basic_node.js

// import express JS module into app
// and creates its variable.
var express = require('express');
var app = express();

// Creates a server which runs on port 3000 and
// can be accessed through localhost:3000
app.listen(3000, function() {
	console.log('server running on port 3000');
} )

// Function callName() is executed whenever
// url is of the form localhost:3000/name
app.get('/name', callName);

function callName(req, res) {

	// Use child_process.spawn method from
	// child_process module and assign it
	// to variable spawn
	var spawn = require("child_process").spawn;

	// Parameters passed in spawn -
	// 1. type_of_script
	// 2. list containing Path of the script
	// and arguments for the script

	// E.g : http://localhost:3000/name?firstname=Mike&lastname=Will
	// so, first name = Mike and last name = Will
	var process = spawn('python',["./hello.py",
							req.query.firstname,
							req.query.lastname] );

	// Takes stdout data from script which executed
	// with arguments and send this data to res object
	process.stdout.on('data', function(data) {
		res.send(data.toString());
	} )
}

// save code as start.js