server.js

const http = require('http')  
const port = 8000

const requestHandler = (request, response) => {  
  console.log(request.url)
  response.statusCode = 200;
  response.setHeader('Content-Type', 'text/plain');
  response.end("Hello, HTTP! \n")
}

const server = http.createServer(requestHandler)

server.listen(port, (err) => {  
  if (err) {
    return console.log('something bad happened', err)
  }
  console.log("server is listening on " + port)
})

server.py

from http.server import HTTPServer, BaseHTTPRequestHandler

class HelloHandler(BaseHTTPRequestHandler):
    def do_GET(self):
        # First, send a 200 OK response.
        self.send_response(200)


        # Then send headers.
        self.send_header('Content-type', 'text/plain; charset=utf-8')
        self.end_headers()


        # Now, write the response body.
        self.wfile.write("Hello, HTTP!\n".encode())

if __name__ == '__main__':
    server_address = ('', 8000)  # Serve on all addresses, port 8000.
    httpd = HTTPServer(server_address, HelloHandler)
    httpd.serve_forever()

server.rb

require "webrick"

class HelloServer < WEBrick::HTTPServlet::AbstractServlet
    def do_GET (request, response)
        response.status = 200
        response.content_type = "text/plain"
        response.body = "Hello, HTTP! \n"
    end
end

server = WEBrick::HTTPServer.new(:Port => 8000)

server.mount "/", HelloServer

server.start