Golang golang-telnet (snippet)

Go programming example 'golang-telnet'

golang-telnet

Golang beginners example: golang-telnet

package main

import (
    "flag"
    "fmt"
    "net"
    "os"
    "strings"
    "time"
)

func handleConnection(c net.Conn, msgchan chan<- string) {
    defer c.Close()
    fmt.Printf("Connection from %v established.\n", c.RemoteAddr())
    c.SetReadDeadline(time.Now().Add(time.Second * 5))
    buf := make([]byte, 4096)
    for {
        n, err := c.Read(buf)
        if (err != nil) || (n == 0) {
            c.Close()
            break
        }
        msgchan <- string(buf[0:n])
    }
    time.Sleep(150 * time.Millisecond)
    fmt.Printf("Connection from %v closed.\n", c.RemoteAddr())
    c.Close()
    return
}

func printMessages(msgchan <-chan string) {
    var count int = 0
    for {
        msg := strings.TrimSpace(<-msgchan)
        count++
        fmt.Printf("Data %d: %s\n", count, msg)
    }
}

func main() {
    flag.Parse()
    port := ":" + flag.Arg(0)
    if port == ":" {
        port = ":2223"
    }
    ln, err := net.Listen("tcp", port)
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
    msgchan := make(chan string)
    go printMessages(msgchan)
    for {
        conn, err := ln.Accept()
        if err != nil {
            fmt.Println(err)
            continue
        }
        go handleConnection(conn, msgchan)
    }
}

Useful links

• Learn Go: https://golangr.com
• Download Go: https://golang.org