如何从谷歌日历获取活动详情

i succeeded in getting a push notification from google calendar into my system, when a new event is created in the calendar. the push notification has no data in the POST body and the POST headers are these:

[Host] => xxxxxx.xxxx.com
[Content-Type] => application/json; charset=UTF-8
[Accept] => */*
[X-Goog-Channel-ID] => xxxxxxx-xxxxxxxx-8824-f0c2166878be
[X-Goog-Channel-Expiration] => Thu, 04 Dec 2014 04:27:13 GMT
[X-Goog-Resource-State] => exists
[X-Goog-Message-Number] => 11897215
[X-Goog-Resource-ID] => xxxxxxxxxx-xxxx-pSbC27qOUfg
[X-Goog-Resource-URI] => https://www.googleapis.com/calendar/v3/calendars/xxxxxxx@gmail.com/events?key=AIzaSyC_0nytiZWHfabrpWiExxxxxxxxxxx&alt=json
[Content-Length] => 0
[Connection] => Keep-alive
[Accept-Encoding] => gzip,deflate
[User-Agent] => APIs-Google; (+https://developers.google.com/webmasters/APIs-Google.html)

在日历中创建的新活动详情在哪里?我如何获得它们?

service = new Google_Service_Calendar($client);         
$channel =  new Google_Service_Calendar_Channel($client);
$uuid = gen_uuid();
$channel->setId($uuid);
$channel->setType('web_hook');
$channel->setExpiration('1919995862000');

global $sugar_config;
$address = $sugar_config['site_url'] . "/index.php?entryPoint=updateFromCal";
$channel->setAddress($address);
$watchEvent = $service->events->watch($bean->google_cal_id_c, $channel);

[address] => https://mydomainXXXX/index.php?entryPoint=updateFromCal
[expiration] => 1919995862000
[id] => xxxxxxxxxxxxxxx--4558-ac19-b82e0ca32206
[kind] => 
[params] => 
[payload] => 
[resourceId] => 
[resourceUri] => 
[token] => 
[type] => web_hook
[modelData:protected] => Array
    (
    )

[processed:protected] => Array
    (
    )