Lazarus Pascal

Example: Http.DownloadAppend method

Demonstrates the DownloadAppend method. Lazarus Pascal

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.Http,
  Chilkat.StringBuilder,
  Chilkat.FileAccess;

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

procedure RunDemo;
var
  success: Boolean;
  targetPath: string;
  http: THttp;
  statusCode: Integer;
  sb: TStringBuilder;
  fac: TFileAccess;

begin
  success := False;

  targetPath := 'c:/temp/qa_output/download.txt';

  http := THttp.Create;
  http.KeepResponseBody := True;

  //  Assume the target file in the local filesystem does not yet exist.
  success := http.DownloadAppend('https://chilkatsoft.com/testData/helloWorld.txt',targetPath);
  statusCode := http.LastStatus;
  if (statusCode = 0) then
    begin
      //  Unable to either send the request or get the response.
      WriteLn(http.LastErrorText);
      Exit;
    end;

  //  Should be 200.
  WriteLn('Response status code: ' + statusCode);

  //  Examine the contents of the file.
  sb := TStringBuilder.Create;
  sb.LoadFile(targetPath,'utf-8');
  WriteLn(sb.GetAsString());

  //  Output: 
  //  Response status code: 200
  //  Hello World!

  //  Download another text file and append to the target file.
  success := http.DownloadAppend('https://chilkatsoft.com/testData/this_is_a_test.txt',targetPath);
  statusCode := http.LastStatus;
  if (statusCode = 0) then
    begin
      //  Unable to either send the request or get the response.
      WriteLn(http.LastErrorText);
      Exit;
    end;

  //  Should be 200.
  WriteLn('Response status code: ' + statusCode);

  //  Examine the contents of the file.
  sb.LoadFile(targetPath,'utf-8');
  WriteLn(sb.GetAsString());

  //  Output:
  //  Response status code: 200
  //  Hello World!This is a Test.

  //  Delete the local target file.
  fac := TFileAccess.Create;
  fac.FileDelete(targetPath);

  //  Try to download a file that does not exist:
  success := http.DownloadAppend('https://chilkatsoft.com/testData/does_not_exist.txt',targetPath);
  statusCode := http.LastStatus;
  if (statusCode = 0) then
    begin
      //  Unable to either send the request or get the response.
      WriteLn(http.LastErrorText);
    end
  else
    begin
      //  We got a response, and we already know it wasn't a 200 success response.
      //  It should be a 404 not found.
      WriteLn('Response status code: ' + statusCode);
      //  Examine the response body.
      WriteLn('Response body:');
      WriteLn(http.LastResponseBody);
    end;


  http.Free;
  sb.Free;
  fac.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.