Dart

Google Translate API Refresh Access Token

See more Google Translate Examples

Demonstrates how to refresh a Google Access Token for the Google Translate API. Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // This example requires the Chilkat API to have been previously unlocked.
  // See Global Unlock Sample for sample code.

  // It is assumed we previously obtained an OAuth2 access token.
  // This example loads the JSON access token file 
  // saved by this example: Get Google Translate API OAuth2 Access Token

  final jsonToken = CkJsonObject();
  try {
    jsonToken.loadFile('qa_data/tokens/_googleTranslate.json');
  } on ChilkatException {
    print('Failed to load _googleTranslate.json');
    return;
  }

  // The access token JSON looks like this:

  // {
  //   "access_token": "ya29.a0AfH6S ... LAZYFUkf0",
  //   "expires_in": 3599,
  //   "refresh_token": "1//0fL_Ov ... ee0",
  //   "scope": "https://www.googleapis.com/auth/cloud-translation",
  //   "token_type": "Bearer"
  // }

  final oauth2 = CkOAuth2();

  oauth2.tokenEndpoint = 'https://www.googleapis.com/oauth2/v4/token';

  // Replace these with actual values.
  oauth2.clientId = 'GOOGLE-CLIENT-ID';
  oauth2.clientSecret = 'GOOGLE-CLIENT-SECRET';

  // Get the "refresh_token"
  oauth2.refreshToken = jsonToken.stringOf('refresh_token');

  // Send the HTTP POST to refresh the access token..
  try {
    oauth2.refreshAccessToken();
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // The response contains a new access token, but we must keep
  // our existing refresh token for when we need to refresh again in the future.
  jsonToken.updateString('access_token', oauth2.accessToken);

  // Save the new JSON access token response to a file.
  final sbJson = CkStringBuilder();
  jsonToken.emitCompact = false;
  jsonToken.emitSb(sbJson);
  sbJson.writeFile('qa_data/tokens/_googleTranslate.json', 'utf-8', false);

  print('OAuth2 authorization granted!');
  print('New Access Token = ${oauth2.accessToken}');
}