Question

I want to know if it is possible to get the “userId” value using the Google+ api, in order to display a link to some specific user profile. For better explanation, I have a PHP application and there is a panel where I can view the existing users in my database. So, when detailing a specific user, I want to show a Google+ badge which will link to that user’s Google+ profile. I don’t have the “userId”, but still have access to his email address. Any suggestions?

Answer 1

There is no endpoint that you can hit to convert an email address into a Google+ userId.

However, you can use the REST API to determine the Google+ userId of the currently logged in user. This will require the user to grant you access to their identity on Google+ via OAuth. To do this use the people get endpoint with me as the userId. You can try this out on the API Explorer to observe what the user experience with the OAuth dialog will be like.

Here’s some code lifted from the PHP starter project that illustrates everything you need to fetch the userId of the current user:

if (ini_get('register_globals') === "1") {
 die("register_globals must be turned off before using the starter application");
}

require_once 'google-api-php-client/src/apiClient.php';
require_once 'google-api-php-client/src/contrib/apiPlusService.php';

session_start();

$client = new apiClient();
$client->setApplicationName("Google+ PHP Starter Application");
// Visit https://code.google.com/apis/console to generate your
// oauth2_client_id, oauth2_client_secret, and to register your oauth2_redirect_uri.
$client->setClientId('insert_your_oauth2_client_id');
$client->setClientSecret('insert_your_oauth2_client_secret');
$client->setRedirectUri('insert_your_oauth2_redirect_uri');
$client->setDeveloperKey('insert_your_developer_key');
$client->setScopes(array('https://www.googleapis.com/auth/plus.me'));
$plus = new apiPlusService($client);

if (isset($_REQUEST['logout'])) {
  unset($_SESSION['access_token']);
}

if (isset($_GET['code'])) {
  $client->authenticate();
  $_SESSION['access_token'] = $client->getAccessToken();
  $redirect = 'http://' . $_SERVER['HTTP_HOST'] . $_SERVER['PHP_SELF'];
  header('Location: ' . filter_var($redirect, FILTER_SANITIZE_URL));
}

if (isset($_SESSION['access_token'])) {
  $client->setAccessToken($_SESSION['access_token']);
}

if ($client->getAccessToken()) {
  $me = $plus->people->get('me');
  // Do stuff with the id
  echo $me['id'];

  // The access token may have been updated lazily.
  $_SESSION['access_token'] = $client->getAccessToken();
} else {
  $authUrl = $client->createAuthUrl();
}