iCal Feed

<?php
/*
Plugin Name: iCal Posts
Plugin URI: http://www.kinggary.com/archives/build-an-ical-feed-from-your-wordpress-posts-plugin
Description: Creates an iCal feed which can be added to calendar applications such as Google Calendar and Microsoft Outlook to create a visual representation of your blog posting.
Version: 1.0
Author: Gary King
Author URI: http://www.kinggary.com/
*/

function ical_feed()
{
    global $wpdb;
    
    if (isset($_GET['debug']))
        define('DEBUG', true);
    
    if ($_GET['category'])
    {
        $categories = get_categories();
        foreach ($categories as $category)
        {
            if ($_GET['category'] == $category->category_nicename)
            {
                $category_id = $category->cat_ID;
                break;
            }
        }
        if (!$category_id)
            $category_id = 0;
    }
    
    if (is_numeric($_GET['limit']))
        $limit = 'LIMIT ' . $_GET['limit'];
    
    // get posts
    if ($_GET['category'])
        $posts = $wpdb->get_results("SELECT $wpdb->posts.ID, UNIX_TIMESTAMP(post_date) AS post_date, post_title FROM $wpdb->posts LEFT JOIN $wpdb->post2cat ON ($wpdb->post2cat.post_id = $wpdb->posts.ID) WHERE post_status = 'publish' AND post_type = 'post' AND $wpdb->post2cat.category_id = $category_id ORDER BY post_date DESC $limit;");
    else
        $posts = $wpdb->get_results("SELECT ID, post_content, UNIX_TIMESTAMP(post_date) AS post_date, post_title FROM $wpdb->posts WHERE post_status = 'publish' AND post_type = 'post' ORDER BY post_date DESC $limit;");
    
    $events = '';
    $space = '      ';
    foreach ($posts as $post)
    {
        $start_time = date('Ymd\THis', $post->post_date);
        $end_time = date('Ymd\THis', $post->post_date + (60 * 60));
        $summary = $post->post_title;
        $permalink = get_permalink($post->ID);
        if (isset($_GET['content']))
        {
            $content = str_replace(',', '\,', str_replace('\\', '\\\\', str_replace("\n", "\n" . $space, strip_tags($post->post_content))));
            $content = $permalink . "\n" . $space . "\n" . $space . $content;
        }
        else
            $content = $permalink;
        
        $events .= <<<EVENT
BEGIN:VEVENT
DTSTART:$start_time
DTEND:$end_time
SUMMARY:$summary
DESCRIPTION:$content
END:VEVENT

EVENT;
    }
    
    $blog_name = get_bloginfo('name');
    $blog_url = get_bloginfo('home');
    
    if (!defined('DEBUG'))
    {
        header('Content-type: text/calendar');
        header('Content-Disposition: attachment; filename="blog_posts.ics"');
    }
    
    $apostrophe = (isset($_GET['content']) ? "'" : '&#8217;');
    
    $content = <<<CONTENT
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//$blog_name//NONSGML v1.0//EN
X-WR-CALNAME:{$blog_name}{$apostrophe}s posts
X-WR-TIMEZONE:US/Eastern
X-ORIGINAL-URL:{$blog_url}
X-WR-CALDESC:Blog posts from {$blog_name}
CALSCALE:GREGORIAN
METHOD:PUBLISH
{$events}END:VCALENDAR
CONTENT;
    
    echo $content;
    
    exit;
}

if (isset($_GET['ical']))
{
    add_action('init', 'ical_feed');
}

?>