github.com/qiuhoude/go-web@v0.0.0-20220223060959-ab545e78f20d/prepare/00_net/udp/example_1/main.go (about)

     1  package main
     2  
     3  import (
     4  	"fmt"
     5  	"github.com/AsynkronIT/goconsole"
     6  	"github.com/prometheus/common/log"
     7  	"net"
     8  )
     9  
    10  func server() {
    11  	addr, err := net.ResolveUDPAddr("udp", "127.0.0.1:8888")
    12  	if err != nil {
    13  		log.Fatal(err)
    14  	}
    15  
    16  	conn, err := net.ListenUDP("udp", addr)
    17  	fmt.Printf("Local: <%s> \n", conn.LocalAddr().String())
    18  
    19  	data := make([]byte, 1024)
    20  
    21  	for {
    22  		n, remoteAddr, err := conn.ReadFromUDP(data)
    23  		if err != nil {
    24  			fmt.Printf("error during read: %s", err)
    25  		}
    26  		fmt.Printf("server : rsv <%s> %s\n", remoteAddr, data[:n])
    27  
    28  		_, err = conn.WriteToUDP([]byte("world"), remoteAddr)
    29  		if err != nil {
    30  			fmt.Printf(err.Error())
    31  		}
    32  	}
    33  }
    34  
    35  func client() {
    36  	sip := net.ParseIP("127.0.0.1")
    37  
    38  	srcAddr := &net.UDPAddr{IP: net.IPv4zero, Port: 0}
    39  	dstAddr := &net.UDPAddr{IP: sip, Port: 8888}
    40  
    41  	conn, err := net.DialUDP("udp", srcAddr, dstAddr)
    42  	if err != nil {
    43  		log.Fatal(err)
    44  	}
    45  	defer conn.Close()
    46  	_, err = conn.Write([]byte(`hello`))
    47  	if err != nil {
    48  		log.Fatal(err)
    49  	}
    50  	fmt.Printf("<%s>\n", conn.RemoteAddr())
    51  	data := make([]byte, 1024)
    52  	n, err := conn.Read(data)
    53  	fmt.Printf("client :read %s from <%s>\n", data[:n], conn.RemoteAddr())
    54  
    55  }
    56  
    57  func main() {
    58  
    59  	go server()
    60  
    61  	client()
    62  
    63  	console.ReadLine()
    64  }