使用Redis缓存来加速WordPress网站

How to load WordPress in a few milliseconds using Redis

Redis is an advanced key-value store. Like memcached on steroids. Everything is in the RAM and you can theoretically reach 100 000 GET per second with Redis.
My solution below will cache all the HTML output in Redis and display it without the need to load WordPress.
A big thanks to Jeedo Aquino who have rewritten and improved my original solution. Details here. This article updated on the October 25, 2012 with the new code.
If you don’t already have your own VPS or server – do these steps first: Guide: WordPress with Maximum Performance and Speed.

Installing Redis

If you are using Debian then just:

apt-get install redis-server

Or else, just see the installation instructions.

Using Predis as a PHP client for Redis

You need a client in order to use PHP to communicate with Redis.
I recommend Predis. Upload predis.php to the WordPress root directory. See more about Predis on Github (if you use a newer version of Predis you need also to modify the script below).

Installing the PHP script for the Frontend Cache

Step 1:

Add the code below to a new file called index-with-redis.php and place it in the WordPress root directory.

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<?php   /* Author: Jim Westergren & Jeedo Aquino File: index-with-redis.php Updated: 2012-10-25   This is a redis caching system for wordpress. see more here: www.jimwestergren.com/wordpress-with-redis-as-a-frontend-cache/   Originally written by Jim Westergren but improved by Jeedo Aquino.   some caching mechanics are different from jim's script which is summarized below:   - cached pages do not expire not unless explicitly deleted or reset - appending a ?c=y to a url deletes the entire cache of the domain, only works when you are logged in - appending a ?r=y to a url deletes the cache of that url - submitting a comment deletes the cache of that page - refreshing (f5) a page deletes the cache of that page - includes a debug mode, stats are displayed at the bottom most part after </html>   for setup and configuration see more here:   www.jeedo.net/lightning-fast-wordpress-with-nginx-redis/   use this script at your own risk. i currently use this albeit a slightly modified version to display a redis badge whenever a cache is displayed.   */   // change vars here $cf = 1; // set to 1 if you are using cloudflare $debug = 0; // set to 1 if you wish to see execution time and cache actions $display_powered_by_redis = 1; // set to 1 if you want to display a powered by redis message with execution time, see below   $start = microtime(); // start timing page exec   // if cloudflare is enabled if ($cf) { if (isset($_SERVER['HTTP_CF_CONNECTING_IP'])) { $_SERVER['REMOTE_ADDR'] = $_SERVER['HTTP_CF_CONNECTING_IP']; } }   // from wp define('WP_USE_THEMES', true);   // init predis include("predis.php"); $redis = new Predis\Client('');   // init vars $domain = $_SERVER['HTTP_HOST']; $url = "http://".$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI']; $url = str_replace('?r=y', '', $url); $url = str_replace('?c=y', '', $url); $dkey = md5($domain); $ukey = md5($url);   // check if page isn't a comment submission (isset($_SERVER['HTTP_CACHE_CONTROL']) && $_SERVER['HTTP_CACHE_CONTROL'] == 'max-age=0') ? $submit = 1 : $submit = 0;   // check if logged in to wp $cookie = var_export($_COOKIE, true); $loggedin = preg_match("/wordpress_logged_in/", $cookie);   // check if a cache of the page exists if ($redis->hexists($dkey, $ukey) && !$loggedin && !$submit && !strpos($url, '/feed/')) {   echo $redis->hget($dkey, $ukey); $cached = 1; $msg = 'this is a cache';   // if a comment was submitted or clear page cache request was made delete cache of page } else if ($submit || substr($_SERVER['REQUEST_URI'], -4) == '?r=y') {   require('./wp-blog-header.php'); $redis->hdel($dkey, $ukey); $msg = 'cache of page deleted';   // delete entire cache, works only if logged in } else if ($loggedin && substr($_SERVER['REQUEST_URI'], -4) == '?c=y') {   require('./wp-blog-header.php'); if ($redis->exists($dkey)) { $redis->del($dkey); $msg = 'domain cache flushed'; } else { $msg = 'no cache to flush'; }   // if logged in don't cache anything } else if ($loggedin) {   require('./wp-blog-header.php'); $msg = 'not cached';   // cache the page } else {   // turn on output buffering ob_start();   require('./wp-blog-header.php');   // get contents of output buffer $html = ob_get_contents();   // clean output buffer ob_end_clean(); echo $html;   // Store to cache only if the page exist and is not a search result. if (!is_404() && !is_search()) { // store html contents to redis cache $redis->hset($dkey, $ukey, $html); $msg = 'cache is set'; } }   $end = microtime(); // get end execution time   // show messages if debug is enabled if ($debug) { echo $msg.': '; echo t_exec($start, $end); }   if ($cached && $display_powered_by_redis) { // You should move this CSS to your CSS file and change the: float:right;margin:20px 0; echo "<style>#redis_powered{float:right;margin:20px 0;background:url(http://images.staticjw.com/jim/3959/redis.png) 10px no-repeat #fff;border:1px solid #D7D8DF;padding:10px;width:190px;} #redis_powered div{width:190px;text-align:right;font:10px/11px arial,sans-serif;color:#000;}</style>"; echo "<a href=\"http://www.jimwestergren.com/wordpress-with-redis-as-a-frontend-cache/\" style=\"text-decoration:none;\"><div id=\"redis_powered\"><div>Page generated in<br/> ".t_exec($start, $end)." sec</div></div></a>"; }   // time diff function t_exec($start, $end) { $t = (getmicrotime($end) - getmicrotime($start)); return round($t,5); }   // get time function getmicrotime($t) { list($usec, $sec) = explode(" ",$t); return ((float)$usec + (float)$sec); }   ?>

view raw index-with-redis.php hosted with ❤ by GitHub

Step 2:

Optional: modify the 3 variables at the top of the file.

Step 3:

If you are using Apache change all occurances of index.php to index-with-redis.php in the .htaccess.
If you are using the more preferred nginx then you need to rename index-with-redis.php to index.php. Unfortunately this also means that you have to replace this file each time you upgrade WordPress. You can also change nginx.conf to access index-with-redis.php instead of index.php but it creates some bugs and I would avoid that.

Step 4:

Deactivate all other caching plugins.

Instructions and info:

• Cached pages do not expire not unless explicitly deleted or reset. My guess is that Redis probably will use around half of your database size in the RAM.
• Appending a ?c=y to a url deletes the entire cache of the domain, only works when you are logged in
• Appending a ?r=y to a url deletes the cache of that url
• Submitting a comment deletes the cache of that page
• Refreshing (f5) a page deletes the cache of that page
• Includes a debug mode, stats are displayed at the bottom most part after </html>
• Optionally display a powered by Redis badge with page generation time.

Benchmark for this blog:

• Average execution without redis: 1.614 seconds for the home page and 0.174 seconds for blog posts (without using any cache plugin).
• Average execution time with redis: 0.00256 seconds (regardless of type of page)

I have been using this setup for this blog for quite some time now and all has been working well.

from http://www.jimwestergren.com/wordpress-with-redis-as-a-frontend-cache/
---------------------------------------

 Redis是一个高级的key-value存储系统，类似memcached，所有内容都存在内存中，因此每秒钟可以超过10万次GET操作。

我下面提出的解决方案是在Redis中缓存所有输出的HTML 内容而无需再让WordPress重复执行页面脚本。这里使用Redis代替Varnish设置简单，而且可能更快。

安装 Redis

如果你使用的是 Debian 或者衍生的操作系统可使用如下命令安装 Redis：

    apt-get install redis-server

或者阅读 安装指南-http://redis.io/download

使用 Predis 作为 Redis 的 PHP 客户端

你需要一个客户端开发包以便 PHP 可以连接到 Redis 服务上。

这里我们推荐 Predis. 上传 predis.php 到 WordPress 的根目录。

前端缓存的PHP脚本

步骤1：在WordPress 的根目录创建新文件 index-with-redis.php ，内容如下：

    <?php

    // Change these two variables:

    $seconds_of_caching = 60*60*24*7; // 7 days.

    $ip_of_this_website = ’204.62.14.112′;

    /*

    - This file is written by Jim Westergren, copyright all rights reserved.
    - See more here: www.jimwestergren.com/wordpress-with-redis-as-a-frontend-cache/
    - The code is free for everyone to use how they want but please mention my name and link to my article when writing about this.
    - Change $ip_of_this_website to the IP of your website above.
    - Add ?refresh=yes to the end of a URL to refresh it’s cache
    - You can also enter the redis client via the command prompt with the command “redis-cli” and then remove all cache with the command “flushdb”.

    */

    // Very necessary if you use Cloudfare:

    if (isset($_SERVER['HTTP_CF_CONNECTING_IP'])) {
    $_SERVER['REMOTE_ADDR'] = $_SERVER['HTTP_CF_CONNECTING_IP'];
    }

    // This is from WordPress:

    define(‘WP_USE_THEMES’, true);

    // Start the timer:

    function getmicrotime($t) {
    list($usec, $sec) = explode(” “,$t);
    return ((float)$usec + (float)$sec);
    }

    $start = microtime();

    // Initiate redis and the PHP client for redis:

    include(“predis.php”);
    $redis = new Predis\Client(”);

    // few variables:

    $current_page_url = “http://”.$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];

    $current_page_url = str_replace(‘?refresh=yes’, ”, $current_page_url);

    $redis_key = md5($current_page_url);

    // This first case is either manual refresh cache by adding ?refresh=yes after the URL or somebody posting a comment

    if (isset($_GET['refresh']) || substr($_SERVER['REQUEST_URI'], -12) == ‘?refresh=yes’ || ($_SERVER['HTTP_REFERER'] == $current_page_url && $_SERVER['REQUEST_URI'] != ‘/’ && $_SERVER['REMOTE_ADDR'] != $ip_of_this_website)) {
    require(‘./wp-blog-header.php’);
    $redis->del($redis_key);

    // Second case: cache exist in redis, let’s display it

    } else if ($redis->exists($redis_key)) {

    $html_of_current_page = $redis->get($redis_key);

    echo $html_of_current_page;

    echo “<!– This is cache –>”;

    // third: a normal visitor without cache. And do not cache a preview page from the wp-admin:

    } else if ($_SERVER['REMOTE_ADDR'] != $ip_of_this_website && strstr($current_page_url, ‘preview=true’) == false) {
    require(‘./wp-blog-header.php’);
    $html_of_current_page = file_get_contents($current_page_url);
    $redis->setex($redis_key, $seconds_of_caching, $html_of_current_page);
    echo “<!– Cache has been set –>”;

    // last case: the normal WordPress. Should only be called with file_get_contents:

    } else {
    require(‘./wp-blog-header.php’);
    }

    // Let’s display some page generation time (note: CloudFlare may strip out comments):

    $end = microtime();
    $t2 = (getmicrotime($end) – getmicrotime($start));
    if ($_SERVER['REMOTE_ADDR'] != $ip_of_this_website) {
    echo “<!– Cache system by Jim Westergren. Page generated in “.round($t2,5).” seconds. –>”;
    }
    ?>

或者直接下载 index-with-redis.php- https://raw.github.com/gist/3053250/c97aa5070a1b6e237428c260b3abe4ae0a59df8e/index-with-redis.php

步骤2：将上述代码中的 IP 地址替换成你网站的 IP 地址

步骤3：在.htaccess 中将所有出现 index.php 的地方改为 index-with-redis.php ，如果你使用的是 Nginx 则修改 nginx.conf 中的 index.php 为 index-with-redis.php（并重载 Nginx ： killall -s HUP nginx）。

性能测试

1.没有Redis 的情况下，平均首页执行1.614 秒，文章页0.174 秒（无任何缓存插件）

2.使用Redis 的情况下，平均页面执行时间0.00256秒

我已经在我的博客中使用了如上的方法进行加速很长时间了，一切运行良好。

其他建议

我的环境是Nginx + PHP-FPM + APC + Cloudflare + Redis. 安装在一个 nano VPS 中，无缓存插件。

请确认使用了gzip压缩，可加快访问速度。

访问 wp-admin

要访问 wp-admin 必须使用 /wp-admin/index.php 代替原来的 /wp-admin/