How does Go WebSocket implement message queue?

Go WebSocket implements message queues by using channels. The implementation steps are as follows: 1. Create a message queue channel. 2. Start a goroutine to listen for incoming messages. 3. In the handler, write the message to the message queue. 4. When a message needs to be sent, write the message to the queue. This approach can be used to build real-time applications such as chat, collaborative editors, and real-time stock updates.

Go WebSocket How to implement message queue

WebSocket is a full-duplex communication protocol that can be used between the client and the server. establish a continuous connection between them. It is based on TCP and can be used to build real-time applications such as chat, collaborative editors, and real-time stock updates.

Go provides native WebSocket support, allowing developers to easily establish and manage WebSocket connections. However, in real applications, it may be necessary to implement a message queue to handle a large number of incoming and outgoing messages.

Implementing a message queue

A simple way to implement a message queue in Go is to use channels. Channels are a synchronous communication mechanism that allow values ​​to be safely exchanged between concurrent coroutines.

Create a message queue channel:

var messageQueue chan []byte

Start a goroutine to listen for incoming messages:

go func() {
    for message := range messageQueue {
        // 处理传入消息
    }
}()

In the handler, write the message to the message queue:

func handleConnection(conn *websocket.Conn) {
    for {
        message, err := conn.ReadMessage()
        if err != nil {
            // 处理错误
        }

        messageQueue <- message.Payload
    }
}

When a message needs to be sent, write the message to the queue:

func sendMessage(message []byte) {
    messageQueue <- message
}

Practical case

Consider a simple chat application where the client and server Use WebSockets to communicate.

Client code:

package main

import (
    "context"
    "flag"
    "fmt"
    "log"

    "github.com/gorilla/websocket"
)

var addr = flag.String("addr", "localhost:8080", "http service address")

func main() {
    flag.Parse()

    // 连接到服务器
    conn, _, err := websocket.DefaultDialer.DialContext(context.Background(), "ws://"+*addr, nil)
    if err != nil {
        log.Fatal("Could not connect to server", err)
    }

    // 读取来自服务器的消息
    go func() {
        for {
            _, message, err := conn.ReadMessage()
            if err != nil {
                log.Println("Could not read message:", err)
                return
            }

            fmt.Println(string(message))
        }
    }()

    // 发送消息到服务器
    scanner := bufio.NewScanner(os.Stdin)
    for scanner.Scan() {
        conn.WriteMessage(websocket.TextMessage, []byte(scanner.Text()))
    }
}

Server code:

package main

import (
    "context"
    "flag"
    "log"
    "net/http"

    "github.com/gorilla/websocket"
)

var upgrader = websocket.Upgrader{
    ReadBufferSize:  1024,
    WriteBufferSize: 1024,
}

var addr = flag.String("addr", ":8080", "http service address")
var messageQueue chan []byte

func main() {
    flag.Parse()

    messageQueue = make(chan []byte)

    // 启动消息队列监听器
    go func() {
        for message := range messageQueue {
            // 处理消息
        }
    }()

    // 处理 WebSocket 连接
    http.HandleFunc("/ws", wsHandler)
    log.Fatal(http.ListenAndServe(*addr, nil))
}

func wsHandler(w http.ResponseWriter, r *http.Request) {
    // 升级到 WebSocket 连接
    conn, err := upgrader.Upgrade(w, r, nil)
    if err != nil {
        log.Println("Could not upgrade", err)
        http.Error(w, "Could not upgrade", http.StatusInternalServerError)
        return
    }

    // 处理连接
    go handleConnection(conn)
}

func handleConnection(conn *websocket.Conn) {
    for {
        // 读取消息
        _, message, err := conn.ReadMessage()
        if err != nil {
            log.Println("Could not read message:", err)
            return
        }

        // 存储消息到队列
        messageQueue <- message
    }
}

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