ArchiveReader and Streams

Comments

• nicocizik

  December 2022

  Hi Adam,
  
  The issue is that your merged archive data is held in the MS1 stream, yet you never assign it to the ArchiveReader after the loop.
  
  Your code above merges multiple archives to a single archive, then exports that to PDF. You could skip the first step and merge the multiple archives (from your DB) directly to PDF.

  begin
  
    lArchiveReader := TppArchiveReader.Create(nil);
    lPDFDevice := TppPDFDevice.Create(nil);
  
    try
  
    lPDFDevice.FileName := 'c:\temp\merged.pdf';
    lPDFDevice.PDFSettings.Title := 'Title';
    lPDFDevice.OpenFile := False;
  
    lPDFDevice.Publisher := lArchiveReader.Publisher;
  
    if not(Table.isempty) then
      begin
  
        while not(Table.eof) do
          begin
            MS2 := TMemoryStream.create;
            try
              TableReportData.SaveToStream(MS2);
              MS2.position := 0;
              lPDFDevice.StartPrintJob := Table.Bof;
              lPDFDevice.EndPrintJob := (Table.RecNo = Table.RecordCount);
              lArchiveReader.ArchiveStream := MS2;
              lArchiveReader.PrintToDevices;
              Table.next;
            finally
              MS2.free;
            end;
          end;
      end;
  
    finally
      lPDFDevice.Free;
      lArchiveReader.Free;
    end;
  
  end;

  Best Regards,
  
  Nico Cizik
  Digital Metaphors
  http://www.digital-metaphors.com
• adam

  December 2022

  Wonderful - thanks Nico!
  
  And thanks for all your help this year too!
• adam

  December 2022

  Hi Nard,
  
  Just a quick question. Instead of using
  
  lPDFDevice.FileName := 'c:\temp\merged.pdf';
  
  I was hoping to save the end result to MS1. (TMemoryStream). Just wondering if this is possible, or whether I have to offload it to a file, and then re-import it?
  
  Thanks & Regards
  
  Adam.
• nicocizik

  January 2023

  Hi Adam,
  
  Rather than assigning the FileName of the PDFDevice, simply set its OutputStream property to the memory stream you would like to write to (MS1).

  begin
  
    MS1 := TMemoryStream.Create;
    lArchiveReader := TppArchiveReader.Create(nil);
    lPDFDevice := TppPDFDevice.Create(nil);
  
    try
  
    lPDFDevice.OutputStream := MS1;
  
  ...

  Best Regards,
  
  Nico Cizik
  Digital Metaphors
  http://www.digital-metaphors.com
• adam

  January 2023

  Thanks Nico. Got it all working well now! Appreciate the help.
• adam

  January 2023 edited January 2023

  For anyone else who may come across this in the future, I ran into some issues with this still not working, and had to add the line:
  
  lDevice.reset
  
  after each itteration of PrintToDevices.
  
  
  The end result is the following functions/procedures which I leave here in case it may come in handy for anyone else looking to do anything similar in the future. (Or incase I forget and find my own question 10 years from now... it's happened before ;-)
  

  function CombineReports(const ReportList: TList<TMemoryStream>): TMemoryStream;
  var
    lArchiveReader: TppArchiveReader;
    lDevice: TppArchiveDevice;
    i: Integer;
  begin
    Result := TMemoryStream.Create;
    lArchiveReader := TppArchiveReader.Create(nil);
    try
      lDevice := TppArchiveDevice.Create(nil);
      try
        lDevice.Publisher := lArchiveReader.Publisher;
        lDevice.OutputStream := Result;
  
        for i := 0 to ReportList.Count - 1 do
        begin
          lDevice.StartPrintJob := (i = 0);
          lDevice.EndPrintJob := (i = ReportList.Count - 1);
          lArchiveReader.ArchiveStream := ReportList[i];
          lArchiveReader.PrintToDevices;
          lDevice.reset;
        end;
      finally
        lDevice.Free;
      end;
    finally
      lArchiveReader.Free;
    end;
  end;
  
  
  procedure RenderRBArchivesToStream(ML: TList<TMemoryStream>; var MS: TMemoryStream; DeviceType: string = dtPDF);
  var
    ms1: TMemoryStream;
    LDevice: TppArchiveDevice;
    LPDFDevice: TppPDFDevice;
    lArchiveReader: TppArchiveReader;
  begin
    if ML = nil then
      exit;
  
    try
      MS1 := CombineReports(ML);
  
  
      if MS1 <> nil then
      begin
        if DeviceType = dtArchive then
          MS.LoadFromStream(MS1)
        else
        begin
          lArchiveReader := TppArchiveReader.Create(nil);
          lPDFDevice := TppPDFDevice.Create(nil);
          LPDFDevice.Publisher := lArchiveReader.Publisher;
          LPDFDevice.outputstream := MS;
          LPDFDevice.StartPrintJob := true;
          LPDFDevice.EndPrintJob := true;
          lArchiveReader.ArchiveStream := ms1;
          lArchiveReader.PrintToDevices;
  
          LPDFDevice.Free;
          lArchiveReader.Free;
        end;
  
        FreeAndNil(MS1);
      end;
  
    except
      try
        LDevice.Free;
        lArchiveReader.Free;
      finally
  
      end;
      raise;
    end;
  
  end;
  
  
  procedure PrintToStream(Report: TPPReport; var MS: TMemoryStream);
  var
    LDevice: TppArchiveDevice;
  begin
    ms := TMemoryStream.create;
    lDevice := TppArchiveDevice.Create(nil);
    if not assigned(MS) then
      ms := TMemoryStream.create
    else
      ms.clear;
  
    try
      lDevice.OutputStream := MS; // assign output stream
      lDevice.Publisher := Report.Publisher;
      Report.PrintToDevices;
      ldevice.free;
    except
      ldevice.free;
      raise;
    end;
    MS.Position := 0;
  end;