How can I insert data (event) into Google Calendar with PHP?

Question

I am trying to insert events into Google Calendar, but I get errors everytime. I've been searching for hours to get answer, but I found nothing for my problem. I tested a lot of examples, without success. I'm new in Google Calendar, and I can't really understand the google api documentation.

I have a Fullcalendar which uses the Google Calendar (Gcal) as backend. I can read data from Gcal without any problems. When I try to displayed using Fullcalendar, but when I want to write some test datas into Gcal it gives me errors. I want to make a Calendar application which serves as a reservation app. So I have a Calendar, which is displayed to everyone who enter the page, and they can reserve appointments, which are stored in my Google Calendar.

The main is problem is that, I don't really know how to make the connection to Google Calendar for writing data. Every sample I've seen, solves the problem different way, major of them are outdated, some of them uses Sessions, but I don't need Session because the Calendar I want to display is FIX, everyone sees the same.

The code:

require_once 'Google/src/Google/autoload.php';
require_once "Google/src/Google/Client.php";
require_once "Google/src/Google/Service/Calendar.php";

$client_id = 'XXXXXXXXXX-f9ltk86b2klat20k1osmfbgpu4u1vqse.apps.googleusercontent.com';
$client_secret = 'XXXXXXXXXXXXXXXXXXXXXXX';
$key = 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX'; // Server Key
$email_address = 'XXXXXXXXXXXX-f9ltk86b2klat20k1osmfbgpu4u1vqse@developer.gserviceaccount.com';


$client = new Google_Client();
$client->setApplicationName("Calendar");
$client->setClientId($client_id);
$client->setClientSecret($client_secret);
$client->setDeveloperKey($key);

$client->setScopes(array(
 'https://www.googleapis.com/auth/plus.login', 
));

$cal = new Google_Service_Calendar($client);

$event = new Google_Service_Calendar_Event();
$event->setSummary('Title');
$event->setDescription('Title');
$event->setLocation('Somewhere');
$start = new Google_Service_Calendar_EventDateTime();
$start->setDateTime('2013-08-17T16:00:00.000-07:00');
$event->setStart($start);
$end = new Google_Service_Calendar_EventDateTime();
$end->setDateTime('2013-08-17T17:00:00.000-07:00');
$event->setEnd($end);
$createdEvent = $cal->events->insert('<Calendar ID>', $event);

The exception it generates:

[19-Jun-2015 09:08:59 Europe/Berlin] PHP Fatal error: Uncaught exception 'Google_Service_Exception' with message 'Error calling POST https://www.googleapis.com/calendar/v3/calendars/hpba8d7p1f6l65ruhbl9qigvks%40group.calendar.google.com/events?key=XXXXXXXXXXXXXXXXXXXXXXXXXXXXX: (401) Login Required' in /var/www/XXXXXXXXXXXXXXXXXXXX/calendar/Google/src/Google/Http/REST.php:110

Answer 1

Login Required means that you have not authenticated properly.

By looking at the scope you are using I think that might give you a hint as to why its not working

'https://www.googleapis.com/auth/plus.login'

You are passing the scope for Google+ you should be passing one of the Google calendars scopes if you want to access Google calendar data.

• https://www.googleapis.com/auth/calendar read/write access to Calendars
• https://www.googleapis.com/auth/calendar.readonly read-only access to Calendars

Authenticate with a service account

<?php
 require_once 'Google/autoload.php';
   session_start();     
/************************************************   
 The following 3 values an befound in the setting   
 for the application you created on Google      
 Developers console.         Developers console.
 The Key file should be placed in a location     
 that is not accessable from the web. outside of 
 web root.   

 In order to access your GA account you must    
 Add the Email address as a user at the     
 ACCOUNT Level in the GA admin.         
 ************************************************/
$client_id = '[your client]';
    $Email_address = '[your service account email]';     
    $key_file_location = '[Your key]';      

    $client = new Google_Client();      
    $client->setApplicationName("Client_Library_Examples");
    $key = file_get_contents($key_file_location);    

// separate additional scopes with a comma   
$scopes ="https://www.googleapis.com/auth/calendar";    
$cred = new Google_Auth_AssertionCredentials(    
    $Email_address,      
    array($scopes),     
    $key         
    );      
$client->setAssertionCredentials($cred);
if($client->getAuth()->isAccessTokenExpired()) {        
    $client->getAuth()->refreshTokenWithAssertion($cred);       
}       
$service = new Google_Service_Calendar($client);    

?>

code ripped from tutorial PHP Google Calendar service account

Tip: make sure that you have given the service account access to the calendar in question. You just need to add the service account email to the calendar like you would any other user.