How to use Nginx to implement WebSocket protocol support

How to use Nginx to implement WebSocket protocol support

The WebSocket protocol is a protocol that implements two-way communication in Web applications. It allows the server to actively send data to the client without the client first initiating a request. . Compared with the traditional HTTP protocol, the WebSocket protocol has lower latency and higher efficiency, and is suitable for application scenarios with high real-time requirements. This article will introduce how to use Nginx as a reverse proxy to support the WebSocket protocol.

Nginx is a high-performance open source reverse proxy server that can be used in load balancing, reverse proxy, static file caching and other scenarios. Nginx also provides some modules and directives to support the WebSocket protocol. The following is a simple configuration example:

http {
    # 其他的http配置

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

    server {
        listen 80;

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

In the above configuration, we define a /ws/ path for processing WebSocket connection requests. WebSocket requests will be proxied to the http://backend address. The proxy_pass directive is used to set the proxy's backend server address, and the proxy_http_version directive is used to set the proxy's HTTP protocol version. The proxy_set_header directive is used to set request header information, of which Upgrade and Connection are required and are used to inform the server to perform protocol upgrades.

It should be noted that the map directive in the above configuration is used to map the Upgrade field in the client request header to $http_upgrade variable and dynamically set the $connection_upgrade variable based on its value. This allows you to set the value of the Upgrade field to the value of the $connection_upgrade field when the Upgrade field is found in the request. Otherwise, the connection will be closed.

After the configuration is completed, we only need to start Nginx:

sudo service nginx start

Now, we have completed the configuration of using Nginx as a reverse proxy to support the WebSocket protocol. We can use the following code snippet to test the WebSocket connection:

var socket = new WebSocket("ws://yourdomain.com/ws/");
socket.onopen = function () {
    console.log("Connection established.");
};
socket.onmessage = function (event) {
    console.log("Received message: ", event.data);
};
socket.onclose = function () {
    console.log("Connection closed.");
};

Replace ws://yourdomain.com/ws/ with the actual WebSocket address and open the browser's developer tool to view console output. If you can connect normally and receive messages, it means that the WebSocket protocol has been successfully supported by Nginx.

In summary, through the above configuration and code examples, we can easily use Nginx to support the WebSocket protocol, thereby achieving two-way communication with high real-time requirements.

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