dotnetCarpenter/index.html

## index.html
<!DOCTYPE html>
<html lang="en">
<head>
	<meta http-equiv="X-UA-Compatible" content="IE=edge">
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<title>Document</title>
</head>
<body>
	<h1>Heading 1</h1>

	<iframe src="text.txt"></iframe>
</body>
</html>

## server.js
const http = require ('http')
const fs   = require ('fs')
const path = require ('path')
const S    = require ('sanctuary')
const $    = require ('sanctuary-def')
const show = require ('sanctuary-show')
const {
    State,
}          = require ('monastic')

const setContentType = response => filePath => {
    switch (path.extname (filePath)) {
        case '.html':
        case '.htm':
            response.setHeader ('Content-Type', 'text/html; charset=utf-8')
            break
        case '.js':
        case '.mjs':
            response.setHeader ('Content-Type', 'application/javascript; charset=utf-8')
            break
        case '.json':
        case '.json5':
        case '.jsonc':
            response.setHeader ('Content-Type', 'application/json; charset=utf-8')
        default:
            response.setHeader ('Content-Type', 'text/plain; charset=utf-8')
    }

    return filePath
}

const readFile = cb => path => {
    fs.readFile (path, { encoding: 'utf-8' }, cb)
    return path
}

const payload = response => (error, data) => {
    if (error) {
        response.statusCode = 500
        response.end (JSON.stringify (error))
    } else {
        response.statusCode = 200
        response.end (String (data))
    }
}

const notAllowed = response => x => {
    response.statusCode = 403
    response.setHeader ('Content-Type', 'text/plain')
    response.end ('Not in allowed list')

    return x
}

// ---------------------------------------------->

const hostname   = '127.0.0.1'
const port       = 3000
const allowed    = {
    '/': path.resolve (__dirname, 'index.html'),
    '/text.txt'  : path.resolve (__dirname, 'text.txt'),
}

const serve = (request, response) => {
    S.pipe ([
        S.flip (S.get (S.is ($.String))) (allowed),
        S.map  (setContentType (response)),
        S.map  (readFile (payload (response))),
        S.when (S.isNothing)
               (notAllowed (response)),
    ])
    (request.url)
}

const server = http.createServer (serve)

server.listen (port, hostname, () => {
    console.log (`Server running at http://${hostname}:${port}/`)
})

## text.txt
Foobar
æøå
	<!DOCTYPE html>
	<html lang="en">
	<head>
	<meta http-equiv="X-UA-Compatible" content="IE=edge">
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<title>Document</title>
	</head>
	<body>
	<h1>Heading 1</h1>

	<iframe src="text.txt"></iframe>
	</body>
	</html>
	const http = require ('http')
	const fs = require ('fs')
	const path = require ('path')
	const S = require ('sanctuary')
	const $ = require ('sanctuary-def')
	const show = require ('sanctuary-show')
	const {
	State,
	} = require ('monastic')

	const setContentType = response => filePath => {
	switch (path.extname (filePath)) {
	case '.html':
	case '.htm':
	response.setHeader ('Content-Type', 'text/html; charset=utf-8')
	break
	case '.js':
	case '.mjs':
	response.setHeader ('Content-Type', 'application/javascript; charset=utf-8')
	break
	case '.json':
	case '.json5':
	case '.jsonc':
	response.setHeader ('Content-Type', 'application/json; charset=utf-8')
	default:
	response.setHeader ('Content-Type', 'text/plain; charset=utf-8')
	}

	return filePath
	}

	const readFile = cb => path => {
	fs.readFile (path, { encoding: 'utf-8' }, cb)
	return path
	}

	const payload = response => (error, data) => {
	if (error) {
	response.statusCode = 500
	response.end (JSON.stringify (error))
	} else {
	response.statusCode = 200
	response.end (String (data))
	}
	}

	const notAllowed = response => x => {
	response.statusCode = 403
	response.setHeader ('Content-Type', 'text/plain')
	response.end ('Not in allowed list')

	return x
	}

	// ---------------------------------------------->

	const hostname = '127.0.0.1'
	const port = 3000
	const allowed = {
	'/': path.resolve (__dirname, 'index.html'),
	'/text.txt' : path.resolve (__dirname, 'text.txt'),
	}

	const serve = (request, response) => {
	S.pipe ([
	S.flip (S.get (S.is ($.String))) (allowed),
	S.map (setContentType (response)),
	S.map (readFile (payload (response))),
	S.when (S.isNothing)
	(notAllowed (response)),
	])
	(request.url)
	}

	const server = http.createServer (serve)

	server.listen (port, hostname, () => {
	console.log (`Server running at http://${hostname}:${port}/`)
	})