How to use Go language for network programming

How to use Go language for network programming

1. Introduction
With the continuous development of the Internet, network programming plays an important role in modern software development. As a simple and efficient programming language, Go language has powerful network programming capabilities. This article will introduce how to use Go language for network programming, and attach some code examples to help readers better understand and use Go language for network development.

2. TCP network programming
TCP is a reliable transmission protocol and is widely used in Internet communications. The following code example demonstrates how to use Go language to build a simple TCP server:

package main

import (
    "fmt"
    "net"
)

func main() {
    // 监听地址和端口
    listen, err := net.Listen("tcp", "localhost:8888")
    if err != nil {
        fmt.Println("Listen error:", err)
        return
    }
    defer listen.Close()

    fmt.Println("Server is running...")

    for {
        // 等待客户端连接
        conn, err := listen.Accept()
        if err != nil {
            fmt.Println("Accept error:", err)
            continue
        }
        fmt.Println("Client connected:", conn.RemoteAddr().String())

        // 处理客户端请求
        go handleConn(conn)
    }
}

func handleConn(conn net.Conn) {
    defer conn.Close()

    for {
        // 读取客户端发送的数据
        buf := make([]byte, 1024)
        n, err := conn.Read(buf)
        if err != nil {
            fmt.Println("Read error:", err)
            return
        }

        // 输出客户端发送的数据
        fmt.Println("Received:", string(buf[:n]))

        // 向客户端发送数据
        conn.Write([]byte("Hello, client!"))
    }
}

The above code implements a simple TCP server, listening to the specified address by calling the net.Listen function and port, and then call the listen.Accept function in a loop to wait for the client to connect. When the client connects successfully, the handleConn function is called to process the connection.

In the handleConn function, read the data sent by the client through the conn.Read function, and send it to the client through the conn.Write function send data. In addition, the client's network address can also be obtained through the conn.RemoteAddr function.

3. HTTP network programming
HTTP is a network protocol widely used in Web development. Go language has a built-in powerful HTTP library to facilitate developers to perform HTTP network programming. The following code example shows how to write a simple HTTP server using Go language:

package main

import (
    "fmt"
    "net/http"
)

func main() {
    // 注册一个处理函数
    http.HandleFunc("/", handler)

    // 启动HTTP服务器
    err := http.ListenAndServe(":8888", nil)
    if err != nil {
        fmt.Println("ListenAndServe error:", err)
        return
    }
}

func handler(w http.ResponseWriter, r *http.Request) {
    // 处理HTTP请求
    fmt.Fprintf(w, "Hello, client!")
}

The above code uses the http.HandleFunc function to register a handler function that will be used when the HTTP request arrives. is called. In the processing function, send an HTTP response to the client through http.ResponseWriter; use http.Request to obtain the client's request information, such as request path, request header, etc.

4. UDP network programming
UDP is an unreliable transmission protocol and is suitable for some scenarios that do not require high data reliability. The following code example demonstrates how to write a simple UDP server using Go language:

package main

import (
    "fmt"
    "net"
)

func main() {
    // 解析UDP地址
    addr, err := net.ResolveUDPAddr("udp", "localhost:8888")
    if err != nil {
        fmt.Println("ResolveUDPAddr error:", err)
        return
    }

    // 创建UDP连接
    conn, err := net.ListenUDP("udp", addr)
    if err != nil {
        fmt.Println("ListenUDP error:", err)
        return
    }
    defer conn.Close()

    fmt.Println("Server is running...")

    for {
        // 读取客户端发送的数据
        buf := make([]byte, 1024)
        n, remoteAddr, err := conn.ReadFromUDP(buf)
        if err != nil {
            fmt.Println("ReadFromUDP error:", err)
            continue
        }

        fmt.Println("Client connected:", remoteAddr.String())

        // 处理客户端请求
        go handleUDPConn(conn, remoteAddr, buf[:n])
    }
}

func handleUDPConn(conn *net.UDPConn, remoteAddr *net.UDPAddr, data []byte) {
    // 处理客户端请求
    fmt.Println("Received:", string(data))

    // 向客户端发送数据
    conn.WriteToUDP([]byte("Hello, client!"), remoteAddr)
}

The above code implements a simple UDP server and creates a UDP connection by calling the net.ListenUDP function , and then loops to call the conn.ReadFromUDP function to read the data sent by the client. After reading the data, call the handleUDPConn function to process the request, and send the data to the client through the conn.WriteToUDP function.

5. Summary
This article introduces how to use Go language for network programming, and provides code examples for TCP, HTTP and UDP network programming. By learning and using these code examples, readers can better master the network programming technology of Go language and provide assistance for actual project development. Network programming is a complex and complex job that requires continuous learning and practice. I hope this article will be helpful to readers.

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