Automatically access google calendar - php

Question

I need help dealing with google calendar. My code is below:
<?php
require_once 'google-api-php-client/src/Google_Client.php';
require_once 'google-api-php-client/src/contrib/Google_CalendarService.php';
session_start();
$client = new Google_Client();
$client->setApplicationName("Google Calendar PHP Starter Application");
// Visit https://code.google.com/apis/console?api=calendar to generate your
// client id, client secret, and to register your redirect uri.
$client->setClientId('client id');
$client->setClientSecret('client secret');
$client->setRedirectUri('redirect uri');
$client->setDeveloperKey('developer key');
$cal = new Google_CalendarService($client);
if (isset($_GET['logout'])) {
unset($_SESSION['token']);
}
if (isset($_GET['code'])) {
$client->authenticate($_GET['code']);
$_SESSION['token'] = $client->getAccessToken();
header('Location: http://' . $_SERVER['HTTP_HOST'] . $_SERVER['PHP_SELF']);
exit();
}
if (isset($_SESSION['token'])) {
$client->setAccessToken($_SESSION['token']);
}
if ($client->getAccessToken()) {
$calList = $cal->calendarList->listCalendarList();
print "<h1>Calendar List</h1><pre>" . print_r($calList, true) . "</pre>";
$_SESSION['token'] = $client->getAccessToken();
// Create a new event and display it.
// Caution: every time you run this script a new event is created. Oh well.
$event = new Google_Event();
$event->setSummary('Appointment');
$event->setLocation('Somewhere');
$start = new Google_EventDateTime();
$start->setDateTime('2013-08-24T10:00:00.000-07:00');
$event->setStart($start);
$end = new Google_EventDateTime();
$end->setDateTime('2013-08-25T10:25:00.000-07:00');
$event->setEnd($end);
$createdEvent = $cal->events->insert('primary', $event);
$events = $cal->events->listEvents('primary');
echo "<pre>" . print_r($events, true) . "</pre>";
}
else {
$authUrl = $client->createAuthUrl();
print "<a class='login' href='$authUrl'>Connect Me!</a>";
exit();
}
?>
Basically this code has a connect me link and when clicked, asks the user to input their gmail account. However, I want to skip this entire process of allowing the person to enter their username and password information and just add the event when I run this code. Does the idea of using service account for google api access solve this or does it involve storing a token in a database and constantly changing it work (which I am struggling to do)? Any help would be appreciated.