Redis为wordpress提供闪存级加速体验绝佳的缓存加速方案

自然 2018年2月7日18:26:11 2 294

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、访问。

我下面介绍的解决方案是在 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。

为wordpress提供闪存级加速体验方案，实现良好的用户体验

安装Redis

yum install -y redis #前提是你的repo源中存在redis安装包

使用 Predis 作为 Redis 的 PHP 客户端

我们需要一个程序作为redis的客户端，可以理解为服务器的中间文件，将php与redis相互链接。这里推荐predis，一个非常不错的开源程序。

项目地址：https://packagist.org/packages/predis/predis

把predis.php放到wordpress根目录下

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 $html_of_current_page;
echo "";
// third: a normal visitor without cache. And do not cache a preview page from the wp-admin:
} else if ($_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 "";
// 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 "";
}
?>

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）。