Facebook calendar parser (add wordwrap after 75 characters in line)

facebook-calendar.php

<?php
error_reporting(0);
ini_set('display_errors', false);

# VALIDATION
if (!isset($_GET['uid'], $_GET['key'], $_GET['type'])) {
    http_response_code(400);
    die('No request params!');
}

if (!preg_match("'^([0-9]+)$'", $_GET['uid'])) {
    http_response_code(400);
    die('Invalid "user ID" request parameter!');
}

if (!preg_match("'^([A-Za-z0-9-]+)$'", $_GET['key'])) {
    http_response_code(400);
    die('Invalid "key" request parameter!');
}

if (!preg_match("'^(upcoming|birthdays)$'", $_GET['type'])) {
    http_response_code(400);
    die('Invalid "type" request parameter!');
}

# RESPONSE
header("Cache-Control: no-store, no-cache, must-revalidate, max-age=0");
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache");

# DOWNLOAD CALENDAR FROM FACEBOOK
$urlPattern = 'https://www.facebook.com/events/ical/%s/?uid=%s&key=%s';
$url = sprintf($urlPattern, $_GET['type'], $_GET['uid'], $_GET['key']);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.12) Gecko/20101026 Firefox/3.6.12');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$response = curl_exec($ch);
curl_close($ch);

if (!preg_match("'^BEGIN:VCALENDAR'", $response)) {
    http_response_code(400);
    die(sprintf('Invalid Facebook content response: %s', $response));
}

# FORMAT LINES
header('Content-type: text/calendar; charset=utf-8');
$endline = "\r\n";
$response = str_replace('X-ORIGINAL-URL:/events/', 'X-ORIGINAL-URL:https://facebook.com/events/', $response);
$response = str_replace('X-PUBLISHED-TTL:PT12H', 'X-PUBLISHED-TTL:P1H', $response);
$response = str_replace('BEGIN:VEVENT', $endline . 'BEGIN:VEVENT', $response);
$response = str_replace('END:VCALENDAR', $endline . 'END:VCALENDAR', $response);
$response = str_replace("\r", '', $response);
$lines = explode("\n", $response);
foreach ($lines as $line) {
    if (preg_match("'^(ORGANIZER|SUMMARY)'", $line)) {
        $line = str_replace('"', '', $line);
    }
    echo wordwrap($line, 75, $endline . " ", true) . $endline;
}