(Delphi ActiveX) Twitter - Application Only Authentication

Demonstrates how to get a Twitter OAuth2 token for application-only authentication.

This example is deprecated and no longer valid.

Note: This example requires Chilkat v11.0.0 or greater.

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

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Integer;
consumerKey: WideString;
consumerSecret: WideString;
http: TChilkatHttp;
req: TChilkatHttpRequest;
resp: TChilkatHttpResponse;
json: TChilkatJsonObject;

begin
success := 0;

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

// Note: Define your Twitter apps at https://apps.twitter.com/

// We're going to send an HTTPS POST that looks like this:

// POST /oauth2/token HTTP/1.1
// Host: api.twitter.com
// User-Agent: My Twitter App v1.0.23
// Authorization: Basic eHZ6MWV2RlM0d0VFUFRHRUZQSEJvZzpMOHFxOVBaeVJn
//                      NmllS0dFS2hab2xHQzB2SldMdzhpRUo4OERSZHlPZw==
// Content-Type: application/x-www-form-urlencoded;charset=UTF-8
// Content-Length: 29
// Accept-Encoding: gzip
// 
// grant_type=client_credentials

// Update these values with your consumer key and secret (also known as API key and API secret).
consumerKey := 'TWITTER_CONSUMER_KEY';
consumerSecret := 'TWITTER_CONSUMER_SECRET';

http := TChilkatHttp.Create(Self);

http.BasicAuth := 1;
http.Login := consumerKey;
http.Password := consumerSecret;

req := TChilkatHttpRequest.Create(Self);
req.AddParam('grant_type','client_credentials');

req.HttpVerb := 'POST';
req.ContentType := 'application/x-www-form-urlencoded';

resp := TChilkatHttpResponse.Create(Self);
success := http.HttpReq('https://api.twitter.com/oauth2/token',req.ControlInterface,resp.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('Response Status Code: ' + IntToStr(resp.StatusCode));

if (resp.StatusCode <> 200) then
  begin
    Memo1.Lines.Add('Expected a 200 response status code for success.');
    Memo1.Lines.Add(resp.BodyStr);
    Exit;
  end;

// We should get a JSON response like this:

// {
//     "token_type":"bearer",
//     "access_token":"..."
// }

json := TChilkatJsonObject.Create(Self);
json.Load(resp.BodyStr);

Memo1.Lines.Add('Access token = ' + json.StringOf('access_token'));
end;