How to Build a URL Shortener With Node.js and MongoDB

How to Build a URL Shortener With Node.js and MongoDB - If you’ve ever embedded a link, you’ve probably used an app liky bit.ly or goo.gl. In this tutorial, we’ll learn how to make our own version of these popular web apps!

In this post, we’ll show you how to build a URL shortening service like bit.ly or goo.gl using Express.js (Node.js) and MongoDB. Here’s a demo of the final product we’ll be building through our MongoDB hosting platform.

How Does a URL Shortener Work?

At a very high level, the URL shortener works by taking an entered URL and creating a relatively shortened version simplified into an easy to share format. The shortened hash will be generated by base-encoding an auto-incremented counter and creates a minimum three-character hash that increases as the number of stored URLs go up.

When the shortened version of the URL is visited, the service will decode the hash to fetch the original URL stored in MongoDB and then redirect your user to it.

Getting Started

Here’s a list of the technologies we’ll use to build the URL shortener in this tutorial:

Express.js (Node.js backend)

A web application framework for Node.js. We’ll use it to build an API for shortening URLs and redirect users to the original URL.

MongoDB (storing URLs)

A web application framework for Node.js. We’ll use it to build an API for shortening URLs and redirect users to the original URL.

HTML, CSS, JavaScript (front-end)

A web application framework for Node.js. We’ll use it to build an API for shortening URLs and redirect users to the original URL.

URL Shortener Tutorial

Setup the MongoDB Database Structure

Let’s start by creating a Shared MongoDB Cluster on ScaleGrid. This is the easiest way to create a quick cluster, but you can also install MongoDB on your machine and get started there.connection string that can be copied with a single click from your Cluster Details page. We’ll need this string to connect to the cluster from our application. Remember, never share your connection string with anyone.We’ll need two collections for the URL shortener:

Collection 1

A web application framework for Node.js. We’ll use it to build an API for shortening URLs and redirect users to the original URL.

Collection 2

A web application framework for Node.js. We’ll use it to build an API for shortening URLs and redirect users to the original URL.

Set Up the Express.js Backend

Let’s start by creating a Shared MongoDB Cluster on ScaleGrid. This is the easiest way to create a quick cluster, but you can also install MongoDB on your machine and get started there.connection string that can be copied with a single click from your Cluster Details page. We’ll need this string to connect to the cluster from our application. Remember, never share your connection string with anyone.We’ll need two collections for the URL shortener:

A web application framework for Node.js. We’ll use it to build an API for shortening URLs and redirect users to the original URL.

{
  "name": "sg-url-shortener",
  "version": "1.0.0",
  "description": "A simple URL shortener built with Node.js and MongoDB",
  "dependencies": {
    "atob": "^2.0.3",
    "body-parser": "^1.15.2",
    "btoa": "^1.1.2",
    "dotenv": "^4.0.0",
    "express": "^4.10.2",
    "mongoose": "^4.13.7"
  },
  "main": "index.js",
  "scripts": {
    "start": "node index.js"
  },
  "engines": {
    "node": "4.8.4"
  }
}

Let’s start by creating a Shared MongoDB Cluster on ScaleGrid. This is the easiest way to create a quick cluster, but you can also install MongoDB on your machine and get started there.connection string that can be copied with a single click from your Cluster Details page. We’ll need this string to connect to the cluster from our application. Remember, never share your connection string with anyone.We’ll need two collections for the URL shortener:

connectionString=mongodb://user:password@devservers

Let’s start by creating a Shared MongoDB Cluster on ScaleGrid. This is the easiest way to create a quick cluster, but you can also install MongoDB on your machine and get started there.connection string that can be copied with a single click from your Cluster Details page. We’ll need this string to connect to the cluster from our application. Remember, never share your connection string with anyone.We’ll need two collections for the URL shortener:

Initializing the Application

Let’s start by creating a Shared MongoDB Cluster on ScaleGrid. This is the easiest way to create a quick cluster, but you can also install MongoDB on your machine and get started there.connection string that can be copied with a single click from your Cluster Details page. We’ll need this string to connect to the cluster from our application. Remember, never share your connection string with anyone.We’ll need two collections for the URL shortener:

if(process.env.NODE_ENV !== 'production') {
    require('dotenv').load();
}

Let’s start by creating a Shared MongoDB Cluster on ScaleGrid. This is the easiest way to create a quick cluster, but you can also install MongoDB on your machine and get started there.connection string that can be copied with a single click from your Cluster Details page. We’ll need this string to connect to the cluster from our application. Remember, never share your connection string with anyone.We’ll need two collections for the URL shortener:

var express = require('express'),
    bodyParser = require('body-parser'),
    app = express(),
    http = require('http').Server(app),
    mongoose = require('mongoose'),
    btoa = require('btoa'),
    atob = require('atob'),
    promise,
    connectionString = process.env.connectionString,
    port = process.env.PORT || 8080;

http.listen(port, function() {
    console.log('Server Started. Listening on *:' + port);
});

app.use(express.static('public'));
app.use(bodyParser.urlencoded({
    extended: true
}));

Let’s start by creating a Shared MongoDB Cluster on ScaleGrid. This is the easiest way to create a quick cluster, but you can also install MongoDB on your machine and get started there.connection string that can be copied with a single click from your Cluster Details page. We’ll need this string to connect to the cluster from our application. Remember, never share your connection string with anyone.We’ll need two collections for the URL shortener:

app.get('/', function(req, res) {
    res.sendFile('views/index.html', {
        root: __dirname
    });
});

Storing URLs in MongoDB

Let’s start by creating a Shared MongoDB Cluster on ScaleGrid. This is the easiest way to create a quick cluster, but you can also install MongoDB on your machine and get started there.connection string that can be copied with a single click from your Cluster Details page. We’ll need this string to connect to the cluster from our application. Remember, never share your connection string with anyone.We’ll need two collections for the URL shortener:

var countersSchema = new mongoose.Schema({
    _id: { type: String, required: true },
    count: { type: Number, default: 0 }
});

var Counter = mongoose.model('Counter', countersSchema);

var urlSchema = new mongoose.Schema({
    _id: {type: Number},
    url: '',
    created_at: ''
});

urlSchema.pre('save', function(next) {
    console.log('running pre-save');
    var doc = this;
    Counter.findByIdAndUpdate({ _id: 'url_count' }, { $inc: { count: 1 } }, function(err, counter) {
        if(err) return next(err);
        console.log(counter);
        console.log(counter.count);
        doc._id = counter.count;
        doc.created_at = new Date();
        console.log(doc);
        next();
    });
});

var URL = mongoose.model('URL', urlSchema);

Let’s start by creating a Shared MongoDB Cluster on ScaleGrid. This is the easiest way to create a quick cluster, but you can also install MongoDB on your machine and get started there.connection string that can be copied with a single click from your Cluster Details page. We’ll need this string to connect to the cluster from our application. Remember, never share your connection string with anyone.We’ll need two collections for the URL shortener:

promise = mongoose.connect(connectionString, {
    useMongoClient: true
});

promise.then(function(db) {
    console.log('connected!');
    URL.remove({}, function() {
        console.log('URL collection removed');
    })
    Counter.remove({}, function() {
        console.log('Counter collection removed');
        var counter = new Counter({_id: 'url_count', count: 10000});
        counter.save(function(err) {
            if(err) return console.error(err);
            console.log('counter inserted');
        });
    });
});

Let’s start by creating a Shared MongoDB Cluster on ScaleGrid. This is the easiest way to create a quick cluster, but you can also install MongoDB on your machine and get started there.connection string that can be copied with a single click from your Cluster Details page. We’ll need this string to connect to the cluster from our application. Remember, never share your connection string with anyone.We’ll need two collections for the URL shortener:

app.post('/shorten', function(req, res, next) {
    console.log(req.body.url);
    var urlData = req.body.url;
    URL.findOne({url: urlData}, function(err, doc) {
        if(doc) {
            console.log('entry found in db');
            res.send({
                url: urlData,
                hash: btoa(doc._id),
                status: 200,
                statusTxt: 'OK'
            });
        } else {
            console.log('entry NOT found in db, saving new');
            var url = new URL({
                url: urlData
            });
            url.save(function(err) {
                if(err) return console.error(err);
                res.send({
                    url: urlData,
                    hash: btoa(url._id),
                    status: 200,
                    statusTxt: 'OK'
                });
            });
        }
    });
});

Let’s start by creating a Shared MongoDB Cluster on ScaleGrid. This is the easiest way to create a quick cluster, but you can also install MongoDB on your machine and get started there.connection string that can be copied with a single click from your Cluster Details page. We’ll need this string to connect to the cluster from our application. Remember, never share your connection string with anyone.We’ll need two collections for the URL shortener:

Redirecting Users

Let’s start by creating a Shared MongoDB Cluster on ScaleGrid. This is the easiest way to create a quick cluster, but you can also install MongoDB on your machine and get started there.connection string that can be copied with a single click from your Cluster Details page. We’ll need this string to connect to the cluster from our application. Remember, never share your connection string with anyone.We’ll need two collections for the URL shortener:

app.get('/:hash', function(req, res) {
    var baseid = req.params.hash;
    var id = atob(baseid);
    URL.findOne({ _id: id }, function(err, doc) {
        if(doc) {
            res.redirect(doc.url);
        } else {
            res.redirect('/');
        }
    });
});

Let’s start by creating a Shared MongoDB Cluster on ScaleGrid. This is the easiest way to create a quick cluster, but you can also install MongoDB on your machine and get started there.connection string that can be copied with a single click from your Cluster Details page. We’ll need this string to connect to the cluster from our application. Remember, never share your connection string with anyone.We’ll need two collections for the URL shortener:

More URL Shortener Enhancements

And we’re done! We have a bare-bones URL shortener that can be used internally to simplify your links. If you’d like to add more bells and whistles, here is a list of things you can additionally implement: