Pascal (Lazarus/Delphi)

HTTP Download to Stream

See more REST Examples

Demonstrates how to stream the response body directly to a stream, which in this case is to a file stream. Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Rest,
  Chilkat.Url,
  Chilkat.Stream;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  rest: TRest;
  url: TUrl;
  bAutoReconnect: Boolean;
  responseStatusCode: Integer;
  bodyStream: TStream;
  errResponse: string;

begin
  success := False;

  //  This example requires the Chilkat API to have been previously unlocked.
  //  See Global Unlock Sample for sample code.

  rest := TRest.Create;

  //  The URL we want to download is: 
  //  https://github.com/chilkatsoft/OAuth2-CSharp-Desktop/archive/master.zip
  url := TUrl.Create;
  url.ParseUrl('https://github.com/chilkatsoft/OAuth2-CSharp-Desktop/archive/master.zip');

  //  Connect to the web server
  bAutoReconnect := True;
  success := rest.Connect(url.Host,url.Port,url.Ssl,bAutoReconnect);
  if (success <> True) then
    begin
      WriteLn(rest.LastErrorText);
      Exit;
    end;

  success := rest.SendReqNoBody('GET',url.Path);
  if (success <> True) then
    begin
      WriteLn(rest.LastErrorText);
      Exit;
    end;

  //  Read the response header.
  responseStatusCode := rest.ReadResponseHeader();
  if (responseStatusCode < 0) then
    begin
      WriteLn(rest.LastErrorText);
      Exit;
    end;

  WriteLn('Response status code = ' + responseStatusCode);

  //  We expect a 200 response status if the file data is coming.
  //  Otherwise, we'll get a string response body with an error message(or no response body).
  if (responseStatusCode = 200) then
    begin

      bodyStream := TStream.Create;

      //  The stream's sink will be a file.
      bodyStream.SinkFile := 'qa_output/OAuth2-CSharp-Desktop/archive/master.zip';

      //  Read the response body to the stream.  Given that we've
      //  set the stream's sink to a file, it will stream directly
      //  to the file.
      success := rest.ReadRespBodyStream(bodyStream,True);
      if (success <> True) then
        begin
          WriteLn(rest.LastErrorText);
          Exit;
        end;

      WriteLn('Successfully downloaded the file.');

    end
  else
    begin
      errResponse := rest.ReadRespBodyString();
      if (rest.LastMethodSuccess <> True) then
        begin
          WriteLn(rest.LastErrorText);
        end
      else
        begin
          WriteLn(errResponse);
        end;
    end;


  rest.Free;
  url.Free;
      bodyStream.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.