CODE EXAMPLE FOR PHP

google calendar api push notifications php

$channel = new Google_Service_Calendar_Channel($client);
$channel->setId('00000000-0000-0000-0000-000000000001');
$channel->setType('web_hook');
$channel->setAddress('https://www.yourserver.com/handleWatch.php');
$watchEvent = $service->events->watch(yourCalendarId, $channel, array());