Write to Client UDP Socket in Go

Question

I\'m looking for a good solution for a client/server communication with UDP sockets in Go language.

The examples I found on the Internet show me how to send data to the

Answer 1

hello_echo.go

 package main                                                                                                          

 import (                                                                                                              
     "bufio"                                                                                                           
     "fmt"                                                                                                             
     "net"                                                                                                             
     "time"                                                                                                            
 )                                                                                                                     

 const proto, addr = "udp", ":8888"                                                                                    

 func main() {  

     go func() {                                                                                                       
         conn, _ := net.ListenPacket(proto, addr)                                                                      
         buf := make([]byte, 1024)                                                                                     
         n, dst, _ := conn.ReadFrom(buf)                                                                               
         fmt.Println("serv recv", string(buf[:n]))                                                                     
         conn.WriteTo(buf, dst)                                                                                        
     }()        

     time.Sleep(1 * time.Second)   

     conn, _ := net.Dial(proto, addr)                                                                                  
     conn.Write([]byte("hello\n"))                                                                                     
     buf, _, _ := bufio.NewReader(conn).ReadLine()                                                                     
     fmt.Println("clnt recv", string(buf))                                                                             
 }                                                                                                                     

Answer 2

Check the below samples for client/server communication over UDP. The sendResponse routine is for sending response back to client.

udpclient.go

package main
import (
    "fmt"
    "net"
    "bufio"
)

func main() {
    p :=  make([]byte, 2048)
    conn, err := net.Dial("udp", "127.0.0.1:1234")
    if err != nil {
        fmt.Printf("Some error %v", err)
        return
    }
    fmt.Fprintf(conn, "Hi UDP Server, How are you doing?")
    _, err = bufio.NewReader(conn).Read(p)
    if err == nil {
        fmt.Printf("%s\n", p)
    } else {
        fmt.Printf("Some error %v\n", err)
    }
    conn.Close()
}

udpserver.go

package main
import (
    "fmt" 
    "net"  
)


func sendResponse(conn *net.UDPConn, addr *net.UDPAddr) {
    _,err := conn.WriteToUDP([]byte("From server: Hello I got your message "), addr)
    if err != nil {
        fmt.Printf("Couldn't send response %v", err)
    }
}


func main() {
    p := make([]byte, 2048)
    addr := net.UDPAddr{
        Port: 1234,
        IP: net.ParseIP("127.0.0.1"),
    }
    ser, err := net.ListenUDP("udp", &addr)
    if err != nil {
        fmt.Printf("Some error %v\n", err)
        return
    }
    for {
        _,remoteaddr,err := ser.ReadFromUDP(p)
        fmt.Printf("Read a message from %v %s \n", remoteaddr, p)
        if err !=  nil {
            fmt.Printf("Some error  %v", err)
            continue
        }
        go sendResponse(ser, remoteaddr)
    }
}