MEAN web development #9: Some last remarks

So by now we’ve seen the full MEAN stack, MongoDB, Express, AngularJS and Node.js. Additionally we’ve seen the templating engine Jade in action as well as used Socket.io for real time web applications. If you combine that with my earlier series on ‘vanilla’ web development you’re already a pretty versatile web developer (well, dependent on how much you practiced)!
In case you missed a MEAN article, here they are:

  1. MEAN web development #1: MEAN, the what and why
  2. MEAN web development #2: Node.js in the back
  3. MEAN web development #3: More Node.js
  4. MEAN web development #4: All aboard the Node.js Express!
  5. MEAN web development #5: Jade and Express
  6. MEAN web development #6: AngularJS in the front
  7. MEAN web development #7: MongoDB and Mongoose
  8. MEAN web development #8: Sockets will rock your socks!
  9. MEAN web development #9: Some last remarks

In this post I’m going to discuss one topic we haven’t covered yet, deployment. Next to that I’m going to give you some alternatives for the technologies we’ve covered in this series.

There is no GitHub repository for this article as there won’t be any code samples.

Deploying a Node.js application

So we haven’t talked about deployment yet. Not even in my web development series. To be honest, deploying software is not what I do, I just write them. Besides, deploying to the Windows laptop you’ve used to build your software is a bit difficult and in most¬†cases isn’t even close to actual deployment. Unfortunately I don’t have any spare web servers laying around ūüôā
That isn’t to say I can’t point you in the right direction.

Node.js is a little different from what you’re used to. Consider the PHP application we wrote earlier in¬†Web development #4: PHP in the back. We wrote our page and got it up and running using XAMPP, where we specified the port and other settings. The PHP file¬†didn’t do anything. Likewise, a C# web application doesn’t do anything until you host it using IIS, which can be configured however you like.
That’s different for a Node.js application. After all we specify the server, where it should run and how it should run in our JavaScript file. And then we could run it from the console. On production environments we really don’t want to run a console though. We probably want to host our application on port 80, which is the default HTTP port, which requires an elevated command prompt. So someone with admin rights should log on to the server to (re)start our Node.js app every time something happens (either the app crashes or the machine is restarted). That doesn’t sound very appealing…

So we could simply write some command script using a loop that restarts Node.js whenever it crashes and start that up, with elevated privileges, either using a service or the built-in scheduler. That solution has¬†some serious limitations though. What if your app goes in an unrecoverable state, making it crash in a loop? Or what if, for some reason, it hogs up all of your memory? A command prompt can’t really give you a detailed log of what’s happening with your application.

That sounds really tiresome and messed up. Luckily there is a better alternative. You can use PM2 (Process Manager 2) to run Node.js (PM2 on GitHub). PM2 can run other scripts such as PHP, CoffeeScript and Ruby as well and it works on Linux, MacOSx and Windows.
You can install PM2 using npm (npm install pm2 -g). Make sure to add ¬†the -g to make a global install. Now you can simply start any Node.js app by running “pm2 start node_app.js”. “pm2 list” will show a list with running applications. Then you can generate a startup script¬†with “pm2 startup” to automatically start your apps on a computer reboot (which unfortunately doesn’t work on Windows, so I haven’t been able to test it). “pm2 monit” will show you some statistics on the current status of your applications.
Next to that PM2 has a deployment system, log management, a development tool (similar to nodemon which we’ve been using in this series), cluster mode (for running on multiple CPU’s, remember Node.js is single threaded)¬†and much more which you can all use as well.

There are some alternatives to PM2, such as forever, but something completely different is to run your Node.js app as a Windows service. You can do this by using NSSM (the Non-Sucking Service Manager) and winser. You can download NSSM from their website and you can install winser using npm (npm install winser). Then you should add the following lines to your package.json:

"scripts": {
    "postinstall": "winser -i -s -c",
    "preuninstall": "winser -r -x -s",
}

Now in the command prompt browse to the folder that contains the package.json and execute “node_modules.bin\winser -i”.¬†You have now installed your Node.js application as a service. To uninstall execute “node_modules.bin\winser -r”.

So I know that’s not much, but at least¬†these are some considerations when deploying a Node.js application.

HTTPS/SSL

You might want to deploy your application using HTTPS for secure SSL-encrypred traffic. For this you’re going to need some certificates, which I dont have.¬†Node.js has an https module, just like it has a http module. So now it shouldn’t be too difficult to write yourself an HTTPS enabled Node.js server.

var https = require('https');
var fs = require('fs');

var options = {
    key: fs.readFileSync('some-key.pem'),
    cert: fs.readFileSync('some-certificate.pem')
};

var server = https.createServer(options, function (req, res) {
    // Stuff...
});
server.listen(80, '127.0.0.1');

And here’s how you can use Express to handle HTTPS.

var app = require('express')();
var https = require('https');
var fs = require('fs');

var options = {
 key: fs.readFileSync('some-key.pem'),
 cert: fs.readFileSync('some-certificate.pem')
};

// Stuff...

var server = https.createServer(options, app`);
server.listen(80, '127.0.0.1');

And now you also know why you should use packages for your routing, you may want to re-use them.

MEAN alternatives

In this series we’ve seen the MEAN stack: MongoDB, Express, AngularJS and Node.js. It offers an alternative to the traditional LAMP stack, Linux, Apache, MySQL and PHP and the Microsoft stack with .NET¬†and IIS.¬†The baseline here is that we programmers just like to come up with cool or clever sounding acronyms. As I said before you can have a perfectly good MEN stack, leaving out the AngularJS. Or put in some Jade, or Sockets.io. Well, people have actually done that and came up with some other nice sounding acronyms. Here are some that I’ve seen: ANNE (AngularJS, Node.js, Neo4j, Express); BEANS (Bootstrap, Express, AngularJS, Node.js, Sockets.io); EARN (Express, AngularJS, Redis, Node.js). My point is that you’re not tied to MEAN, it’s simply a couple of technologies that work well together and can help you get things done.

If you like you can have a look at Sails.js, which is built on Express, but adds MVC and an ORM, among other things. Another alternative for Express (or Sails.js) is Hapi.js, which focuses more on configuration than code.

As alternative for MongoDB we’ve already seen Neo4j (a NoSQL graph database) and Redis (a NoSQL key-value store). They don’t actually have to be alternatives as you can use both in a single project. An actual alternative could be CouchDB, which is also a NoSQL document database and is probably the second most popular document database after MongoDB,
But who said you have to stick to NoSQL? If you’d like to use MySQL with Node.js that’s perfectly fine too!
If you just look at the Express database capabilities you’ll find databases such as Cassandra, PostgreSQL and ElasticSearch are supported out of the box.
And there are drivers for SQL Server and Oracle too.

Let’s look at some AngularJS alternatives. Of course there’s always jQuery that you can still use in your projects. Get some Knockout.js in your project too and you might not need AngularJS at all (although AngularJS is probably your first choice for SPAs (Single Page Applications).
While AngularJS is the most popular front end framework, it’s not your only choice. Underscore.js is another popular framework that is a little less bloated than AngularJS (but does less as well).
Another framework that you might want to try is Ember.js, which does pretty much everything that AngularJS does too. If you want to read more about Ember.js I can recommend Erik Hanchett’s blog.

And if you wish for another HTML template engine (or no template engine at all) you can ignore Jade and go with, for example, Mustache or Handlebars. Keep in mind you can use templating both on your back end and in your front end.

I’d mention alternatives for Node.js, but that would kind of defeat the purpose of MEAN and the (almost) all JavaScript stack. So let’s not do that (besides, you probably know them already).

Other popular modules

Let’s quickly check out some other popular Node.js modules. I’ll let you figure out how to use them on your own, but I’ll give a quick overview and a link to the website (with documentation).

The first library you might want to check is Browserify, which let’s you use require() in the browser. That’s pretty sweet!

Another popular library that you can use in both Node.js and in your front end is async. It provides many functions for asynchronous execution, such as each, map and filter on arrays.
It can also help you with asynchronous flow control. That is executing one task after another in an elegant and asynchronous manner. And for this same purpose the creator of async also gives us Nimble. And you might want to take a look at the alternatives Seq and Step as well.

So how about your minification, compilation, unit testing, linting (checking for syntax errors) etc.? For these tasks you can use Gulp or Grunt. Both applications are popular ‘task runners’ and can be easily installed using npm (using -g) and automate these kinds of tasks. They might take some configuration and some time to get¬†used to, but they’re worth it.

Last I’d like to point out commander. Since¬†everything nowadays seems to be working with the command prompt you might want to make your application command prompt configurable too. Something like “node server.js -super” where -super (or -s for short) starts your application in superman mode.¬†You don’t need a library for this, but it does come in handy. Commander seems to be the most popular one.

So that’s it for the entire MEAN series. I hope you’ve learned and enjoyed it as much as I have! This is the end of the MEAN series, but certainly not the end of my blogging career. In the future you may expect more posts on¬†web development, JavaScript, NoSQL, and who knows what. I’m always open for suggestions!

For additional reading on MEAN and related technologies I can once again recommend the Succinctly series by Syncfusion. They have many free ebooks like Node.js Succinctly, AngularJS Succinctly and MongoDB Succinctly. I’m also a big fan of the books by Manning Publications. Though not free they’re definitely worth your money. Books like Node.js In Action (second edition coming up), AngularJS In Action, MongoDB In Action (also a second edition coming up) and even Express In Action.¬†A book on the entire MEAN stack, Getting MEAN, is also in the writing (so get it early)!

I’ll be on a vacation in Poland for the next two weeks, so don’t expect a new blog post for at least another three weeks. Maybe a short one on a rainy day and if I have wi-fi in the hotel, but I’m not making any promises.

Thanks for sticking with me and happy coding!

MEAN web development #8: Sockets will rock your socks!

This week I’m planning to keep it short. We’ll look at sockets and how to utilize them using Node.js. Luckily this is a relatively easy task for which Node.js is famous. Sockets enable you to build real time websites, something that is difficult at best using HTTP.
This will also be the last article in the series in which we’ll look at a new technology. If you¬†read¬†everything up til now you’re pretty well on your way to becoming a MEAN web developer! Next week we’ll have a wrap up and after that, who knows ūüôā

  1. MEAN web development #1: MEAN, the what and why
  2. MEAN web development #2: Node.js in the back
  3. MEAN web development #3: More Node.js
  4. MEAN web development #4: All aboard the Node.js Express!
  5. MEAN web development #5: Jade and Express
  6. MEAN web development #6: AngularJS in the front
  7. MEAN web development #7: MongoDB and Mongoose
  8. MEAN web development #8: Sockets will rock your socks!
  9. MEAN web development #9: Some last remarks

As usual you can find the code samples for this post on my GitHub page under the mean8-blog repository.

What are sockets?

I won’t really go into technical details about sockets, or networks sockets.¬†What is important to know is that a socket is basically an endpoint connection that allows communication between computers in a network. In an earlier post,¬†Web development #1: Internet and the World Wide Web, I have briefly discussed the internet protocols TCP/IP (Transmission Control Protocol/Internet Protocol) and I have mentioned other protocols such as UDP (User Datagram Protocol). Those protocols make use of sockets to transfer data across the web.

As we have seen protocols such as HTTP (and HTTPS) make use of the TCP/IP protocol, which makes use of sockets. As we know HTTP is a one way street, although the data flow isn’t. Think about it, with HTTP we can request data, but that data also has to be sent back to the client. What HTTP can’t do, but sockets obviously can, is sent data to a client. Now what if a server could send data to a client even though the client didn’t request it (at that exact moment)? Look no further! And that is exactly why sockets programming is becoming more and more popular!

The protocol used for this bi-directional exchange of data is called WebSockets and was standardized in 2011. As this is still pretty new keep in mind that older web browsers do not support this protocol. One thing to keep in mind is that WebSockets is really an upgrade from HTTP. A socket connection is actually established using an HTTP request.

Node.js has made it pretty easy to work with sockets. There are actually already quite a lot of tutorials out there and most of them let you build a chat application. Of course you can build anything¬†requiring real time data. Think of real time Facebook or Twitter updates. It’s especially interesting when you consider the recent Internet of Things (or IoT) where everything is connected to the web. Let’s say someone rings your doorbell, which is connected to the web and sends you a picture of your front porch when someone rings the bell. Would you want to use HTTP to constantly poll/request if someone has just rang your doorbell? No you wouldn’t! In these scenario’s sockets are a necessity!

Sockets and Node.js

So let’s set up a small Node.js server that supports sockets. We could use ‘pure’ WebSockets for this, but¬†I’m going to use a library for this called socket.io. This will make our life a lot easier on both the back- and front-end. socket.io is a layer around WebSockets that simplifies the API and, more importantly, falls back on other methods if WebSockets isn’t¬†supported.

We’ll start by creating a Node.js server that serves some HTML page. We’ve done that a few times before, so that should be no problem.¬†Remember that WebSockets requires HTTP to work, so we’ll need the HTTP module as well. And, as always, I’ll be using Express as well.

var express = require('express');
var app = express();
var http = require('http').Server(app);

app.use(express.static('public'));

app.get(['/', '/index'], function (req, res) {
    res.sendFile(__dirname + '/public/client.html');
});

http.listen(80, '127.0.0.1');

After that we can install socket.io (npm install socket.io).

var express = require('express');
var app = express();
var http = require('http').Server(app);
var io = require('socket.io')(http);

app.use(express.static('public'));

app.get(['/', '/index'], function (req, res) {
    res.sendFile(__dirname + '/public/client.html');
});

io.on('connection', function(socket){
    console.log('A user connected!');
});

http.listen(80, '127.0.0.1');

As you can see the http object is used to create an instance of socket.io. After that we can listen to the connection event for incoming sockets.

Now socket.io does a little magic trick, it automatically serves socket.io to our front-end. That means creating a socket instance on the client is really easy. First of all we need to include the script somewhere.

<html>
    <head>
        <meta charset="utf-8">
        <title>Sockets example</title>
        <script src="/socket.io/socket.io.js"></script>
        <script src="client.js"></script>
    </head>
    <body>
        <h1>Sockets example</h1>
    </body>
</html>

And then we can use sockets in client.js.

var socket = io();

Wow, that was easy!

And you’ll notice that if you put that in /public/client.html and browse to localhost Node.js will log ‘A user connected!’ to the console! So we’re already connecting.

Now we’ve talked about EventEmitters before in¬†MEAN web development #3: More Node.js. socket.io uses them extensively. Each socket has a special ”disconnect” event.

io.on('connection', function(socket){
    console.log('A user connected!');
    socket.on('disconnect', function () {
        console.log('A user disconnected...');
    });
});

If you try that, browse to localhost, and refresh the page, you’ll see¬†“A user connectioned!”, “A user disconnected…” and “A user connected!” in the console. So this already works pretty sweet, right?

Let’s add another event. You know I like music and albums are always a favorite test object for me.

io.on('connection', function(socket){
    console.log('A user connected!');
    socket.on('disconnect', function () {
        console.log('A user disconnected...');
    });
    socket.on('add-album', function (album) {
        console.log(album);
    });
});

“Wait a minute!”, I hear you say, “No way a socket has an add-album event!” Well, not yet… Let’s check back in our front-end JavaScript again.

var socket = io();
socket.emit('add-album', {
    artist: 'Led Zeppelin',
    title: 'Led Zeppelin III'
});

Save it, browse to localhost again and surely will the console print the album. That’s pretty sweet!

But we’ll need more. After all, we want to receive data on our client! Of course we aren’t going to see any data unless we show it on our page.

Let’s first check out the server. This is really very easy. Ready?

io.emit('add-album', album);

Nice, we can simply use io.emit and all connections will get an update. So our client sends out an ‘add-album’ event to the server and the server sends an ‘add-album’ event back to the client. We could’ve used any name as event.

Let’s check the front-end.¬†I’ve added in some AngularJS, which I’ve talked about before in¬†MEAN web development #6: AngularJS in the front. Actually I’ve copied this example from that post and changed ‘book’ to ‘album’.

<html>
    <head>
        <meta charset="utf-8">
        <title>Sockets example</title>
        <script src="angular.min.js"></script>
        <script src="/socket.io/socket.io.js"></script>
        <script src="client.js"></script>
    </head>
        <body ng-app="socketsApp">
        <div ng-controller="socketsController">
 
            <h1>Sockets example</h1>
            <ul>
                <li ng-repeat="album in albums">
 {{ album.artist + ' - ' + album.title }}
                </li>
            </ul>
 
            <input type="text" ng-model="newArtist" />
            <input type="text" ng-model="newTitle" />
            <button ng-click="addAlbum()">Add album</button>
        </div>
    </body>
</html>

And here’s the JavaScript.

angular.module('socketsApp', [])
    .controller('socketsController', function ($scope) {
        
        var socket = io();
        
        $scope.newArtist = null;
        $scope.newTitle = null;
        $scope.albums = [];
        $scope.addAlbum = function () {
            socket.emit('add-album', {
                artist: $scope.newArtist,
                title: $scope.newTitle
            });
            $scope.newArtist = null;
            $scope.newTitle = null;
        };
        
        socket.on('add-album', function (album) {
            $scope.$apply(function () {
                $scope.albums.push(album);
            });
        });
    });

Notice the $apply function of AngularJS. It’s a detail, but I need it to execute the code in the AngularJS context so that the view gets updated immediately.
What really matters is the socket.on function. I don’t have to explain it, you know how it works. It’s the exact same code you use on the server!

Now open up two tabs, two browsers, two windows, two whatever, and browse to localhost. Enter an artist and title in one window and submit. Now switch to the other window and you’ll see the album you’ve just added in the other window! No refresh, no nothing! If you’re really using two windows put them next to each other and see the effect live in real time.

Now maybe you’re thinking this is awesome, but there’s no need to send back the object to the client that just sent it to the server. For this you can use socket.broadcast.emit. This will send out a message to all sockets, except the one that’s¬†broadcasting.

socket.broadcast.emit('add-album', album);

And the front-end would now look as follows.

$scope.addAlbum = function () {
    var album = {
        artist: $scope.newArtist,
        title: $scope.newTitle
    };
    socket.emit('add-album', album);
    $scope.albums.push(album);
    $scope.newArtist = null;
    $scope.newTitle = null;
};

Pretty sweet!

Rooms

Let’s say you’re building that chat app we were talking about earlier (basically what we created here too). Now maybe you want your web site to have multiple chat rooms. A room for C# discussion, a room for JavaScript discussion, or maybe people can create their own rooms about whatever (maybe cars, music, movies). And perhaps you want to implement a private chat as well (one on one, or only invited people). How can you do this?

I’ll leave the previous example for what it is and start a new one. From our page we want to be able to create a room, join a room, send a message and leave a room. So let’s check out the Node.js server side.

io.on('connection', function(socket){
    console.log('A user connected!');
    socket.on('disconnect', function () {
        console.log('A user disconnected...');
    });
    socket.on('add-room', function (room) {
        console.log('Added:');
        console.log(room);
        socket.join(room.name);
        socket.broadcast.emit('add-room', room);
    });
    socket.on('join-room', function (room) {
        console.log('Joined:');
        console.log(room);
        socket.join(room);
    });
    socket.on('send-message', function (message) {
        console.log('Send:');
        console.log(message);         socket.broadcast.to(message.roomName).emit('receive-message', message);
    });
    socket.on('leave-room', function (room) {
        console.log('Leave:');
        console.log(room);
        socket.leave(room);
    });
});

That’s quite a bit of code, but there’s not much new, really! When someone adds a room we just broadcast the room to all other clients so everyone can see the new room. Additionally we ‘join’ the room using socket.join. This creates a group of sockets that can be notified at once. When a user joins a room we simply pass in a room name and again call socket.join. Then when someone sends a message to a room we simply call socket.broadcast.to(roomName) and now only clients that have joined that specific group will get a notification. That’s pretty easy, right?¬†When we leave a room we simply call socket.leave and the client will stop receiving notifications from that specific room.

The client-side scripting¬†for this example isn’t really interesting. You can get the complete example¬†from GitHub. And yes, I admit, the HTML could use a little work. The JavaScript works¬†the same as in the previous example. We simply use socket.emit, to send events to the server, and socket.on to receive events from the server. I’ll leave it as practice for the reader to add user names, persist chat rooms, get a list of active rooms, implement private rooms, etc.

If you want to do more with sockets and socket.io I can recommend reading Syncfusion’s Node.js Succinctly. It has a chapter on ‘vanilla’ sockets programming in Node.js (including an example on UDP) and a chapter on socket.io. If you’re still struggling with AngularJS I can recommend reading AngularJS Succinctly.
Additionally Manning has a great book on Node.js, Node.js in Action, which, of course, also covers sockets. A second edition of the book is also in the making!

Next week we’ll be wrapping up the MEAN web programming series! Happy coding!

MEAN web development #7: MongoDB and Mongoose

Last week we’ve seen some of the basic functionality of AngularJS, at least enough to get you started. Before that we’ve seen Node.js and Express. So that’s EAN and we’re left with the M. Well, Dial M for¬†MongoDB because that’s what we’re going to look at this week.

  1. MEAN web development #1: MEAN, the what and why
  2. MEAN web development #2: Node.js in the back
  3. MEAN web development #3: More Node.js
  4. MEAN web development #4: All aboard the Node.js Express!
  5. MEAN web development #5: Jade and Express
  6. MEAN web development #6: AngularJS in the front
  7. MEAN web development #7: MongoDB and Mongoose
  8. MEAN web development #8: Sockets will rock your socks!
  9. MEAN web development #9: Some last remarks

As usual you can find the examples for this post on my GitHub page in the mean7-blog repository.

Hello persistent data

I’ve already written an entire post¬†on NoSQL and MongoDB, A first look at NoSQL and MongoDB in particular. I’ve already told you to read it in the first part of this series, MEAN web development #1: MEAN, the what and why. If you haven’t read either of those I suggest you do so before continuing because I won’t repeat how to install MongoDB and MongoVUE. Don’t worry I’ll wait…

Before we continue I should mention that everything we’re going to do is async. That means lots of callback functions. We don’t want to block our main thread after all! It also means that the callbacks may not be called in the same order as their ‘parent functions’ are. Or that the records are actually inserted before we query them! Because I wanted to keep it simple in the complete example file I haven’t nested all examples in callbacks, but keep in mind that you may get some odd results. It worked fine for me by the way, if you get some weird results try running the examples one by one (simply commenting out the others).

So let’s just get a Node.js server up and running and write some data to the database real quick! You’ll be surprised how easy it is. First of all install the MongoDB driver using npm (npm install mongodb).
Next we’ll make a connection to our MongoDB instance.

var app = require('express')();
var MongoClient = require('mongodb').MongoClient;
     
var urlWithCreds = 'mongodb://user:password@localhost:27017/local';
var url = 'mongodb://localhost:27017/local';
MongoClient.connect(url, function (err, db) {
    if (err) {
        console.log(err);
    } else {
        console.log('Connected to the database.');
        db.close();
    }
});
var server = app.listen(80, '127.0.0.1');

So first of all we require Express (which isn’t necessary for MongoDB) and MongoDB. We take the MongoClient property of the MongoDB module. We use this client to connect to the database using the connect function, which takes a URI and a callback function. The callback has a MongoError (in case you can’t log in, for example if you have wrong credentials) and a Db as parameters.
We can use the Db object to do all kinds of stuff like creating and dropping databases, collections and indices and do our CRUD operations (Create, Read, Update, Delete). Let’s insert a simple object.

var url = 'mongodb://localhost:27017/local';
MongoClient.connect(url, function (err, db) {
    if (err) {
        console.log(err);
    } else {
        var artist = {
            name: 'Massive Attack',
            countryCode: 'GB'
        };
        var collection = db.collection('artists');
        collection.insertOne(artist);
        console.log(artist._id);
        db.close();
    }
});

As you can see we use the db parameter to get a collection (the MongoDB variant of a database table) using the collection function. If the collection does not exist it will create one automatically. We can then simply insert an object using the insertOne function of the collection. Now something funny has happened. After calling insertOne our artist object suddenly has an _id property. MongoDB uses this _id to uniquely identify objects.
So that wasn’t so bad right? Let’s look at other CRUD functionality!

CRUD with MongoDB

So let’s retrieve the record we just inserted. We can do this using the findOne function of the collection.

MongoClient.connect(url, function (err, db) {
    if (err) {
        console.log(err);
    } else {
        var collection = db.collection('artists');
        collection.findOne({ name: 'Massive Attack' }, function (err, artist) {
            if (err) {
                console.log(err);
            } else {
                console.log(artist);
            }
            db.close();
        });
    }
});

So the object that is passed to the findOne function is actually a search parameter. In this case we’re looking for documents (or records) that have a name equal to ‘Massive Attack’. The second parameter is a callback function that gives us an error, if any occurred, and the document that was retrieved. If you ran the previous example multiple times Massive Attack will be in your database more than once (having different values for _id), in this case findOne simply returns the first document it finds.

So let’s insert a few more artists, just so we’ve got a little set to work with. We can use the insertMany function for this.

collection.insertMany([
{
    name: 'The Beatles',
    countryCode: 'GB',
    members: [
        'John Lennon',
        'Paul McCartney',
        'George Harrison',
        'Ringo Starr'
    ]
},
{
    name: 'Justin Bieber',
    countryCode: 'No one wants him'
},
{
    name: 'Metallica',
    countryCode: 'USA'
},
{
    name: 'Lady Gaga',
    countryCode: 'USA'
}
], function (err, result) {
    if (err) {
        console.log(err);
    } else {
        console.log(result);
    }
});

Now you may think there’s a findMany function as well, but it’s actually just called find. find returns a Cursor which is something like an array, but not quite. We can use the toArray method though. The find function has a query parameter which is just an object that describes what fields of a document must have which values. We can search fields with AND, OR, NOT, IN, greater than, lesser than, regular expressions and everything you’re used to in SQL databases.

var findCallback = function (err, artists) {
    if (err) {
        console.log(err);
    } else {
        console.log('\n\nFound artists:');
        artists.forEach(function (a) {
            console.log(a);
        });
    }
};

// All documents.
collection.find().toArray(findCallback);

// Name not equal to Justin Bieber.
collection.find({ name: { $ne: 'Justin Bieber' } }).toArray(findCallback);

// Name equal to Massive Attach or name equal to The Beatles.
collection.find({ $or: [{ name: 'Massive Attack' }, { name: 'The Beatles' }] }).toArray(findCallback);

// Members contains John Lennon.
collection.find({ members: 'John Lennon' }).toArray(findCallback);

Now¬†let’s update a record.

collection.findOneAndUpdate({ name: 'Massive Attack' },
    { $set: {
        cds: [
            {
                title: 'Collected',
                year: 2006,
                label: {
                    name: 'Virgin'
                },
                comment: 'Best Of'
            },
            {
                title: 'Mezzanine',
                year: 1998,
                label: 'Virgin'
            },
            {
                title: 'No Protection: Massive Attack v Mad Professor',
                year: 1995,
                label: 'Circa Records',
                comment: 'Remixes'
            },
            {
                title: 'Protection',
                year: 1994,
                label: {
                    name: 'Circa'
                }
            }
        ]
        }
    }, function (err, result) {
    console.log('\n\nUpdated artist:');
    if (err) {
        console.log(err);
    } else {
        console.log(result);
    }
});

Here we see the findOneAndUpdate in action. Alternatively we could’ve used updateOne. And for¬†multiple updates we can¬†use¬†updateMany.

Now¬†let’s delete a record.¬†There’s one guy I really don’t want in my database (yes, I’ve added him so I wouldn’t feel guilty about deleting him). ¬†And for this we can, of course, use findOneAndDelete.

collection.findOneAndDelete({ name: 'Justin Bieber' }, function (err, result) {
    console.log('\n\nDeleted artist:');
    if (err) {
        console.log(err);
    } else {
        console.log(result);
    }
});

Really no surprises there. Alternatively there’s deleteOne and to delete many use, you guessed it, deleteMany.

Mongoose

So MongoDB with Node.js looks really good, right? It wasn’t very hard to use. It’s really just a matter of working with JavaScript objects. And as we all know JavaScript objects are very dynamic. In the previous examples we’ve already seen that¬†some artists have a member property defined and then when we updated we all of a sudden had a cds property and some CD’s¬†have a comment while others don’t… And MongoDB has no problem with it at all. We just save and fetch what is there.

Now try this.

var app = require('express')();
var MongoClient = require('mongodb').MongoClient;

var Artist = function (name, activeFrom, activeTo) {
    if (!(this instanceof Artist)) {
       return new Artist(name, activeFrom, activeTo);
    }
    var self = this;
    self.name = name;
    self.activeFrom = activeFrom;
    self.activeTo = activeTo;
    self.yearsActive = function () {
        if (self.activeTo) {
            return self.activeTo - self.activeFrom;
        } else {
            return new Date().getFullYear() - self.activeFrom;
        }
    };
};

var url = 'mongodb://localhost:27017/local';
MongoClient.connect(url, function (err, db) {
    if (err) {
        console.log(err);
    } else {
        var collection = db.collection('artists');
        // Empty the collection
        // so the next examples can be run more than once.
        collection.deleteMany();
        
        var massiveAttack = new Artist('Massive Attack', 1988);
        console.log('\n\n' + massiveAttack.name + ' has been active for ' + massiveAttack.yearsActive() +  ' years.');
        
        collection.insertOne(massiveAttack);
        
        collection.findOne({ name: massiveAttack.name }, function (err, result) {
            if (err) {
                console.log(err);
            } else {
                try {
                    console.log('\n\n' + result.name + ' has been active for ' + result.yearsActive() +  ' years.');
                } catch (ex) {
                    console.log(ex);
                }
            }
        });
        
    }
});

var server = app.listen(80, '127.0.0.1');

What happens is that MongoDB doesn’t store the yearsActive function nor the constructor function. What MongoDB stores are just the non-function values. The result is that when we retrieve our object it will no longer be an Artist object, but just an object that just so happens to have the same properties as an Artist.

This is where Mongoose comes to the rescue! Mongoose adds a schema to your MongoDB objects. Let’s see how that works.

To add Mongoose to your project you can install it using npm install mongoose.

So first we can use mongoose.connect to get a connection to the database.

var app = require('express')();
var mongoose = require('mongoose');

var url = 'mongodb://localhost:27017/local';
mongoose.connect(url);
var db = mongoose.connection;
db.on('error', function (err) {
    console.log(err);
});
db.once('open', function (callback) {
    // ...
});

var server = app.listen(80, '127.0.0.1');

After that we can define a schema using the Schema function.

db.once('open', function (callback) {
    var artistSchema = mongoose.Schema({
        name: String,
        activeFrom: Number,
        activeTo: Number
    });
    artistSchema.methods.yearsActive = function () {
        var self = this;
        if (self.activeTo) {
            return self.activeTo - self.activeFrom;
        } else {
            return new Date().getFullYear() - self.activeFrom;
        }
    };
});

And as you can see I’ve appended the yearsActive function to the artistSchema.methods object. After that we can create a¬†Model¬†using mongoose.model.

var Artist = mongoose.model('Artist', artistSchema);

And after that the Artist variable (a Model) is actually the portal to your collection. It’s also a constructor function for artists. So let’s create our Massive Attack artist.

var massiveAttack = new Artist({ name: 'Massive Attack', activeFrom: 1988 });
console.log('\n\n' + massiveAttack.name + ' has been active for ' + massiveAttack.yearsActive() + ' years.');

And then we can save it using the save function.

massiveAttack.save(function (err, result) {
    if (err) {
        console.log(err);
    } else {
        // ...
    }
});

And now that the artist is saved let’s retrieve it and call that yearsActive function again. We can simply retrieve our object using Model.findOne.

Artist.findOne({ name: massiveAttack.name }, function (err, result) {
    if (err) {
        console.log(err);
    } else {
        try {
            console.log('\n\n' + result.name + ' has been active for ' + result.yearsActive() +  ' years.');
        } catch (ex) {
            console.log(ex);
        }
    }
});

And here I’ve put the findOne directly in the callback function of save, which I didn’t do before. I needed this because calling findOne directly after save didn’t yield any results (timing issue I guess). More importantly it did successfully execute the yearsActive function!

And like with the regular MongoDB driver we can use find, remove, findOneAndRemove and findOneAndUpdate.

So we’ve looked at the MongoDB driver and at the problem of schemaless objects which Mongoose fixes. I can recommend practicing a bit, as it’s really very easy to drop, create, insert, update, read and remove data, and reading the API documentation of both. We’ve only scratched the surface here, but it got you on your way.

And of course I’m going to recommend some additional reading. The Node.js Succinctly book is just a great resource for Node.js in general and it has a tiny bit on MongoDB and SQLite as well. I can also recommend MongoDB Succinctly. And Getting MEAN from Manning even has a chapter on MongoDB and Mongoose.

Happy coding!