nodejs+socket.io用nginx反向代理提示400 Bad Request及ws://…无法连接
2017-07-13 10:43:10 点击：

server {
     listen 80;
     server_name 123.com www.123.com;
     root /www/web/123/public_html;
     index index.html index.php index.htm;
     location / {
          proxy_pass http://127.0.0.1:8000;
          ......
          proxy_http_version 1.1;
          proxy_set_header Upgrade $http_upgrade;
          proxy_set_header Connection "upgrade";
     }
}

红色部分为最关键的内容，在你的.conf文件里加上这三行就可以了。

下面是英文原文：

WebSocket proxying

To turn a connection between a client and server from HTTP/1.1 into WebSocket, the protocol switch mechanism available in HTTP/1.1 is used.

There is one subtlety however: since the “Upgrade” is a hop-by-hop header, it is not passed from a client to proxied server. With forward proxying, clients may use the CONNECT method to circumvent this issue. This does not work with reverse proxying however, since clients are not aware of any proxy servers, and special processing on a proxy server is required.

Since version 1.3.13, nginx implements special mode of operation that allows setting up a tunnel between a client and proxied server if the proxied server returned a response with the code 101 (Switching Protocols), and the client asked for a protocol switch via the “Upgrade” header in a request.

As noted above, hop-by-hop headers including “Upgrade” and “Connection” are not passed from a client to proxied server, therefore in order for the proxied server to know about the client’s intention to switch a protocol to WebSocket, these headers have to be passed explicitly:

location /chat/ {
    proxy_pass http://backend;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
}

A more sophisticated example in which a value of the “Connection” header field in a request to the proxied server depends on the presence of the “Upgrade” field in the client request header:

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

    server {
        ...

        location /chat/ {
            proxy_pass http://backend;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection $connection_upgrade;
        }
    }

By default, the connection will be closed if the proxied server does not transmit any data within 60 seconds. This timeout can be increased with the proxy_read_timeout directive. Alternatively, the proxied server can be configured to periodically send WebSocket ping frames to reset the timeout and check if the connection is still alive.