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How to use WebSocket in golang for real-time data update

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2023-12-18 09:06:451167browse

How to use WebSocket in golang for real-time data update

How to use WebSocket in Golang for real-time data updates

Overview:
WebSocket is a method for full duplex between a web browser and a server Communication technology designed for communication. In Golang, we can use net/http and github.com/gorilla/websocket in the standard library to implement WebSocket functionality. This article will introduce how to use WebSocket in Golang for real-time data updates and provide some code examples.

Steps:

Step One: Create HTTP Server
First, we need to create an HTTP server to handle WebSocket connection requests. Here is a simple example code:

package main

import (
    "log"
    "net/http"
)

func main() {
    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        http.ServeFile(w, r, "index.html")
    })

    log.Println("HTTP server is starting at http://localhost:8080")
    log.Fatal(http.ListenAndServe(":8080", nil))
}

This code creates a simple HTTP server that maps the root path ("/") to a file called index.html static files.

Step 2: Handle WebSocket connections
Next, we need to modify the code of the HTTP server so that it can handle WebSocket connection requests. We can use the github.com/gorilla/websocket library to handle WebSocket connections. The following is the modified sample code:

package main

import (
    "log"
    "net/http"

    "github.com/gorilla/websocket"
)

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

    clients = make(map[*websocket.Conn]bool)
)

func main() {
    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        http.ServeFile(w, r, "index.html")
    })

    http.HandleFunc("/ws", func(w http.ResponseWriter, r *http.Request) {
        conn, err := upgrader.Upgrade(w, r, nil)
        if err != nil {
            log.Println("Failed to upgrade connection:", err)
            return
        }
        clients[conn] = true

        for {
            _, msg, err := conn.ReadMessage()
            if err != nil {
                log.Println("Failed to read message from client:", err)
                delete(clients, conn)
                break
            }

            for client := range clients {
                err := client.WriteMessage(websocket.TextMessage, msg)
                if err != nil {
                    log.Println("Failed to write message to client:", err)
                    client.Close()
                    delete(clients, conn)
                }
            }
        }
    })

    log.Println("WebSocket server is starting at ws://localhost:8080/ws")
    log.Fatal(http.ListenAndServe(":8080", nil))
}

In this code, we create an upgrader object and define a clients variable to save all connections client. When there is a new WebSocket request, we upgrade the connection to a WebSocket connection and add it to the clients variable. Then, we read the message from the client through a loop and send the message to all connected clients.

Step 3: Create a front-end page
Finally, we need to create a front-end page to connect to the WebSocket server and display real-time data updates. The following is a simple HTML page example (index.html):

<!DOCTYPE html>
<html>

<head>
    <title>WebSocket Demo</title>
</head>

<body>
    <h1>WebSocket Demo</h1>

    <input type="text" id="message-input">
    <button onclick="send()">Send</button>

    <ul id="message-list"></ul>

    <script>
        var socket = new WebSocket("ws://localhost:8080/ws");

        socket.onmessage = function(event) {
            var message = document.createElement("li");
            message.textContent = event.data;
            document.getElementById("message-list").appendChild(message);
        };

        function send() {
            var input = document.getElementById("message-input");
            var message = input.value;
            input.value = "";

            socket.send(message);
        }
    </script>
</body>

</html>

This code creates a WebSocket connection and listens to the onmessage event when a message arrives When, add the message to a ul element for display. In addition, an input box and a send button are provided so that users can enter messages and send them to the server via WebSocket.

Summary:
Through the above steps, we can use WebSocket in Golang for real-time data updates. By creating HTTP servers, handling WebSocket connections, and interacting with front-end pages, we can achieve real-time data communication in web applications. Of course, this is just a simple example and may need to be expanded and modified according to specific needs during actual use. I hope this article was helpful and I wish you success when using WebSocket!

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