| http_accept | 浏览器支持的 MIME 类型 | text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8 | 
 | http_accept_encoding | 浏览器支持的压缩编码 | gzip, deflate, br | 
 | http_accept_language | 浏览器支持的语言 | zh-CN,zh;q=0.9,en;q=0.8 | 
 | http_cache_control | 浏览器缓存 | max-age=0 | 
 | http_connection | 客户端与服务连接类型 |  | 
 | http_cookie | 浏览器请求 cookie | a=1; b=2 | 
 | http_host | 浏览器请求 host | echo.xuexb.com | 
 | http_referer | 浏览器来源 | https://echo.xuexb.com/ | 
 | http_upgrade_insecure_requests | 是一个请求首部,用来向服务器端发送信号,表示客户端优先选择加密及带有身份验证的响应,并且它可以成功处理 upgrade-insecure-requests CSP 指令 | 1 | 
 | http_user_agent | 用户设备标识 | Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36 | 
 | http_x_requested_with | 异步请求标识 | true | 
 | http_x_forwarded_for | 反向代理原 IP | 198.13.61.105 |