I had the same problem and found the solution (in a round about way) here:
Inserting Google Calendar Entries with Service Account
First thing is to set up your Google calendar correctly (see above mentioned post which describes it very well), then download the API code for the Calendar from here https://github.com/google/google-api-php-client
It's the Download ZIP link on the right of that page.
Then here is some sample code which works for me (private keys replaced with xxxx where appropriate, but otherwise it's exactly what I'm using).
I'm now trying to find out how to read & clear a Google Calendar, which is proving even more challenging!
<?php
//
// built from example at:
// https://stackoverflow.com/questions/26064095/inserting-google-calendar-entries-with-service-account
//
$startdate = new DateTime('2015-01-29 10:00', new DateTimeZone('Europe/London'));
$startdate = $startdate->format('c');
$enddate = new DateTime('2015-01-29 10:00', new DateTimeZone('Europe/London'));
$enddate = $enddate->format('c');
//
// call function to add one event to the calendar (xxxxxxxxxxx@googlemail.com = the calendar owner)
//
calendarize('Test Appointment','Test appt description',$startdate,$enddate,'xxxxxxxxxxx@googlemail.com');
//-----------------------------------------------//
// funtion to add an event to my Google calendar //
//-----------------------------------------------//
function calendarize ($title, $desc, $start_ev_datetime, $end_ev_datetime, $cal_id) {
session_start();
require_once '../google-api-php-client-master/autoload.php';
//Google credentials
$client_id = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.apps.googleusercontent.com';
$service_account_name = 'xxxxxxxxxxxxxxxxxxxxxxxxxx@developer.gserviceaccount.com';
$key_file_location = '../google-api-php-client-master/API Project-xxxxxxxxxx.p12';
if (!strlen($service_account_name) || !strlen($key_file_location))
echo missingServiceAccountDetailsWarning();
$client = new Google_Client();
$client->setApplicationName("Whatever the name of your app is");
if (isset($_SESSION['service_token'])) {
$client->setAccessToken($_SESSION['service_token']);
}
$key = file_get_contents($key_file_location);
$cred = new Google_Auth_AssertionCredentials(
$service_account_name,
array('https://www.googleapis.com/auth/calendar'),
$key
);
$client->setAssertionCredentials($cred);
if($client->getAuth()->isAccessTokenExpired()) {
try {
$client->getAuth()->refreshTokenWithAssertion($cred);
} catch (Exception $e) {
var_dump($e->getMessage());
}
}
$_SESSION['service_token'] = $client->getAccessToken();
$calendarService = new Google_Service_Calendar($client);
$calendarList = $calendarService->calendarList;
//Set the Event data
$event = new Google_Service_Calendar_Event();
$event->setSummary($title);
$event->setDescription($desc);
$start = new Google_Service_Calendar_EventDateTime();
$start->setDateTime($start_ev_datetime);
$start->setTimeZone('Europe/London');
$event->setStart($start);
$end = new Google_Service_Calendar_EventDateTime();
$end->setDateTime($end_ev_datetime);
$end->setTimeZone('Europe/London');
$event->setEnd($end);
try {
$createdEvent = $calendarService->events->insert($cal_id, $event);
} catch (Exception $e) {
var_dump($e->getMessage());
}
echo 'Event Successfully Added with ID: '.$createdEvent->getId();
}
?>
