用Redis缓存来给WordPress站点加速-适用于Apache和Nginx

  Redis是一个开源、支持网络、基于内存的key-value存储系统，类似memcached，性能极高，支持超过100K+ 每秒的读写频率，一些大型的网站例如ITeye(JavaEye)和CSDN现在都用到了Redis。

        与memcached相比，Redis提供了持久化存储，重启了服务器后memcached需要重新创建缓存，而Redis依赖快照进行持久化，即使服务器刚开机启动也不会导致负载陡增。Redis缓存比较适合大流量的Wordpress。

        当你的WordPress中的文章达到上万篇，随着流量的增加，Wordpress的服务器压力也随之不断加大，Wordpress发布文章和后台相关的操作都会变得缓慢，这时如果单从硬件上投入来提高Wordpress性能显然不划算。

        利用Redis将WordPress页面直接缓存在服务器的内存中，这样在避免了PHP重复执行操作的同时，内存的极速响应能够最大限度地提升Wordpress页面的访问速度，部落实际测试发现页面执行时间可以降低到0.00X秒级别，比没有使用Redis缓存提升几倍甚至十几倍以上。

一、 在VPS或者服务器上安装Redis

1、有些LNMP一键安装包直接提供了Redis安装，例如：http://blog.linuxeye.com/31.html，这是一个LNMP、LAMP、LANMP一键安装脚本，根据自己需求安装memcached、redis。

2、而对于一般的VPS，我们可以直接用以下命令安装（注意：redis-2.8.9是当前稳定版本，大家可以及时关注官网获得最新的：http://redis.io/download）：

wget http://download.redis.io/releases/redis-2.8.9.tar.gztar xzf redis-2.8.9.tar.gzcd redis-2.8.9make

点击查看图片

3、Redis会在src目录下生成几个可执行文件如：redis-benchmark,redis-check-aof,redis-check-dump,redis-cli,redis-sentinel,redis-server。执行：src/redis-server或者service redis-server start就是启动Redis。

4、配置开机启动Redis，执行以下命令：vi /etc/rc.d/rc.local，加入redis-server路径，例如：/src/redis-server

5、在VPS上和服务器上安装并运行Redis了后，可以在phpinfo看到。

点击查看图片

二、用Predis.php作为Redis的PHP客户端

1、我们可以使用Predis.php来作为PHP客户端，直接将Predis.php下载并上传到Wordpress的根目录下，CD到Wordpress根目录，执行以下命令：

wget http://uploads.staticjw.com/ji/jim/predis.phpchown www.www ./predis.php

2、这是Predis.php的备份下载：Predis.php下载。你可以手动下载并上传。

点击查看图片

三、安装Redis前端缓存的PHP脚本

1、Redis前端缓存的PHP脚本来自：http://www.jimwestergren.com/wordpress-with-redis-as-a-frontend-cache/

<?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 enabledif ($cf) {    if (isset($_SERVER['HTTP_CF_CONNECTING_IP'])) {        $_SERVER['REMOTE_ADDR'] = $_SERVER['HTTP_CF_CONNECTING_IP'];    }}// from wpdefine('WP_USE_THEMES', true);// init predisinclude("predis.php");$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/", $cookie);// check if a cache of the page existsif ($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 enabledif ($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, $end)." sec</div></div></a>";}// time difffunction t_exec($start, $end) {    $t = (getmicrotime($end) - getmicrotime($start));    return round($t,5);}// get timefunction getmicrotime($t) {    list($usec, $sec) = explode(" ",$t);    return ((float)$usec + (float)$sec);}?>

 

2、 你也可以直接点击备用下载：index-with-redis.php下载地址。 Github项目：https://gist.github.com/JimWestergren/3053250#file-index-with-redis-php

3、 如果你正在使用cloudflare，请设置cf = 1; ，如果你想在页面上看到脚本执行时间和缓存加载时间，请设置$debug = 1; display_powered_by_redis = 1表示显示powered_by信息。

点击查看图片

4、将index-with-redis.php上传到Wordpress的根目录，如果你使用的是nginx，重命令原来的index.php为任意其它名字，把index-with-redis.php重命名为index.php。

点击查看图片

5、如果你使用的是Apache，则需要把.htaccess中出现的index.php替换成index-with-redis.php。

点击查看图片

6、所有的操作完成后，你就可以刷新一下Wordpress页面，查看Redis缓存效果了。

7、实际使用过程中发现以上代码会出现Wordpress首页和分类没有及时缓存，这里再给出优化版本，出自http://www.jeedo.net/lightning-fast-wordpress-with-nginx-redis/。

8、功能差不多，主要有：登录时页面不缓存、除非删除或者重置否则不删除缓存页面、登录时在任意URL后加上?c=y可以删除整个网站缓存、在任意URL后面加上?c=y可以清除此URL缓存、allow_fopen被禁止也可以正常运行、发表评论时删除该页面缓存。

9、index-with-redis.php优化版本的源码是：

<?php/*    author: jeedo aquino    file: wp-index-redis.php    credit: jim westergren    updated: 2012-10-23    this is a redis caching system for wordpress inspired by jim westergren.    see more here: www.jimwestergren.com/wordpress-with-redis-as-a-frontend-cache/    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    - script still works even if allow_fopen is disabled    - 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     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$cf = 0;                // set to 1 if you are using cloudflare$debug = 0;             // set to 1 if you wish to see execution time and cache actions$start = microtime();   // start timing page exec// if cloudflare is enabledif ($cf) {    if (isset($_SERVER['HTTP_CF_CONNECTING_IP'])) {        $_SERVER['REMOTE_ADDR'] = $_SERVER['HTTP_CF_CONNECTING_IP'];    }}// from wpdefine('WP_USE_THEMES', true);// init predisinclude("predis.php");$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($url);// check if page isn't a comment submission(($_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/", $cookie);// check if a cache of the page existsif ($redis->hexists($dkey, $ukey) && !$loggedin && !$submit) {    echo $redis->hget($dkey, $ukey);    if (!$debug) exit(0);    $msg = 'this is a cache';// if a comment was submitted or clear page cache request was made delete cache of page} else if ($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 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 enabledif ($debug) {    echo $msg.': ';    echo t_exec($start, $end);}// time difffunction t_exec($start, $end) {    $t = (getmicrotime($end) - getmicrotime($start));    return round($t,5);}// get timefunction getmicrotime($t) {    list($usec, $sec) = explode(" ",$t);    return ((float)$usec + (float)$sec);}?>

 

四、Wordpress删除Redis页面缓存的方法

1、删除某一个页面的缓存：发表评论、按下F5刷新、在URL后面加上?r=y回车。

2、删除整站页面缓存：登录到Wordpress后台，在任意URL后面加上?r=y回车。

3、更新文章时自动刷新首页缓存：在你的Wordpress的Function.php中加入以下代码(出自：https://blog.zts1993.com/4738.html)：

function newPostRefresh() {$temp=file_get_contents(“http://xxxxxxx/?r=y”); //xxxxxx自己替换}add_action(‘publish_post’, ‘newPostRefresh’);add_action(‘edit_post’, ‘newPostRefresh’);add_action(‘delete_post’, ‘newPostRefresh’);add_action(‘comment_post’, ‘newPostRefresh’);add_action(‘edit_comment’, ‘newPostRefresh’);add_action(‘delete_comment’, ‘newPostRefresh’);add_action(‘wp_set_comment_status’, ‘newPostRefresh’);add_action(‘switch_theme’, ‘newPostRefresh’);

 

4、自动更新Wordpress缓存：在crontab中配置每10分钟用curl访问首页更新缓存，每天凌晨对首页或者分类页面进行更新。

*/10 * * * * curl http://www.freehao123.com/?r=y 1 1 * * * curl http://www.freehao123.com/fenye/?r=y

 

五、Wordpress Redis缓存加速效果

1、当Wordpress页面生成时，会弄成Redis缓存。

点击查看图片

2、第二次访问该页面时，由于Redis缓存，页面执行时间降低到0.00X左右，效果明显。

点击查看图片

3、发表评论等可以删除评论。

点击查看图片

4、如果使用index-with-redis.php的Debug开启模式，会在页面最下方看到执行时间。

点击查看图片

六、Wordpress Redis缓存使用小结

1、注意，Wordpress Redis缓存PHP版本在5.3以上，LNMP一键安装包在安装时需要选择PHP 5.3以上版本，而WDCP默认安装PHP是5.2.17，还需要自己手动升级PHP版本。

2、Wordpress Redis缓存加速效果无疑是明显的，特别页面多访问大的网站博客，在使用Wordpress Redis缓存加速时请禁止其它的所有缓存插件，以免造成不必要的冲突。

3、经过部落测试Wordpress Redis缓存在使用过程中主要存在的问题就是文章更新时，相应的Tag和分类、首页等内容不会实时更新，我们需要手动更新或者利用自动更新命令。