Inserting Google Calendar Entries with Service Account

Question 1

I'm trying to use a service account to create entries on a Google calendar. I'm really close on this, but the very last line won't work. I get a 500 Internal Service Error when I let this run. Otherwise, the program runs error free, for whatever that is worth.

The Calendar.php file contents can be found here. The insert() method that I am trying to call begins on line 1455 of that file.

<?php

function calendarize ($title, $desc, $ev_date, $cal_id) {

    session_start();

    /************************************************
    Make an API request authenticated with a service
    account.
    ************************************************/
    set_include_path( '../google-api-php-client/src/');

    require_once 'Google/Client.php';
    require_once 'Google/Service/Calendar.php';

    // (not real keys)
    $client_id = '843319906820-jarm3f5ctbtjj9b7lp5qdcqal54p1he6.apps.googleusercontent.com';
    $service_account_name = '843319906820-jarm3f5ctbtjj7b7lp5qdcqal54p1he6@developer.gserviceaccount.com';
    $key_file_location = '../google-api-php-client/calendar-249226a7a27a.p12';

//    echo pageHeader("Service Account Access");
    if (!strlen($service_account_name) || !strlen($key_file_location))
        echo missingServiceAccountDetailsWarning();

    $client = new Google_Client();
    $client->setApplicationName("xxxx Add Google Calendar Entries");

    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()) {
        $client->getAuth()->refreshTokenWithAssertion($cred);
    }
    $_SESSION['service_token'] = $client->getAccessToken();

    // Prior to this, the code has mostly come from Google's example
    //     google-api-php-client / examples / service-account.php
    // and relates to getting the access tokens. 

    // The rest of this is about setting up the calendar entry.
    //Set the Event data
    $event = new Google_Service_Calendar_Event();
    $event->setSummary($title);
    $event->setDescription($desc);

    $start = new Google_Service_Calendar_EventDateTime();
    $start->setDate($ev_date);
    $event->setStart($start);

    $end = new Google_Service_Calendar_EventDateTime();
    $end->setDate($ev_date);     
    $event->setEnd($end);

    $calendarService = new Google_Service_Calendar($client);
    $calendarList = $calendarService->calendarList;

    $events = $calendarService->events;

    // if I leave this line, my code won't crash (but it won't do anything, either)
    //echo "here"; die(); 

    $events.insert($cal_id, $event, false);
} 

?>

Question 2

I figured this out. Since I don't see any complete examples of using service accounts with API v3, I'm just going to post my complete solution for reference. There are a few of things that you need to do in addition to implementing the code, however:

1) You need to go to the Google Developer's console and mark your account as a 'service account'. This will differentiate it from a web application. The important difference is that nobody will be prompted to log in to their account before the events are added since the account will belong to your application, not an end user. For more information see this article, starting on page 5.

2) You need to create a public/private key pair. From the developer's console, click on Credentials. Under you service account, click on 'Generate new P12 key'. You'll need to store this somewhere. That file location becomes the $key_file_location variable string in the code below.

3) Also from the developer's console, you need to enable the Calendar API. From your project, on the left margin you'll see APIs. Select that and find the Calendar API. Click it, accept the terms of service, and verify that it is now displayed under Enabled APIs with a status of On

4) In Google Calendar that you want to add events to, under settings, click Calendar Settings then on 'Share this Calendar' at the top. Under 'Share with specific people' in the 'Person' field, paste in the email address from the service account credentials. Change the permission settings to 'Make changes to events'. Don't forget to save the change.

Then, implement this code somewhere.

Comment if something is confusing or omitted. Good luck!

<?php

function calendarize ($title, $desc, $ev_date, $cal_id) {

    session_start();

    /************************************************
    Make an API request authenticated with a service
    account.
    ************************************************/
    set_include_path( '../google-api-php-client/src/');

    require_once 'Google/Client.php';
    require_once 'Google/Service/Calendar.php';

    //obviously, insert your own credentials from the service account in the Google Developer's console
    $client_id = '843319906820-xxxxxxxxxxxxxxxxxxxdcqal54p1he6.apps.googleusercontent.com';
    $service_account_name = '843319906820-xxxxxxxxxxxxxxxxxxxdcqal54p1he6@developer.gserviceaccount.com';
    $key_file_location = '../google-api-php-client/calendar-xxxxxxxxxxxx.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()) {
        $client->getAuth()->refreshTokenWithAssertion($cred);
    }
    $_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();
    $start->setDateTime($ev_date);
    $event->setStart($start);

    $end = new Google_Service_Calendar_EventDateTime();
    $end->setDateTime($ev_date);
    $event->setEnd($end);

    $createdEvent = $calendarService->events->insert($cal_id, $event);

    echo $createdEvent->getId();
} 

?>

Some helpful resources:
Github example for service accounts
Google Developers Console for inserting events in API v3
Using OAuth 2.0 to Access Google APIs

Question 3

Answering this question because the other one is too short and vague.

Instead of passing the ID returned by profile.getId(), pass the one returned by googleUser.getAuthResponse().id_token as your id_token (the id field of the POST request you use to send the user's id over to your server).

A great tip for any developer: If you think you did everything you were supposed to do, and it is working for them, but it is not working for you, then you did not do everything you were supposed to do.

Question 4

Some of the Google APIs let you access them using a public non authenticated user. It is not hooked to a project on Google Developer console due to that fact there is a very strict limit to how much data you can request from it.

(403) Daily Limit for Unauthenticated - Means that you are running with that. non authenticated user. You need to fix your code to use a client id from Google Developer console.

Question 5

I am curious as to why your first attempt with the service account tutorial didn't work. What was wrong? Was there an error?

Remember service accounts are not you. The service account has its own Google calendar account, so if you are trying to read one of your "personal calendars", it will not work. You are going to have to share your personal calendar with the service account.

Here is another example using the Json service account key file.

string[] scopes = new string[] { CalendarService.Scope.Calendar };
GoogleCredential credential;
using (var stream = new FileStream(serviceAccountCredentialFilePath, FileMode.Open, FileAccess.Read))
{
    credential = GoogleCredential.FromStream(stream)
                     .CreateScoped(scopes);
}

// Create the Calendar service.
var service = new CalendarService(new BaseClientService.Initializer()
{
    HttpClientInitializer = credential,
    ApplicationName = "Calendar Authentication Sample",
});

Question 6

For anyone in the future who needs this. It started working after:

1) enabling domain-wide delegation 2) adding user to service account as owner 3) probably most important** : went on google admin and gave api access to the service account

Inserting Google Calendar Entries with Service Account

Answers

php,google-calendar-api,google-api-php-client