(Delphi DLL) HTTP Download to Stream

Demonstrates how to stream the response body directly to a stream, which in this case is to a file stream.

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Rest, Url, Stream;

...

procedure TForm1.Button1Click(Sender: TObject);
var
rest: HCkRest;
url: HCkUrl;
bAutoReconnect: Boolean;
success: Boolean;
responseStatusCode: Integer;
bodyStream: HCkStream;
errResponse: PWideChar;

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

rest := CkRest_Create();

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

// Connect to the web server
bAutoReconnect := True;
success := CkRest_Connect(rest,CkUrl__host(url),CkUrl_getPort(url),CkUrl_getSsl(url),bAutoReconnect);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

success := CkRest_SendReqNoBody(rest,'GET',CkUrl__path(url));
if (success <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

// Read the response header.
responseStatusCode := CkRest_ReadResponseHeader(rest);
if (responseStatusCode < 0) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

Memo1.Lines.Add('Response status code = ' + IntToStr(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 := CkStream_Create();

    // The stream's sink will be a file.
    CkStream_putSinkFile(bodyStream,'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 := CkRest_ReadRespBodyStream(rest,bodyStream,True);
    if (success <> True) then
      begin
        Memo1.Lines.Add(CkRest__lastErrorText(rest));
        Exit;
      end;

    Memo1.Lines.Add('Successfully downloaded the file.');

  end
else
  begin
    errResponse := CkRest__readRespBodyString(rest);
    if (CkRest_getLastMethodSuccess(rest) <> True) then
      begin
        Memo1.Lines.Add(CkRest__lastErrorText(rest));
      end
    else
      begin
        Memo1.Lines.Add(errResponse);
      end;
  end;

CkRest_Dispose(rest);
CkUrl_Dispose(url);
    CkStream_Dispose(bodyStream);

end;