Stream a REST Response Body to a Destination

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Demonstrates Rest.SetResponseBodyStream, which configures a Stream destination for response bodies received by the full-request convenience methods. The body is written to the stream only when the response status code matches the expected status.

The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

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.Stream,
  Chilkat.Rest;

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

procedure RunDemo;
var
  success: Boolean;
  rest: TRest;
  bTls: Boolean;
  bAutoReconnect: Boolean;
  respStream: TStream;
  bAutoSetCharset: Boolean;
  expectedStatus: Integer;
  responseText: string;

begin
  success := False;

  rest := TRest.Create;
  bTls := True;
  bAutoReconnect := True;
  success := rest.Connect('example.com',443,bTls,bAutoReconnect);
  if (success = False) then
    begin
      WriteLn(rest.LastErrorText);
      Exit;
    end;
  //  The file paths are relative to the application's current working directory.  Absolute paths
  //  may also be used.  Supply the paths appropriate to your own environment.

  //  Configure a Stream destination for response bodies received by the full-request convenience
  //  methods.  The body is written to the stream only when the response status code matches the 1st
  //  argument.
  respStream := TStream.Create;
  respStream.SinkFile := 'qa_output/response_body.dat';

  //  The 2nd argument sets the stream character set from the response Content-Type charset for textual
  //  responses.  The 3rd argument is the destination Stream.
  bAutoSetCharset := True;
  expectedStatus := 200;
  success := rest.SetResponseBodyStream(expectedStatus,bAutoSetCharset,respStream);
  if (success = False) then
    begin
      WriteLn(rest.LastErrorText);
      Exit;
    end;

  //  The full-request call now streams the response body to the sink instead of returning it.
  responseText := rest.FullRequestNoBody('GET','/api/largefile');
  if (rest.LastMethodSuccess = False) then
    begin
      WriteLn(rest.LastErrorText);
      Exit;
    end;
  WriteLn('Response streamed to file.  Status: ' + rest.ResponseStatusCode);


  rest.Free;
  respStream.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.