go tcp

TCP编程

1、客户端和服务器

2、服务端的处理流程

• 监听端口
• 接收客户端的链接
• 创建goroutine，处理该链接

3、客户端的处理流程

• 建立与服务端的链接
• 进行数据收发
• 关闭链接

服务端代码

package main

import (
	"fmt"
	"net"
)

func main() {
	fmt.Println("start server...")
	listen, err := net.Listen("tcp", "0.0.0.0:50000")
	if err != nil {
		fmt.Println("listen failed, err:", err)
		return
	}
	for {
		conn, err := listen.Accept()
		if err != nil {
			fmt.Println("accept failed, err:", err)
			continue
		}
		go process(conn)
	}
}
func process(conn net.Conn) {
	defer conn.Close()
	for {
		buf := make([]byte, 512)
		n, err := conn.Read(buf)
		if err != nil {
			fmt.Println("read err:", err)
			return
		}

		fmt.Printf(string(buf[0:n]))
	}
}

客户端代码

package main

import (
	"bufio"
	"fmt"
	"net"
	"os"
	"strings"
)

func main() {

	conn, err := net.Dial("tcp", "localhost:50000")
	if err != nil {
		fmt.Println("Error dialing", err.Error())
		return
	}

	defer conn.Close()
	inputReader := bufio.NewReader(os.Stdin)
	for {
		input, _ := inputReader.ReadString('\n')
		trimmedInput := strings.Trim(input, "\r\n")
		if trimmedInput == "Q" {
			return
		}
		_, err = conn.Write([]byte(trimmedInput))
		if err != nil {
			return
		}
	}
}

发送http请求

package main

import (
	"fmt"
	"io"
	"net"
)

func main() {

	conn, err := net.Dial("tcp", "www.baidu.com:80")
	if err != nil {
		fmt.Println("Error dialing", err.Error())
		return
	}
	defer conn.Close()
	msg := "GET / HTTP/1.1\r\n"
	msg += "Host:www.baidu.com\r\n"
	msg += "Connection:keep-alive\r\n"
	//msg += "User-Agent:Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36\r\n"
	msg += "\r\n\r\n"

	//io.WriteString(os.Stdout, msg)
	n, err := io.WriteString(conn, msg)
	if err != nil {
		fmt.Println("write string failed, ", err)
		return
	}
	fmt.Println("send to baidu.com bytes:", n)
	buf := make([]byte, 4096)
	for {
		count, err := conn.Read(buf)
		fmt.Println("count:", count, "err:", err)
		if err != nil {
			break
		}
		fmt.Println(string(buf[0:count]))
	}
}