Google Calendar Push Notifications SetUp

I'm trying to setup a Push Notifications for Google Calendar using PHP and V3 api.

I've got the Auth2.0 Permission and I'm able to create events on google from my application. Now I want to know when a user makes any change on google calendar (CRUD Operations).

This is my code:

private $imageService;
public $google_client;
public $google_calendar;

public function __construct()
{
    $this->imageService = new ImageService();
    $this->google_client = new Google_Client();
    $this->google_client->setApplicationName($_ENV['GOOGLE_APP_NAME']);
    $this->google_client->setDeveloperKey($_ENV['GOOGLE_API_KEY']);
    $this->google_client->setClientId($_ENV['CLIENT_ID']);
    $this->google_client->setClientSecret($_ENV['CLIENT_SECRET']);
    $this->google_client->setAccessType('offline');
    $this->google_client->setIncludeGrantedScopes(true);
    $this->google_client->setScopes(array('email', 'profile', 'https://www.googleapis.com/auth/plus.me', 'https://www.googleapis.com/auth/calendar'));
    $this->google_calendar = new Google_Service_Calendar($this->google_client);

}

 public function googleCalendarWatch($uuid){

    $channel =  new Google_Service_Calendar_Channel($this->google_client);
    $channel->setId($uuid);
    $channel->setType('web_hook');
    $channel->setAddress("https://example.com/google/googleNotifications");
    $channel->setExpiration("1919995862000");
    $this->google_calendar->events->watch('primary', $channel);

}

And this is the output:

Google_Service_Calendar_Channel Object (
    [internal_gapi_mappings:protected] => Array ( ) 
    [address] => 
    [expiration] => 1426272395000 
    [id] => aee2b430-34bf-42bc-a597-ada46db42799 
    [kind] => api#channel 
    [params] => 
    [payload] => 
    [resourceId] => 51IKGpOwCJ6EMraQMUc1_04MODk 
    [resourceUri] => https://www.googleapis.com/calendar/v3/calendars/primary/events?key=AIzaSyBFUvq3OZO6ugAKvz7l8NgLS0V6DUJq8Vc&alt=json 
    [token] => 
    [type] => 
    [modelData:protected] => Array ( ) 
    [processed:protected] => Array ( ) )

This far I don't know why address returns null, maybe that's the problem. But I don't know how to fix it.

Also reading this: #26730263 and looking my own code there's no much difference.

I did all the stuff that google says, Register domain, add credentials, api key, push domain allowed and all..

Create a notification channel for every individual resource, then any modification to that resource you will be then notified. Information below is directly from Google (Creating notification channels).

Making watch requests:

Each watchable Google Calendar API resource has an associated watch method at a URI of the following form:

https://www.googleapis.com/**apiName**/**apiVersion**/**resourcePath**/watch

To set up a notification channel for messages about changes to a particular resource, send a POST request to the watch method for the resource. Each notification channel is associated both with a particular user and a particular resource (or set of resources). A watch request will not be successful unless the current user owns or has permission to access this resource.

Example:

Start watching for changes to a collection of events on a given calendar:

POST https://www.googleapis.com/calendar/v3/calendars/[email protected]/events/watch
Authorization: Bearer auth_token_for_current_user
Content-Type: application/json

{
  "id": "01234567-89ab-cdef-0123456789ab", // Your channel ID.
  "type": "web_hook",
  "address": "https://example.com/notifications", // Your receiving URL.
  ...
  "token": "target=myApp-myCalendarChannelDest", // (Optional) Your channel token.
  "expiration": 1426325213000 // (Optional) Your requested channel expiration time.
  }
}

Reference: Google (Creating notification channels) (19-Mar-2018).

• Address?
• Token?

<?php
require __DIR__ . '/vendor/autoload.php';

if (php_sapi_name() != 'cli') {
    throw new Exception('This application must be run on the command line.');
}

/**
 * Returns an authorized API client.
 * @return Google_Client the authorized client object
 */
function getClient()
{
    $client = new Google_Client();
    $client->setApplicationName('Google Calendar API PHP Quickstart');
    $client->setScopes(Google_Service_Calendar::CALENDAR_READONLY);
    $client->setAuthConfig('credentials.json');
    $client->setAccessType('offline');
    $client->setPrompt('select_account consent');

    // Load previously authorized token from a file, if it exists.
    // The file token.json stores the user's access and refresh tokens, and is
    // created automatically when the authorization flow completes for the first
    // time.
    $tokenPath = 'token.json';
    if (file_exists($tokenPath)) {
        $accessToken = json_decode(file_get_contents($tokenPath), true);
        $client->setAccessToken($accessToken);
    }

    // If there is no previous token or it's expired.
    if ($client->isAccessTokenExpired()) {
        // Refresh the token if possible, else fetch a new one.
        if ($client->getRefreshToken()) {
            $client->fetchAccessTokenWithRefreshToken($client->getRefreshToken());
        } else {
            // Request authorization from the user.
            $authUrl = $client->createAuthUrl();
            printf("Open the following link in your browser:\n%s\n", $authUrl);
            print 'Enter verification code: ';
            $authCode = trim(fgets(STDIN));

            // Exchange authorization code for an access token.
            $accessToken = $client->fetchAccessTokenWithAuthCode($authCode);
            $client->setAccessToken($accessToken);

            // Check to see if there was an error.
            if (array_key_exists('error', $accessToken)) {
                throw new Exception(join(', ', $accessToken));
            }
        }
        // Save the token to a file.
        if (!file_exists(dirname($tokenPath))) {
            mkdir(dirname($tokenPath), 0700, true);
        }
        file_put_contents($tokenPath, json_encode($client->getAccessToken()));
    }
    return $client;
}


// Get the API client and construct the service object.
$client = getClient();
$service = new Google_Service_Calendar($client);

// Print the next 10 events on the user's calendar.
$calendarId = 'primary';
$optParams = array(
  'maxResults' => 10,
  'orderBy' => 'startTime',
  'singleEvents' => true,
  'timeMin' => date('c'),
);
$results = $service->events->listEvents($calendarId, $optParams);
$events = $results->getItems();

if (empty($events)) {
    print "No upcoming events found.\n";
} else {
    print "Upcoming events:\n";
    foreach ($events as $event) {
        $start = $event->start->dateTime;
        if (empty($start)) {
            $start = $event->start->date;
        }
        printf("%s (%s)\n", $event->getSummary(), $start);
    }
}

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