Dart Requires Chilkat v10.1.2+

Google OAuth2 Access Token

See more OAuth2 Examples

Demonstrates how to get a Google OAuth2 access token from a desktop application or script. Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // To further clarify, see OAuth 2.0 Authorization Flow

  final oauth2 = CkOAuth2();

  // For Google OAuth2, set the listen port equal to the port used
  // in the Authorized Redirect URL for the Client ID.
  // For example, in this case the Authorized Redirect URL would be http://localhost:55568/
  // Your app should choose a port not likely not used by another application.
  oauth2.listenPort = 55568;

  oauth2.authorizationEndpoint = 'https://accounts.google.com/o/oauth2/v2/auth';
  oauth2.tokenEndpoint = 'https://www.googleapis.com/oauth2/v4/token';

  // Replace this with your actual client ID.
  oauth2.clientId = 'GOOGLE-CLIENT-ID';

  // This is the scope for Google Drive.
  // See https://developers.google.com/identity/protocols/googlescopes
  // Add the scopes that you need.
  oauth2.scope = 'https://www.googleapis.com/auth/drive';

  // Begin the OAuth2 authorization code flow.  This returns a URL that should be loaded in a browser.
  final String url;
  try {
    url = oauth2.startAuth();
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Launch the default browser on the system and navigate to the url.
  // The LaunchBrowser method was added in Chilkat v10.1.2.
  try {
    oauth2.launchBrowser(url);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Wait for the interactive user to grant permission in the interactive browser session.
  // We'll wait for a max of 90 seconds.
  var numMsWaited = 0;
  while ((numMsWaited < 90000) && (oauth2.authFlowState < 3)) {
    oauth2.sleepMs(100);
    numMsWaited += 100;
  }

  // If there was no response from the browser within 90 seconds, then 
  // the AuthFlowState will be equal to 1 or 2.
  // 1: Waiting for Redirect. The OAuth2 background thread is waiting to receive the redirect HTTP request from the browser.
  // 2: Waiting for Final Response. The OAuth2 background thread is waiting for the final access token response.
  // In that case, cancel the background task started in the call to StartAuth.
  if (oauth2.authFlowState < 3) {
    oauth2.cancel();
    print('No response from the browser!');
    return;
  }

  // Check the AuthFlowState to see if authorization was granted, denied, or if some error occurred
  // The possible AuthFlowState values are:
  // 3: Completed with Success. The OAuth2 flow has completed, the background thread exited, and the successful JSON response is available in AccessTokenResponse property.
  // 4: Completed with Access Denied. The OAuth2 flow has completed, the background thread exited, and the error JSON is available in AccessTokenResponse property.
  // 5: Failed Prior to Completion. The OAuth2 flow failed to complete, the background thread exited, and the error information is available in the FailureInfo property.
  if (oauth2.authFlowState == 5) {
    print('OAuth2 failed to complete.');
    print(oauth2.failureInfo);
    return;
  }

  if (oauth2.authFlowState == 4) {
    print('OAuth2 authorization was denied.');
    print(oauth2.accessTokenResponse);
    return;
  }

  if (oauth2.authFlowState != 3) {
    print('Unexpected AuthFlowState:${oauth2.authFlowState}');
    return;
  }

  // Save the full JSON access token response to a file.
  final sbJson = CkStringBuilder();
  sbJson.append(oauth2.accessTokenResponse);
  sbJson.writeFile('qa_data/tokens/_googleDrive.json', 'utf-8', false);

  // The saved JSON response looks like this:

  // 	{
  // 	 "access_token": "ya39.Ci-XA_C5bGgRDC3UaD-h0_NeL-DVIQnI2gHtBBBHkZzrwlARkwX6R3O0PCDEzRlfaQ",
  // 	 "token_type": "Bearer",
  // 	 "expires_in": 3600,
  // 	 "refresh_token": "1/r_2c_7jddspcdfesrrfKqfXtqo08D6Q-gUU0DsdfVMsx0c"
  // 	}
  // 
  print('OAuth2 authorization granted!');
  print('Access Token = ${oauth2.accessToken}');

  // Here is an example showing how to define your OAuth 2.0 Credential in the Google Cloud Console
  // Note: Even though your application is technically not a web app, you should still select "Web Application"
  // because the Redirect URI is going to http://localhost:55568/ where Chilkat will receive it in a background thread.

  // 
}