[Plugin: W3 Total Cache] varnish cache not purged – sends GET requests instead of PURGE

Hi,thanks for writing W3TC. It’s pretty awesome.

However I’ve encountered an issue with varnish cache purging.

I did the folowing:

1. enabled varnish purges
2. set the blog’s domain as a varnish server URL
3. enabled varnish debugging

varnishlog and also w3tc’s varnish debugging log show that GET requests have been sent to varnish instead of PURGE.

Although I am far from being expert on PHP, after looking at the code I noticed that w3tc uses the WP_Http class to send the PURGE requests. The WP_Http class documentation states the following:

Accepted ‘method’ values are ‘GET’, ‘POST’, and ‘HEAD’, some transports technically allow others, but should not be assumed.

I’ve searched the web, but haven’t found much information.

Will this be fixed?

I currently modified w3-total-cache/lib/W3/Varnish.php like shown below.

<?php

/**
 * Varnish purge object
 */

/**
 * Class W3_Varnish
 */
class W3_Varnish {
    /**
     * Debug flag
     *
     * @var bool
     */
    var $_debug = false;

    /**
     * Varnish servers
     *
     * @var array
     */
    var $_servers = array();

    /**
     * Operation timeout
     *
     * @var int
     */
    var $_timeout = 30;

    /**
     * PHP5-style constructor
     */
    function __construct() {
        $config = & w3_instance('W3_Config');

        $this->_debug = $config->get_boolean('varnish.debug');
        $this->_servers = $config->get_array('varnish.servers');
        $this->_timeout = $config->get_integer('timelimit.varnish_purge');
    }

    /**
     * PHP4-style constructor
     */
    function W3_Varnish() {
        $this->__construct();
    }

    /**
     * Purge URI
     *
     * @param string $uri
     * @return boolean
     */
    function purge($uri) {
        require_once W3TC_INC_DIR . '/functions/http.php';

        @set_time_limit($this->_timeout);

        if (strpos($uri, '/') !== 0) {
            $uri = '/' . $uri;
        }

        foreach ((array) $this->_servers as $server) {
            $url = sprintf('http://%s%s', $server, $uri);

	    $ch = curl_init();
	    curl_setopt($ch, CURLOPT_TIMEOUT, 5);
	    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 2);
	    curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'PURGE');
	    curl_setopt($ch, CURLOPT_URL, $url);
	    curl_setopt($ch, CURLOPT_USERAGENT, W3TC_POWERED_BY);
	    curl_exec($ch);
	    if (!curl_errno($ch)) {
		$respinfo = curl_getinfo($ch);
	        $this->_log($url, $respinfo['http_code'] . ' (' . $respinfo['total_time'] . ' sec)');
	    } else {
		$this->_log($url, 'Curl error: ' . curl_error($ch));
	    }
	    curl_close ($ch);
	    unset($ch);
	}

        return true;
    }

    /**
     * Write log entry
     *
     * @param string $url
     * @param string $error
     * @return bool|int
     */
    function _log($url, $error) {
        if ($this->_debug) {
            $data = sprintf("[%s] [%s] %s\n", date('r'), $url, $error);

            return @file_put_contents(W3TC_VARNISH_LOG_FILE, $data, FILE_APPEND);
        }

        return true;
    }
}

It works, but some PURGE requests take long to complete and time out.

Thanks for your insight.

http://wordpress.org/extend/plugins/w3-total-cache/