使用Cron的Google API日历

I am trying to access to a calendar created by my application via cron, and I get a calendar with the same name that the calendar the application creates, but the id is absolutely different... This is my code:

public function cronTest()
{
    $this->g_client = new Google_Client();
    $this->g_client->setApplicationName($this->config->item("APPLICATION_NAME"));
    $service    = $this->getCronService("CalendarTest-46bde015a16.p12");
    $calendar   = $this->getCalendar($service);
}
private function getCronService($file)
{
    $key  = file_get_contents(CREDENTIALS_PATH.$file); 
    $cred = new Google_Auth_AssertionCredentials($this->config->item("google_service_id"), SCOPES, $key);
    $this->g_client->setAssertionCredentials($cred);
    if($this->g_client->getAuth()->isAccessTokenExpired())
         $this->g_client->getAuth()->refreshTokenWithAssertion($cred);
    return new Google_Service_Calendar($this->g_client);
}
private function getCalendar($service)
{
    $calendarList = $service->calendarList->listCalendarList();
    echo "getCalendar<br>";
    foreach ($calendarList->getItems() as $calendarListEntry)
    {
        echo $calendarListEntry->getSummary()." with id:".$calendarListEntry->getId()."<br>";
        echo "<br>";
        if($calendarListEntry->getSummary()=="Auto-Citas")
            echo "found";
            //return $calendarListEntry->getId();
    }
    die;
}

When I execute it from the command line (simulating the cron):

wget www.domain.com/prototipo/alien/cronTest

I get this:

Calendar  
Auto-Citas with id:h0gefmo7vjqlr4lp0r2n93vk9c@group.calendar.google.com  
found

But, the id of calendar created with this application doesn´t match with this id...
Before this attempt with ron, I had to learn how to use the API, in this way I needed to remove sometimes the same calendar. So what I do, was remove one more time the Auto-Citas on my calendar, and call the function on my app to create a new calendar with a different name, then I made again the request of the "simulated cron" (wget www.domain.com/prototipo/alien/cronTest) and the result is the same than before: only one calendar called Auto-Citas, but nothing about the new calendar.
The functionality is to create a module anti-absenteeism, sending an email or sms to the user two hours before the appointment(cita=appointment)
For this tasks I have to function more... but they aren´t important for the case:

$events     = $this->getDates($service,$calendar,$min,$max);
$this->transformDates($events, $service, ",phone");

Ok... I find solution just here (the google official docs). I need to use the option of user_to_impersonate.

$client_email = '1234567890-a1b2c3d4e5f6g7h8i@developer.gserviceaccount.com';
$private_key = file_get_contents('MyProject.p12');
$scopes = implode(' ', array(Google_Service_Calendar::CALENDAR));
$user_to_impersonate = 'user@example.org';
$credentials = new Google_Auth_AssertionCredentials(
    $client_email,
    $scopes,
    $private_key,
    'notasecret',                                 // Default P12 password
    'http://oauth.net/grant_type/jwt/1.0/bearer', // Default grant type
    $user_to_impersonate,
);