Analysis of the WebSocket communication implementation principle of swoole development function

Analysis of the WebSocket communication implementation principle of swoole development function

WebSocket is a protocol for full-duplex communication between the client and the server, which allows the server to proactively Send data to the client instead of just responding to the client's request. In actual development, we can use swoole extensions to develop WebSocket applications to implement real-time communication, chat rooms and other functions.

This article will introduce how swoole implements the function of WebSocket communication by analyzing the principles of WebSocket and the use examples of swoole.

1. The principle of WebSocket

The WebSocket protocol is based on the HTTP protocol. It upgrades the HTTP connection to a WebSocket connection by upgrading the protocol during the handshake phase. During the handshake phase, a special HTTP request and response are made between the client and the server. After the handshake is successful, a persistent connection will be established between the client and the server, and both parties can send and receive data at any time.

Different from the HTTP protocol, the communication process of WebSocket is full-duplex. The server can actively send data to the client, and the client can also actively send data to the server. WebSocket uses a special data frame to transmit data. The data frame includes a data header and a data body. The data header contains the format information and control information of the data.

2. Sample code for swoole to implement WebSocket communication

The following is a sample code for using swoole extension to implement WebSocket communication:

<?php

// 创建WebSocket服务器
$server = new swoole_websocket_server("0.0.0.0", 9501);

// 监听WebSocket连接打开事件
$server->on('open', function (swoole_websocket_server $server, $request) {
    echo "client {$request->fd} connected
";
});

// 监听WebSocket消息事件
$server->on('message', function (swoole_websocket_server $server, $frame) {
    echo "received message: {$frame->data}
";

    // 向客户端发送消息
    $server->push($frame->fd, "server received: {$frame->data}");
});

// 监听WebSocket连接关闭事件
$server->on('close', function ($ser, $fd) {
    echo "client {$fd} closed
";
});

// 启动WebSocket服务器
$server->start();

In the above code, we First, a WebSocket server is created, listening on port 9501 at 0.0.0.0. Then the processing logic for the WebSocket connection open event, message event and connection close event is set through the callback function.

In the connection open event, we output the client's fd, indicating that the client's connection has been established. In the message event, we output the received message and send a message to the client through the $server->push() method. In the connection closing event, we output the client's fd, indicating that the client's connection has been closed.

Through the above code, we can start the WebSocket server in the terminal and access the address of the WebSocket server in the browser to conduct interactive communication.

3. Summary

This article introduces how swoole implements the function of WebSocket communication by analyzing the principles of WebSocket and the sample code of using swoole extension to implement WebSocket communication. The full-duplex communication characteristics of WebSocket make it widely used in real-time communication, chat rooms and other scenarios. As a high-performance PHP extension, swoole provides Web developers with a convenient and fast development method, further improving the performance and efficiency of WebSocket applications.

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