socketio 握手前中断报错

前两天折腾了下socketio，部署完发现通过nginx代理之后前端的socket无法和后端通信了，于是暴查一通，最后解决问题：

location / {
    proxy_pass http://127.0.0.1:9999;
    proxy_connect_timeout 60;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-NginX-Proxy true;

    # 下面是关键
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    # 这是配置webpysessoin丢失的问题
    fastcgi_param  SCRIPT_NAME        "";
}

参考： 1. http://nginx.org/en/docs/http/websocket.html