Build your first RESTful API with Node.js

Node.js is one intimidating JavaScript framework, especially for beginners. This article serves as a quick quide to Node.js, Express.js and MongoDB. We’ll building a simple REST API that’ll serve as a basic foundation for an application.

For the purpose of this tutorial, you’ll be creating the base for a ToDo List application (yeah its kinda like the convention to start with ToDo list apps). You’ll use all CRUD (create, read, update and delete) actions on the API.

What is REST?

REST is an acronym for Representational State Transfer. It is a web standards architecture and HTTP Protocol. The REST protocol, decribes six (6) constraints:

  1. Uniform Interface
  2. Cacheable
  3. Client-Server
  4. Stateless
  5. Code on Demand
  6. Layered System

REST is composed of methods such as a base URL, media types, etc. RESTful applicaitons uses HTTP requests to perform the CRUD operations.

Setup

You’ll need to have Node installed, if not in place get in here.

I’m on Elementary OS (an Ubuntu flavoured distro), so i’ll be using the command line alot.

In a new directory todoApp or whatever you’d like to name yours, we’ll need a package.json file, so we’ll use npm to generate one:

npm init

Feel free to use or change the defaults. Once that’s done, you should be a package.json file generated in the root directory.

We need Express as our web framework, body-parser to help handle JSON requests, MongoDB for the database, and Nodemon to watch for file changes while our app is being served.

npm install --save express body-parser mongoose && npm install --save-dev nodemon
  • You may need root access for npm to write out files, just append sudo to the command to grant root access.
  • We’ll be using Mongoose to interact with a MongoDB instance, you’ll still need to have MongoDB server installed on your machine

After the package installation is done, your complete package.json file should look like this:

{
"name": "todoApp",
"version": "0.0.0",
"description": "Building a REST API with Node.js",

"author": "Francis Sunday",
"license": "MIT",
"dependencies": {
"body-parser": "^1.17.2",
"express": "^4.15.3",
"mongoose": "^4.10.4"
},
"devDependencies": {
"nodemon": "^1.11.0"
}
}

Serving up the App

If you check your directory you’d notice a new folder node_modules that’s where the dependencies were saved by the npm install command. We need to require them and start up our app. Go ahead and create a server.js file with this content:

const express = require('express');
const app = express();
const port = process.env.PORT || 3000;
const mongoose = require('mongoose');
const bodyParser = require('body-parser');
// get our server running
app.listen(port, () => {
console.log("App up and running on" + port);
});

Now run node server.js and you’d see the log.

File Structure

We need to structure or directory so we have dedicated files for various actions — routes, models, and controllers. Go ahead and create the following directory structure:

--todoApp
- api
- models
- controllers
- routes
- node_modules
- server.js
- package.json
...

We create the dedicated files in their directories- ` api/models/todoModel.js api/controllers/todoController.js api/routes/todoRoutes.js `

Your directory structure should look like this now:

--todoApp
- api
- models
- todoModel.js
- controllers
- todoController.js
- routes
- todoRoutes.js
- node_modules
- server.js
- package.json
...

CRUD Routes

For this api, you’ll create four (4) different routes, to handle CREAting a todo item, READing an item, UPDATE and item, and DELETE an item. You’re also gonna need to test your API while developing, so we’ll use an awesome app called Postman, which will allow us make simple HTTP requests.

Your First Route

Routing refers to determining how an application responds to requests, which is a URI and a specific request method (POST, GET, DELETE, etc).

We’re gonna define two basic routes /tasks and /tasks/{taskid}

// api/models/todoRoutes.js
module.exports = (app) => {
let todoList = require('../controllers/todoController');
    // our Routes
app.route('/tasks')
.get(todoList.getTasks)
.post(todoList.createTask);

app.route('/tasks/:taskId')
.get(todoList.readTask)
.put(todoList.updateTask)
.delete(todoList.deleteTask);
}

In the code above, the API’s routes are defined under different verbs; when a request is made for the tasks route e.g todoApp.dev/tasks, it calls the getTasks method from the required todoList controller, same for the post, put, and delete routes. The tasks/:taskId route, handles a single task. We can grab a task via its ID - /tasks/3 update or delete it too.

Database Schema

We’ll be using Mongoose to interact with a MongoDB instance. In the todoModel.js file, we’ll define a schema for our Tasks collection. With Mongoose, we can create Schemas easily by defining the fields and their types.

You’ll need to have MongoDB server installed locally, if you want to serve your database. You can also use a remote database, there’s a free tier from MLab
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
let TaskSchema = new Schema({
name: {
type: String,
Required: 'Task label is required!'
},
Created_date: {
type: Date,
default: Date.now
},
status: {
type: [{
type: String,
enum: ['completed', 'ongoing', 'pending']
}],
default: ['pending']
}
});
module.exports = mongoose.model('Tasks', TaskSchema);

In the taskModel file, we created a schema for it. As you can see, it the task collection(table) will contain a name: a string, and the date it was created.

Setting up Controllers

Remember those methods attached to each verb in the todoRoutes.js file, they are controller methods, and we are creating them in the api/controllers/todoController.js file:

const mongoose = require("mongoose");
const Task = mongoose.model("Tasks");
// get all tasks
exports.getTasks = (req, res) => {
Task.find({}, (err, task) => {
if (err)
res.send(err);

res.json(task);
});
};
// create a task
exports.createTask = (req, res) => {
let newTask = new Task(req.body);
newTask.save( (err, task) => {
if (err)
res.send(err);

res.json(task);
});
};
// read a single task 
exports.readTask = (req, res) => {
Task.findById(req.params.id, (err, task) => {
if (err)
res.send(err);
        res.json(task);
});
};
// update a particular task 
exports.updateTask = (req, res) => {
Task.findOneAndUpdate(req.params.id, req.body, { new: true }, (err, task) => {
if (err)
res.send(err);
    res.json(task);
});
};
// delete a single task 
exports.deleteTask = (req, res) => {
Task.remove({
_id: req.params.id
}, (err, task) => {
if (err)
res.send(err);
res.json({ message: 'Task deleted!!' });
});
};

Coupling everything

Back in our server.js file, we’ll connect to our database, by adding a URL to the mongoose connection instance, Load the created Model (task), register our created routes. Update your server.js file to look like this:

const express = require("express"); // express framework
const app = express();
const port = process.env.PORT || 3000;
const mongoose = require("mongoose");
const Task = require("./api/models/todoListModel");
const bodyParser = require('body-parser');
mongoose.Promise = global.Promise;
mongoose.connect("mongodb://localhost:2701/todoApp"); // connect to MongoDB
// handle incoming requests
app.use(bodyParser.urlencoded({ extended: true }));
app.use(bodyParser.json());
// middleware to handle wrong routes 
app.use( (req, res) => {
res.status(404).send({ url: req.originalUrl + 'not found' });
});
let routes = require("./api/routes/todoListRoute");
routes(app); // register our routes
app.listen(port); 
console.log('App running on ' + port);

Testing with Postman

To test your API using postman, startup the server nodemon server.js and then open up the postman app and pass in your url

Get all tasks

Create a Task

Note: To use the post method on postman, the Body should be set to x-www-form-urlencode

That’s it!

You have a working Node.js API which makes use of the four major HTTP verbs (GET, POST, PUT, DELETE).

This tutorial was created to give you a familarity with the Node.js development environment along side Express.js and MongoDB.

Was this helpful? feel free to leave a comment below. Also, if you have questions, noticed an error, please do well to let me know.

Thanks!

Originally published on HakaseLabs

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