse.Routing.TagValue := Request.Routing.TagValue;
      lResponse.Code := CNT_MESSAGE_CODE_OK;
      lResponse.Response := CNT_MESSAGE_TEXT_OK;
      if Device  nil then
        lResponse.assign(Device);

      try
        Socket.Send( lResponse.Serialize() );
      except
        on e: exception do
        begin
          WriteToLog(e.message);
        end;
      end;

    end);
  end);
end;

procedure TQTXTaskService.HandleGetDeviceByName(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
begin
  var lMessage := TQTXFileGetDeviceByNameRequest(request);

  FindDeviceByName(nil, lMessage.Username, lMessage.DeviceName,
  procedure (TagValue: variant; Device: JDeviceInfo; Error: Exception)
  begin
    if Error  nil then
    begin
      WriteToLog(Error.Message);
      SendError(Socket, Request, Error.Message);
      exit;
    end;

    var lResponse := TQTXFileGetDeviceByNameResponse.Create(request.ticket);
    lResponse.UserName := lMessage.UserName;
    lResponse.Code := CNT_MESSAGE_CODE_OK;
    lResponse.Response := CNT_MESSAGE_TEXT_OK;
    if Device  nil then
      lResponse.assign(Device);

    try
      Socket.Send( lResponse.Serialize() );
    except
      on e: exception do
      begin
        WriteToLog(e.message);
      end;
    end;
  end);

end;

procedure TQTXTaskService.HandleGetDevices(Socket: TNJWebSocketSocket; Request: TQTXBaseMessage);
begin
  var lMessage := TQTXFileGetDeviceListRequest(Request);
  GetDevicesForUser(nil, lMessage.Username,
  procedure (TagValue: variant; Devices: JDeviceList; Error: Exception)
  begin
    if Error  nil then
    begin
      WriteToLog(Error.Message);
      SendError(Socket, Request, Error.Message);
      exit;
    end;

    var lResponse := TQTXFileGetDeviceListResponse.Create(request.ticket);
    lResponse.UserName := lMessage.UserName;
    lResponse.Code := CNT_MESSAGE_CODE_OK;
    lResponse.Response := CNT_MESSAGE_TEXT_OK;
    if Devices  nil then
      lResponse.assign(Devices);

    try
      Socket.Send( lResponse.Serialize() );
    except
      on e: exception do
      begin
        WriteToLog(e.message);
      end;
    end;

  end);
end;

procedure TQTXTaskService.AfterServerStarted;
begin
  inherited;

  // Check prefs if zconfig should be applied
  if self.FPrefs.ReadBoolean("zconfig", "active", false) then
  begin
    // ZConfig should only run on the master instance.
    // We dont want to register our endpoint for each worker
    if NodeJSClusterAPI().isWorker then
      exit;

    writeln("Setting up Zero-Configuration layer");
    FZConfig.port := FPrefs.ReadInteger('zconfig', 'bindport', 2109);
    FZConfig.address := GetMachineIP();
    FZConfig.Start(nil, procedure (Sender: TObject; TagValue: variant; Error: Exception)
    begin
      if FPrefs.ReadBoolean("zconfig", "broadcast", true) then
        FZConfig.Socket.setBroadcast(true);

      // Build up the endpoint (URL) for our websocket server
      var lEndpoint := '';

      if FPrefs.ReadBoolean('networking', 'secure', false) then
        lEndpoint := 'wss://'
      else
        lEndpoint := 'ws://';

      lEndpoint += GetMachineIP();
      lEndpoint += ':' + Port.ToString();

      // Ping the ZConfig service on interval, until our service is registered
      // We keep track of the interval handle so we can stop calling on interval later
      FRegHandle := TQTXDispatch.SetInterval( procedure ()
      begin
        inc(FRegCount);

        // Only output once to avoid overkill in the log
        if FRegCount = 1 then
          WriteToLogF("ZConfig registration begins [%s]", [lEndpoint]);

        FZConfig.RegisterService(nil, CNT_ZCONFIG_SERVICE_NAME, SERVICE_ID_TASKMANAGER, lEndpoint,
        procedure (TagValue: variant; Error: Exception)
        begin
          if Error = nil then
          begin
            WriteToLog("Service registered");
            TQTXDispatch.ClearInterval(FRegHandle);
            FRegCount := 0;
            exit;
          end;
        end);
      end, 1000);

    end);
  end;
end;

procedure TQTXTaskService.BeforeServerStopped;
begin
  inherited;
end;

procedure TQTXTaskService.Dispatch(Socket: TNJWebSocketSocket; Message: TQTXBaseMessage);
begin
  var LInfo := MessageDispatch.GetMessageInfoForClass(Message);
  if LInfo  nil then
  begin
    try
      LInfo.MessageHandler(Socket, Message);
    except
      on e: exception do
      begin
        //Log error
        WriteToLog(e.message);
      end;
    end;
  end;
end;

end.


 

Delphi Dying? Think again, Tiobe

March 8, 2020 11 comments

At the beginning of last week, Tiobe once again threw a punch at Object Pascal. Playing the whole “Delphi is dying” tune, while focusing on outdated and quite frankly irrelevant episodes from the past. Hoping no doubt, to leave the reader with an impression that Delphi is stuck in the 90s.

This is the same pattern we often see whenever Delphi or Object Pascal in general experience significant growth; or to be blunt, when the author cannot be bothered to think independently, but simply parrot hearsay and misinformation on autopilot.

It is lame, superficial and Tiobe’s biggest mistake to date.

Tiobe

Guess “alternative news” is no longer limited to individuals like Alex Jones

Just to underline the problem areas here. The ranking is based on their internal system (there is no standard for how to rank popularity), and while I have issues with how they build up their score, it’s ultimately the March editorial text that has caused irritation and shock. You don’t declare a language as dead when there are over 10 million developers using it. This type of editorial could have very real consequences – which in turn brings us to their ranking system and how they arrived at their conclusions.

I would have understood their statement if it was issued between 2007 and 2010, because Delphi was at that time transitioning between Borland and Embarcadero. But to issue something like this in 2020? After a decade worth of restoration, optimization, modernization and above all – forging a thriving community that goes from victory to victory month after month, year after year? It makes absolutely no sense.

Significant growth

In 2018 there were roughly six million Delphi developers (I worked at Embarcadero at the time), with a total estimate of ten million Object Pascal developers worldwide when counting all alternative compilers, dialects and indeed – known piracy issues.

“Tiobe failed stupendously in their data mining operation, they seem to be oblivious regarding the demographic in which the language is used”

Since that time Delphi has made strides into the universities in Scandinavia, South-America and the Middle-East. Turkey recently announced their dedication to native and archetypal software development with Delphi (provided free for students), which adds a whopping one million students to the already large body of users.

Embarcadero has slowly but steadily rebuilt much of the infrastructure that existed under Borland. From professional training at Embarcadero Academy, to entry level training at LearnDelphi.org. The Idera community pages likewise produce a large body of articles on a weekly basis. Comparing the Delphi and C++Builder ecosystem today with it’s tragic state back in 2010, is like day and night.

academy

Training is available for both Enterprise level developers and students alike

With so much positive happening in the world of Object Pascal, Tiobe’s article comes across as a grave, intentional misrepresentation at worst, or an intellectual emergency at best. It is completely out of place and carries the tell-tell signs of an echo chamber.

Tiobe has lost all credibility

I have to be honest. I have never taken Tiobe that serious, because they have made to many mistakes in the past to have any form of credibility when it comes to Delphi and Object Pascal as a language. And when I say mistakes, I mean monumental blunders that just annihilate all possibility that they treat languages on equal footing.

“not only have Tiobe failed in their indexing, they have completely and utterly misunderstood the demographic in which the language is used”

If we go back a decade, Tiobe actually based their numbers on the keyword “Pascal”. In other words they excluded not just Delphi commits to GitHub, BitBucket and similar services – they also managed to exclude Freepascal and every subsequent dialect that signify Object Pascal as a whole. So for quite some time their entire statistics was based on the off chance that people typed “Pascal” in their project or commit entries.

To make matters worse, their search tech was not smart enough to recognize “Pascal” in composite words. So if you wrote “ObjectPascal” in a single word, the commit was excluded; As was “Freepascal”, “Smartpascal”, “Oxygenepascal” and variations using a hyphen (and the same for abbreviations).

Developers also use the term Lazarus and FPC interchangeably since Lazarus typically means people use the LCL, the visual framework used to write desktop applications with Freepascal. So while Freepascal has nothing to do with Delphi in terms of intellectual property, the two compilers are used by the community as a whole.

But let’s look at why Tiobe’s indexing fails for Delphi. Just what are they doing wrong?

  • Delphi has been around for 25 years, and it’s roots stretch back to the birth of C. Using Stack Overflow as an indicator for popularity is ludacris, since the majority of errors and problems have been largely ironed out in the past, leaving only extremely advanced and rare topics. If problems is the criteria, then I guess that explains why C# and Java soars in the ranking.
  • Nobody searches google for “Delphi programming”. You search for explicit topics like composite polygon clipping with GDI+ and then add “delphi” to limit the search to said language. Just like C/C++, Object Pascal is an archetypal language. It stretches from kernel work with inline assembly, to cloud services and HTML5 rendering. So the topics people search for are usually straight out of the operating-system strata.
  • Delphi developers communicate in dedicated groups, such as Delphi Developer on Facebook. There is also a thriving community on the Delphi Praxis forums, not to mention the Freepascal forums. None of which seem to be included in Tiobe’s activity statistics.
  • Object Pascal has several frameworks and run-time libraries. Delphi ships with two:
  • Freepascal operates with its own, open-source variation called the LCL
  • Freepascal also targets WebAssembly and JavaScript and have variations of the LCL adapted those targets
  • And then there is third party, commercial alternatives that covers HTML5/JS like TMS WebCore, Smart Pascal, Oxygene Pascal and the upcoming Quartex Pascal. Around these runtime libraries (VCL, FMX and LCL) there are thousands of libraries, components and frameworks, large and small, that don’t necessarily put  “Delphi” or “Object Pascal” in their metadata.
  • Tiobe also fails to include feeds like BeginEnd.net or DelphiFeeds, which syndicate on average 3000 unique blog-posts a year, representing a consistent and very much alive stream of information and content.

Delphi and Freepascal, which represents the most widely used compilers, are predominantly used to write commercial, closed source products. Which by consequence means that code and the activity involved is not public. For Tiobe to so utterly misunderstand the demographic for Object Pascal in general, is quite frankly outrageous. If you are going to rank a language that involves millions of users -then at least have the decency of investigating the communities it involves.

Excluding the factors I have outlined above, makes as much sense as excluding mono from C#.

Incompetence or plain ignorance?

It was only after an avalanche of complaints in 2014, orchestrated by yours truly, where members of the Delphi Developer group on Facebook sent complaints en-mass to Tiobe that they addressed the use of “Pascal” to represent Delphi and associated dialects. Yet for all the complaints, outlined in letters that no sentient human being could misunderstand – all Tiobe managed to do was to add “Object Pascal” to their list. Which, believe it or not, was unfamiliar to them.

It’s funny because it’s true

But do you think they bothered to do it right? Afraid not. Instead of aggregating all of the dialects, frameworks and variations of names under a single banner, they still to this day operate with two very specific search elements, namely “Delphi” or “Object Pascal”.

I sure hope the dairy industry doesn’t hire Tiobe to do statistics on milk, because if their coverage of Object Pascal is anything to go by, they will be ranking by yogurt.

No updates since 2018? Really Tiobe?

When a global Index service like Tiobe manage to write, and I quote:

However, the latest Delphi release is from 2018” -Source: Tiobe, March report

You really have to ponder if human beings are involved in their business at all. I’m not expecting much, honestly, but I do expect them to interact with the community they supposedly track and build a statistic on. Have they visited Delphi Developer and talked to the admins about growth numbers? Have they talked to Embarcadero to get some figures and coverage there? Did they contact the Freepascal community to get some download statistics from them?

Delphi 10.3 was released on november 21st 2019. The version that Tiobe seem to think is the last update, is in fact the last release with a city name (which was launched in 2018). Since then there have been three successive, regular updates; most developers are now using version 10.3.3. With 10.3.4 about to be released. This just underlines how oblivious Tiobe is to our part of the industry.

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Modern Delphi is used by millions of professional developers globally

Delphi and Freepascal is different in more ways than one, but beyond language compatibility there is one aspect that is quintessential for them both; namely their role in the commercial sector. Where other languages, like C/C++ or (for example) JavaScript see a lot of open-source activity, especially with regards to Linux and Node.js – Delphi and Freepascal are predominantly used to write high-quality, commercial, closed source business applications. In other words, the vast majority of code produced by the millions of Object Pascal developers around the world – is never publicly committed to GitHub or BitBucket.

So not only have Tiobe failed stupendously in their data mining operation, they seem oblivious to the demographic in which the language is used.

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The selection of books, video tutorials and coding material for Delphi is recovering at a rapid pace. And much like C/C++ there are classic books on Amazon that are just as relevant today as they were 10 years ago. Thankfully Delphi don’t suffer the “learn Delphi in 2 weeks” style books, because any developer worth his salt knows that such books are for the gullible and naive.

Developers use Delphi and Freepascal to deliver rock solid, data driven services; services that is expected to run 24/7 with zero downtime, processing millions of transactions. Delphi is used to write medical software that manages networks of hospitals, with tens of thousands of patients. Delphi is used by banks to power their ATM machines, and Delphi is used to do the heavy lifting in thousands of POS (point of sale) terminals across Europe. Terminals that don’t have time to wait for a garbage collector to kick in, only to cause catastrophic CPU spikes (I won’t mention names, but attempting to switch to C# was a disaster for one of the biggest POS terminal suppliers in Europe).

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Delphi represents the back-bone of the medical software industry in Scandinavia and Europe at large. Many have tried to replace Delphi, but end up with expensive lessons in why archetypal languages are indeed called archetypal.

Object Pascal is used by governments, fortune 500 companies and the guy with a million dollar idea working out of his parents garage; It is used to write cloud accounting software, invoicing systems and medical journaling; It is used by the music industry and graphical design. There are large and extremely successful products out there that don’t advertise that it’s written in Delphi (just like you don’t stamp “made with C++” on a piece of software). You would be surprised!

Object Pascal it’s used by developers who value speed, security, creative freedom and the benefit of a mature feature matrix that only C/C++ and Object Pascal brings. C is by definition three years older than Pascal, but these two archetypal languages have evolved side by side.

There is a reason these two languages represented the university curriculum for close to two decades; further still if we include Turbo Pascal. And Delphi is once again returning home to academia. To the applause of teachers who were forced to teach Java, and hated every minute of it (I helped setup two universities with Delphi in Norway, so I have some first hand accounts in the matter).

Reflections

Since Delphi is growing aggressively these days, Embarcadero is making waves. A few months back we saw how a well known team of C# influencers took a stab at Delphi (and me in particular, no doubt because I have been so outspoken). And as Delphi now returns to academia – Tiobe is demonstrating a bias that leaves little to the imagination. Especially when you know their numbers account for nothing and are bordering on fiction.

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If I didn’t know better, I would say someone is worried. And it’s not the Delphi and Freepascal communities. Modern Delphi is a power-house for software development, and it has the potential to disrupt and restore the devtool market.

There is a lot of money involved, so I am not surprised we are seeing a string of attempts at undermining the importance of Object Pascal. I had hoped Tiobe would adopt a higher standard though.

Then again, the ship of credibility sailed when they couldn’t tell Turbo Pascal from Object Pascal.

Delphi 25th Webinar signup

February 9, 2020 Leave a comment

Delphi25th Splash WallpaperDelphi is turning 25 and in connection with that, Jim Mckeeth is preparing a webinar! So make sure you register for the webinar in time! There is some very special and unique stuff lined up, so this is going to rock!

You can register here:
https://register.gotowebinar.com/register/8514999980241029644

25 years, wow. It seems only yesterday that I moved from Turbo Pascal to Delphi, and here we are a quarter of a century later. Such a wonderful language platform.

Very much looking forward to this talk — see you there guys!

 

Five unique features in Delphi for Windows 10

January 24, 2020 Leave a comment

I recently did an article on the Idera / Embarcadero Community website on Interbase 2020 and why that should be your next database.

Im following up with a second article about five features of Delphi that are intimately connected to Windows 10. I know that a lot of people are still clinging to Windows 7, but Microsoft phased that out last week, which means it’s now officially a legacy OS. So if you haven’t bothered updating, have a peek and think it over.

5win10

Turkish ministry of education secures free access to Delphi for an estimated one million students

January 20, 2020 13 comments

Edit: The title in my initial post could be misinterpreted, so i have altered it to better reflect the nature of the situation. My apologies for the misunderstanding, I used the initial text copied verbatim from the source, translated from Turkish to Norwegian (and further to English), and in this case an important nuance was lost in that process.


The ministry of education in Turkey recently announced that they will be offering Delphi free of charge to their body of students. An estimated one million students will thus have access to Delphi through this initiative.

Getting object-pascal back into universities and education is very important. Not just for Delphi as a product or Embarcadero as a company, but to ensure that the next generation of software developers are given a firm grasp on fundamental programming concepts; concepts that represent the building-blocks that all software rests on, and that will benefit the students for a lifetime.

I find it incredibly sad that Java and C# somehow crept into the curriculum of computer sciences around the turn of the century. The result of that opportunistic move is that we have several generations of developers who has graduated utterly oblivious to fundamental concepts; concepts such as memory management, interrupts, low-level optimization, inline assembler and (to be blunt) how a computer actually works beyond the desktop. This is why a formal education of C and Pascal is powerful and enduring. It gives the student a depth and wingspan that is hard to match.

Object Pascal as a language (including Freepascal, Oxygene and various alternative compilers) have been fluctuating between #11 and #14 on the Tiobe Index for a few years. Tiobe is an index that tracks the use and popularity of languages around the world, and helps companies get an indication of where to invest. So despite what people have been led to believe, Delphi has seen stable growth for many years and is far more widespread than sceptics like to admit.

As an ardent Delphi developer myself this is excellent news! Not only will it help the next generation of students learn proper engineering from the ground up – but it will also help to retire some of the unfounded myths surrounding the language (and Delphi in particular) that is sadly still in circulation. Most of these rumors stem from the hostile takeover (or elimination) of Borland by Microsoft some two decades ago, and does in no way reflect the reality of 2020. Delphi in particular has been through several phases of evolution, and is today en par with it’s companion language C/C++.

I am thrilled that so many young developers will now have access to a modern and relevant Delphi edition. Delphi has been a favorite of teachers and students everywhere, and the return of Delphi to academia – is a sign that the age of compromise is losing its grip.

Thank you to Hür Akdülger for informing the Delphi Developer community about this. Truly a monumental sign of growth. Congratulations Embarcadero and the Turkish students!

Source [in Turkish]:
https://www.timeturk.com/meb-den-1-milyon-meslek-lisesi-ogrencisine-yazilim-egitimi/haber-1337091

Interbase for 2020 and beyond

January 19, 2020 Leave a comment

I just published an article about InterBase on the Embarcadero community pages! Interbase is a much loved database that has seen some radical improvements. Check out my top 5 reasons to use InterBase with your Delphi, C++Builder or Sencha applications here: https://community.idera.com/developer-tools/b/blog/posts/five-reasons-to-use-interbase-in-2020-and-beyond

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Check out my top five InterBase features for 2020 and beyond

Nodebuilder, QTX and the release of my brand new social platform

January 2, 2020 9 comments

First, let me wish everyone a wonderful new year! With xmas and the silly season firmly behind us, and my batteries recharged – I feel my coding fingers itch to get started again.

2019 was a very busy year for me. Exhausting even. I have juggled both a full time job, kids and family, as well as our community project, Quartex Media Desktop. And since that project has grown considerably, I had to stop and work on the tooling. Which is what NodeBuilder is all about.

I have also released my own social media platform (see further down). This was initially scheduled for Q4 2020, but Facebook pissed me off something insanely, so I set it up in december instead.

NodeBuilder

node

For those of you that read my blog you probably remember the message system I made for the Quartex Desktop, called Ragnarok? This is a system for dealing with message dispatching and RPC, except that the handling is decoupled from the transport medium. In other words, it doesnt care how you deliver a message (WebSocket, UDP, REST), but rather takes care of serialization, binary data and security.

All the back-end services that make up the desktop system, are constructed around Ragnarok. So each service exposes a set of methods that the core can call, much like a normal RPC / SOAP service would. Each method is represented by a request and response object, which Ragnarok serialize to a JSON message envelope.

In our current model I use WebSocket, which is a full duplex, long-term connection (to avoid overhead of having to connect and perform a handshake for each call). But there is nothing in the way of implementing a REST transport layer (UDP is already supported, it’s used by the Zero-Config system. The services automatically find each other and register, as long as they are connected to the same router or switch). For the public service I think REST makes more sense, since it will better utilize the software clustering that node.js offers.

nodebuilder

Node Builder is a relatively simple service designer, but highly effective for our needs

 

Now for small services that expose just a handful of methods (like our chat service), writing the message classes manually is not really a problem. But the moment you start having 20 or 30 methods – and need to implement up to 60 message classes manually – this approach quickly becomes unmanageable and prone to errors. So I simply had to stop before xmas and work on our service designer. That way we can generate the boilerplate code in seconds rather than days and weeks.

While I dont have time to evolve this software beyond that of a simple service designer (well, I kinda did already), I have no problem seeing this system as a beginning of a wonderful, universal service authoring system. One that includes coding, libraries and the full scope of the QTX runtime-library.

In fact, most of the needed parts are in the codebase already, but not everything has been activated. I don’t have time to build both a native development system AND the development system for the desktop.

nodebuilder4

NodeBuilder already have a fully functional form designer and code editor, but it is dormant for now due to time restrictions. Quartex Media Desktop comes first

But right now, we have bigger fish to fry.

Quartex Media Desktop

We have made tremendous progress on our universal desktop environment, to the point where the baseline services are very close to completion. A month should be enough to finish this unless something unforeseen comes up.

desktop

Quartex Media Desktop provides an ecosystem for advanced web applications

You have to factor in that, this project has only had weekends and the odd after work hours allocated for it. So even though we have been developing this for 12 months, the actual amount of days is roughly half of that.

So all things considered I think we have done a massive amount of code in such a short time. Even simple 2d games usually take 2 years of daily development, and that includes a team of at least 5 people! Im a single developer working in my spare time.

So what exactly is left?

The last thing we did before xmas was upon us, was to throw out the last remnants of Smart Mobile Studio code. The back-end services are now completely implemented in our own QTX runtime-library, which has been written from scratch. There is not a line of code from Smart Mobile Studio in QTX, which means we no longer have to care what that system does or where it goes.

To sum up:

  • Push all file handling code out of the core
  • Implement file-handling as it’s own service

Those two steps might seem simple enough, but you have to remember that the older code was based on the Linux path system, and was read-only.

So when pushing that code out of the core, we also have to add all the functionality that was never implemented in our prototype.

nodebuilder2

Each class actually represents a separate “mini” program, and there are still many more methods to go before we can put this service into production.

Since Javascript does not support threads, each method needs to be implemented as a separate program. So when a method is called, the file/task manager literally spawns a new process just for that task. And the result is swiftly returned back to the caller in async manner.

So what is ultimately simple, becomes more elaborate if you want to do it right. This is the price we pay for universality and a cluster enabled service-stack.

This is also why I have put the service development on pause until we have finished the NodeBuilder tooling. And I did this because I know by experience that the moment the baseline is ready, both myself and users of the system is going to go “oh we need this, and that and those”. Being able to quickly design and auto-generate all the boilerplate code will save us months of work. So I would rather spend a couple of weeks on NodeBuilder than wasting months having to manually write all that boilerplate code down the line.

What about the QTX runtime-library?

Writing an RTL from scratch was not something I could have anticipated before we started this project. But thankfully the worst part of this job is already finished.

The RTL is divided into two parts:

  • Non Visual code. Classes and methods that makes QTX an RTL
  • Visual code. Custom Controls + standard controls (buttons, lists etc)
  • Visual designer

As you can see, the non-visual aspect of the system is finished and working beautifully. It’s a lot faster than the code I wrote for Smart Mobile Studio (roughly twice as fast on average). I also implemented a full visual designer, both as a Delphi visual component and QTX visual component.

nodebuilder3

Quartex Media Desktop makes running on several machines [cluster] easy and seamless

So fundamental visual classes like TCustomControl is already there. What I haven’t had time to finish are the standard-controls, like TButton, TListBox, TEdit and those type of visual components. That will be added after the release of QTX, at which point we throw out the absolute last remnants of Smart Mobile Studio from the client (HTML5 part) software too.

Why is the QTX Runtime-Library important again?

When the desktop is out the door, the true work begins! The desktop has several roles to play, but the most important aspect of the desktop – is to provide an ecosystem capable of hosting web based applications. Offering features and methods traditionally only found in Windows, Linux or OS X. It truly is a complete cloud system that can scale from a single affordable SBC (single board computer), to a high-end cluster of powerful servers.

Clustering and writing distributed applications has always been difficult, but Quartex Media Desktop makes it simple. It is no more difficult for a user to work on a clustered system, as it is to work on a normal, single OS. The difficult part has already been taken care of, and as long as people follow the rules, there will be no issues beyond ordinary maintenance.

And the first commercial application to come out of Quartex Components, is Cloud Forge, which is the development system for the platform. It has the same role as Visual Studio for Windows, or X Code for Apple OS X.

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The Quartex Media Desktop Cluster cube. A $400 super computer

I have prepared 3 compilers for the system already. First there is C/C++ courtesy of Clang. So C developers will be able to jump in and get productive immediately. The second compiler is freepascal, or more precise pas2js, which allows you to compile ordinary freepascal code (which is highly Delphi compatible) to both JavaScript and WebAssembly.

And last but not least, there is my fork of DWScript, which is the same compiler that Smart Mobile Studio uses. Except that my fork is based on the absolute latest version, and i have modified it heavily to better match special features in QTX. So right out of the door CloudForge will have C/C++, two Object Pascal compilers, and vanilla Javascript and typescript. TypeScript also has its own WebAssembly compiler, so doing hard-core development directly in a browser or HTML5 viewport is where we are headed.

Once the IDE is finished I can finally, finally continue on the LDEF bytecode runtime, which will be used in my BlitzBasic port and ultimately replace both clang, freepascal and DWScript. As a bonus it will emit native code for a variety of systems, including x86, ARM, 68k [including 68080] and PPC.

This might sound incredibly ambitious, if not impossible. But what I’m ultimately doing here -is moving existing code that I already have into a new paradigm.

The beauty of object pascal is the sheer size and volume of available components and code. Some refactoring must be done due to the async nature of JS, but when needed we fall back on WebAssembly via Freepascal (WASM executes linear, just like ordinary native code does).

A brand new social platform

During december Facebook royally pissed me off. I cannot underline enough how much i loath A.I censorship, and the mistakes that A.I does – in which you are utterly powerless to complain or be heard by a human being. In my case i posted a gif from their own mobile application, of a female body builder that did push-ups while doing hand-stands. In other words, a completely harmless gif with strength as the punchline. The A.I was not able to distinguish between a leotard and bare-skin, and just like that i was muted for over a week. No human being would make such a ruling. As an admin of a fairly large set of groups, there are many cases where bans are the result. Disgruntled members that acts out of revenge and report technical posts about coding as porn or offensive. Again, you are helpless because there are nobody you can talk to about resolving the issue. And this time I had enough.

It was always planned that we would launch our own social media platform, an alternative to Facebook aimed at adult geeks rather than kids (Facebook operates with an age limit of 12 years). So instead of waiting I rushed out and set up a brand new social network. One where those banale restrictions Facebook has conditioned us with, does not apply.

Just to underline, this is not some simple and small web forum. This is more or less a carbon copy of Facebook the way it used to be 8-9 years ago. So instead of having a single group on facebook, we can now have as many groups as we like, on a platform that looks more or less identical to Facebook – but under our control and human rules.

AD1

Amigadisrupt.com is a brand new social media platform for geeks

You can visit the site right now at https://www.amigadisrupt.com. Obviously the major content on the platform right now is dominated by retro computing – but groups like Delphi Developer and FPC developer has already been setup and are in use. But if you are expecting thousands of active users, that will take time. We are now closing in on 250 active users which is pretty good for such a short period of time. I dont want a platform anywhere near as big as FB. The goal is to get 10k users and have a stable community of coders, retro geeks, builders and creative individuals.

AD (Amiga Disrupt) will be a standard application that comes with Quartex Media Desktop. This is the beauty of web technology, in that it can unify different resources under one roof. And we will have our cake and eat it come hell or high water.

Disclaimer: Amiga Disrupt has a lower age limit of 18 years. This is a platform meant for adults. Which means there will be profanity, jokes that would get you banned on Facebook and content that is not meant for kids. This is hacker-land, and political correctness is considered toilet paper. So if you need social toffery like FB and Twitter deals with, you will be kicked by one of the admins.

After you sign up your feed will be completely empty. Here is how to get it started. And feel free to add me to your friends-list!thumb

Hydra, what’s the big deal anyway?

October 29, 2019 7 comments

RemObjects Hydra is a product I have used for years in concert with Delphi, and like most developers that come into contact with RemObjects products – once the full scope of the components hit you, you never want to go back to not using Hydra in your applications.

Note: It’s easy to dismiss Hydra as a “Delphi product”, but Hydra for .Net and Java does the exact same thing, namely let you mix and match modules from different languages in your programs. So if you are a C# developer looking for ways to incorporate Java, Delphi, Elements or Freepascal components in your application, then keep reading.

But let’s start with what Hydra can do for Delphi developers.

What is Hydra anyways?

Hydra is a component package for Delphi, Freepascal, .Net and Java that takes plugins to a whole new level. Now bear with me for a second, because these plugins is in a completely different league from anything you have used in the past.

In short, Hydra allows you to wrap code and components from other languages, and use them from Delphi or Lazarus. There are thousands of really amazing components for the .Net and Java platforms, and Hydra allows you compile those into modules (or “plugins” if you prefer that); modules that can then be used in your applications like they were native components.

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Hydra, here using a C# component in a Delphi application

But it doesn’t stop there; you can also mix VCL and FMX modules in the same application. This is extremely powerful since it offers a clear path to modernizing your codebase gradually rather than doing a time consuming and costly re-write.

So if you want to move your aging VCL codebase to Firemonkey, but the cost of having to re-write all your forms and business logic for FMX would break your budget -that’s where Hydra gives you a second option: namely that you can continue to use your VCL code from FMX and refactor the application in your own tempo and with minimal financial impact.

The best of all worlds

Not long ago RemObjects added support for Lazarus (Freepascal) to the mix, which once again opens a whole new ecosystem that Delphi, C# and Java developers can benefit from. Delphi has a lot of really cool components, but Lazarus have components that are not always available for Delphi. There are some really good developers in the Freepascal community, and you will find hundreds of components and classes (if not thousands) that are open-source; For example, Lazarus has a branch of Synedit that is much more evolved and polished than the fork available for Delphi. And with Hydra you can compile that into a module / plugin and use it in your Delphi applications.

This is also true for Java and C# developers. Some of the components available for native languages might not have similar functionality in the .Net world, and by using Hydra you can tap into the wealth that native languages have to offer.

As a Delphi or Freepascal developer, perhaps you have seen some of the fancy grids C# and Java coders enjoy? Developer Express have some of the coolest components available for any platform, but their focus is more on .Net these days than Delphi. They do maintain the control packages they have, but compared to the amount of development done for C# their Delphi offerings are abysmal. So with Hydra you can tap into the .Net side of things and use the latest components and libraries in your Delphi applications.

Financial savings

One of coolest features of Hydra, is that you can use it across Delphi versions. This has helped me leverage the price-tag of updating to the latest Delphi.

It’s easy to forget that whenever you update Delphi, you also need to update the components you have bought. This was one of the reasons I was reluctant to upgrade my Delphi license until Embarcadero released Delphi 10.2. Because I had thousands of dollars invested in components – and updating all my licenses would cost a small fortune.

So to get around this, I put the components into a Hydra module and compiled that using my older Delphi. And then i simply used those modules from my new Delphi installation. This way I was able to cut cost by thousands of dollars and enjoy the latest Delphi.

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Using Firemonkey controls under VCL is easy with Hydra

A couple of years back I also took the time to wrap a ton of older components that work fine but are no longer maintained or sold. I used an older version of Delphi to get these components into a Hydra module – and I can now use those with Delphi 10.3 (!). In my case there was a component-set for working closely with Active Directory that I have used in a customer’s project (and much faster than having to go the route via SQL). The company that made these don’t exist any more, and I have no source-code for the components.

The only way I could have used these without Hydra, would be to compile them into a .dll file and painstakingly export every single method (or use COM+ to cross the 32-bit / 64-bit barrier), which would have taken me a week since we are talking a large body of quality code. With Hydra i was able to wrap the whole thing in less than an hour.

I’m not advocating that people stop updating their components. But I am very thankful for the opportunity to delay having to update my entire component stack just to enjoy a modern version of Delphi.

Hydra gives me that opportunity, which means I can upgrade when my wallet allows it.

Building better applications

There is also another side to Hydra, namely that it allows you to design applications in a modular way. If you have the luxury of starting a brand new project and use Hydra from day one, you can isolate each part of your application as a module. Avoiding the trap of monolithic applications.

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Hydra for .Net allows you to use Delphi, Java and FPC modules under C#

This way of working has great impact on how you maintain your software, and consequently how you issue hotfixes and updates. If you have isolated each key part of your application as separate modules, you don’t need to ship a full build every time.

This also safeguards you from having all your eggs in one basket. If you have isolated each form (for example) as separate modules, there is nothing stopping you from rewriting some of these forms in another language – or cross the VCL and FMX barrier. You have to admit that being able to use the latest components from Developer Express is pretty cool. There is not a shadow of a doubt that Developer-Express makes the best damn components around for any platform. There are many grids for Delphi, but they cant hold a candle to the latest and greatest from Developer Express.

Why can’t I just use packages?

If you are thinking “hey, this sounds exactly like packages, why should I buy Hydra when packages does the exact same thing?“. Actually that’s not how packages work for Delphi.

Delphi packages are cool, but they are also severely limited. One of the reasons you have to update your components whenever you buy a newer version of Delphi, is because packages are not backwards compatible.

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Delphi packages are great, but severely limited

A Delphi package must be compiled with the same RTL as the host (your program), and version information and RTTI must match. This is because packages use the same RTL and more importantly, the same memory manager.

Hydra modules are not packages. They are clean and lean library files (*.dll files) that includes whatever RTL you compiled them with. In other words, you can safely load a Hydra module compiled with Delphi 7, into a Delphi 10.3 application without having to re-compile.

Once you start to work with Hydra, you gradually build up modules of functionality that you can recycle in the future. In many ways Hydra is a whole new take on components and RAD. This is how Delphi packages and libraries should have been.

Without saying anything bad about Delphi, because Delphi is a system that I love very much; but having to update your entire component stack just to use the latest Delphi, is sadly one of the factors that have led developers to abandon the platform. If you have USD 10.000 in dependencies, having to pay that as well as buying Delphi can be difficult to justify; especially when comparing with other languages and ecosystems.

For me, Hydra has been a tremendous boon for Delphi. It has allowed me to keep current with Delphi and all it’s many new features, without losing the money I have already invested in components packages.

If you are looking for something to bring your product to the next level, then I urge you to spend a few hours with Hydra. The documentation is exceptional, the features and benefits are outstanding — and you will wonder how you ever managed to work without them.

External resources

Disclaimer: I am not a salesman by any stretch of the imagination. I realize that promoting a product made by the company you work for might come across as a sales pitch; but that’s just it: I started to work for RemObjects for a reason. And that reason is that I have used their products since they came on the market. I have worked with these components long before I started working at RemObjects.

.NetRocks, you made my day!

October 11, 2019 4 comments

72462670_10156562141710906_5626655686042583040_nA popular website for .Net developers is called dot-net-rocks. This is an interesting site that has been going for a while now; well worth the visit if you do work with the .Net framework via RemObjects Elements, VS or Mono.

Now it turns out that the guys over at dot–net-rocks just did an episode on their podcast where they open by labeling me as a “raving lunatic” (I clearly have my moments); which I find absolutely hilarious, but not for the same reasons as them.

Long story short: They are doing a podcast on how to migrate legacy Delphi applications to C#, and in that context they somehow tracked down an article I posted way back in 2016, which was meant as a satire piece. Now don’t get me wrong, there are serious points in the article, like how the .Net framework was modeled on the Delphi VCL, and how the concepts around CLR and JIT were researched at Borland; but the tone of the whole thing, the “larger than life” claims etc. was meant to demonstrate just how some .Net developers behave when faced with alternative eco-systems. Having managed some 16+ usergroups for Delphi, C#, JavaScript (a total of six languages) on Facebook for close to 15 years, as well as working for Embarcadero that makes Delphi -I speak from experience.

It might be news to these guys that large companies around Europe is still using Delphi, modern Delphi, and that Object Pascal as a language scores well on the Tiobi index of popular programming languages. And no amount of echo-chamber mentality is going to change that fact. Heck, as late as 2018 and The Walt Disney Company wanted to replace C# with Delphi, because it turns out that bytecodes and embedded tech is not the best combination (cpu spikes when the GC kicks in, no real-time interrupt handling possible, GPIO delays, the list goes on).

I mean, the post i made back in 2016 is such obvious, low-hanging fruit for a show their size to pound on. You have this massive show that takes on a single, albeit ranting (and probably a bit of a lunatic if I don’t get my coffee) coder’s post. Underlying in the process how little they know about the object pascal community at large. They just demonstrated my point in bold, italic and underline 😀

Look before you shoot

DotNetRocks is either oblivious that Delphi still have millions of users around the world, or that Pascal is in fact available for .Net (which is a bit worrying since .Net is supposed to be their game). The alternative is that the facts I listed hit a little too close to home. I’ll leave it up to the reader to decide. Microsoft has lost at least 10 Universities around Europe to Delphi in 2018 that I know of, two of them Norwegian where I was personally involved in the license sales. While only speculation, I do find the timing for their podcast and focus on me in particular to be, “curious”.

72704588_10156562141590906_7030064639744409600_nAnd for the record, the most obvious solution when faced with “that legacy Delphi project”, is to just go and buy a modern version of Delphi. DotNetRocks delivered a perfect example of that very arrogance my 2016 post was designed to convey; namely that “brogrammers” often act like Delphi 7 was the last Delphi. They also resorted to lies to sell their points: I never said that Anders was dogged for creating Delphi. Quite the opposite. I simply underlined that by ridiculing Delphi in one hand, and praising it’s author with the other – you are indirectly (and paradoxically) invalidating half his career. Anders is an awesome developer, but why exclude how he evolved his skills? Ofcourse Ander’s products will have his architectural signature on them.

Not once did they mention Embarcadero or the fact that Delphi has been aggressively developed since Borland kicked the bucket. Probably hoping that undermining the messenger will somehow invalidate the message.

vspas

Porting Delphi to C# manually? Ok.. why not install Elements and just compile it into an assembly? You don’t even have to leave Visual Studio

Also, such an odd podcast for professional developers to run with. I mean, who the hell converts a Delphi project to C# manually? It’s like listening to a graphics artist that dont know that Photoshop and Illustrator are the de-facto tools to use. How is that even possible? A website dedicated to .Net, yet with no insight into the languages that run on the CLR? Wow.

If you want to port something from Delphi to .Net, you don’t sit down and manually convert stuff. You use proper tools like Elements from RemObjects; This gives you Object-Pascal for .Net (so a lot of code will compile just fine with only minor changes). Elements also ships with source-conversion tools, so once you have it running under Oxygene Pascal (the dialect is called Oxygene) you either just use the assemblies — or convert the Pascal code to C# through a tool called an Oxidizer.

vsdelphi

The most obvious solution is to just upgrade to a Delphi version from this century

The other solution is to use Hydra, also a RemObjects product. They can then compile the Delphi code into a library (including visual parts like forms and frames), and simply use that as any other assembly from within C#. This allows you to gradually phase out older parts without breaking the product. You can also use C# assemblies from Delphi with Hydra.

So by all means, call me what you like. You have only proved my point so far. You clearly have zero insight into the predominant Object-Pascal eco-systems, you clearly don’t know the tools developers use to interop between arcetypical and contextual languages — and instead of fact checking some of the points I made, dry humor notwithstanding, you just reacted like brogrammers do.

Well, It’s been weeks since I laughed this hard 😀 You really need to check before you pick someone to verbally abuse on the first date, because you might just bite yourself in the arse here he he

Cheers

 

Why move to Windows 10?

September 6, 2019 1 comment

When it comes to Windows editions, Windows 7 is probably the most successful operating-system Microsoft has ever released. When it hit stores back in October of 2009, it replaced Windows Vista (Longhorn) which, truth be told, caused more problems than it solved. The issues surrounding Vista were catastrophic for many reasons, but they were especially severe for developers. I remember buying a brand new laptop with Vista pre-installed, but in less than a week I rolled back to Windows XP.

win7

In retrospect, Vista was perhaps not as bad as it’s reputation would have it. I honestly feel it’s a very misunderstood edition of Windows, one that brought features common to the NT family into the mainstream. But back then people were still unfamiliar with what exactly that meant; things like “roaming profiles” was alien to users and developers with no background in networking. In my case Vista came at a juncture where I had two product releases on my hand. Time was of the essence, and spending days refactoring my code for the changes could not have come at a worse moment.

Be this as it may, the rejection of Vista forced Microsoft to replace it with something better. Vista was supposed to have a 10 year life-cycle, but Microsoft put Vista out of its misery in 3 years.

Windows 7 retirement plan

Windows 7 has been a wonderful system to work with. I can honestly say that with exception of Windows 10, it’s been the best operating system I have ever used. And i include OS X and Ubuntu in that equation. But as great as it was, Windows 7 is now 10 years old; an eternity in the software business. The needs of consumers and developers are radically different today, and with Windows 10 available as a free upgrade – it’s time to let the system go.

Microsoft actually ended mainstream support back in January of 2015 (!), but due to its popularity and massive adoption, they decided to extend support a few more years. This means that Windows 7, although practically retro in computing terms, still receives driver updates and security patches. But that is about to change sooner than you think.

Come next January (read: over xmas) and Windows 7 has an appointment with the gallows; something that will affect laptops, servers and desktop systems alike. This means there will be no more security patches, no more feature updates and no new virus definitions for Windows Defender. In other words January 14 2020 is the day Microsoft take Windows 7 off life-support.

This retirement also affects tablets, so if you have a Windows 7 based Surface, the time has come to jump ship and get Windows 10 installed. The same is true for Windows 7 Enterprise – it’s already obsolete by half a decade.

Some have stated that the embedded version of Windows 7, used primarily in custom-made products like ATMs, POS and kiosk type products, somehow avoids this retirement; but that’s just it – retirement truly means retirement. January 14 2020 really is the day Microsoft puts Windows 7 in the ground; be it laptop, server, desktop or surface.

The king is dead, long live the king

You might be wondering, since Windows 7 is still so popular, why would Microsoft seek to replace it? Well there are many reasons. First of all Windows 7 is based on the old NT kernel, which by today’s standard is a dinosaur compared to competing operating-systems. NT was constructed around a security scheme that has served humanity well, but it’s poorly equipped to deal with modern threats. Windows 7 also has a considerably larger memory footprint compared to Windows 10 – not to mention that Windows 10 has been optimized from scratch for better performance on all supported devices. So it’s never really been a question of why, but rather when and at which cost.

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Windows 10 comes in many shapes and sizes

You also have to factor in that Windows 10 introduces a host of new features that is unique to that OS. Things like support for touch interfaces (both display and navigation devices) is one of them, but developers will be more affected by the new application model (UWP) and UI framework. Truth be told, UWP was first introduced in Windows 8 as a part of Microsoft’s plan to streamline all versions of their OS (tablet, mobile, desktop and server). The promise of UWP is that, if you follow the guidelines and stick to the APIs – the same application can run on all variations of the same OS; regardless of CPU even (more about that below).

Since this was introduced Microsoft sadly dropped out of the smartphone OS business though. Their Windows for mobile never gained the recognition it deserved, and they retired it in favor of Android. Personally i loved their phones; they somehow managed to take the best features from both Apple iOS and Android, and combine them intuitively and elegantly. Not to mention that they cost 40% of what an iPhone of Samsung Galaxy sold for.

Windows 10 is also the first OS from Microsoft that treats XBox as a first-class citizen, so developing titles for XBox has become easier. DirectX now aims at delivering console level experience for laptop and desktop computers; it’s pretty much been refactored from scratch, with aggressive and radical optimization (read: hand written assembly) to get every last drop of performance out of the hardware.

Unlike previous editions of DirectX, Microsoft has toned down the amount of insulation between your code and the actual hardware. DirectX was always padded left and right with interfaces and abstractions, making raw access to GPU resources impossible (or at least, impractical). Thankfully Microsoft has realized that they took this too far, and trimmed the insulation layers accordingly; meaning that developers can now access resources en-par with AMD Mantle, Apple Metal and Vulcan (Factoid: Vulcan is a replacement for OpenGL. OpenGL originated with Silicon Graphics machines, a graphics workstation that was hugely popular back in the 90s and early 2k’s).

WinRT, ARM and the beyond

While developers who focus on business applications could care less about DirectX and multimedia, the underlying changes to the Windows 10 core are of such a magnitude that all avenues of development will be affected. Some of the UI changes are profoundly linked to the work that makes Windows 10 unique – and Microsoft has made it perfectly clear that all future endeavors is built on the Windows 10 baseline.

Windows-10-Mobile

Windows is moving to ARM, and Windows 10 technology is the foundation

Besides purely technical changes, access to the Microsoft Store is one of the features that have a more immediate, financial effect on software development. Marco Cantu actually blogged about this back in 2016, regarding how you can use WDB (Windows Desktop Bridge, a.k.a “project Centennial”) to publish Firemonkey applications to Microsoft store. I mean, any modern developer who makes a living from selling software, having their products available through official channels is pretty essential. And that excludes Windows 7 by default.

And last but not least, there is WinRT, short for Windows Runtime, a sand boxed version of windows that allows applications to be deployed to both x86 and ARM. WinRT involves x86 emulation on ARM SoCs (system on a chip), meaning that you will be able to run applications compiled for x86 on Microsoft’s upcoming Windows for ARM release. But performance wise emulation will obviously not deliver the same level of performance as native ARM code. The emulation layer is meant as an intermediate solution, allowing developers time to evolve compilers that can target ARM directly.

I probably don’t have to outline the business opportunities Windows on ARM represent.

Market adoption

If the features and promise of Windows 10 is not enough to convince you to update immediately, consider the following: There are more than 1 billion Windows users in the world. Windows 7 presently holds 37% of the global market (with Windows 10 at 43%), which means that hundreds of millions of computers will be affected by the now immanent retirement plan.

segment

ARM is still a hardware platform companies can afford to postpone, but with both Apple and Microsoft being open about their move to ARM in the near future, the risk for developers being left behind is very real. And having to deal with the cost of refactoring your entire portfolio over something as trivial as an update, well – I’m sure you see my point.

There really is zero strategic advantage in sticking with the lowest common denominator, which in this case is the stock WinAPI that has defined Windows since the nineties. Especially not when upgrading to Windows 10 is free of charge.

Reflections

From a personal point of view, I cannot imagine being a developer in 2019 and relying on an operating-system that is retired. I must admit that I do own virtual machines where Windows 7 is used, but those are not instances where I do software development; I use them primarily for stress testing software running in other VMWare instances, which conceptually is not a problem.

Microsoft is still offering a free upgrade plan for Windows 7 users. In other words there is no financial loss in updating your development machines, be they physical or virtual.

I look forward to Microsoft’s next phase, where virtual reality and augmented reality technology is implemented more closely for all supported hardware platforms. As for changes that affect desktop business applications, have a look at the following links:

 

Using multiple languages is the same project

August 21, 2019 1 comment

Most compilers can only handle a single syntax for any project, but the Elements compiler from RemObjects deals with 5 (five!) different languages -even within the same project. That’s pretty awesome and opens up for some considerable savings.

I mean, it’s not always easy to find developers for a single language, but when you can approach your codebase from C#, Java, Go, Swift and Oxygene (object pascal) at the same time (inside the same project even!), you suddenly have some options.  Especially since you can pick exotic targets like WebAssembly. Or what about compiling Java to .net bytecodes? Or using the VCL from C#? It’s pretty awesome stuff!

Check out Marc Hoffmans article on the Elements compiler toolchain and how you can mix and match between languages, picking the best from each — while still compiling to a single binary of llvm optimized code:

mixins

Click on the picture to be redirected

 

Check out RemObjects Remoting SDK

July 22, 2019 3 comments

RemObjects Remoting SDK is one of those component packages that have become more than the sum of it’s part. Just like project Jedi has become standard equipment almost, Remoting SDK is a system that all Delphi and Freepascal developers should have in their toolbox.

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In this article I’m going to present the SDK in broad strokes; from a viewpoint of someone who haven’t used the SDK before. There are still a large number of Delphi developers that don’t know it even exists – hopefully this post will shed some light on why the system is worth every penny and what it can do for you.

I should also add, that this is a personal blog. This is not an official RemObjects presentation, but a piece written by me based on my subjective experience and notions. We have a lot of running dialog at Delphi Developer on Facebook, so if I read overly harsh on a subject, that is my personal view as a Delphi Developer.

Stop re-inventing the wheel

Delphi has always been a great tool for writing system services. It has accumulated a vast ecosystem of non-visual components over the years, both commercial and non-commercial, and this allows developers to quickly aggregate and expose complex behavior — everything from graphics processing to databases, file processing to networking.

The challenge for Delphi is that writing large composite systems, where you have more than a single service doing work in concert, is not factored into the RTL or project type. Delphi provides a bare-bone project type for system services, and that’s it. Depending on how you look at it, it’s either a blessing or a curse. You essentially start on C level.

So fundamental things like IPC (inter process communication) is something you have to deal with yourself. If you want multi-tenancy that is likewise not supported out of the box. And all of this is before we venture into protocol standards, message formats and async vs synchronous execution.

The idea behind Remoting SDK is to get away from this style of low-level hacking. Without sounding negative, it provides the missing pieces that Delphi lacks, including the stuff that C# developers enjoy under .net (and then some). So if you are a Delphi developer who look over at C# with smudge of envy, then you are going to love Remoting SDK.

Say goodbye to boilerplate mistakes

Writing distributed servers and services is boring work. For each function you expose, you have to define the parameters and data-types in a portable way, then you have to implement the code that represents the exposed function and finally the interface itself that can be consumed by clients. The latter must be defined in a way that works with other languages too, not just Delphi. So while server tech in it’s essential form is quite simple, it’s the infrastructure that sets the stage of how quickly you can apply improvements and adapt to change.

For example, let’s say you have implemented a wonderful new service. It exposes 60 awesome functions that your customers can consume in their own work. The amount of boilerplate code for 60 distributed functions, especially if you operate with composite data types, is horrendous. It is a nightmare to manage and opens up for sloppy, unnecessary mistakes.

ide_int

After you install Remoting SDK, the service designer becomes a part of the IDE

This is where Remoting SDK truly shines. When you install the software, it integrates it’s editors and wizards closely with the Delphi IDE. It adds a ton of new project types, components and whatnot – but the most important feature is without a doubt the service designer.

bonjour

Start the service-designer in any server or service project and you can edit the methods, data types and interfaces your system expose to the world

As the name implies, the service designer allows you to visually define your services. Adding a new function is a simple click, the same goes for datatypes and structures (record types). These datatypes are exposed too and can be consumed from any modern language. So a service you make in Delphi can be used from C#, C/C++, Java, Oxygene, Swift (and visa-versa).

Auto generated code

A service designer is all good and well I hear you say, but what about that boilerplate code? Well Remoting SDK takes care of that too (kinda the point). Whenever you edit your services, the designer will auto-generate a new interface unit for you. This contains the classes and definitions that describe your service. It will also generate an implementation unit, with empty functions; you just need to fill in the blanks.

The designer is also smart enough not to remove code. So if you go in and change something, it won’t just delete the older implementation procedure. Only the params and names will be changed if you have already written some code.

bonjour_source

Having changed a service, hitting F9 re-generates the interface code automatically. Your only job is to fill in the code for each method in the implementation units. The SDK takes care of everything else for you

The service information, including the type information, is stored in a special file format called “rodl”. This format is very close to Microsoft WSDL format, but it holds more information. It’s important to underline that you can import the service directly from your servers (optional naturally) as WSDL. So if you want to consume a Remoting SDK service using Delphi’s ordinary RIO components, that is not a problem. Visual Studio likewise imports and consumes services – so Remoting SDK behaves identical regardless of platform or language used.

Remoting SDK is not just for Delphi, just to be clear on that. If you are presently using both Delphi and C# (which is a common situation), you can buy a license for both C# and Delphi and use whatever language you feel is best for a particular task or service. You can even get Remoting SDK for Javascript and call your service-stack directly from your website if you like. So there are a lot of options for leveraging the technology.

Transport is not content

OK so Remoting SDK makes it easy to define distributed services and servers. But what about communication? Are we boxed into RemObjects way of doing things?

The remoting framework comes with a ton of components, divided into 3 primary groups:

  • Servers
  • Channels (clients)
  • Messages

The reason for this distinction is simple: the ability to transport data, is never the same as the ability to describe data. For example, a message is always connected to a standard. It’s job is ultimately to serialize (represent) and de-serialize data according to a format. The server’s job is to receive a request and send a response. So these concepts are neatly decoupled for maximum agility.

As of writing the SDK offers the following message formats:

  • Binary
  • Post
  • SOAP
  • JSON

If you are exposing a service that will be consumed from JavaScript, throwing in a TROJSONMessage component is the way to go. If you expect messages to be posted from your website using ordinary web forms, then TROPostMessage is a perfect match. If you want XML then TROSOAPMessage rocks, and if you want fast, binary messages – well then there is TROBinaryMessage.

What you must understand is that you don’t have to pick just one! You can drop all 4 of these message formats and hook them up to your server or channel. The SDK is smart enough to recognize the format and use the correct component for serialization. So creating a distributed service that can be consumed from all major platforms is a matter of dropping components and setting a property.

channels

If you double-click on a server or channel, you can link message components with a simple click. No messy code snippets in sight.

Multi-tenancy out of the box

With the release of Rad-Server as a part of Delphi, people have started to ask what exactly multi-tenancy is and why it matters. I have to be honest and say that yes, it does matter if you are creating a service stack where you want to isolate the logic for each customer in compartments – but the idea that this is somehow new or unique is not the case. Remoting SDK have given users multi-tenancy support for 15+ years, which is also why I haven’t been too enthusiastic with Rad-Server.

Now don’t get me wrong, I don’t have an axe to grind with Rad-Server. The only reason I mention it is because people have asked how i feel about it. The tech itself is absolutely welcome, but it’s the licensing and throwing Interbase in there that rubs me the wrong way. If it could run on SQLite3 and was free with Enterprise I would have felt different about it.

mt-models

There are various models for multi-tenancy, but they revolve around the same principles

To get back on topic: multi-tenancy means that you can dynamically load services and expose them on demand. You can look at it as a form of plugin functionality. The idea in Rad-Server is that you can isolate a customer’s service in a separate package – and then load the package into your server whenever you need it.

ro_comps

Some of the components that ship with the system

The reason I dislike Rad-Server in this respect, is because they force you to compile with packages. So if you want to write a Rad-Server system, you have to compile your entire project as package-based, and ship a ton of .dpk files with your system. Packages is not wrong or bad per-se, but they open your system up on a fundamental level. There is nothing stopping a customer from rolling his own spoof package and potentially bypass your security.

There is also an issue with un-loading a package, where right now the package remains in memory. This means that hot-swapping packages without killing the server wont work.

Rad-Server is also hardcoded to use Interbase, which suddenly bring in licensing issues that rubs people the wrong way. Considering the price of Delphi in 2019, Rad-Server stands out as a bit of an oddity. And hardcoding a database into it, with the licensing issues that brings -just rendered the whole system mute for me. Why should I pay more to get less? Especially when I have been using multi-tenancy with RemObjects for some 15 years?

With Remoting SDK you have something called DLL servers, which does the exact same thing – but using ordinary DLL files (not packages!). You don’t have to compile your system with packages, and it takes just one line of code to make your main dispatcher aware of the loaded service.

This actually works so well that I use Remoting SDK as my primary “plugin” system. Even when I write ordinary desktop applications that has nothing to do with servers or services – I always try to compartmentalize features that could be replaced in the future.

For example, I’m a huge fan of ElevateDB, which is a native Delphi database engine that compiles directly into your executable. By isolating that inside a DLL as a service, my application is now engine agnostic – and I get a break from buying a truck load of components every time Delphi is updated.

Saving money

The thing about DLL services, is that you can save a lot of money. I’m actually using an ElevateDB license that was for Delphi 2007. I compiled the engine using D2007 into a DLL service — and then I consume that DLL from my more modern Delphi editions. I have no problem supporting or paying for components, that is right and fair, but having to buy new licenses for every single component each time Delphi is updated? This is unheard of in other languages, and I would rather ditch the platform all together than forking out $10k ever time I update.

dll_project

A DLL server can be used for many things if you are creative about it

While we are on the subject – Hydra is another great money saver. It allows you to use .net and Java libraries (both visual and non-visual) with Delphi. With Hydra you can design something in .net, compile it into a DLL file, and then use that from Delphi.

But — you can also compile things from Delphi, and use it in newer versions of Delphi. Im not forking out for a Developer Express update just to use what I have already paid for in the latest Delphi. I have one license, I compile the forms and components into a Hydra Module — and then use it from newer Delphi editions.

hydra

Hydra, which is a separate product, allows you to stuff visual components and forms inside a vanilla DLL. It allows cross  language use, so you can finally use Java and .net components inside your Delphi application

Bonjour support

Another feature I love is the zero configuration support. This is one of those things that you often forget, but that suddenly becomes important once you deploy a service stack on cluster level.

apple_bonjour_medium-e1485166557218Remoting SDK comes with support for Apple Bonjour, so if you want to use that functionality you have to install the Bonjour library from Apple. Once installed on your host machines, your RemObjects services can find each other.

ZeroConfig is not that hard to code manually. You can roll your own using UDP or vanilla messages. But getting service discovery right can be fiddly. One thing is broadcasting an UDP message saying “here I am”, it’s something else entirely to allow service discovery on cluster level.

If Bonjour is not your cup of tea, the SDK provides a second option, which is RemObjects own zero-config hub. You can dig into the documentation to find out more about this.

What about that IPC stuff you mentioned?

I mentioned IPC (inter process communication) at the beginning here, which is a must have if you are making a service stack where each member is expected to talk to the others. In a large server-system the services might not exist on the same, physical hardware either, so you want to take height for that.

With the SDK this is just another service. It takes 10 minutes to create a DLL server with the functionality to send and receive messages – and then you just load and plug that into all your services. Done. Finished.

Interestingly, Remoting SDK supports named-pipes. So if you are running on a Windows network it’s even easier. Personally I prefer to use a vanilla TCP/IP based server and channel, that way I can make use of my Linux blades too.

Building on the system

There is nothing stopping you from expanding the system that RemObjects have established. You are not forced to only use their server types, message types and class framework. You can mix and match as you see fit – and also inherit out your own variation if you need something special.

firm_foundation-720x340For example, WebSocket is an emerging standard that has become wildly popular. Remoting SDK does not support that out of the box, the reason is that the standard is practically identical to the RemObjects super-server, and partly because there must be room for third party vendors.

Andre Mussche took the time to implement a WebSocket server for Remoting SDK a few years back. Demonstrating in the process just how easy it is to build on the existing infrastructure. If you are already using Remoting SDK or want WebSocket support, head over to his github repository and grab the code there: https://github.com/andremussche/DelphiWebsockets

I could probably write a whole book covering this framework. For the past 15 years, RemObjects Remoting SDK is the first product I install after Delphi. It has become standard for me and remains an integral part of my toolkit. Other packages have come and gone, but this one remains.

Hopefully this post has tickled your interest in the product. No matter if you are maintaining a legacy service stack, or thinking about re implementing your existing system in something future-proof, this framework will make your life much, much easier. And it wont break the bank either.

You can visit the product page here: https://www.remotingsdk.com/ro/default.aspx

And you can check out the documentation here: https://docs.remotingsdk.com/

30% discount on all RemObjects products!

July 8, 2019 Leave a comment

This is brilliant. RemObjects is giving a whopping 30% discount on all products!

This means you can now pick up RemObjects Remoting Framework, Data Abstract, Hydra or the Elements compiler toolchain – with a massive 30% saving!

These are battle-hardened, enterprise level solutions that have been polished over years and they are in constant development. Each solution integrates seamlessly into Embarcadero Delphi and provides a smooth path to delivering quality products in days rather than weeks.

But you better hurry because it’s only valid for one week (!)

Use the coupon code: “DelphiDeveloper”

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Use the Delphi Developer coupon to get 30% discount – click here

 

A Delphi propertybag

July 7, 2019 14 comments

A long, long time ago, way back in the previous century, I often had to adjust a Visual Basic project my company maintained. Going from object-pascal to VB was more than a little debilitating; Visual Basic was not a compiled language like Delphi is, and it lacked more or less every feature you needed to produce good software.

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I could probably make a VB clone using Delphi pretty easily. But I think the world has experienced enough suffering, no need to add more evil to the universe

Having said that, I have always been a huge fan of Basic (it was my first language after all, it’s what schools taught in the 70s and 80s). I think it was a terrible mistake for Microsoft to retire Basic as a language, because it’s a great way to teach kids the fundamentals of programming.

Visual Basic is still there though, available for the .Net framework, but to call it Basic is an insult of the likes of GFA Basic, Amos Basic and Blitz Basic; the mighty compilers of the past. If you enjoyed basic before Microsoft pushed out the monstrosity that is Visual Basic, then perhaps swing by GitHub and pick up a copy of BlitzBasic?  BlitzBasic is a completely different beast. It compiles to machine-code, allows inline assembly, and has been wildly popular for game developers over the years.

A property bag

The only feature that I found somewhat useful in Visual Basic, was an object called a propertybag. It’s just a fancy name for a dictionary, but it had a couple of redeeming factors beyond lookup ability. Like being able to load name-value-pairs from a string, recognizing datatypes and exposing type-aware read/write methods. Nothing fancy but handy when dealing with database connection-strings, shell parameters and the like.

So you could feed it strings like this:

first=12;second=hello there;third=3.14

And the class would parse out the names and values, stuff it in a dictionary, and you could easily extract the data you needed. Nothing fancy, but handy on rare occasions.

A Delphi version

Im mostly porting code from Delphi to Oxygene these days, but here is my Delphi implementation of the propertybag object. Please note that I haven’t bothered to implement the propertybag available in .Net. The Delphi version below is based on the Visual Basic 6 version, with some dependency injection thrown in for good measure.

unit fslib.params;

interface

{.$DEFINE SUPPORT_URI_ENCODING}

uses
  System.SysUtils,
  System.Classes,
  Generics.Collections;

type

  (* Exceptions *)
  EPropertybag           = class(exception);
  EPropertybagReadError  = class(EPropertybag);
  EPropertybagWriteError = class(EPropertybag);
  EPropertybagParseError = class(EPropertybag);

  (* Datatypes *)
  TPropertyBagDictionary = TDictionary ;

  IPropertyElement = interface
    ['{C6C937DF-50FA-4984-BA6F-EBB0B367D3F3}']
    function  GetAsInt: integer;
    procedure SetAsInt(const Value: integer);

    function  GetAsString: string;
    procedure SetAsString(const Value: string);

    function  GetAsBool: boolean;
    procedure SetAsBool(const Value: boolean);

    function  GetAsFloat: double;
    procedure SetAsFloat(const Value: double);

    function  GetEmpty: boolean;

    property Empty: boolean read GetEmpty;
    property AsFloat: double read GetAsFloat write SetAsFloat;
    property AsBoolean: boolean read GetAsBool write SetAsBool;
    property AsInteger: integer read GetAsInt write SetAsInt;
    property AsString: string read GetAsString write SetAsString;
  end;

  TPropertyBag = Class(TInterfacedObject)
  strict private
    FLUT:       TPropertyBagDictionary;
  strict protected
    procedure   Parse(NameValuePairs: string);
  public
    function    Read(Name: string): IPropertyElement;
    function    Write(Name: string; Value: string): IPropertyElement;

    procedure   SaveToStream(const Stream: TStream);
    procedure   LoadFromStream(const Stream: TStream);
    function    ToString: string; override;
    procedure   Clear; virtual;

    constructor Create(NameValuePairs: string); virtual;
    destructor  Destroy; override;
  end;

implementation

{$IFDEF SUPPORT_URI_ENCODING}
uses
  system.NetEncoding;
{$ENDIF}

const
  cnt_err_sourceparameters_parse =
  'Failed to parse input, invalid or damaged text error [%s]';

  cnt_err_sourceparameters_write_id =
  'Write failed, invalid or empty identifier error';

  cnt_err_sourceparameters_read_id =
  'Read failed, invalid or empty identifier error';

type

  TPropertyElement = class(TInterfacedObject, IPropertyElement)
  strict private
    FName:      string;
    FData:      string;
    FStorage:   TPropertyBagDictionary;
  strict protected
    function    GetEmpty: boolean; inline;

    function    GetAsInt: integer; inline;
    procedure   SetAsInt(const Value: integer); inline;

    function    GetAsString: string; inline;
    procedure   SetAsString(const Value: string); inline;

    function    GetAsBool: boolean; inline;
    procedure   SetAsBool(const Value: boolean); inline;

    function    GetAsFloat: double; inline;
    procedure   SetAsFloat(const Value: double); inline;

  public
    property    AsFloat: double read GetAsFloat write SetAsFloat;
    property    AsBoolean: boolean read GetAsBool write SetAsBool;
    property    AsInteger: integer read GetAsInt write SetAsInt;
    property    AsString: string read GetAsString write SetAsString;
    property    Empty: boolean read GetEmpty;

    constructor Create(const Storage: TPropertyBagDictionary; Name: string; Data: string); overload; virtual;
    constructor Create(Data: string); overload; virtual;
  end;

//#############################################################################
// TPropertyElement
//#############################################################################

constructor TPropertyElement.Create(Data: string);
begin
  inherited Create;
  FData := Data.Trim();
end;

constructor TPropertyElement.Create(const Storage: TPropertyBagDictionary;
  Name: string; Data: string);
begin
  inherited Create;
  FStorage := Storage;
  FName := Name.Trim().ToLower();
  FData := Data.Trim();
end;

function TPropertyElement.GetEmpty: boolean;
begin
  result := FData.Length < 1;
end;

function TPropertyElement.GetAsString: string;
begin
  result := FData;
end;

procedure TPropertyElement.SetAsString(const Value: string);
begin
  if Value  FData then
  begin
    FData := Value;
    if FName.Length > 0 then
    begin
      if FStorage  nil then
        FStorage.AddOrSetValue(FName, Value);
    end;
  end;
end;

function TPropertyElement.GetAsBool: boolean;
begin
  TryStrToBool(FData, result);
end;

procedure TPropertyElement.SetAsBool(const Value: boolean);
begin
  FData := BoolToStr(Value, true);

  if FName.Length > 0 then
  begin
    if FStorage  nil then
      FStorage.AddOrSetValue(FName, FData);
  end;
end;

function TPropertyElement.GetAsFloat: double;
begin
  TryStrToFloat(FData, result);
end;

procedure TPropertyElement.SetAsFloat(const Value: double);
begin
  FData := FloatToStr(Value);
  if FName.Length > 0 then
  begin
    if FStorage  nil then
      FStorage.AddOrSetValue(FName, FData);
  end;
end;

function TPropertyElement.GetAsInt: integer;
begin
  TryStrToInt(FData, Result);
end;

procedure TPropertyElement.SetAsInt(const Value: integer);
begin
  FData := IntToStr(Value);
  if FName.Length > 0 then
  begin
    if FStorage  nil then
      FStorage.AddOrSetValue(FName, FData);
  end;
end;

//#############################################################################
// TPropertyBag
//#############################################################################

constructor TPropertyBag.Create(NameValuePairs: string);

begin
  inherited Create;
  FLUT := TDictionary.Create();

  NameValuePairs := NameValuePairs.Trim();
  if NameValuePairs.Length > 0 then
    Parse(NameValuePairs);
end;

destructor TPropertyBag.Destroy;
begin
  FLut.Free;
  inherited;
end;

procedure TPropertyBag.Clear;
begin
  FLut.Clear;
end;

procedure TPropertyBag.Parse(NameValuePairs: string);
var
  LList:      TStringList;
  x:          integer;
  LId:        string;
  LValue:     string;
  LOriginal:  string;
  {$IFDEF SUPPORT_URI_ENCODING}
  LPos:       integer;
  {$ENDIF}
begin
  // Reset content
  FLUT.Clear();

  // Make a copy of the original text
  LOriginal := NameValuePairs;

  // Trim and prepare
  NameValuePairs := NameValuePairs.Trim();

  // Anything to work with?
  if NameValuePairs.Length > 0 then
  begin
    {$IFDEF SUPPORT_URI_ENCODING}
    // Check if the data is URL-encoded
    LPos := pos('%', NameValuePairs);
    if  (LPos >= low(NameValuePairs) )
    and (LPos  0 then
    Begin
      (* Populate our lookup table *)
      LList := TStringList.Create;
      try
        LList.Delimiter := ';';
        LList.StrictDelimiter := true;
        LList.DelimitedText := NameValuePairs;

        if LList.Count = 0 then
          raise EPropertybagParseError.CreateFmt(cnt_err_sourceparameters_parse, [LOriginal]);

        try
          for x := 0 to LList.Count-1 do
          begin
            LId := LList.Names[x].Trim().ToLower();
            if (LId.Length > 0) then
            begin
              LValue := LList.ValueFromIndex[x].Trim();
              Write(LId, LValue);
            end;
          end;
        except
          on e: exception do
          raise EPropertybagParseError.CreateFmt(cnt_err_sourceparameters_parse, [LOriginal]);
        end;
      finally
        LList.Free;
      end;
    end;
  end;
end;

function TPropertyBag.ToString: string;
var
  LItem: TPair;
begin
  setlength(result, 0);
  for LItem in FLut do
  begin
    if LItem.Key.Trim().Length > 0 then
    begin
      result := result + Format('%s=%s;', [LItem.Key, LItem.Value]);
    end;
  end;
end;

procedure TPropertyBag.SaveToStream(const Stream: TStream);
var
  LData: TStringStream;
begin
  LData := TStringStream.Create(ToString(), TEncoding.UTF8);
  try
    LData.SaveToStream(Stream);
  finally
    LData.Free;
  end;
end;

procedure TPropertyBag.LoadFromStream(const Stream: TStream);
var
  LData: TStringStream;
begin
  LData := TStringStream.Create('', TEncoding.UTF8);
  try
    LData.LoadFromStream(Stream);
    Parse(LData.DataString);
  finally
    LData.Free;
  end;
end;

function TPropertyBag.Write(Name: string; Value: string): IPropertyElement;
begin
  Name := Name.Trim().ToLower();
  if Name.Length > 0 then
  begin
    if not FLUT.ContainsKey(Name) then
      FLut.Add(Name, Value);

    result := TPropertyElement.Create(FLut, Name, Value) as IPropertyElement;
  end else
  raise EPropertybagWriteError.Create(cnt_err_sourceparameters_write_id);
end;

function TPropertyBag.Read(Name: string): IPropertyElement;
var
  LData:  String;
begin
  Name := Name.Trim().ToLower();
  if Name.Length > 0  then
  begin
    if FLut.TryGetValue(Name, LData) then
      result := TPropertyElement.Create(LData) as IPropertyElement
    else
      raise EPropertybagReadError.Create(cnt_err_sourceparameters_read_id);
  end else
  raise EPropertybagReadError.Create(cnt_err_sourceparameters_read_id);
end;


end.

BTree for Delphi

July 7, 2019 3 comments
lookup

Click here to read

A few weeks back I posted an article on RemObjects blog regarding universal code, and how you with a little bit of care can write code that easily compiled with both Oxygene, Delphi and Freepascal. With emphasis on Oxygene.

The example I used was a BTree class that I originally ported from Delphi to Smart Pascal, and then finally to Oxygene to run under WebAssembly.

Long story short I was asked if I could port the code back to Delphi in its more or less universal form. Naturally there are small differences here and there, but nothing special that distinctly separates the Delphi version from Oxygene or Smart Pascal.

Why this version?

If you google BTree and Delphi you will find loads of implementations. They all operate more or less identical, using records and pointers for optimal speed. I decided to base my version on classes for convenience, but it shouldn’t be difficult to revert that to use records if you absolutely need it.

What I like about this BTree implementation is that it’s very functional. Its easy to traverse the nodes using the ForEach() method, you can add items using a number as an identifier, but it also supports string identifiers.

I also changed the typical data reference. The data each node represent is usually a pointer. I changed this to variant to make it more functional.

Well, here is the Delphi version as promised. Happy to help.

unit btree;

interface

uses
  System.Generics.Collections,
  System.Sysutils,
  System.Classes;

type

  // BTree leaf object
  TQTXBTreeNode = class(TObject)
  public
    Identifier: integer;
    Data:       variant;
    Left:       TQTXBTreeNode;
    Right:      TQTXBTreeNode;
  end;

  [Weak]
  TQTXBTreeProcessCB = reference to procedure (const Node: TQTXBTreeNode; var Cancel: boolean);

  EBTreeError = class(Exception);

  TQTXBTree = class(TObject)
  private
    FRoot:    TQTXBTreeNode;
    FCurrent: TQTXBTreeNode;
  protected
    function  GetEmpty: boolean;  virtual;
    function  GetPackedNodes: TList;

  public
    property  Root: TQTXBTreeNode read FRoot;
    property  Empty: boolean read GetEmpty;

    function  Add(const Ident: integer; const Data: variant): TQTXBTreeNode; overload; virtual;
    function  Add(const Ident: string; const Data: variant): TQTXBTreeNode; overload; virtual;

    function  Contains(const Ident: integer): boolean; overload; virtual;
    function  Contains(const Ident: string): boolean; overload; virtual;

    function  Remove(const Ident: integer): boolean; overload; virtual;
    function  Remove(const Ident: string): boolean; overload; virtual;

    function  Read(const Ident: integer): variant; overload; virtual;
    function  Read(const Ident: string): variant; overload; virtual;

    procedure Write(const Ident: string; const NewData: variant); overload; virtual;
    procedure Write(const Ident: integer; const NewData: variant); overload; virtual;

    procedure Clear; overload; virtual;
    procedure Clear(const Process: TQTXBTreeProcessCB); overload; virtual;

    function  ToDataArray: TList;
    function  Count: integer;

    procedure ForEach(const Process: TQTXBTreeProcessCB);

    destructor Destroy; override;
  end;

implementation

//#############################################################################
// TQTXBTree
//#############################################################################

destructor TQTXBTree.Destroy;
begin
  if FRoot  nil then
    Clear();
  inherited;
end;

procedure TQTXBTree.Clear;
var
  lTemp:  TList;
  x:  integer;
begin
  if FRoot  nil then
  begin
    // pack all nodes to a linear list
    lTemp := GetPackedNodes();

    try
      // release each node
      for x := 0 to ltemp.Count-1 do
      begin
        lTemp[x].Free;
      end;
    finally
      // dispose of list
      lTemp.Free;

      // reset pointers
      FCurrent := nil;
      FRoot := nil;
    end;
  end;
end;

procedure TQTXBTree.Clear(const Process: TQTXBTreeProcessCB);
begin
  ForEach(Process);
  Clear();
end;

function TQTXBTree.GetPackedNodes: TList;
var
  LData:  Tlist;
begin
  LData := TList.Create();
  ForEach( procedure (const Node: TQTXBTreeNode; var Cancel: boolean)
  begin
    LData.Add(Node);
    Cancel  := false;
  end);
  result := LData;
end;

function TQTXBTree.GetEmpty: boolean;
begin
  result := FRoot = nil;
end;

function TQTXBTree.Count: integer;
var
  LCount: integer;
begin
  ForEach( procedure (const Node: TQTXBTreeNode; var Cancel: boolean)
    begin
      inc(LCount);
      Cancel  := false;
    end);
  result := LCount;
end;

function TQTXBTree.ToDataArray: TList;
var
  Data: TList;
begin
  Data := TList.Create();

  ForEach( procedure (const Node: TQTXBTreeNode; var Cancel: boolean)
    begin
      Data.add(Node.data);
      Cancel := false;
    end);
  result := data;
end;

function TQTXBTree.Add(const Ident: string; const Data: variant): TQTXBTreeNode;
begin
  result := Add( Ident.GetHashCode(), Data);
end;

function TQTXBTree.Add(const Ident: integer; const Data: variant): TQTXBTreeNode;
var
  lNode:  TQTXBtreeNode;
begin
  LNode := TQTXBTreeNode.Create();
  LNode.Identifier := Ident;
  LNode.Data := data;

  if FRoot = nil then
    FRoot := LNode;

  FCurrent := FRoot;

  while true do
  begin
    if (Ident  FCurrent.Identifier) then
    begin
      if (FCurrent.right = nil) then
      begin
        FCurrent.right := LNode;
        break;
      end else
      FCurrent := FCurrent.right;
    end else
    break;
  end;
  result := LNode;
end;

function TQTXBTree.Read(const Ident: string): variant;
begin
  result := Read( Ident.GetHashCode() );
end;

function TQTXBTree.Read(const Ident: integer): variant;
begin
  FCurrent := FRoot;
  while FCurrent  nil do
  begin
    if (Ident  Fcurrent.Identifier) then
      FCurrent := FCurrent.Right
    else
    begin
      result := FCUrrent.Data;
      break;
    end
  end;
end;

procedure TQTXBTree.Write(const Ident: string; const NewData: variant);
begin
  Write( Ident.GetHashCode(), NewData);
end;

procedure TQTXBTree.Write(const Ident: integer; const NewData: variant);
begin
  FCurrent := FRoot;
  while (FCurrent  nil) do
  begin
    if (Ident  Fcurrent.Identifier) then
      FCurrent := FCurrent.Right
    else
    begin
      FCurrent.Data := NewData;
      break;
    end
  end;
end;

function  TQTXBTree.Contains(const Ident: string): boolean;
begin
  result := Contains( Ident.GetHashCode() );
end;

function TQTXBTree.Contains(const Ident: integer): boolean;
begin
  result := false;
  if FRoot  nil then
  begin
    FCurrent := FRoot;

    while ( (not Result) and (FCurrent  nil) ) do
    begin
      if (Ident  Fcurrent.Identifier) then
        FCurrent := FCurrent.Right
      else
      begin
        Result := true;
        break;
      end
    end;
  end;
end;

function TQTXBTree.Remove(const Ident: string): boolean;
begin
  result := Remove( Ident.GetHashCode() );
end;

function TQTXBTree.Remove(const Ident: integer): boolean;
var
  LFound: boolean;
  LParent: TQTXBTreeNode;
  LReplacement,
  LReplacementParent: TQTXBTreeNode;
  LChildCount: integer;
begin
  FCurrent := FRoot;
  LFound := false;
  LParent := nil;
  LReplacement := nil;
  LReplacementParent := nil;

  while (not LFound) and (FCurrent  nil) do
  begin
    if (Ident  FCurrent.Identifier) then
    begin
      LParent := FCurrent;
      FCurrent := FCurrent.right;
    end else
    LFound := true;

    if LFound then
    begin
      LChildCount := 0;

      if (FCurrent.left  nil) then
        inc(LChildCount);

      if (FCurrent.right  nil) then
        inc(LChildCount);

      if FCurrent = FRoot then
      begin
        case (LChildCOunt) of
        0:  begin
              FRoot := nil;
            end;
        1:  begin
              if FCurrent.right = nil then
                FRoot := FCurrent.left
              else
                FRoot :=FCurrent.Right;
            end;
        2:  begin
              LReplacement := FRoot.left;
              while (LReplacement.right  nil) do
              begin
                LReplacementParent := LReplacement;
                LReplacement := LReplacement.right;
              end;

            if (LReplacementParent  nil) then
            begin
              LReplacementParent.right := LReplacement.Left;
              LReplacement.right := FRoot.Right;
              LReplacement.left := FRoot.left;
            end else
            LReplacement.right := FRoot.right;
          end;
        end;

        FRoot := LReplacement;
      end else
      begin
        case LChildCount of
        0:  if (FCurrent.Identifier < LParent.Identifier) then
            Lparent.left  := nil else
            LParent.right := nil;
        1:  if (FCurrent.Identifier < LParent.Identifier) then
            begin
              if (FCurrent.Left = NIL) then
              LParent.left := FCurrent.Right else
              LParent.Left := FCurrent.Left;
            end else
            begin
              if (FCurrent.Left = NIL) then
              LParent.right := FCurrent.Right else
              LParent.right := FCurrent.Left;
            end;
        2:  begin
              LReplacement := FCurrent.left;
              LReplacementParent := FCurrent;

              while LReplacement.right  nil do
              begin
                LReplacementParent := LReplacement;
                LReplacement := LReplacement.right;
              end;
              LReplacementParent.right := LReplacement.left;

              LReplacement.right := FCurrent.right;
              LReplacement.left := FCurrent.left;

              if (FCurrent.Identifier < LParent.Identifier) then
                LParent.left := LReplacement
              else
                LParent.right := LReplacement;
            end;
          end;
        end;
      end;
  end;

  result := LFound;
end;

procedure TQTXBTree.ForEach(const Process: TQTXBTreeProcessCB);

  function ProcessNode(const Node: TQTXBTreeNode): boolean;
  begin
    if Node  nil then
    begin
      if Node.left  nil then
      begin
        result := ProcessNode(Node.left);
        if result then
          exit;
      end;

      Process(Node, result);
      if result then
        exit;

      if (Node.right  nil) then
      begin
        result := ProcessNode(Node.right);
        if result then
          exit;
      end;
    end;
  end;

begin
  ProcessNode(FRoot);
end;

end.

Calling node.js from Delphi

July 6, 2019 Leave a comment

We got a good question about how to start a node.js program from Delphi on our Facebook group today (third one in a week?). When you have been coding for years you often forget that things like this might not be immediately obvious. Hopefully I can shed some light on the options in this post.

Node or chrome?

nodeJust to be clear: node.js has nothing to do with chrome or chromium embedded. Chrome is a web-browser, a completely visual environment and ecosystem.

Node.js is the complete opposite. It is purely a shell based environment, meaning that it’s designed to run services and servers, with emphasis on the latter.

The only thing node.js and chrome have in common, is that they both use the V8 JavaScript runtime engine to load, JIT compile and execute scripts at high speed. Beyond that, they are utterly alien to each other.

Can node.js be embedded into a Delphi program?

Technically there is nothing stopping a C/C++ developer from compiling the node.js core system as C++ builder compatible .obj files; files that can then be linked into a Delphi application through references. But this also requires a bit of scaffolding, like adding support for malloc_, free_ and a few other procedures – so that your .obj files uses the same memory manager as your Delphi code. But until someone does just that and publish it, im afraid you are stuck with two options:

  • Use a library called Toby, that keeps node.js in a single DLL file. This is the most practical way if you insist on hosting your own version of node.js
  • Add node.js as a prerequisite and give users the option to locate the node.exe in your application’s preferences. This is the way I would go, because you really don’t want to force users to stick with your potentially outdated or buggy build.

So yes, you can use toby and just add the toby dll file to your program folder, but I have to strongly advice against that. There is no point setting yourself up for maintaining a whole separate programming language, just because you want JavaScript support.

“How many in your company can write high quality WebAssembly modules?”

If all you want to do is support JavaScript in your application, then I would much rather install Besen into Delphi. Besen is a JavaScript runtime engine written in Freepascal. It is fully compatible with Delphi, and follows the ECMA standard to the letter. So it is extremely compatible, fast and easy to use.

Like all Delphi components Besen is compiled into your application, so you have no dependencies to worry about.

Starting a node.js script

The easiest way to start a node.js script, is to simply shell-execute out of your Delphi application. This can be done as easily as:

ShellExecute(Handle, 'open', PChar('node.exe'), pchar('script.js'), nil, SW_SHOW);

This is more than enough if you just want to start a service, server or do some work that doesn’t require that you capture the result.

If you need to capture the result, the data that your node.js program emits on stdout, there is a nice component in the Jedi Component Library. Also plenty of examples online on how to do that.

If you need even further communication, you need to look for a shell-execute that support pipes. All node.js programs have something called a message-channel in the Javascript world. In reality though, this is just a named pipe that is automatically created when your script starts (with the same moniker as the PID [process identifier]).

If you opt for the latter you have a direct, full duplex message channel directly into your node.js application. You just have to agree with yourself on a protocol so that your Delphi code understands what node.js is saying, and visa versa.

UDP or TCP

If you don’t want to get your hands dirty with named pipes and rolling your own protocol, you can just use UDP to let your Delphi application communicate with your node.js process. UDP is practically without cost since its fundamental to all networking stacks, and in your case you will be shipping messages purely between processes on localhost. Meaning: packets are never sent on the network, but rather delegated between processes on the same machine.

In that case, I suggest you ship in the port you want your UDP server to listen on, so that your node.js service acts as the server. A simple command-line statement like:

node.exe myservice.js 8090

Inside node.js you can setup an UDP server with very little fuzz:


function setupServer(port) {
  var os = require("os");
  var dgram = require("dgram");
  var socket = dgram.createSocket("udp4");

  var MULTICAST_HOST = "224.0.0.236";
  var BROADCAST_HOST = "255.255.255.255";
  var ALL_PORT = 60540;
  var MULTICAST_TTL = 1; // Local network

  socket.bind(port);
  socket.on('listening', function() {
    socket.setMulticastLoopback(true);
    socket.setMulticastTTL(MULTICAST_TTL);
    socket.addMembership(multicastHost);
    if(broadcast) { socket.setBroadcast(true); }
  });
  socket.on('message', parseMessage);
}

function parseMessage(message, rinfo) {
try {
  var messageObject = JSON.parse(message);
  var eventType = messageObject.eventType;
  } catch(e) {
  }
}

Note: the code above assumes a JSON text message.

You can then use any Delphi UDP client to communicate with your node.js server, Indy is good, Synapse is a good library with less overhead – there are many options here.

Do I have to learn Javascript to use node.js?

If you download DWScript you can hook-up the JS-codegen library (see library folder in the DWScript repository), and use that to compile DWScript (object pascal) to kick-ass Javascript. This is the same compiler that was used in Smart Mobile Studio.

“Adding WebAssembly to your resume is going to be a hell of a lot more valuable in the years to come than C# or Java”

Another alternative is to use Freepascal, they have a pas2js project where you can compile ordinary object-pascal to javascript. Naturally there are a few things to keep in mind, both for DWScript and Freepascal – like avoiding pointers. But clean object pascal compiles just fine.

If JavaScript is not your cup of tea, or you simply don’t have time to learn the delicate nuances between the DOM (document object model, used by browsers) and the 100% package oriented approach deployed by node.js — then you can just straight up to webassembly.

RemObjects Software has a kick-ass webassembly compiler, perfect if you dont have the energy or time to learn JavaScript. As of writing this is the fastest and most powerful toolchain available. And I have tested them all.

WebAssembly, no Javascript needed

RO-Single-Gear-512You might remember Oxygene? It used to be shipped with Delphi as a way to target Microsoft CLR (common language runtime) and the .net framework.

Since then Oxygene and the RemObjects toolchain has evolved dramatically and is now capable of a lot more than CLR support.

  • You can compile to raw, llvm optimized machine code for 8 platforms
  • You can compile to CLR/.Net
  • You can compile to Java bytecodes
  • You can compile to WebAssembly!

WebAssembly is not Javascript, it’s important to underline that. WebAssembly was created especially for developers using traditional languages, so that traditional compilers can emit web friendly, binary code. Unlike Javascript, WebAssembly is a purely binary format. Just like Delphi generates machine-code that is linked into a final executable, WebAssembly is likewise compiled, linked and emitted in binary form.

If that sounds like a sales pitch, it’s not. It’s a matter of practicality.

  • WebAssembly is completely barren out of the box. The runtime environment, be it V8 for the browser or V8 for node.js, gives you nothing out of the box. You don’t even have WriteLn() to emit text.
  • Google expects compiler makers to provide their own RTL functions, from the fundamental to the advanced. The only thing V8 gives you, is a barebone way of referencing objects and functions on the other side, meaning the JS and DOM world. And that’s it.

So the reason i’m talking a lot about Oxygene and RemObjects Elements (Elements is the name of the compiler toolchain RemObjects offers), is because it ships with an RTL. So you are not forced to start on actual, literal assembly level.

studio

If you don’t want to study JavaScript, Oxygene and Elements from RemObjects is the solution

RemObjects also delivers a DelphiVCL compatibility framework. This is a clone of the Delphi VCL / Freepascal LCL. Since WebAssembly is still brand new, work is being done on this framework on a daily basis, with updates being issued all the time.

Note: The Delphi VCL framework is not just for WebAssembly. It represents a unified framework that can work anywhere. So if you switch from WebAssembly to say Android, you get the same result.

The most important part of the above, is actually not the visual stuff. I mean, having HTML5 visual controls is cool – but chances are you want to use a library like Sencha, SwiftUI or jQueryUI to compose your forms right? Which means you just want to interface with the widgets in the DOM to set and get values.

jQuery UI Bootstrap

You probably want to use a fancy UI library, like jQuery UI. This works perfectly with Elements because you can reference the controls from your WebAssembly module. You dont have to create TButton, TListbox etc manually

The more interesting stuff is actually the non-visual code you get access to. Hundreds of familiar classes from the VCL, painstakingly re-created, and usable from any of the 5 languages Elements supports.

You can check it out here: https://github.com/remobjects/DelphiRTL

Skipping JavaScript all together

I dont believe in single languages. Not any more. There was a time when all you needed was Delphi and a diploma and you were set to conquer the world. But those days are long gone, and a programmer needs to be flexible and have a well stocked toolbox.

At least try the alternatives before you settle on a phone

Knowing where you want to be is half the journey

The world really don’t need yet-another-c# developer. There are millions of C# developers in India alone. C# is just “so what?”. Which is also why C# jobs pays less than Delphi or node.js system service jobs.

What you want, is to learn the things others avoid. If JavaScript looks alien and you feel uneasy about the whole thing – that means you are growing as a developer. All new things are learned by venturing outside your comfort zone.

How many in your company can write high quality WebAssembly modules?

How many within one hour driving distance from your office or home are experts at WebAssembly? How many are capable of writing industrial scale, production ready system services for node.js that can scale from a single instance to 1000 instances in a large, clustered cloud environment?

Any idiot can pick up node.js and knock out a service, but with your background from Delphi or C++ builder you have a massive advantage. All those places that can throw an exception that JS devs usually ignore? As a Delphi or Oxygene developer you know better. And when you re-apply that experience under a different language, suddenly you can do stuff others cant. Which makes your skills valuable.

qtx

The Quartex Media Desktop have made even experienced node / web developers gasp. They are not used to writing custom-controls and large-scale systems, which is my advantage

So would you learn JavaScript or just skip to WebAssembly? Honestly? Learn a bit of both. You don’t have to be an expert in JavaScript to compliment WebAssembly. Just get a cheap book, like “Node.js for beginners” and “JavaScript the good parts” ($20 a piece) and that should be more than enough to cover the JS side of things.

Adding WebAssembly to your resume and having the material to prove you know your stuff, is going to be a hell of a lot more valuable in the years to come than C#, Java or Python. THAT I can guarantee you.

And, we have a wicked cool group on Facebook you can join too: Click here to visit RemObjects Developer.

 

Getting into Node.js from Delphi

July 1, 2019 Leave a comment

Delphi is one of the best development toolchains for Windows. I have been an avid fan of Delphi since it was first released, and before that – Turbo Pascal too. Delphi has a healthy following – and despite popular belief, Delphi scores quite well on the Tiobe Index.

As cool and efficient as Delphi might be, there are situations where native code wont work. Or at the very least, be less efficient than the alternatives. Delphi has a broad wingspan, from low-level assembler all the way to classes and generics. But JavaScript and emerging web technology is based on a completely different philosophy, one where native code is regarded as negative since it binds you to hardware.

Getting to grips with the whole JavaScript phenomenon, be it for mobile, embedded or back-end services, can be daunting if all you know is native code. But thankfully there are alternatives that can help you become productive quickly, something I will brush over in this post.

JavaScript without JavaScript

Before we dig into the tools of the trade, I want to cover alternative ways of enjoying the power of node.js and Javascript. Namely by using compilers that can convert code from a traditional language – and emit fully working JavaScript. There are a lot more options than you think:

qtx

Quartex Media Desktop is a complete environment written purely in JavaScript. Both Server, Cluster and front-end is pure JavaScript. A good example of what can be done.

  • Swift compiles for JavaScript, and Apple is doing some amazing things with the new and sexy SwiftUI tookit. If you know your way around Swift, you can compile for Javascript
  • Go can likewise be compiled to JS:
    • RemObjects Elements supports the Go language. Elements can target both native (llvm), .Net, Java and WebAssembly.
    • Go2Js
    • GopherJs
    • TARDISgo
  • C/C++ can be compiled to asm.js courtesy of EmScripten. It uses clang to first compile your code to llvm bitcode, and then it converts that into asm.js. You have probably seen games like Quake run in the browser? That was asm.js, a kind of precursor to WebAssembly.
  • NS Basic compiles for JavaScript, this is a Visual Basic 6 style environment with its own IDE even

For those coming straight from Delphi, there are a couple of options to pick from:

  • Freepascal (pas2js project)
  • DWScript compiles code to JavaScript, this is the same compiler that we used in Smart Pascal earlier
  • Oxygene, the next generation object-pascal from RemObjects compiles to WebAssembly. This is by far the best option of them all.
studio

I strongly urge you to have a look at Elements, here running in Visual Studio

JavaScript, Asm.js or WebAssembly?

Asm.js is by far the most misunderstood technology in the JavaScript ecosystem, so let me just cover that before we move on:

A few years back JavaScript gained support for memory buffers and typed arrays. This might not sound very exciting, but in terms of speed – the difference is tremendous. The default variable type in JavaScript is what Delphi developers know as Variant. It assumes the datatype of the values you assign to it. Needless to say, there is a lot of overhead when working with variants – so JavaScript suddenly getting proper typed arrays was a huge deal.

It was then discovered that JavaScript could manipulate these arrays and buffers at high speed, providing it only used a subset of the language. A subset that the JavaScript runtime could JIT compile more easily (turn into machine-code).

So what the EmScripten team did was to implement a bytecode based virtual-machine in Javascript, and then they compile C/C++ to bytecodes. I know, it’s a huge project, but the results speak for themselves — before WebAssembly, this was as fast as it got with JavaScript.

WebAssembly

WebAssembly is different from both vanilla JavaScript and Asm.js. First of all, it’s executed at high speed by the browser itself. Not like asm.js where these bytecodes were executed by JavaScript code.

water

Water is a fast, slick and platform independent IDE for Elements. The same IDE for OS X is called Fire. You can use RemObjects Elements from either Visual Studio or Water

Secondly, WebAssembly is completely JIT compiled by the browser or node.js when loading. It’s not like Asm.js where some parts are compiled, others are interpreted. WebAssembly runs at full speed and have nothing to do with traditional JavaScript. It’s actually a completely separate engine.

Out of all the options on the table, WebAssembly is the technology with the best performance.

Kits and strategies

The first thing you need to be clear about, is what you want to work with. The needs and requirements of a game developer will be very different from a system service developer.

Here are a couple of kits to think about:

  • Mobile developer
    • Implement your mobile applications using Oxygene, compiling for WebAssembly (Elements)
    • RemObjects Remoting SDK for client / server communication
    • Use Freepascal for vanilla JavaScript scaffolding when needed
  • Service developer
    • Implement libraries in Oxygene to benefit from the speed of WebAssembly
    • Use RemObjects Data Abstract to make data-access uniform and fast
    • Use Freepascal for boilerplate node.js logic
  • Desktop developer
    • For platform independent desktop applications, WebAssembly is the way to go. You will need some scaffolding (plain Javascript) to communicate with the application host  – but the 99.9% of your code will be better under WebAssembly.
    • Use Cordova / Phonegap to “bundle” your WebAssembly, HTML5 files and CSS styling into a single, final executable.

The most important part to think about when getting into JavaScript, is to look closely at the benefits and limitation of each technology.

WebAssembly is fast, wicked fast, and let’s you write code like you are used to from Delphi. Things like pointers etc are supported in Elements, which means ordinary code that use pointers will port over with ease. You are also not bound on hand-and-feet to a particular framework.

For example, EmScripten for C/C++ have almost nothing in terms of UI functionality. The visual part is a custom build of SDL (simple directmedia layer), which fakes the graphics onto an ordinary HTML5 canvas. This makes EmScripten a good candidate for porting games written in C/C++ to the web — but it’s less than optimal for writing serious applications.

Setting up the common tools

So far we have looked at a couple of alternatives for getting into the wonderful world of JavaScript in lieu of other languages. But what if you just want to get started with the typical tools JS developers use?

vscode

Visual Studio Code is a pretty amazing code-editor

The first “must have” is Visual Studio Code. This is actually a great example of what you can achieve with JavaScript, because the entire editor and program is written in JavaScript. But I want to stress that this editor is THE editor to get. The way you work with files in JS is very different from Delphi, C# and Java. JavaScript projects are often more fragmented, with less code in each file – organized by name.

typescript

TypeScript was invented by Anders Hejlsberg, who also made Delphi and C#

The next “must have” is without a doubt TypeScript. Personally im not too fond of TypeScript, but if ordinary JavaScript makes your head hurt and you want classes and ordinary inheritance, then TypeScript is a step up.

assemblyscriptNext on the list is AssemblyScript. This is a post-processor for TypeScript that converts your code into WebAssembly. It lacks much of the charm and elegance of Oxygene, but I suspect that has to do with old habits. When you have been reading object-pascal for 20 years, you feel more at home there.

nodeYou will also need to install node.js, which is the runtime engine for running JavaScript as services. Node.js is heavily optimized for writing server software, but it’s actually a brilliant way to write services that are multi-platform. Because Node.js delivers the same behavior regardless of underlying operating system.

phonegapAnd finally, since you definitely want to convert your JavaScript and/or WebAssembly into a stand-alone executable: you will need Adobe Phonegap.

Visual Studio

No matter if you want to enter JavaScript via Elements or something else, Visual Studio will save you a lot of time, especially if you plan on targeting Azure or Amazon services. Downloading and installing the community edition is a good idea, and you can use that while exploring your options.

dotnet-visual-studio

When it comes to writing system services, you also want to check out NPM, the node.js package manager. The JavaScript ecosystem is heavily package oriented – and npm gives you some 800.000 packages to play with free of charge.

Just to be clear, npm is a shell command you use to install or remove packages. NPM is also a online repository of said packages, where you can search and find what you need. Most packages are hosted on github, but when you install a package locally into your application folder – npm figures out dependencies etc. automatically for you.

Books, glorious books

41QSvp9fTcL._SX331_BO1,204,203,200_Last but not least, get some good books. Seriously, it will save you so much time and frustration. Amazon have tons of great books, be it vanilla JavaScript, TypeScript, Node.js — pick some good ones and take the time to consume the material.

And again, I strongly urge you to have a look at Elements when it comes to WebAssembly. WebAssembly is a harsh and barren canvas, and being able to use the Elements RTL is a huge boost.

But regardless of path you pick, you will always benefit from learning vanilla JavaScript.

 

Two new groups in the Developer family

July 1, 2019 2 comments

Delphi Developer is a group on Facebook that have been going strong for 12+ years. It was one of the first groups on Facebook, created the same week that Facebook allowed groups. With that group well established, it’s time to expand and clean up the feed.

RO-Single-Gear-512Last month I introduced a new group, RemObjects Developer, which is a group for developers that use RemObjects components, like the Remoting SDK, Data Abstract and/or Hydra – but more in particular, developers using Oxygene, C#, Swift, Java or Go via Elements (RemObjects compiler toolchain).

Two new groups

To further simplify syndication, and clean up the feeds (which so far has been a pot-purrey of many topics, dialects and products) an additional two groups is now in place:

Obviously there will be some overlapping. Since FPC and Delphi has much in common and are for the most part compatible, some news will be shared between those groups. But all in all this is to clean up the newsfeed which has so far been a mix and match of everything.

org

Simple overview of the groups

Node.js Developer is not meant to be purely about vanilla JavaScript. Node.js is ultimately a JavaScript runtime-engine. Which means you can use it to run or host WebAssembly libraries (as produced by Oxygene), or generate code via DWScript or Freepascal. You can think of it as a service-host if you like.

So if you are writing WebAssembly applications using Elements, then the node.js group will no doubt be interesting too. Same goes for DWScript users, Smart Pascal users and Freepascal users – providing web tech is what they like.

What is this Quartex Components?

It’s easier to manage multiple groups if you attach them to a parent-page. So if you wonder why all the groups says “by Quartex Components”, that is just a top-level page that helps me deal with with syndication. For some reason Facebook’s API only works for pages, not groups. So it’s impossible to auto-import news (for example) without a page.

The name, “Quartex Components” is ultimately the name of my personal company. I used to produce security components for Delphi, but decided to open-source those for the community.

So Quartex Components is just an organizational element.