Android Datasnap Send Image

Question

I have an Android App , where I save the image and convert it to PNG .

  Stream := TMemoryStream.Create;
  try
    Stream.Position:=0;
    Surf := TBitmapSurface.Create;
    try

      Surf.Assign(imgObject.Bitmap);

      // convert BMP to PNG
      TBitmapCodecManager.SaveToStream(Stream,Surf,'.png');

    finally
      Surf.Free;
    end;

    // here do the save to file which we later upload
    FileDate:=FormatDateTime('yyyymmddhhnnsszzz',now);

    IniWrite(Main.FilePath+'/temp.BatchData','DATA','LocationID',ID);
    IniWrite(Main.FilePath+'/temp.BatchData','DATA','BatchNumber',edtBatch.Text);
    IniWrite(Main.FilePath+'/temp.BatchData','DATA','Type','BatchTrack');

    // write the image
    Stream.SaveToFile(Main.FilePath+'/'+FileDate+'.img');

    RenameFile(Main.FilePath+'/temp.BatchData',Main.FilePath+'/'+FileDate+'.out');
  finally
    Stream.Free;
  end;

Since I had to make sure the Image is saved correctly I created a test procedure for it :

procedure TMain.Button1Click(Sender: TObject);
var tmpFiles : TStringDynArray;
    Files : TStringDynArray;

    ImageFile : string;
    Image : TMemoryStream;

    surf : TBitmapSurface;
    Bitmap : TBitmap;
begin

   Files := TDirectory.GetFiles(FilePath+'/','*.out');

  ImageFile := ChangeFileExt(Files[0],'.img');

  Image := TMemoryStream.Create;

  Image.LoadFromFile(ImageFile);

  Image.Position:=0;

  surf := TBitmapSurface.Create;

  TBitmapCodecManager.LoadFromStream(Image,surf);

  Image1.Bitmap.Assign(surf);

end;

The Image loads correctly on the Android device.

I have following function to upload data via DataSnap :

LocationID := inireadInt(Files[0],'DATA','LocationID');
BatchName := inireadStr(Files[0],'DATA','BatchNumber');

ImageFile := ChangeFileExt(Files[0],'.img');

Image := TMemoryStream.Create;
Image.LoadFromFile(ImageFile);
Image.Position:=0;

if FileType = 'BatchTrack' then
begin
  if Temp.BATCH_TRACK(LocationID,BatchName,Image) = 1 then
  begin
    System.SysUtils.DeleteFile(Files[0]);
  end;
end;

The BATCH_TRACK function itself on the client looks like this :

function TServerMethods1Client.BATCH_TRACK(HeadID: integer; BatchNumber: string;
  Image: TMemoryStream): integer;
begin

  if FBATCH_TRACKCommand = nil then
  begin
    FBATCH_TRACKCommand := FDBXConnection.CreateCommand;
    FBATCH_TRACKCommand.CommandType := TDBXCommandTypes.DSServerMethod;
    FBATCH_TRACKCommand.Text := 'TServerMethods1.BATCH_TRACK';
    FBATCH_TRACKCommand.Prepare;
  end;

  FBATCH_TRACKCommand.Parameters[0].Value.SetInt32(HeadID);
  FBATCH_TRACKCommand.Parameters[1].Value.SetWideString(BatchNumber);
  FBATCH_TRACKCommand.Parameters[2].Value.SetStream(Image,FInstanceOwner);

  FBATCH_TRACKCommand.ExecuteUpdate;

  Result := FBATCH_TRACKCommand.Parameters[3].Value.GetInt32;
end;

on the Server itself I now have a empty function :

function TServerMethods1.BATCH_TRACK(HeadID : integer; Batchnumber : string; Image : TMemoryStream) : integer;
var MS : TMemoryStream;
begin

  try
 
    MS := TMemoryStream.Create;
    MS.LoadFromStream(Image);
    MS.Position:=0;
    
    Result := 1;
  except
    Result := -1;
  end;
    
end;

I get a Invalid Typecast error when debugging the client .

Please help.

UPDATE 1

I have changed both Server and Client from TMemoryStream to TStream. This works but only for very small files.

If I try to send an image for example 75Kbyte . I get a Unable to Expand Memory Stream due to lack of memory .