server.js

'use strict'

const {createConnection} = require('net')
const {createServer: createHttpServer} = require('http')
const url = require('url')
const {createServer: createWsServer} = require('websocket-stream')
const pump = require('pump')
const debug = require('debug')('tcp-over-websockets:server')

const verifyRequest = (req, res) => {
	if (req.upgrade) return
	res.statusCode = 405
	res.end('connect via WebSocket protocol')
}

const startServer = (port, cb) => {
	const httpServer = createHttpServer(verifyRequest)

	const verifyClient = ({req}, cb) => {
		const target = url.parse(req.url).pathname.slice(1)
		const [hostname, port] = target.split(':')
		req.tunnelPort = +port
		req.tunnelHostname = hostname
		cb(!isNaN(port) && hostname, 400, 'invalid target')
	}

	const wsServer = createWsServer({
		server: httpServer,
		verifyClient
	}, (remote, req) => {
		const target = createConnection(req.tunnelPort, req.tunnelHostname)
		target.on('error', console.error)

		const onStreamError = (err) => {
			if (err) debug(err)
		}
		target.once('connect', () => {
			pump(remote, target, onStreamError)
			pump(target, remote, onStreamError)
		})
	})

	httpServer.listen(port, cb)
	return {httpServer, wsServer}
}

module.exports = startServer