Sabre\VObject\ITip\Broker::processMessage PHP Method

    public function processMessage(Message $itipMessage, VCalendar $existingObject = null)
    {
        // We only support events at the moment.
        if ($itipMessage->component !== 'VEVENT') {
            return false;
        }
        switch ($itipMessage->method) {
            case 'REQUEST':
                return $this->processMessageRequest($itipMessage, $existingObject);
            case 'CANCEL':
                return $this->processMessageCancel($itipMessage, $existingObject);
            case 'REPLY':
                return $this->processMessageReply($itipMessage, $existingObject);
            default:
                // Unsupported iTip message
                return null;
        }
        return $existingObject;
    }

 function process($input, $existingObject = null, $expected = false)
 {
     $version = \Sabre\VObject\Version::VERSION;
     $vcal = Reader::read($input);
     foreach ($vcal->getComponents() as $mainComponent) {
         break;
     }
     $message = new Message();
     $message->message = $vcal;
     $message->method = isset($vcal->METHOD) ? $vcal->METHOD->getValue() : null;
     $message->component = $mainComponent->name;
     $message->uid = $mainComponent->UID->getValue();
     $message->sequence = isset($vcal->VEVENT[0]) ? (string) $vcal->VEVENT[0]->SEQUENCE : null;
     if ($message->method === 'REPLY') {
         $message->sender = $mainComponent->ATTENDEE->getValue();
         $message->senderName = isset($mainComponent->ATTENDEE['CN']) ? $mainComponent->ATTENDEE['CN']->getValue() : null;
         $message->recipient = $mainComponent->ORGANIZER->getValue();
         $message->recipientName = isset($mainComponent->ORGANIZER['CN']) ? $mainComponent->ORGANIZER['CN'] : null;
     }
     $broker = new Broker();
     if (is_string($existingObject)) {
         $existingObject = str_replace('%foo%', "VERSION:2.0\nPRODID:-//Sabre//Sabre VObject {$version}//EN\nCALSCALE:GREGORIAN", $existingObject);
         $existingObject = Reader::read($existingObject);
     }
     $result = $broker->processMessage($message, $existingObject);
     if (is_null($expected)) {
         $this->assertTrue(!$result);
         return;
     }
     $this->assertVObjectEqualsVObject($expected, $result);
 }