getAccessToken method

Implementation

Future<String> getAccessToken() async {
  final account = await _ensureSessionRestored();
  if (account == null) {
    throw Exception('Not signed in to Google.');
  }

  final auth = await account.authentication;
  final token = auth.accessToken;
  if (token == null || token.isEmpty) {
    // Force token refresh.
    dev.log('Refreshing Google access token', name: 'GoogleAuth');
    final freshAuth = await account.authentication;
    final freshToken = freshAuth.accessToken;
    if (freshToken == null || freshToken.isEmpty) {
      throw Exception('Failed to get Google access token.');
    }
    return freshToken;
  }
  return token;
}