Implement WebSocket service using PHP

With the development of the Internet, WebSocket technology is increasingly widely used. WebSocket technology can realize two-way real-time communication and is suitable for some application scenarios such as instant messaging and games, and can provide a better user experience. This article will introduce how to implement WebSocket service using PHP.

1. Introduction to WebSocket
WebSocket is a new protocol proposed by HTML5. It is a protocol for full-duplex communication on a single TCP connection. It supports real-time communication and has lower latency than HTTP. , which can carry out large amounts of data transmission. Using WebSocket can achieve real-time communication while reducing server overhead and saving network bandwidth.

2. WebSocket implementation method

1. Server

(1)Create WebSocket server:

// 创建WebSocket服务器
$server = new swoole_websocket_server("0.0.0.0", 9502);

// 监听WebSocket连接事件
$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) {
    // 处理接收到的消息
    $message = "server received message: {$frame->data}
";
    // 向WebSocket客户端发送消息
    $server->push($frame->fd, $message);
});

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

// 启动WebSocket服务器
$server->start();

(2)Server Push message:

// 向WebSocket客户端发送消息
$server->push($frame->fd, $message);

2. Client

(1) Create WebSocket connection:

// 创建WebSocket连接
var ws = new WebSocket("ws://localhost:9502");

// 监听WebSocket连接事件
ws.onopen = function() {
    console.log("WebSocket连接已打开");
};

// 监听WebSocket消息事件
ws.onmessage = function(event) {
    console.log("WebSocket收到消息：" + event.data);
};

// 监听WebSocket关闭事件
ws.onclose = function() {
    console.log("WebSocket连接已关闭");
};

(2) Client sends message:

// 向WebSocket服务器发送消息
ws.send("hello");

3. Detailed explanation of the implementation process

Below we will introduce in detail each part of the above code block.

1. Server

(1) Create a WebSocket server:

// 创建WebSocket服务器
$server = new swoole_websocket_server("0.0.0.0", 9502);

This code creates a WebSocket server, specifying the IP address as 0.0.0.0 , the port is 9502.

(2) Listen to WebSocket connection events:

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

When a WebSocket client is connected, the 'open' event will be triggered. $request here is an object that contains some information about the client connection, such as the client's IP address, connection time, etc.

(3) Listen to WebSocket message events:

// 监听WebSocket消息事件
$server->on('message', function (swoole_websocket_server $server, $frame) {
    // 处理接收到的消息
    $message = "server received message: {$frame->data}
";
    // 向WebSocket客户端发送消息
    $server->push($frame->fd, $message);
});

When the WebSocket client sends a message, the 'message' event will be triggered. The $frame here is an object that contains some information about the received message, such as the content of the message, sending time, etc.

(4) Listen to the WebSocket closing event:

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

When the WebSocket client closes the connection, the 'close' event will be triggered. $fd here is the unique identifier of the client connection.

(5) Start the WebSocket server:

// 启动WebSocket服务器
$server->start();

Use the start() method to start the WebSocket server so that it can start monitoring client connections and messages.

(6) Server push message:

// 向WebSocket客户端发送消息
$server->push($frame->fd, $message);

Use the push() method to send a message to the specified client. $frame->fd is the unique identifier of the client connection, and $message is the content of the message to be sent.

2. Client

(1) Create a WebSocket connection:

// 创建WebSocket连接
var ws = new WebSocket("ws://localhost:9502");

This code creates a WebSocket connection, specifying the URL as ws:// localhost:9502. Among them, ws represents the protocol type, localhost represents the IP address of the WebSocket server, and 9502 represents the listening port number.

(2) Listen to WebSocket connection events:

// 监听WebSocket连接事件
ws.onopen = function() {
    console.log("WebSocket连接已打开");
};

When the WebSocket connection is successful, the 'open' event will be triggered. Here we use the console.log() method to output a message.

(3) Listen to WebSocket message events:

// 监听WebSocket消息事件
ws.onmessage = function(event) {
    console.log("WebSocket收到消息：" + event.data);
};

When the WebSocket client receives a message, the 'message' event will be triggered. Here we use the console.log() method to output a message.

(4) Listen to the WebSocket closing event:

// 监听WebSocket关闭事件
ws.onclose = function() {
    console.log("WebSocket连接已关闭");
};

When the WebSocket connection is closed, the 'close' event will be triggered. Here we use the console.log() method to output a message.

(5) The client sends a message:

// 向WebSocket服务器发送消息
ws.send("hello");

Use the send() method to send a message to the WebSocket server. Here we send a string "hello".

4. Summary

This article introduces the method of using PHP to implement WebSocket service. WebSocket technology is widely used in real-time communications, games and other fields. It has lower latency than HTTP and can provide a better user experience. Using PHP to implement WebSocket services can quickly and easily achieve real-time communication, reduce server overhead, and save network bandwidth.

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