Hi,
In a recent assignment, I was supposed to create a PoC of how Nodejs would work with Mongodb to offer RESTful web services. I was very new to Javascript programming as well as Nodejs platform. Then I started reading about Nodejs and went through couple of tutorials and a ebook to understand what it stands for.
Here are few things I noticed and remember after completing my PoC.
1.) It’s
built using Chrome’s Javascript runtime
2.) It’s
lightweight and efficient because of it’s event driven and non-blocking I/O
architecture
3.) Best
for data intensive realtime applications like web services, analytics,
dashboard service etc.
Benefits and possible usage:
1.) Great
Performance – it’s all javascript running with chrome’s javascript engine.
2.) Fast
development – You don’t need a lot of software setup the way you need for Java
or Microsoft projects.
3.) Huge
flexibility to do both high level and low level functionality.
4.) It
is natural choice for developing a backend system which needs to be scaled
faster and still maintain it’s performance.
5.) Good
choice to create various collaborative components like chat room or message
boards.
6.) You
can achieve both scalability and performance on commodity servers. You don’t
need high end servers in order to achieve these features for your apps.
7.) A
good choice for developing web services with Mongodb, because both of them
understand JSON like their first language.
8.) For
any web portal using extensive Javascript (be it Angular or ExtJS or any other
form), Nodejs can be very natural and obvious choice since using Javascript on
both sides would give you better performance & flexibility.
9.) Nodejs
community publishes various kinds of packages (like express and others), which
can be plugged into your development and reused like never before. Since it’s
plain javascript, more and more packages are coming out faster & often.
This, in turn supports faster development as well as it support community
development.
10.) More and
more Mobile apps and sites are being developed using various Javascript
libraries like JQuery and AngularJS instead of Notive code. Hence, Nodejs
becomes obvious choice for all such mobile app projects for their backend
services.
11.) In a
recent trend, Nodejs is increasingly being used to create backend components to
analyze log files, convert images/videos and sending out communications like
emails and SMSs (also push notifications).
Then the code that I first developed for my PoC. A RESTful service with Nodejs and Mongodb.
This Nodejs web service is deployed on IBM Bluemix PaaS (Platform as a Service).
//following content go into app.js file
// This application uses express as it's web server
// for more info, see: http://expressjs.com
var express = require('express');
var http = require('http');
//var express = require('express');
var mongo = require('mongodb');
var MongoClient = mongo.MongoClient;
var connectionString = 'mongodb://<username>:<password>@<mongodb-host-name>:<mongodb-port>/dbname';
// cfenv provides access to your Cloud Foundry environment
// for more info, see: https://www.npmjs.com/package/cfenv
var cfenv = require('cfenv');
// create a new express server
var app = express();
// serve the files out of ./public as our main files
app.use(express.static(__dirname + '/public'));
app.get('/test', function (req, res) {
res.send('Hello World');
});
app.get('/users/:username', function (req, res) {
MongoClient.connect(connectionString, function (err, db) {
if (err) throw err;
if (!err) {
console.log("Connected to database");
var collection = db.collection('users');
var uname = req.params.username;
//retrive user
collection.find({"username": uname}).toArray(function (err, result) {
if (err) {
console.log(err);
res.send(err);
} else if (result.length) {
console.log('Found:', result);
res.send(result);
} else {
console.log('No document(s) found with defined "find" criteria!');
res.send('No document(s) found with defined "find" criteria!');
}
//Close connection
db.close();
});
}
})
});
//This one updates password or creates new username in DB
app.post('/users/:username/:password', function (req, res) {
MongoClient.connect(connectionString, function (err, db) {
if (err) throw err;
if (!err) {
console.log("Connected to database");
var collection = db.collection('users');
var uname = req.params.username;
var pwd = req.params.password;
//create JSON for insert
var user = {"username": uname, "password": pwd};
//First try to update
collection.update({"username": uname}, {$set: {"password": pwd}}, function (err, numUpdated) {
if (err) {
console.log(err);
res.send(err);
} else if (numUpdated) {
console.log('Updated Successfully %d document(s).', numUpdated);
res.send('Updated Successfully - ' + numUpdated.nModified + ' document(s).');
} else {
console.log('No document found with defined "find" criteria!');
// Insert one user because its not found
collection.insertOne(user, function (err, result) {
if (err) {
console.log(err);
res.send(err);
} else {
console.log('Inserted document! Thanks!');
res.send('Inserted document! Thanks!' + result);
}
}
);
}
//Close connection
console.log('Now we are closing the db connection...');
db.close();
}
);
}
})
});
// get the app environment from Cloud Foundry
var appEnv = cfenv.getAppEnv();
// start server on the specified port and binding host
app.listen(appEnv.port, appEnv.bind, function() {
// print a message when the server starts listening
console.log("server starting on " + appEnv.url);
});
