如何在本地开发环境中使用WordPress安装Tollmanz Memcached对象缓存

Question

Zack Tollmanz has written a new Memcached Object Cache Library for WordPress. This library is based on the WordPress Memcache Plugin developed by Ryan Boren .

WordPress comes with a default Object Cache . This default Cache can be replaced by copying a file called object-cache.php file into the root of the wp-content folder. The object-cache.php file would contain an implementation of the replacement Object Cache.

The Tollmanz Memcached Object Cache Library is not a Plugin. It is a replacement version of the object-cache.php file. Here is the Tollmanz source code and installation instructions . The problem is that the Tollmanz Library assumes that the PECL Memcached library is installed in the Development Environment and that a Memcache Server instance exists. We have multiple developers on our project and need to be able to work in local Development Environments (like laptops) where Memcached is not installed. The Memcache Servers and PECL libraries of course are installed in our Integration and Production Environments.

The question is how to setup the Tollmanz Memcached Object Cache Library in a way that it can be used in local environments that do not have Memcached installed?

Answer 1

Good question John. The answer is to create a "stub" object-cache.php file and place it into the root of the wp-content folder. This "stub' file can check an Environment Constant to determine whether to load the Tollmanz Memcached Object Cache Library. If the Tollmanz Memcached Cache is not loaded then WordPress will revert to its default Object Cache.

To summarize:

1. Follow the Tollmanz installations instructions
2. Copy the Tollmanz object-cache.php file into a new "plugins" folder. This example used a folder called: /plugins/pecl-memcached-object-cache/
3. Copy the below "stub" object-cache.php file into the /wp-content folder. WordPress will load this file during the object cache setup part of the bootstrap sequence.
4. If a Constant called MEMCACHED_IS_ENABLED is defined in the wp-confile.php file then the "stub" will load the Tollmanz Object Cache. Otherwise it does nothing and the default WordPress Object Cache is used.
5. The source code for the "stub" object-cache.php file is listed below.

    <?php
    //
    // WordPress PECL Memcached Object Cache Stub File
    //
    // Name this file "object-cache.php" and place in the root of the /wp-content folder.  
    //
    // This "stub" file integrates WordPress with the Tollmanz PECL Memcached Object Cache
    // https://github.com/tollmanz/wordpress-pecl-memcached-object-cache
    //
    // This Constant can be defined in the wp-config.php file.
    if (defined('MEMCACHED_IS_ENABLED') && MEMCACHED_IS_ENABLED) {  

        // The Tollmanz Memcached Object Cache uses this global variable for the list of Memcached Servers
        global $memcached_servers;
        $memcached_servers = array(
            array(
                '127.0.0.1', // Memcached server IP address
                11211        // Memcached server port
            )
        );

        // Load the Tollmanz Memcached Library  
        // This example assumes that the Library file was copied to a plugins folder called "pecl-memcached-object-cache".
        $memcache_plugin_file = dirname(__FILE__) . '/plugins/pecl-memcached-object-cache/object-cache.php';
        require_once($memcache_plugin_file);
    }