Google Calendar API error redirect_uri_mismatch

Question

I am trying to use the google API to manage the user´s calendar, and I am finding a problem. I created and configured a google project on the Google Developers Console. One of the settings was the allowed redirecting uris... and I think it is ok, because after some test where google threw the same error (redirect_uri_mismatch), I got that google ask me for permissions... the problem I think is this line: $this->client->authenticate($_GET['code']);
I am going to show the code and explain what it does

function __construct() 
{
    parent::__construct();
    require __DIR__ . '/vendor/autoload.php';

    define('APPLICATION_NAME', 'Google Calendar API PHP Quickstart');
    define('CLIENT_SECRET_PATH', __DIR__ . '/credentials/client_secret.json');
    define('CREDENTIALS_PATH', __DIR__ .'/credentials/');
    define('SCOPES', implode(' ', array(Google_Service_Calendar::CALENDAR_READONLY)));
    // If modifying these scopes, delete your previously saved credentials
    // at ~/.credentials/calendar-php-quickstart.json

    $this->client = new Google_Client();
    $this->client->setApplicationName(APPLICATION_NAME);
    $this->client->setScopes(SCOPES);
    $this->client->setAuthConfigFile(CLIENT_SECRET_PATH);

    if (!file_exists(CLIENT_SECRET_PATH.$this->session->userdata("identity").".json") && !$this->input->get("code"))
        $this->getCredentials();
}

public function responseCredentials()
{
    $authCode           = $this->input->get("code");
    $this->client->authenticate($_GET['code']);
    $accessToken        = $this->client->client->getAccessToken();
    $credentialsPath    = CLIENT_SECRET_PATH.$this->session->userdata("identity").".json";
    mkdir(dirname($credentialsPath), 0700, true);

    file_put_contents($credentialsPath, $accessToken);
    redirect(base_url("dashboard"));
}
private function getCredentials()
{
    $this->client->setRedirectUri(base_url('calendar/responseCredentials'));
    $authUrl = $this->client->createAuthUrl();
    header('Location: ' . filter_var($authUrl, FILTER_SANITIZE_URL));
}

Ok... the first... the constructor it load the google api autoloader, and the constants, creates a new Google_Client object, and inspect if exists a permissions file for the user and there is no "code" index on the get.
If not it invokes the getCredentials function that redirect to google.
After give permissions, the user is redirect to http://domain.com/calendar/responseCredentials (that it is configured on the console.developers.google)

The error thrown is this:

Fatal error: Uncaught exception 'Google_Auth_Exception' with message 
'Error fetching OAuth2 access token, message: 'redirect_uri_mismatch'' in 
/var/www/html/prototipo/application/controllers/vendor/google/apiclient/src/Google/Auth/OAuth2.php:126 
Stack trace: 
#0 /var/www/html/prototipo/application/controllers/vendor/google/apiclient/src/Google/Client.php(128): Google_Auth_OAuth2->authenticate('4/rkAKNAmiVgs1Z...', false) 
#1 /var/www/html/prototipo/application/controllers/calendar.php(52): Google_Client->authenticate('4/rkAKNAmiVgs1Z...') 
#2 [internal function]: Calendar->responseCredentials() 
#3 /var/www/html/prototipo/system/core/CodeIgniter.php(360): call_user_func_array(Array, Array) 
#4 /var/www/html/prototipo/index.php(202): require_once('/var/www/html/p...') 
#5 {main} thrown in/var/www/html/prototipo/application/controllers/vendor/google/apiclient/src/Google/Auth/OAuth2.php on line 126

What am I doing wrong??
Thank you.

EDIT

I just realized that at the end of the code variable on the return uri there always is a pad... something like this:
http://pedro.eatec.es/prototipo/calendar_test_stack/responseCredentials?code=4/PL7nK1s9m5vpBow7HScaPmkpWpoW3J4uzUxlD7NE49g#
The example here: https://developers.google.com/identity/protocols/OAuth2WebServer#handlingresponse doesn´t show this pad... I tried to do this:

$this->client->authenticate($_GET['code']."#");

But... of course, doesn´t work.
PS: I tried to do it because with echo $_GET['code']; didn´t show the pad.

Answer 1

Hello and Thanks @thepieterdc finally you were reason...

I was setting up correctly the project on console.developers... but my mistake was that I need make some trying to get a correct configuration and when I got to make disappear the error 400 (with the broken robot) and it ask me for permission, on the redirecting function when I make $this->g_client->authenticate($_GET['code']); the code try to make other request (on OAuth2.php) to https://accounts.google.com/o/oauth2/token and it use the client_id.json that you need to refresh... and I didn´t. I WAS USING THE FIRST EDITION OF THE CLIENT_ID.JSON I need to re-download (or re-write) if you change something on the console.

Thanks.