Pascal (Lazarus/Delphi)

Schwab OAuth2 in a Desktop App

See more Schwab Examples

Demonstrates how to get a Charles Schwab OAuth2 access token from a desktop application or script. Pascal (Lazarus/Delphi)

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.OAuth2,
  Chilkat.StringBuilder;

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

procedure RunDemo;
var
  success: Boolean;
  oauth2: TOAuth2;
  url: string;
  numMsWaited: Integer;
  sbJson: TStringBuilder;

begin
  success := False;

  //  To further clarify, see OAuth 2.0 Authorization Flow

  //  This is the way to initially obtain the OAuth2 access token.  Afterwards it can be 
  //  repeatedly refreshed without user interaction, as shown in this example: Refresh Schwab OAuth2 Access Token.

  oauth2 := TOAuth2.Create;

  //  Your applicaton must use your own public web server as an intermediate
  //  to receive and forward the redirect to localhost.
  //  See Using Your Web Server as an Intermediary for OAuth2 Redirect to localhost

  oauth2.AppCallbackUrl := 'https://yourwebserver.com/OAuth2.php';
  oauth2.ListenPort := 3017;

  oauth2.AuthorizationEndpoint := 'https://api.schwabapi.com/v1/oauth/authorize';
  oauth2.TokenEndpoint := 'https://api.schwabapi.com/v1/oauth/token';

  //  Replace these with actual values.
  oauth2.ClientId := 'APP_KEY';
  oauth2.ClientSecret := 'APP_SECRET';
  oauth2.UseBasicAuth := True;
  oauth2.CodeChallenge := False;

  oauth2.Scope := '';

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

  WriteLn('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 = False) then
    begin
      WriteLn(oauth2.LastErrorText);
      Exit;
    end;

  //  Wait for the user to approve or deny authorization in the browser.
  numMsWaited := 0;
  while (numMsWaited < 90000) 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();
      WriteLn('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
      WriteLn('OAuth2 failed to complete.');
      WriteLn(oauth2.FailureInfo);
      Exit;
    end;

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

  if (oauth2.AuthFlowState <> 3) then
    begin
      WriteLn('Unexpected AuthFlowState:' + oauth2.AuthFlowState);
      Exit;
    end;

  //  Save the full JSON access token response to a file.
  sbJson := TStringBuilder.Create;
  sbJson.Append(oauth2.AccessTokenResponse);
  sbJson.WriteFile('qa_data/tokens/schwab-access-token.json','utf-8',False);

  //  The full JSON received looks like this:
  //  {
  //    "expires_in": 3600,
  //    "x_refresh_token_expires_in": 8726400,
  //    "refresh_token": "L011546037639r ... 3vR2DrbOmg0Sdagw",
  //    "access_token": "eyJlbmMiOiJBMTI4Q0 ... oETJEMbeggg",
  //    "token_type": "bearer"
  //  }

  WriteLn('OAuth2 authorization granted!');
  WriteLn('Access Token = ' + oauth2.AccessToken);


  oauth2.Free;
  sbJson.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.