[nginx小技巧]httpheader准确显示命中状态

nginx缓没缓存请求是我们关心的问题，把缓存状态显示在header里是个不错的选择。

方法如下：

    使用$upstream_cache_status 变量

    示例：add_header ADKS-Cache     "$upstream_cache_status  from  www.front2end.com";    变量值：

• MISS
• EXPIRED - expired, request was passed to backend
• UPDATING - expired, stale response was used due to proxy/fastcgi_cache_use_stale updating
• STALE - expired, stale response was used due to proxy/fastcgi_cache_use_stale
• HIT

效果：

 相应头信息