Fake Telnet Server

main.go

package main

import (
	"fmt"

	"github.com/reiver/go-oi"
	"github.com/reiver/go-telnet"
)

func main() {
	var stdLogger telnet.Logger= &StdLogger{}
	stdLogger.Debug("A fake Telnet Server By ihipop@gmail.com")
	stdLogger.Debug("Wait for new connection on 0.0.0.0:23")
	server := &telnet.Server{
		Addr:    "0.0.0.0:23",
		Handler: FakeLoginHandler{},
		Logger: stdLogger,
	}
	err := server.ListenAndServe()
	if nil != err {
		//@TODO: Handle this error better.
		panic(err)
	}
}
type StdLogger struct{}

func (*StdLogger) Debug(args ...interface{}) {
	fmt.Println(args...)
}
func (*StdLogger) Debugf(format string, args  ...interface{}) {
	fmt.Printf(format,args...);
	fmt.Println("")
}

func (*StdLogger) Error(args ...interface{}) {
	fmt.Println(args...)
}
func (StdLogger) Errorf(format string, args ...interface{}) {
	fmt.Printf(format,args...)
	fmt.Println("")
}

func (*StdLogger) Trace(args ...interface{}) {
	fmt.Println(args...)
}
func (*StdLogger) Tracef(format string, args ...interface{}) {
	fmt.Printf(format,args...)
	fmt.Println("")
}

func (*StdLogger) Warn(args ...interface{}) {
	fmt.Println(args...)
}
func (*StdLogger) Warnf(format string, args ...interface{}) {
	fmt.Printf(format,args...)
	fmt.Println("")
}

type FakeLoginHandler struct{}

func (handler FakeLoginHandler) ServeTELNET(ctx telnet.Context, w telnet.Writer, r telnet.Reader) {
	var receivedLine string
	var buffer [1]byte // Seems like the length of the buffer needs to be small, otherwise will have to wait for buffer to fill up.
	p := buffer[:]
	ctx.Logger().Debug("started new login connection")
	_, _ = oi.LongWrite(w, []byte("stb login:"))
	step := "username"
	for {
		n, err := r.Read(p)

		if n > 0 {
			if string(p[:n]) == "\n" {
				reply := "Received "+step+": "+receivedLine
				_, _ = oi.LongWriteString(w, reply+"\n")
				ctx.Logger().Debug(reply)
				receivedLine = ""
				if step == "username" {
					step = "password"
					_, _ = oi.LongWrite(w, []byte("Password:"))
				} else if step == "password" {
					step = "text"
					_, _ = oi.LongWrite(w, []byte("Login Success! Welcome!"+"\n"))
				}
			} else {
				receivedLine += string(p[:n])
			}
			// if nextstep == "" {
			// 	oi.LongWrite(w, p[:n])
			// }
		}

		if nil != err {
			ctx.Logger().Error(err)
			break
		}
	}
}