Go language basic TCP programming combined with Goroutine multiple clients to access a server

We can usually upload files to a server by multiple users. This can be done through TCP programming. We can do it as long as we combine the concurrency of the go language.

server first

package main

import (
   "net"
   "os"
//"fmt"
"io"
   "fmt"
)      

func main() {
   tcpaddr , _ := net.ResolveTCPAddr( "tcp" , ":34521" ) //determine IP address
 listener , _ := net.ListenTCP( "tcp" , tcpaddr) //listen port
 for {
      
      conn , _ := listener.Accept() //Request connection
    fmt.Println( "A client is connected" , conn.RemoteAddr())
      d := make([]byte, 2048)

      go func(conn net.Conn) {
         f1, _ := os.OpenFile("e:\\205.jpg", os.O_WRONLY|os.O_CREATE, 0777)
         for {
            count , err := conn.Read(d) //Start reading after receiving the file from the client
 if err != nil {
                break
 }                        
            f1.Write(d[:count]) //Write the read content to the file and save it
          }

      }(conn)
      conn.Close() //Close the connection }
    }
}

then the client

package main

import (
   "net"
   "io/ioutil"
   "fmt"
)

func main(){
   tcpaddr,_:=net.ResolveTCPAddr("tcp","192.168.31.168:34521")//确定服务器的地址
   tcpconn,_:=net.DialTCP("tcp",nil,tcpaddr)//申请连接
   defer tcpconn.Close()//完事后关闭
   d,_:=ioutil.ReadFile("D:\\205.jpg")  //读取本地文件
   tcpconn.Write(d)  //把文件写给服务器
   fmt.Println(len(d))


}