Newsapps Varnish plugin for Wordpress (handles targeted invalidation)

newsapps-varnish-admin.php

<?php
	if($_POST['varnish_hidden'] == 'Y') {
		//Process form data
		$varnish_server1 = (!isset($_POST['varnish_server1'])? '': $_POST['varnish_server1']);
		update_site_option('varnish_server1', $varnish_server1);
		
		$varnish_server2 = (!isset($_POST['varnish_server2'])? '': $_POST['varnish_server2']);
		update_site_option('varnish_server2', $varnish_server2);
		
		$varnish_server3 = (!isset($_POST['varnish_server3'])? '': $_POST['varnish_server3']);
		update_site_option('varnish_server3', $varnish_server3);
		
		$varnish_server4 = (!isset($_POST['varnish_server4'])? '': $_POST['varnish_server4']);
		update_site_option('varnish_server4', $varnish_server4);

		$varnish_debug = (!isset($_POST['varnish_debug'])? '': $_POST['varnish_debug']);
		update_site_option('varnish_debug', $varnish_debug);

		?>
		<div class="updated"><p><strong><?php _e('Options saved.' ); ?></strong></p></div>
		<?php
	} else {
		$varnish_server1 = get_site_option('varnish_server1');
		$varnish_server2 = get_site_option('varnish_server2');
		$varnish_server3 = get_site_option('varnish_server3');
		$varnish_server4 = get_site_option('varnish_server4');
		$varnish_debug = get_site_option('varnish_debug');
	}
?>

<div class="wrap">
	<h2>Newsapps Varnish</h2>
	<form name="varnish" method="post" action="<?php echo str_replace( '%7E', '~', $_SERVER['REQUEST_URI']); ?>">
		<input type="hidden" name="varnish_hidden" value="Y">
		
		<h4>Varnish Servers</h4>
		<p>Enter up to four server hostnames (or IP addresses).<br />If the server is running on a port other than 80, enter it after the hostname, separated by a colon.</p>
		<div>
			<p><?php _e("Hostname 1: "); ?><input type="text" name="varnish_server1" value="<?php echo $varnish_server1 ?>" /> (Example: localhost:80)</p>
			<p><?php _e("Hostname 2: "); ?><input type="text" name="varnish_server2" value="<?php echo $varnish_server2 ?>" /></p>
			<p><?php _e("Hostname 3: "); ?><input type="text" name="varnish_server3" value="<?php echo $varnish_server3 ?>" /></p>
			<p><?php _e("Hostname 4: "); ?><input type="text" name="varnish_server4" value="<?php echo $varnish_server4 ?>" /></p>
		</div>

        <div>
            <p><input type="checkbox" name="varnish_debug" value="True" <?php if ($varnish_debug == 'True') { echo 'checked'; } ?>/> Enable debug mode (log cache purges to PHP error_log)</input></p>
        </div>
	
		 <p class="submit"><input type="submit" name="Submit" value="Update Options" /></p>
	
	</form>
</div>

newsapps-varnish.php

<?php
/*
Plugin Name: Newsapps Varnish
Plugin URI: http://apps.chicagotribune.com
Version: 0.2
Author: Chris Groskopf, Brian Boyer, inspired by http://github.com/pkhamre/wp-varnish
Description: Purges varnish cache when posts are changed.
Network: true
*/

class NewsAppsVarnish {

	function NewsAppsVarnish() {
		add_action('network_admin_menu', array(&$this, 'VarnishAdminActions'));
		add_action('save_post', array(&$this, 'PurgePost'), 99);
		add_action('edit_comment', array(&$this, 'PurgePostOnComment'), 99);
		add_action('comment_post', array(&$this, 'PurgePostOnComment'), 99);
		add_action('wp_set_comment_status', array(&$this, 'PurgePostOnComment'), 99);
	}

	function VarnishAdmin() {
		include('newsapps-varnish-admin.php');
	}

    function VarnishAdminActions($args) {
        add_menu_page(
            "Varnish",
            "Varnish",
            "manage_network_options",
            "varnish_admin_actions_file_str",
            array(&$this, 'VarnishAdmin')
        );
	}

	function PurgePost($post_id) {
		//if the permalink doesn't end with autosave -- wordpress fires edit_post on autosave. wheee.
		//also, save is called twice, once for your update, and once for updating the revision, which we don't care about busting.
        //if this ends up being weird, maybe check out wp_is_post_revision?
        $debug = (get_site_option('varnish_debug') == 'True') ? True : False ;
        
        $post = get_post($post_id);

        if ($post->post_status == 'auto-draft') {
            if ($debug) {
                error_log('Skipped purging auto-draft.');
            }
            return;
        }

        if ($post->post_status == 'draft') {
            if ($debug) {
                error_log('Skipped purging draft.');
            }
            return;
        }

        if ($post->post_status == 'inherit') {
            if ($debug) {
                error_log('Skipped purging inherit (attached image).');
            }
            return;
        }

		$post_host = parse_url(get_permalink($post_id), PHP_URL_HOST);
		$site_host = parse_url(get_bloginfo('wpurl'), PHP_URL_HOST);
		$post_path = parse_url(get_permalink($post_id), PHP_URL_PATH);
		$blog_path = parse_url(get_bloginfo('wpurl'), PHP_URL_PATH);
		
		if(!preg_match('/(autosave|\d+-revision)/', $post_path)) {
			$to_purge = array();
			
            array_push($to_purge, $post_path);
            
            if ($blog_path) {
                array_push($to_purge, $blog_path . '/');
                array_push($to_purge, $blog_path . '/rss/');
                array_push($to_purge, $blog_path . '/sitemap-web.xml');
                array_push($to_purge, $blog_path . '/sitemap-news-google.xml');
                array_push($to_purge, $blog_path . '/sitemap-news-yahoo.xml');
			}

			$this->Purge($to_purge);
		}
	}
	
	function PurgePostOnComment($comment_id) {
		$comment = get_comment($comment_id, ARRAY_A);
		$post_id = $comment['comment_post_ID'];
        $post_path = parse_url(get_permalink($post_id), PHP_URL_PATH);
		$this->Purge($post_path);
	}
	
	function Purge($urls) {
		$servers = array();
		$servers[0] = get_site_option('varnish_server1');
		$servers[1] = get_site_option('varnish_server2');
		$servers[2] = get_site_option('varnish_server3');
		$servers[3] = get_site_option('varnish_server4');
        $debug = (get_site_option('varnish_debug') == 'True') ? True : False ;
		
		// Accept strings as well as arrays
		if(is_string($urls)){
			$urls = array($urls);
		}
		// Note: Purge wants unescaped periods
		$urls_regex = '(' . implode('|', $urls) . ')$'; 
		
		$blog_hostname = parse_url(get_bloginfo('wpurl'), PHP_URL_HOST);

        // Construct purge request
		$purge = "PURGE $urls_regex HTTP/1.0\r\n";
		$purge .= "Host: $blog_hostname\r\n";
		$purge .= "Connection: Close\r\n\r\n";
		
		foreach($servers as $server) {
			if (empty($server)) {
				continue;
			}
			
			if ($p = strpos($server, ':')) {
				$varnish_host = substr($server, 0, $p);
				$varnish_port = substr($server, $p + 1);
			} else {
				$varnish_host = $server;
				$varnish_port = "80";
			}
			
			$varnish_sock = fsockopen($varnish_host, $varnish_port, $errno, $errstr, 30);

            // Log response
			if (!$varnish_sock) {
                if ($debug) {
                    error_log("NEWSAPPS-VARNISH: $errstr ($errno)");
                }
			} else {	
                if ($debug) {
                    error_log("NEWSAPPS-VARNISH: $purge");
                }

				fwrite($varnish_sock, $purge);
				fclose($varnish_sock);
			}
		}
	}
}

$varnish = & new NewsAppsVarnish();
?>