Simple Foursquare last checkin proxy

whereami.php

<?php
/**
 * Foursquare last checkin proxy
 *
 * Setup:
 * Create file .token with your OAuth token. (You can get it here: https://elie.im/foursquare)
 *
 * Usage:
 * //example.com/whereami.php?callback=func
 *
 * @author Artem Sapegin
 * @copyright 2012 Artem Sapegin (sapegin.me)
 * @license MIT
 */

function get_last_checkin() {
	$curl = curl_init();
	curl_setopt_array($curl, array(
		CURLOPT_HTTPHEADER => array('Content-type: application/json'),
		CURLOPT_RETURNTRANSFER => true,
		CURLOPT_SSL_VERIFYPEER => false,
		CURLOPT_URL => 'https://api.foursquare.com/v2/users/self/checkins?limit=1&oauth_token=' . OAUTH_TOKEN . '&v=' . date('Ymd')
	));
	$result = curl_exec($curl);
	curl_close($curl);

	if ($result) {
		return $result;
	}
	return false;
}

define('OAUTH_TOKEN', file_get_contents('.token'));

if (!OAUTH_TOKEN || empty($_GET['callback'])) {
	header('HTTP/1.0 400 Bad request');
	exit();
}

header('Content-type: application/x-javascript; charset=UTF-8');
print $_GET['callback'] . "('" . get_last_checkin() . "')";

?>