Google Api v3 get modified event via watch(web_hook) - php

Question

Am using Google Api v3 for adding and modifying google events .
most of the thing works fine except am unable to get the changes made in google events
am using the below code :
require_once 'google-api-php-client/src/Google/Client.php';
require_once 'google-api-php-client/src/Google/Service/Analytics.php';
require_once 'google-api-php-client/src/Google/Service/Calendar.php';
$client_id = 'my-client_id'; // works without this
$Email_address = 'my-Email_address';
$key_file_location = 'my-key_file_location.p12';
$client = new Google_Client();
$client->setApplicationName("app-name"); // works without random names
$key = file_get_contents($key_file_location);
$scopes = array('https://www.googleapis.com/auth/calendar', 'https://www.googleapis.com/auth/calendar.readonly');
$cred = new Google_Auth_AssertionCredentials($Email_address, $scopes , $key);
$client->setAssertionCredentials($cred);
if ($client->getAuth()->isAccessTokenExpired())
{
$client->getAuth()->refreshTokenWithAssertion($cred);
}
$service = new Google_Service_Calendar($client);
$cals = $service->calendarList->listCalendarList();
$event = new Google_Service_Calendar_Event();
$event->setSummary('04/03 appointment -1');
$start = new Google_Service_Calendar_EventDateTime();
$start->setDateTime('2015-03-27T11:00:00.000-00:00');
$start->setTimeZone('Asia/Calcutta');
$event->setStart($start);
$end = new Google_Service_Calendar_EventDateTime();
$end->setDateTime('2015-03-27T11:25:00.000-00:00');
$end->setTimeZone('Asia/Calcutta');
$event->setEnd($end);
$attendee1 = new Google_Service_Calendar_EventAttendee();
$attendee1->setEmail('myemail#gmail.com');
$attendees = array($attendee1);
$event->attendees = $attendees;
$recurringEvent = $service->events->insert('randome-id#group.calendar.google.com', $event);
echo $dynamicId = $recurringEvent->getId();
$events = $service->events->listEvents('randome-id#group.calendar.google.com');
echo "<br>start - into web hoot <br>";
$service = new Google_Service_Calendar($client);
$channel = new Google_Service_Calendar_Channel($client);
$channel->setId($dynamicId);
$channel->setType('web_hook');
echo '<br>';
echo $url = 'https://mydomain.com.return.php';
$channel->setAddress($url);
$timetoExpire = time()+3600000;
$optParams = array('ttl' => $timetoExpire);
$channel->setParams($optParams);
try
{
echo "<br>";
$watchEvent = $service->events->watch('randome-id#group.calendar.google.com', $channel);
print_r($watchEvent);
echo "<br>hook applied<br>";
}
catch(Exception $e)
{
echo $e;
echo "web hook not working<br />.";
}
echo "<br>end";
exit;
return response comes properly in https://mydomain.com.return.php but still am not sure how to read the response
and am unsure
what is
[resourceId] =7U94nhlXTXH_tK13-5JIrZTBWU0
[resourceUri] =https://www.googleapis.com/calendar/v3/calendars/randome-id#group.calendar.google.com/events?alt=json
please help me to figure out how to get the modified event date in goggle calender Thanks in advance