toy proxy for NodeJs (http+https support)

proxy.ts

//from: https://stackoverflow.com/a/49864522/1115220  re question: https://stackoverflow.com/questions/8165570/https-proxy-server-in-node-js

import http = require( 'http' )
const port: number = Number.parseInt( process.env.PORT ) || 9191;
import net = require( 'net' )
import url = require( 'url' )

import xlib = require( "xlib" );




import __ = xlib.lolo;

import log = xlib.diagnostics.log;



const requestHandler = ( req, res ) => { // discard all request to proxy server except HTTP/1.1 CONNECT method
	res.writeHead( 405, { 'Content-Type': 'text/plain' } )
	res.end( 'Method not allowed' )
}

const server = http.createServer( requestHandler )

const listener = server.listen( port, ( err ) => {
	if ( err ) {
		return console.error( err )
	}
	const info = listener.address()
	if ( typeof ( info ) === "string" ) {
		console.log( `Server is listening:  info: ${ info }` );
	} else {
		console.log( `Server is listening on address ${ info.address } port ${ info.port }` )
	}
} )

server.on( 'connect', ( req: http.IncomingMessage, clientSocket: net.Socket, head: Buffer ) => { // listen only for HTTP/1.1 CONNECT method
	console.log( clientSocket.remoteAddress, clientSocket.remotePort, req.method, req.url )
	if ( !req.headers[ 'proxy-authorization' ] ) { // here you can add check for any username/password, I just check that this header must exist!
		log.trace( "no auth passed.  closing connection.  here you can add check for any username/password, I just check that this header must exist!" );

		clientSocket.write( [
			'HTTP/1.1 407 Proxy Authentication Required',
			'Proxy-Authenticate: Basic realm="proxy"',
			'Proxy-Connection: close',
		].join( '\r\n' ) )
		clientSocket.end( '\r\n\r\n' )  // empty body

		return;
	}
	else {
		//log.trace( `auth passed:  req.headers[ 'proxy-authorization' ]===${ req.headers[ 'proxy-authorization' ] }` );
		if ( req.url.includes( "example" ) ) {
			log.info( "req passed:", req );
		}
	}
	const destUrl = url.parse( `//${ req.url }`, false, true ) // extract destination host and port from CONNECT request

	if ( destUrl.hostname && destUrl.port ) {
		const serverErrorHandler = ( err ) => {
			console.error( err.message )
			if ( clientSocket ) {
				clientSocket.end( `HTTP/1.1 500 ${ err.message }\r\n` )
			}
		}
		const serverEndHandler = () => {
			if ( clientSocket ) {
				clientSocket.end( `HTTP/1.1 500 External Server End\r\n` )
			}
		}
		const serverSocket = net.connect( Number.parseInt( destUrl.port ), destUrl.hostname ) // connect to destination host and port
		const clientErrorHandler = ( err ) => {
			console.error( err.message )
			if ( serverSocket ) {
				serverSocket.end()
			}
		}
		const clientEndHandler = () => {
			if ( serverSocket ) {
				serverSocket.end()
			}
		}
		clientSocket.on( 'error', clientErrorHandler )
		clientSocket.on( 'end', clientEndHandler )
		serverSocket.on( 'error', serverErrorHandler )
		serverSocket.on( 'end', serverEndHandler )
		serverSocket.on( 'connect', () => {
			clientSocket.write( [
				'HTTP/1.1 200 Connection Established',
				'Proxy-agent: Node-VPN',
			].join( '\r\n' ) )
			clientSocket.write( '\r\n\r\n' ) // empty body
			// "blindly" (for performance) pipe client socket and destination socket between each other
			serverSocket.pipe( clientSocket, { end: false } )
			clientSocket.pipe( serverSocket, { end: false } )
		} )
	} else {
		clientSocket.end( 'HTTP/1.1 400 Bad Request\r\n' )
		clientSocket.destroy()
	}
} )

note: https proxy works, but http proxy seems not to. I think http proxy needs to pipe requests (not just handle connect events)