Nginx 代理 WebSocket

Nginx 代理 WebSocket 的要点是设置Upgrade和Connection响应头。

配置 Nginx 根据Upgrade（即$http_upgrade）来设置Connection：

• 如果请求头中有Upgrade，就直接设置到相应头中，并把Connection设置为upgrade。如 WebSocket 请求头会带上Upgrade: websocket，则响应头有

  Upgrade: websocket
  Connection: upgrade
  

• 否则把Connection设置为close。如普通HTTP请求。

最终 Nginx 配置如下：

map $http_upgrade $connection_upgrade {
  default upgrade;
  '' close;
}

server {
  listen 8000;
  location / {
    proxy_pass http://localhost:4000;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection $connection_upgrade;
  }
}