package main import (
"fmt"
"io"
"log"
"net"
"os"
) func showBytes(bytes []byte) string {
var str []byte
for _, b := range bytes {
if b >= 33 && b <= 126 && b != 92 {
str = append(str, b)
} else {
str = append(str, fmt.Sprintf("\\%02X", b)...)
}
}
return string(str)
} func writeAllTCP(con *net.TCPConn, message []byte) error {
defer con.CloseWrite()
for len(message) > 0 {
l, err := con.Write(message)
if err != nil {
return err
}
message = message[l:]
}
return nil
} func handleTCP(client *net.TCPConn, message []byte) {
defer client.Close()
addrStr := client.RemoteAddr().String()
log.Printf("Client %s connected\n", addrStr)
var data [1024]byte
n, err := io.ReadFull(client, data[:])
if err != nil && err != io.ErrUnexpectedEOF {
log.Printf("Failed to read: %v\n", err)
return
}
log.Printf("From %s: %s\n", addrStr, showBytes(data[:n]))
if err := writeAllTCP(client, message); err != nil {
log.Printf("Failed to write: %v\n", err)
return
}
} func main() {
if len(os.Args) != 5 || os.Args[1] != "tcp" && os.Args[1] != "udp" || os.Args[2] != "server" && os.Args[2] != "client" {
fmt.Fprintf(os.Stderr, "Usage: %s tcp|udp server|client <server address> <message>\n", os.Args[0])
os.Exit(1)
}
if os.Args[1] == "tcp" {
addr, err := net.ResolveTCPAddr("tcp", os.Args[3])
if err != nil {
panic(err)
}
if os.Args[2] == "server" {
con, err := net.ListenTCP("tcp", addr)
if err != nil {
panic(err)
}
defer con.Close()
for {
client, err := con.AcceptTCP()
if err != nil {
log.Printf("Failed to accept: %v\n", err)
continue
}
go handleTCP(client, []byte(os.Args[4]))
}
} else {
con, err := net.DialTCP("tcp", nil, addr)
if err != nil {
panic(err)
}
defer con.Close()
if err := writeAllTCP(con, []byte(os.Args[4])); err != nil {
panic(err)
}
var data [1024]byte
n, err := io.ReadFull(con, data[:])
if err != nil && err != io.ErrUnexpectedEOF {
panic(err)
}
fmt.Println(showBytes(data[:n]))
}
} else {
addr, err := net.ResolveUDPAddr("udp", os.Args[3])
if err != nil {
panic(err)
}
if os.Args[2] == "server" {
con, err := net.ListenUDP("udp", addr)
if err != nil {
panic(err)
}
defer con.Close()
for {
var data [1024]byte
n, addr, err := con.ReadFromUDP(data[:])
if err != nil {
log.Printf("Failed to read: %v\n", err)
continue
}
log.Printf("From %v: %s\n", addr, showBytes(data[:n]))
_, err = con.WriteTo([]byte(os.Args[4]), addr)
if err != nil {
log.Printf("Failed to write: %v\n", err)
continue
}
}
} else {
con, err := net.DialUDP("udp", nil, addr)
if err != nil {
panic(err)
}
defer con.Close()
_, err = con.Write([]byte(os.Args[4]))
if err != nil {
panic(err)
}
var data [1024]byte
n, _, err := con.ReadFromUDP(data[:])
if err != nil {
panic(err)
}
fmt.Println(showBytes(data[:n]))
}
}
}
https://gitee.com/thhh_sunny/go-net-hello?_from=gitee_search
https://gitee.com/YePitfall/socket-programming/tree/master/udpclient
