OAuth2\OAuth2::finishClientAuthorization PHP Method

    public function finishClientAuthorization($isAuthorized, $data = null, Request $request = null, $scope = null)
    {
        // In theory, this could be POSTed by a 3rd-party (because we are not
        // internally enforcing NONCEs, etc)
        $params = $this->getAuthorizeParams($request);
        /**
         * Associative array as below:
         *   - response_type: The requested response: an access token, an
         *     authorization code, or both.
         *   - client_id: The client identifier as described in Section 2.
         *   - redirect_uri: An absolute URI to which the authorization server
         *     will redirect the user-agent to when the end-user authorization
         *     step is completed.
         *   - scope: (optional) The scope of the access request expressed as a
         *     list of space-delimited strings.
         *   - state: (optional) An opaque value used by the client to maintain
         *     state between the request and callback.
         *
         * @var array
         */
        $params += array('state' => null);
        $result = array();
        if ($isAuthorized === false) {
            $method = $params["response_type"] == self::RESPONSE_TYPE_AUTH_CODE ? self::TRANSPORT_QUERY : self::TRANSPORT_FRAGMENT;
            throw new OAuth2RedirectException($params["redirect_uri"], self::ERROR_USER_DENIED, "The user denied access to your application", $params["state"], $method);
        } else {
            if ($params["response_type"] === self::RESPONSE_TYPE_AUTH_CODE) {
                $result[self::TRANSPORT_QUERY]['state'] = $params["state"];
                $result[self::TRANSPORT_QUERY]["code"] = $this->createAuthCode($params["client"], $data, $params["redirect_uri"], $scope);
            } elseif ($params["response_type"] === self::RESPONSE_TYPE_ACCESS_TOKEN) {
                $result[self::TRANSPORT_FRAGMENT]['state'] = $params["state"];
                $result[self::TRANSPORT_FRAGMENT] += $this->createAccessToken($params["client"], $data, $scope, null, false);
            }
        }
        return $this->createRedirectUriCallbackResponse($params["redirect_uri"], $result);
    }

 /**
  * Creates and returns access token for a user
  * @param  AdvancedUserInterface $user [description]
  * @return [type]                      [description]
  */
 public function generateAccessToken(AdvancedUserInterface $user)
 {
     if (is_null($user->getOAuthClient()->getId())) {
         throw new \Exception('User must have an OAuth Client', 500);
     }
     // Search valid token
     $oauth_access_token = $this->oauth_manipulator->getValidTokenForClient($user->getOAuthClient());
     if (!is_null($oauth_access_token)) {
         return $oauth_access_token->getToken();
     }
     // Or else, creates a new one
     // Forge request to satisfy OAuth2 server
     $request = new Request();
     $request->query->add(['client_id' => $user->getOAuthClient()->getPublicId(), 'response_type' => OAuth2::RESPONSE_TYPE_ACCESS_TOKEN, 'redirect_uri' => $user->getOAuthClient()->getRedirectUris()[0]]);
     $response = $this->oauth2->finishClientAuthorization(true, $user, $request, null);
     if ($response instanceof Response) {
         $location = str_replace('#', '?', $response->headers->get('location'));
         $query_string = parse_url($location, PHP_URL_QUERY);
         parse_str($query_string, $queries);
         if (isset($queries['access_token'])) {
             $access_token = $queries['access_token'];
             return $access_token;
         }
     } else {
         throw new Exception("Token creation ; unknown response type : " . get_class($response), 500);
     }
 }