telsh

Overview ¶

Package telsh provides "middleware" (for the telnet package) that can be used to implement a TELNET or TELNETS server that provides a "shell" interface (also known as a "command-line interface" or "CLI").

Shell interfaces you may be familiar with include: "bash", "csh", "sh", "zsk", etc.

TELNET Server ¶

Here is an example usage:

package main

import (
	"github.com/reiver/go-oi"
	"github.com/reiver/go-telnet"
	"github.com/reiver/go-telnet/telsh"

	"io"
)

func main() {

	telnetHandler := telsh.NewShellHandler()

	if err := telnetHandler.RegisterElse(
		telsh.ProducerFunc(
			func(ctx telnet.Context, name string, args ...string) telsh.Handler {
				return telsh.PromoteHandlerFunc(
					func(stdin io.ReadCloser, stdout io.WriteCloser, stderr io.WriteCloser, args ...string) error {
						oi.LongWrite(stdout, []byte{'w','a','t','?', '\r','\n'})

						return nil
					},
				)
			},
		),
	); nil != err {
		panic(err)
	}

	if err := telnetHandler.Register("help",
		telsh.ProducerFunc(
			func(ctx telnet.Context, name string, args ...string) telsh.Handler {
			return telsh.PromoteHandlerFunc(
					func(stdin io.ReadCloser, stdout io.WriteCloser, stderr io.WriteCloser, args ...string) error {
						oi.LongWrite(stdout, []byte{'r','t','f','m','!', '\r','\n'})

						return nil
					},
				)
			},
		),
	); nil != err {
		panic(err)
	}

	err := telnet.ListenAndServe(":5555", telnetHandler)
	if nil != err {
		//@TODO: Handle this error better.
		panic(err)
	}
}

Here is a more "unpacked" example:

package main

import (
	"github.com/reiver/go-oi"
	"github.com/reiver/go-telnet"
	"github.com/reiver/go-telnet/telsh"

	"io"
	"time"
)

var (
	shellHandler = telsh.NewShellHandler()
)

func init() {

	shellHandler.Register("dance", telsh.ProducerFunc(producer))

	shellHandler.WelcomeMessage = `
 __          __ ______  _        _____   ____   __  __  ______
 \ \        / /|  ____|| |      / ____| / __ \ |  \/  ||  ____|
  \ \  /\  / / | |__   | |     | |     | |  | || \  / || |__
   \ \/  \/ /  |  __|  | |     | |     | |  | || |\/| ||  __|
    \  /\  /   | |____ | |____ | |____ | |__| || |  | || |____
     \/  \/    |______||______| \_____| \____/ |_|  |_||______|

`
}

func producer(ctx telnet.Context, name string, args ...string) telsh.Handler{
	return telsh.PromoteHandlerFunc(handler)
}

func handler(stdin io.ReadCloser, stdout io.WriteCloser, stderr io.WriteCloser, args ...string) error {
	for i:=0; i<20; i++ {
		oi.LongWriteString(stdout, "\r⠋")
		time.Sleep(50*time.Millisecond)

		oi.LongWriteString(stdout, "\r⠙")
		time.Sleep(50*time.Millisecond)

		oi.LongWriteString(stdout, "\r⠹")
		time.Sleep(50*time.Millisecond)

		oi.LongWriteString(stdout, "\r⠸")
		time.Sleep(50*time.Millisecond)

		oi.LongWriteString(stdout, "\r⠼")
		time.Sleep(50*time.Millisecond)

		oi.LongWriteString(stdout, "\r⠴")
		time.Sleep(50*time.Millisecond)

		oi.LongWriteString(stdout, "\r⠦")
		time.Sleep(50*time.Millisecond)

		oi.LongWriteString(stdout, "\r⠧")
		time.Sleep(50*time.Millisecond)

		oi.LongWriteString(stdout, "\r⠇")
		time.Sleep(50*time.Millisecond)

		oi.LongWriteString(stdout, "\r⠏")
		time.Sleep(50*time.Millisecond)
	}
	oi.LongWriteString(stdout, "\r \r\n")

	return nil
}

func main() {

	addr := ":5555"
	if err := telnet.ListenAndServe(addr, shellHandler); nil != err {
		panic(err)
	}
}