PHP Code - Google Calendar using Zend GData

glogin.php

<?php
require_once 'Zend/Loader.php';
Zend_Loader::loadClass('Zend_Gdata');
Zend_Loader::loadClass('Zend_Gdata_AuthSub');
Zend_Loader::loadClass('Zend_Gdata_Calendar');
Zend_Loader::loadClass('Zend_Gdata_Calendar_ListFeed');
Zend_Loader::loadClass('Zend_Http_Client');
Zend_Loader::loadClass('Zend_Gdata_App_Exception');
Zend_Loader::loadClass('Zend_Gdata_Calendar_ListEntry');

/** Retrieve the current URL so that the AuthSub server knows where to
 * redirect the user after authentication is complete.
 */
function getCurrentUrl() {
	global $_SERVER;
	// Filter php_self to avoid a security vulnerability.
	$php_request_uri = htmlentities(substr($_SERVER['REQUEST_URI'], 0, strcspn($_SERVER['REQUEST_URI'], "\n\r")), ENT_QUOTES);
	if (isset($_SERVER['HTTPS']) && strtolower($_SERVER['HTTPS']) == 'on') {
		$protocol = 'https://';
	} else {
		$protocol = 'http://';
	}
	$host = $_SERVER['HTTP_HOST'];
	if ($_SERVER['HTTP_PORT'] != '' &&
		(($protocol == 'http://' && $_SERVER['HTTP_PORT'] != '80') ||
		($protocol == 'https://' && $_SERVER['HTTP_PORT'] != '443'))) {
			$port = ':' . $_SERVER['HTTP_PORT'];
		} else {
			$port = '';
		}
	return $protocol . $host . $port . $php_request_uri;
}

/** Obtain an AuthSub authenticated HTTP client, redirecting the user to the
 *  AuthSub server to login if necessary.
 */
function getAuthSubHttpClient() {
	global $_SESSION, $_GET;

	// If there is no AuthSub session or one-time token waiting for us,
	// redirect the user to the AuthSub server to get one.
	if (!isset($_SESSION['sessionToken']) && !isset($_GET['token'])) {
		// Parameters to give to AuthSub server
		$next = getCurrentUrl();
		$scope = "http://www.google.com/calendar/feeds/";
		$secure = false;
		$session = true;

		// Redirect the user to the AuthSub server to sign in
		$authSubUrl = Zend_Gdata_AuthSub::getAuthSubTokenUri($next, $scope, $secure, $session);
		header("HTTP/1.0 307 Temporary redirect");
		header("Location: " . $authSubUrl);
		exit();
	}

	// Convert an AuthSub one-time token into a session token if needed
	if (!isset($_SESSION['sessionToken']) && isset($_GET['token'])) {
		$_SESSION['sessionToken'] =
			Zend_Gdata_AuthSub::getAuthSubSessionToken($_GET['token']);
	}

	// At this point we are authenticated via AuthSub and can obtain an
	// authenticated HTTP client instance
	// Create an authenticated HTTP client
	$client = Zend_Gdata_AuthSub::getHttpClient($_SESSION['sessionToken']);
	return $client;
}

// -> Script execution begins here <-
// Make sure http://code.google.com/apis/gdata/reference.html#Queriesthat the user has a valid session, so we can record the
// AuthSub session token once it is available.
session_start();
// Create an instance of the Calendar service, redirecting the user
// to the AuthSub server if necessary.
$httpClient = getAuthSubHttpClient();
$service = new Zend_Gdata_Calendar($httpClient);
try {
	$listFeed= $service->getCalendarListFeed();
	echo "<h1>Calendar List Feed</h1>";
	echo "<ul>";
	foreach ($listFeed as $calendar) {
		echo "<li>" . $calendar->title .
			" (Event Feed: " . $calendar->id . ")</li>";
	}
	echo "</ul>";
} catch (Zend_Gdata_App_Exception $e) {
	echo "Error: " . $e->getMessage();
}

?>