using service account to access google calendar but answer variables are empty

Question

I have created a service account to access a certain google calendar. this service account user also got the permission in the calendar settings as is described in this blog: "allow my user to add meeting in my calendar with Google Calendar API with PHP without auth".

As I can see in Google Cloud Platform under APIs + Services -> Credentials in the Service Account section the created service account is used with all services (last 30 days) every time, when I fire this php script, but in the browser window I get no error, that there would be a problem with authentication but: Uncaught Error: Call to a member function getSummary() on null in line... of the php-script Script and Settings in Google Cloud Platform are as described in the mentioned post.

Any idea what could be the problem? Has there anything changed with google calendar api since this post in 2019?

require '../google-api-php-client/vendor/autoload.php';
ini_set('display_errors', 1);

$client = new Google_Client();
$client->addScope("https://www.googleapis.com/auth/calendar");

$client->setAuthConfig(dirname(__FILE__).'/credentials/credentials.json');

$service = new Google_Service_Calendar($client);

$calendarList = $service->calendarList->listCalendarList();

while(true) {

  foreach ($calendarList->getItems() as $calendarListEntry) {
    echo $calendarListEntry->getSummary();
    echo "\n------------------------------\n\n";

    // get events 
    $events = $service->events->listEvents($calendarListEntry->id);

    foreach ($events->getItems() as $event) {
        echo "- " . $event->getSummary() . "\n";
        echo "- " . $event->getStart()->getDateTime() . "\n\n";
    }

  }

  $pageToken = $calendarList->getNextPageToken();

  if ($pageToken) {
    $optParams = array('pageToken' => $pageToken);
    $calendarList = $service->calendarList->listCalendarList($optParams);
  } else {

    echo "break";
   break;
  }

}
    echo "calendar summary: " . $calendarListEntry->getSummary();
    echo "\ncalendar id: " . $calendarListEntry->getId();
    echo "\n------------------------------\n\n";

Obviously the $calendarList and $calendarListEntry is empty....

You are trying to call a method on an undefined class. If you post your code we may be able to help you better. Remember to remove your authentication details. — Cornel Verster, May 25 '20 at 16:32
Can you share your code where you define your service account? — Rafa Guillermo, May 26 '20 at 07:42
isn't the service account declared in the credentials.json, that is included by ->setAuthConfig() ? Is something else necessary to define the service account? — Su Art, May 26 '20 at 08:07
It is, but you need to use a different library for the auth flow when using a service account than a regular user. Check the answer on [this question](https://stackoverflow.com/a/20939305/11551468) out. — Rafa Guillermo, May 26 '20 at 08:31

score 0 · Accepted Answer · answered May 28 '20 at 12:08

The reason why function getSummary() cannot render any results (is null or empty) is because a new service account user has an empty calendarList. By giving permission in any other calendar to the service account user does not automatically insert this calender to the calendarList of the service account user.

So you first have to insert / create a calenderList for the service account:

$calendarListEntry = new Google_Service_Calendar_CalendarListEntry();
$calendarListEntry->setId("calendar_address_you_want_to_add");
$createdCalendarListEntry = $service->calendarList->insert($calendarListEntry);
echo $createdCalendarListEntry->getSummary();

When using the first script now you will get results of calendarEvents (as far as there are any coming events posted in the calendar) the getSummary() function and the getId() function.

using service account to access google calendar but answer variables are empty

1 Answers1