HTTP 小练习

1. 在command line中输入ncat -l 9999, 本地开一个服务器监听9999端口
   
2. 在浏览器中输入localhost:9999
   
3. 此时命令行中出现

   GET / HTTP/1.1
   Host: localhost:8989
   Connection: keep-alive
   Cache-Control: max-age=0
   Upgrade-Insecure-Requests: 1
   User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.139 Safari/537.36
   Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8
   Accept-Encoding: gzip, deflate, br
   Accept-Language: zh-CN,zh;q=0.9,en-US;q=0.8,en;q=0.7

4. 此时在命令行中可以输入response

   HTTP/1.1 200 OK
   Content-type: text/html; charset=UTF-8
   Contetn-length: 79//此行可不写，那么浏览器将可以永久保持连接

5. 敲回车空一行，再输入任何内容都将出现在浏览器上（字节数不能超过Content-length）
6. 还可以

   HTTP/1.1 301 Moved Permanently
   Location: https://www.baidu.com