invoiceninja/app/Ninja/OAuth/OAuth.php

<?php namespace App\Ninja\OAuth;

use App\Models\LookupUser;
use App\Models\User;

class OAuth {

    const SOCIAL_GOOGLE = 1;
    const SOCIAL_FACEBOOK = 2;
    const SOCIAL_GITHUB = 3;
    const SOCIAL_LINKEDIN = 4;

    private $providerInstance;
    private $providerId;

    public function __construct()
    {
    }

    public function getProvider($provider)
    {
        switch ($provider)
        {
            case 'google';
                $this->providerInstance = new Providers\Google();
                $this->providerId = self::SOCIAL_GOOGLE;
                return $this;

            default:
                return null;
                break;
        }
    }

    public function getTokenResponse($token)
    {
        $user = null;

        $payload = $this->providerInstance->getTokenResponse($token);
        $oauthUserId = $this->providerInstance->harvestSubField($payload);

        LookupUser::setServerByField('oauth_user_key', $this->providerId . '-' . $oauthUserId);

        if($this->providerInstance)
          $user = User::where('oauth_user_id', $oauthUserId)->where('oauth_provider_id', $this->providerId)->first();


        if ($user)
            return $user;
        else
            return false;

    }


}
?>