Google_Auth_Exception: Error fetching OAuth2 access token, message: 'invalid_request'

Question

I'm trying to get an access token, using the latest version of the google-api-php-client (take a look at this https://github.com/google/google-api-php-client), and I'm following this official doc: https://developers.google.com/api-client-library/php/guide/aaa_oauth2_web

The only difference is that I'd like to use the service Google_Service_Plus, instead of Google_Service_Urlshortener.

Basically I do these steps:

• I initialize the Google Client $client specifying client ID, client secret, developer key, scopes and redirect URI (which points to my localhost Ubuntu 12.04 - PHP 5.3.10).
• I initialize the Google Plus Service $plus using the Google Client $client.
• I redirect the user to the Auth URL using $client->createAuthUrl().
• The user can see the Consent Page and accepts.
• I obtain an authorization code $_GET['code'] to use for token exchange.
• Then, in the callback page, I try to do $client->authenticate($_GET['code']); but google server returns HTTP 400 and I get a Google_Auth_Exception: Error fetching OAuth2 access token, message: 'invalid_request'.
  
  

The flow breaks here.
What's wrong?

Any help will be appreciated.

Thanks in advance,
Niccolò.

Answer 1

Once I set the JSON configuration file for the $client, it worked for me.

Example:$client->setAuthConfigFile(__dir__.'/../conf/client_secrets.json');

Answer 2

I created an oauth2callback.php file and was experiencing this problem. The problem went away when I setup my Google_Client properly. At first I was only setting the clientId and secret. As soon as I set the redirectUri, my code started working. I didn't think I needed to set the redirectUri since I know the redirect had already occurred (I was on the redirect page). I figured this answer might help others experiencing a similar problem.