GO语言实现的简单TCP服务代码

GO语言实现的简单TCP服务代码

package main
import (
"net"
"fmt"
)
var (   maxRead = 1100
	msgStop   = []byte("cmdStop")
	msgStart  = []byte("cmdContinue")
    )
func main() {
	hostAndPort := "localhost:54321"
	listener := initServer(hostAndPort)
	for {
		conn, err := listener.Accept()
		checkError(err, "Accept: ")
		go connectionHandler(conn)
	}
}
func initServer(hostAndPort string) *net.TCPListener {
	serverAddr, err := net.ResolveTCPAddr("tcp", hostAndPort)
	checkError(err, "Resolving address:port failed: '" + hostAndPort + "'")
	listener, err := net.ListenTCP("tcp", serverAddr)
	checkError(err, "ListenTCP: ")
	println("Listening to: ", listener.Addr().String())
	return listener
}
func connectionHandler(conn net.Conn) {
	connFrom := conn.RemoteAddr().String()
	println("Connection from: ", connFrom)
	talktoclients(conn)
	for {
		var ibuf []byte = make([]byte, maxRead + 1)
		length, err := conn.Read(ibuf[0:maxRead])
	    ibuf[maxRead] = 0 // to prevent overflow
	switch err {
	case nil:
	    handleMsg(length, err, ibuf)
	default:
	    goto DISCONNECT
	}
	}
	DISCONNECT:
	err := conn.Close()
	println("Closed connection:" , connFrom)
	checkError(err, "Close:" )
	}
func talktoclients(to net.Conn) {
	wrote, err := to.Write(msgStart)
	checkError(err, "Write: wrote " + string(wrote) + " bytes.")
}
func handleMsg(length int, err error, msg []byte) {
	if length > 0 {
		
		for i := 0; ; i++ {
			if msg[i] == 0 {
				break
			}
		}
		fmt.Printf("Received data: %v", string(msg[0:length]))
		fmt.Println("   length:",length)
	}
}
func checkError(error error, info string) {
	if error != nil {
panic("ERROR: " + info + " " + error.Error()) // terminate program
}
}