WebSocket 介绍
WebSocket是目前比较成熟的技术了,大部分现在的浏览器都支持WebSocket,比如Firefox,IE,Chrome,Safari,Opera,并且越来越多的服务器框架现在也同样支持WebSocket。WebSocket 和HTTP虽然是不同协议,但是两者“握手”方式兼容。通过HTTP升级机制,使用HTTP的Upgrade和Connection协议头的方式可以将连接从HTTP升级为WebSocket。NGINX从1.3版本开始支持WebSocket,其可以作为一个反向代理和为WebSocket程序做负载均衡。即将Upgrade: websocket和Connection: Upgrade必须设置一致
GET /app/websocket/ HTTP/1.1
Host: localhost
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Key: dddskkkdsjss
Origin: http://localhost
Sec-WebSocket-Version: 13
一个典型的Websocket握手请求如下:
客户端请求:
GET / HTTP/1.1
Upgrade: websocket
Connection: Upgrade
Host: example.com
Origin: http://example.com
Sec-WebSocket-Key: sN9cRrP/n9NdMgdcy2VJFQ==
Sec-WebSocket-Version: 13
服务器回应:
HTTP/1.1 101 Switching Protocols
Upgrade: websocket
Connection: