查看“Nginx缓存”的源代码

=== 缓存介绍 ===
1.代理服务器端缓存作用

减少后端压力，提高网站并发延时

2.缓存常见类型

服务器端缓存：代理缓存,获取服务器端内容进行缓存

浏览器端缓存

3.nginx代理缓存：proxy_cache

=== 浏览器缓存 ===
==== Expires ====
原理: 给http添加Cache-Control、Expires头

 Syntax:  expires [modified] time;
 		 expires epoch | max |off ;
 Default: expires off;
 Context: http, server, location;

expires指令控制HTTP应答中的“Expires”和“Cache-Control”Header头部信息，启动控制页面缓存的作用

time:可以使用正数或负数。“Expires”头标的值将通过当前系统时间加上设定time值来设定。

time值还控制"Cache-Control"的值：

负数表示no-cache

epoch：指定“Expires”的值为 1 January,1970,00:00:01 GMT

max:指定“Expires”的值为31 December2037 23:59:59GMT,"Cache-Control"的值为10年。

-1：指定“Expires”的值为当前服务器时间-1s，即永远过期。

off：不修改“Expires”和"Cache-Control"的值

 server {
                listen 80;
                server_name aaa.hbk.com;
                access_log logs/aaa.access.log combined;
                root /root/hbk/aaa;
                location / {
                        index index.html;
                        root /root/hbk/aaa/;
                }

                location ~ .*\.(css|js)$ {
                        expires 1h;
                }
        }

=== 代理缓存配置 ===

[[File:nginx-cache-3.jpg|500px|center|border]]

[[File:nginx-cache-4.jpg|500px|center|border]]

==== 缓存配置 ====

 #vim /usr/local/nginx/conf/nginx.conf 
 upstream node {
    server 192.9.191.31:8081;
    server 192.9.191.31:8082;
 }
 proxy_cache_path /cache levels=1:2 keys_zone=cache:10m max_size=10g inactive=60m use_temp_path=off;
 server {
    listen 80;
    server_name www.test.com;
    index index.html;
    location / {
    proxy_pass http://node;
    proxy_cache cache;
    proxy_cache_valid   200 304 12h;
    proxy_cache_valid   any 10m;
    add_header  Nginx-Cache "$upstream_cache_status";
    proxy_next_upstream error timeout invalid_header http_500 http_502 http_503 http_504;
        }
    }
==== 参数详解 ====

 proxy_cache_path /soft/cache levels=1:2 keys_zone=cache:10m max_size=10g inactive=60m use_temp_path=off;
    #proxy_cache    //存放缓存临时文件
    #levels         //按照两层目录分级
    #keys_zone      //开辟空间名,10m:开辟空间大小,1m可存放8000key
    #max_size       //控制最大大小,超过后Nginx会启用淘汰规则
    #inactive       //60分钟没有被访问缓存会被清理
    #use_temp_path  //临时文件,会影响性能,建议关闭
 proxy_cache cache;
 proxy_cache_valid   200 304 12h;
 proxy_cache_valid   any 10m;
 add_header  Nginx-Cache "$upstream_cache_status";
 proxy_next_upstream error timeout invalid_header http_500 http_502 http_503 http_504;
    #proxy_cache            //开启缓存
    #proxy_cache_valid      //状态码200|304的过期为12h,其余状态码10分钟过期
    #proxy_cache_key        //缓存key
    #add_header             //增加头信息,观察客户端respoce是否命中
    #proxy_next_upstream    //出现502-504或错误,会跳过此台服务器访问下一台服务器

==== 创建缓存目录 ====

 mkdir /cache 
 nginx -t 
 nginx -s reload 

==== 清除缓存 ====
1.rm删除已缓存的数据

 rm -rf /cache/*
2.通过ngx_cache_purge扩展模块清理,需要编译安装nginx

==== 部分页面不缓存 ====
1.nginx配置

 #vim /usr/local/nginx/conf/nginx.conf 
 upstream node {
        server 192.9.191.31:8081;
        server 192.9.191.31:8082;
 }
 proxy_cache_path /cache levels=1:2 keys_zone=cache:10m max_size=10g inactive=60m use_temp_path=off;
 server {
        listen 80;
        server_name www.test.com;
        index index.html;
        if ($request_uri ~ ^/(static|login|register|password)) {
                set $cookie_nocache 1;
                }
        location / {
                proxy_pass http://node;
                proxy_cache     cache;
                proxy_cache_valid       200 304 12h;
                proxy_cache_valid       any     10m;
                add_header      Nginx-Cache     "$upstream_cache_status";
                proxy_next_upstream     error timeout invalid_header http_500 http_502 http_503 http_504;
                proxy_no_cache $cookie_nocache $arg_nocache $arg_comment;
                proxy_no_cache $http_pargma $http_authorization;
                }
        }

重启加验证

 nginx -t 
 nginx -s reload 

==== 统计日志命中率 ====
日志格式:变量$upstream_cache_status"

 #vim /usr/local/nginx/conf/nginx.conf       
 log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                  '$status $body_bytes_sent "$http_referer" '
                  '"$http_user_agent" "$http_x_forwarded_for" "$upstream_cache_status"';
 access_log logs/access.log main;
 error_log logs/error.log;

统计日志命中率加入到计划任务中这里省略

 awk '{if($NF = "HIT"){count++;}} END{printf "%.2f%",count/NR*100}' /usr/local/nginx/logs/access.log