nginx规则：自动降级，手机用户访问跳转手机版与PC版页面

工作中为满足业务需要以及保证服务的可用性，配置的一些nginx跳转规则，与公司业务相关信息已经抹去，提供出来希望对大家有帮助。

1. 当后端服务器出现异常，响应码为500 501 502 503 504，请求转发到静态降级服务器，从而保证业务不至于完全无法访问，对于浏览型且实时性要求不高的站点非常有用。

app_servers：应用服务器，提供正常服务页面

shopwebstatic：静态服务器，提供定时爬取的静态页面

2.请求重试：

proxy_next_upstream           http_500  http_502  http_504 error timeout invalid_header;

3.根据user agent,cookie特定字段，将来源为PC版用户的请求转发到手机版页面或者恢复访问PC版本页面。

默认手机用户访问站点会跳转到手机版本，跳转判断依据是user agent，当用户点击访问电脑版本的时候，除了要判断用户的user agent外还需要判断用户的访问模式，通过cookie中特定字段的值来判断用户访问请求是到手机版本还是到PC版本。

mode=pc，mode标记用户的访问模式是PC版本，通过此cookie字段，可判断是否将user agent匹配智能手机字段的用户的请求转发到手机版本。

limit_conn_zone $server_name zone=limit:10m;
  upstream app_servers {
    server                        app_server01_ip:80 weight=1 max_fails=2;
    server                        app_server01_ip:80 weight=1 max_fails=2 backup;
  }
    upstream shopwebstatic {
    server shopwebstatic_server01_ip:80 weight=5;
    server shopwebstatic_server02_ip:80 weight=5;
    }
                                                                                                                                                                                   
  server {
    listen                        80;
    server_name                   qunying.liu.dianping.com;
    # config_apps_begin
    root                          /data/webapps/shops-web/shared/webroot;
    access_log                    logs/shops-web.access.log     main;
    error_log                     logs/shops-web.error.log      notice;
    # config_apps_end
    limit_conn limit              280; 
    proxy_next_upstream           http_500  http_502  http_504 error timeout invalid_header;
                                                                                                                                                                                 
    location / {
                                                                                                              
      proxy_intercept_errors on;
           location  ~* ^/shop/(\d+)/menu{
               set $mobile 0;
               set $shopid  $1;
               set $hostid 0;
               if ( $http_user_agent ~* "(Android|iPhone|Windows Phone)" ){
                   set  $mobile "${mobile}1";
               }
               if ( $host ~* "m\.dianping\.com" ){
                   set  $hostid "${hostid}1";
               }
                                                                                                                                                                                                 
              if ( $http_cookie !~* "mode=pc"){
                  set  $mobile "${mobile}1";
              }                         
                                                                                                                                                                                                 
               if ( $hostid = "01" ){
                   proxy_pass                http://app_servers/shop/$shopid/mobilemenu;
                   break;
                 }
               if ( $mobile = "011" ){
                   rewrite  ^/(.*)$  http://mobile-servers/$1 redirect;
                   break;
                 }
                   proxy_pass                http://app_servers;
                   break;
            }
           location  ~* ^/shop/(\d+)/dish-(.*){
               set $mobile 0;
               set $shopid  $1;
               set $dishurl $2;
               if ( $http_user_agent ~* "(Android|iPhone|Windows Phone)" ){
                   set  $mobile "${mobile}1";
               }                                                                                                          
              if ( $http_cookie !~* "mode=pc"){
                  set  $mobile "${mobile}1";
              }                         
                                                                                                                                                     
               if ( $mobile = "011" ){
                   rewrite  ^/(.*)$  http://mobile-servers/shop/$shopid/product-$dishurl redirect;
                   break;
                 }      
                   proxy_pass                http://app_servers;
                   break;
            }
           location  ~* ^/map/shop/(\d+)$ {
                      set $shopid  $1;      
                   rewrite  ^/(.*)$  http://www.servers/shop/$shopid/map permanent;
                   proxy_set_header Host "www.servers";
                   break;
            }
           location  ~* ^/shop/(\d+)(/map|/)?$ {
               set $mobile 0;
               if ( $http_user_agent ~* "(Android|iPhone|Windows Phone)" ){
                   set  $mobile "${mobile}1";
               }                                                                                                                    
              if ( $http_cookie !~* "mode=pc"){
                  set  $mobile "${mobile}1";
              }                         
                                                                                                              
               if ( $mobile = "011" ){
                   rewrite  ^/(.*)$  http://mobile-servers/$1 redirect;
                   break;
                 }         
                   proxy_pass                http://app_servers;
                   break;
            }                       
    # appserverfavcion
      location ~* ^.*/favicon.ico$ {
        root                      /data/webapps;
        expires                   30d;
        break;
      }
      if ( !-f $request_filename ) {
        proxy_pass                http://app_servers;
        break;
      }
    }
    error_page                    500 501 502 503 504 @shopstatic;
    location                      @shopstatic {
      access_log                  logs/shops-static-web.access.log       retry;
      proxy_pass                  http://shopwebstatic;
    }

本文出自 “从菜鸟到老鸟” 博客，请务必保留此出处http://liuqunying.blog.51cto.com/3984207/1406952

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