nginx模块之ngx_http_headers_module

说明：该模块是用于在响应给客户端的报文中添加首部

1.add_header name value
Syntax: add_header name value [always];
Default: —
Context: http, server, location, if in location
向响应报文添加自定义首部，并赋值

示例：
add_header X-Via $server_addr;

2.expires
Syntax: expires [modified] time;
expires epoch | max | off;
Default:
expires off;
Context: http, server, location, if in location
用于添加Expire和Cache-Control首部或修改首部的值