iCal to JSON (for FullCalendar)

<?php
/* 
    Output a JSON array that can be consumed by FullCalendar (fullcalendar.io).
    
    This uses code.google.com/p/ics-parser which is problematic because it doesn't handle recurring events.
    
    TODO: Rewrite it to use github.com/johngrogg/ics-parser as that seems to support recurring events and more.
*/

// Include the iCal Reader library
require_once('lib/ics-parser.php');
// Change this to use iCalReader instead!
//require_once('lib/class.iCalReader.php');

// Initialize the iCal Reader
$ical   = new ICal('https://calendar.example.com/path/to/your/calendar.ics');

// Get Unix timestamps for 12:00AM today, and 12:00AM tomorrow.
$beginningOfToday = mktime( 0, 0, 0, date("n"), date("j"), date("Y") );
$beginningOfTomorrow = $beginningOfToday + 86400;

// Use those to define a time range for the iCal library, and get the events
$events = $ical->eventsFromRange($beginningOfToday, $beginningOfTomorrow);


// We only need some information from each event
// Create an empty array to store our "processed" versions.
$out = array();

// Loop thru events from the iCal reader
foreach ($events as $event) {

    // Convert the start and end times to Unix timestamps
    $start = strtotime($event['DTSTART']);
    $end = strtotime($event['DTEND']);
    
    // Determine if its an "All-Day" event
    if ($end - $start == 86400) $allday = true;
    else $allday = false;
    
    // This is hacky. If we use a public iCal feed from Zimbra, it won't
    // contain any private events at all. I *want* to display the private
    // events, so people see that I'm busy, but I don't want to display
    // the event details. So I use a private iCal and replace the name
    // of any events flagged as "PRIVATE" with "Private Event".
    if ($event['CLASS'] !== "PUBLIC") $event['SUMMARY'] = "Private Event";

    // Put the collected data into our "out" array.
    $out[] = array(
        "title" => $event['SUMMARY'],
        "allDay" => $allday,
        "start" => $start,
        "end" => $end,
    );
}

// Send a JSON header to comply with HTTP protocol.
header("Content-type: application/json");

// Convert the "out" array into a JSON string and send it.
echo json_encode($out);
?>