(Delphi ActiveX) X.com OAuth 2.0 Authorization Code with PKCE

See more X Examples

Note: This example requires Chilkat v10.1.2 or greater.

For more information, see https://docs.x.com/resources/fundamentals/authentication/oauth-2-0/authorization-code

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
oauth2: TChilkatOAuth2;
url: WideString;
success: Integer;
numMsWaited: Integer;
json: TChilkatJsonObject;
dtExpire: TCkDateTime;

begin
// For more information about the OAuth2, see OAuth 2.0 Authorization Flow

oauth2 := TChilkatOAuth2.Create(Self);

// The port should match the Authorized Redirect URL in your X.com app, 
// which would look like "http://127.0.0.1:3017/"
// See the screenshot below of the App Settings in the X Developer Portal
oauth2.LocalHost := '127.0.0.1';
oauth2.ListenPort := 3017;

oauth2.AuthorizationEndpoint := 'https://x.com/i/oauth2/authorize';
oauth2.TokenEndpoint := 'https://api.x.com/2/oauth2/token';

// Replace this with your actual X.com OAuth2 Client ID and Client Secret
oauth2.ClientId := 'OAUTH2_CLIENT_ID';
oauth2.ClientSecret := 'OAUTH2_CLIENT_SECRET';

// This is for Require Proof Key for Code Exchange (PKCE)
// See OAuth2 PKCE Explained
oauth2.CodeChallenge := 1;
oauth2.CodeChallengeMethod := 'S256';

// Space separated scopes...
oauth2.Scope := 'tweet.read tweet.write users.read follows.read follows.write offline.access like.read like.write block.read block.write';

// Begin the OAuth2 Authorization code flow.  This returns a URL that should be loaded in a browser.
url := oauth2.StartAuth();
if (oauth2.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(oauth2.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('url = ' + url);

// Launch the default browser on the system and navigate to the url.
// The LaunchBrowser method was added in Chilkat v10.1.2.
success := oauth2.LaunchBrowser(url);
if (success = 0) then
  begin
    Memo1.Lines.Add(oauth2.LastErrorText);
    Exit;
  end;

// Wait for the user to approve or deny authorization in the browser.
numMsWaited := 0;
while (numMsWaited < 10000) and (oauth2.AuthFlowState < 3) do
  begin
    oauth2.SleepMs(100);
    numMsWaited := numMsWaited + 100;
  end;

// If the browser does not respond within the specified time, AuthFlowState will be:
// 
// 1: Waiting for Redirect - The OAuth2 background thread is waiting for the browser's redirect request.
// 2: Waiting for Final Response - The thread is awaiting the final access token response.
// In either case, cancel the background task initiated by StartAuth.

if (oauth2.AuthFlowState < 3) then
  begin
    oauth2.Cancel();
    Memo1.Lines.Add('No response from the browser!');
    Exit;
  end;

// Check AuthFlowState to determine if authorization was granted, denied, or failed:
// 
// 3: Success - OAuth2 flow completed, the background thread exited, and the successful response is in AccessTokenResponse.
// 4: Access Denied - OAuth2 flow completed, the background thread exited, and the error response is in AccessTokenResponse.
// 5: Failure - OAuth2 flow failed before completion, the background thread exited, and error details are in FailureInfo.

if (oauth2.AuthFlowState = 5) then
  begin
    Memo1.Lines.Add('OAuth2 failed to complete.');
    Memo1.Lines.Add(oauth2.FailureInfo);
    Exit;
  end;

if (oauth2.AuthFlowState = 4) then
  begin
    Memo1.Lines.Add('OAuth2 authorization was denied.');
    Memo1.Lines.Add(oauth2.AccessTokenResponse);
    Exit;
  end;

if (oauth2.AuthFlowState <> 3) then
  begin
    Memo1.Lines.Add('Unexpected AuthFlowState:' + IntToStr(oauth2.AuthFlowState));
    Exit;
  end;

Memo1.Lines.Add('OAuth2 authorization granted!');

json := TChilkatJsonObject.Create(Self);
json.Load(oauth2.AccessTokenResponse);
json.EmitCompact := 0;

// If an "expires_on" member does not exist, then add the JSON member by
// getting the current system date/time and adding the "expires_in" seconds.
// This way we'll know when the token expires.
if (json.HasMember('expires_on') = 0) then
  begin
    dtExpire := TCkDateTime.Create(Self);
    dtExpire.SetFromCurrentSystemTime();
    dtExpire.AddSeconds(json.IntOf('expires_in'));
    json.AppendString('expires_on',dtExpire.GetAsUnixTimeStr(0));
  end;

Memo1.Lines.Add('Access Token Response = ' + json.Emit());

// A sample access token response:

// {
//   "token_type": "bearer",
//   "expires_in": 7200,
//   "access_token": "VmNDLVZiYUZwejY5Mkx3RblFTmo3ek1leTRGclMuZFVOUTVUTWpNbVZKb1N5OjE3NDAxNjk4MDVxNTE6MToxOaF0OjE",
//   "scope": "block.read follows.read offline.access tweet.write block.write like.write like.read users.read tweet.read follows.write",
//   "refresh_token": "eThOWVVFSTRqdVp3QTFndGsxM2ZGZmFyNWVrU0phM1JKbGdrbGNWRGJzb1loOjE3NDAwMjk4MDUxNTI6MTowOnJ0OjE"
// }

Memo1.Lines.Add('Access Token = ' + oauth2.AccessToken);

// Save the JSON access token response to a file for subsequent use..
json.WriteFile('qa_data/tokens/x.json');

// 
end;