golang Websocket tutorial: How to develop online file transfer function-Golang-php.cn

golang Websocket tutorial: How to develop online file transfer function

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Release： 2023-12-17 14:46:10

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golang Websocket教程：如何开发在线文件传输功能

Golang Websocket Tutorial: How to Develop Online File Transfer Function

Introduction:
With the rapid development of the Internet, file transfer has become a common problem that people often face on the Internet. needs. Using Websocket technology, we can easily implement online file transfer functions. This article will introduce how to use Golang to develop an online file transfer application based on Websocket, and provide specific code examples.

1. Introduction to Websocket
Websocket is a full-duplex communication protocol based on TCP connection. It can establish a persistent connection between the browser and the server to achieve real-time data transmission. Compared with the traditional HTTP protocol, Websocket has lower latency, higher concurrency performance and better data transmission capabilities, making it an ideal choice for developing real-time applications and online interactive functions.

2. Development environment preparation
In order to complete this tutorial, you need to install the Golang development environment first and have a certain foundation of Golang programming. At the same time, we also need to introduce a third-party Websocket library for rapid development.

Install the third-party Websocket library:

go get github.com/gorilla/websocket

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3. Project structure and code description
Our project will contain two main files: main.go and index.html. Among them, main.go is the server code and index.html is the client code. Below, we will introduce the code implementation of these two files one by one.

main.go:

Import required packages:

package main

import (
 "log"
 "net/http"

 "github.com/gorilla/websocket"
)

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Define WebSocket connection upgrader:

var upgrader = websocket.Upgrader{
 CheckOrigin: func(r *http.Request) bool {
     return true
 },
}

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Define the WebSocket processor function:

func websocketHandler(w http.ResponseWriter, r *http.Request) {
 conn, err := upgrader.Upgrade(w, r, nil)
 if err != nil {
     log.Println(err)
     return
 }

 // 处理文件传输逻辑
}

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Start the HTTP server and register the WebSocket processor:

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

 log.Println("Server started on localhost:8000")
 log.Fatal(http.ListenAndServe(":8000", nil))
}

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index.html：

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>文件传输</title>
</head>
<body>
    <input type="file" id="file" name="file" />
    <button onclick="sendFile()">传输文件</button>

    <script>
        var ws = new WebSocket("ws://localhost:8000/ws");

        ws.onopen = function(){
            console.log("已连接");
        }

        ws.onmessage = function(e){
            console.log("接收到消息");
            // 处理接收到的文件数据
        }

        ws.onclose = function(){
            console.log("连接已关闭");
        }

        function sendFile(){
            var fileInput = document.getElementById("file");
            var file = fileInput.files[0];

            if(file){
                var reader = new FileReader();
                reader.readAsBinaryString(file);

                reader.onload = function(e){
                    var fileData = e.target.result;
                    ws.send(fileData);
                }
            }
        }
    </script>
</body>
</html>

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4. File transfer implementation
In the websocketHandler function in main.go, we can write specific file transfer logic. Here we take simple file reading and sending as an example:

func websocketHandler(w http.ResponseWriter, r *http.Request) {
    conn, err := upgrader.Upgrade(w, r, nil)
    if err != nil {
        log.Println(err)
        return
    }

    // 文件读取
    filePath := "example.txt"
    file, err := os.Open(filePath)
    if err != nil {
        log.Println(err)
        return
    }
    defer file.Close()

    fileData, err := ioutil.ReadAll(file)
    if err != nil {
        log.Println(err)
        return
    }

    // 文件发送
    if err := conn.WriteMessage(websocket.BinaryMessage, fileData); err != nil {
        log.Println(err)
        return
    }
}

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In index.html, we use JavaScript’s FileReader object to read the file data to be transferred and send it to the server through WebSocket:

function sendFile(){
    var fileInput = document.getElementById("file");
    var file = fileInput.files[0];

    if(file){
        var reader = new FileReader();
        reader.readAsBinaryString(file);

        reader.onload = function(e){
            var fileData = e.target.result;
            ws.send(fileData);
        }
    }
}

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5. Run the project
In the command line, enter the project directory and execute the following command to start the server:

go run main.go

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Then visit http://localhost:8000 in the browser and click "Transfer File" button to select a file to transfer. The server reads the file data and sends it to the client, and the client receives and processes the file data through WebSocket. At this point, the development of an online file transfer function based on Golang and Websocket is completed.

Conclusion:
This article introduces how to use Golang to develop an online file transfer application based on Websocket, and provides specific code examples. By using Golang and Websocket, we can easily implement real-time file transfer function. I hope this tutorial is helpful for learning and developing Websocket applications!

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