Node Js Tutorial Creating a REST API #02 Adding Routes To The API And Use The Nodemon Package

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Repository   

https://github.com/nodejs/node

What Will I Learn? 

I will learn how to add routes to our project using the GET, POST , PATCH and DELETE requests .

• How to add routes to the sponsors ( Get, Post, Patch and Delete )
• How to add routes to the contributions (Get , Post )
• How to restart the server automatically with nodemon package .

Requirements  

• Knowledge about JavaScript language .
• Basic Knowledge about Command Line window .
• An editor for example notepad ++ .

Difficulty   

• Basic

Tutorial Contents

In this tutorial we will learn how to create a rest api with Node  Js , in the previous tutorial we have created only one route (one URL) , and today we will create other routes , so let's start .. 

Let's create the API but firstly we must create the folder routes to organize the project and to use the URL of each route .

By the cmd I have created the ' api ' folder inside the nodeRestUtopian folder which is our project .

By the cd api I have entered inside the API folder and I created another folder named ' routes ' by mkdir routes  that means ' make directory with the name routes ' , and this is the result : 

In my API folder I have the routes folder , I have created also a JS file ' sponsors.js ' , why I created this file ? 

Simply because the plan of my project is to build a REST API with sponsors and Contributions and this is the plan : 

As I mentioned in the last tutorial we will generate the ' GET , Post and Patch id ' Verbs , so the ' /sponsors ' will be the resource or the URL , for the PATCH if we have the link /sponsors/3 for example in this format /sponsors/{id} it will give you the specific sponsor , the question is how to do that ?

Firstly we import the express framework by declaring a varibale and using the ' require ' code 

var express = require('express');

After that I need to create an instance of the express  ' Router() ' with capital R , it will give us the permission  to determining how your application responds to a client request.

var router = express.Router();

By this instance we can use the method get('/...') to handle a coming get request from the client , the method get has two parameters :

1. The first is the URL or the resource .
2. The second is the function .

There is two different solutions , the first is to keep the URL like router.get('/sponsors') , but if we have many routes for example I propose to let the URL like router.get('/'); just a ' / ' that means all the requests targeting anything with the '/sponsors ' will be redirect to the sponsors.js file .

I think it was a little difficult to understand , let's do an example to clarify the idea .

Firstly let's import our sopnsors route and make it inside a variable named for example sponsorsR by the require we just write the URL of our route 

var sponsorsR = require('./api/routes/sponsors');

This is our route without .js in the end , now when the request is targeting to /sponsors , let's see what happens ..

app.use('/sponsors', sponsorsR);

By the variable app I used the method 'use' this method has two parameters , when the user  requests the sponsors page he will be forwareded to the sponsors.js file by this route './api/routes/sponsors ' .

So the first parameter is the URL that the user requests , and the second is the route , and when we return to the sponsors.js file we have the method router.get('/'); and now I can explain to you why I used only the '/' not '/sponsors' as parameter to the get method .

When the user requests the sponsors page it will enter /sponsors , the system will redirect the user to the sponsors by the verbs that he requested , now the URL has '/sponsors ' if we write router.get('/sponsors') it will be '/sponsors/sponsors/' but if we let '/' it will be '/sponsors' .

The method router.get('/') has another parameter which is a function , this function actually has two parameters , the request and the response , I will use the response to send a JSON response with a message and this is the code 

router.get('/', function(req, res){

res.status(200).json({

message : "Get request to /sponsors"

});

});

The status is (200 ok ) as I explained in the previous tutorial , the response with the method .json has the attribute message with the value = get request to sponsors , it's just a message you can write anything just to test if the get request works or no ! 

This is the sponsors.js file and this is the message in the get request , we have two variables as I mentioned above , by the response I sent a message and this is the app.js file 

I have my sposorsR variable which require the route and I have used the ' use ' method .

Now let's start the our server which listen to the port 3000 ..

I will test it by the Postman localhost:3000/ is our localhost and this is the result 

The Postman gives us an error because there is no page in this route localhost:3000 , but what do you think if we write localhost:3000/sponsors ? with the get request ?

Great ! our message was appeared , you can sure replace the message by the page that you want or anything , but if we chose ' post ' it will give an error why ? because we added just the get so let's add the post request .

router.post('/', function(req, res){

res.status(200).json({

message : "Post request to /sponsors"

});

});

This is the code so I used the post method with the same parameters , and I just changed the message to see the difference between the post and get .

Now we have generated the post and get requests , I need to get a specific sponsor by id for example and to do that we need a variable inside the get request router.get('/:idS'); and inside the function we create a variable to get the id var id = req.params.idS; ,then we check if the id for example == to ' 0 ' we return a message , this is the full code :

And I checked if the id equals to 0 so this is the best sponsor else if the id is not equals to 0 it's normal sponsor and this is the result :

The message is the best sponsor and the id is 0 , it works ! , and if we enter another id this is the result 

We have completed the get , post and get with a special id , now I want to add a PATCH request to update a sponsor and a DELETE request to delete also a sponsor , how to do it ?

router.patch('/idS'); 

We specify the id of the sponsor to update and we send the request , then I will just test by a message , this is the full code :

router.patch('/:idS', function(req, res){

var id = req.params.idS;

res.status(200).json({

message : "This sponsor "+ id + " was updated"

});

});

I specify the id and I just send a message that the sponsor with this id was updated and this is the result from Postman

I need to delete a sponsor for example and to do that I need a delete request with the id and this is the code 

router.delete('/:idS', function(req, res){

var id = req.params.idS;

res.status(200).json({

message : "This sponsor "+ id + " was deleted"

});

});

The same format I sepecified the id of the sponsor and I send the message the sponsor was deleted with the id that the user entered ,  now let's do the same thing for the contributions , we need POST and GET verbs ..

This is the full code from the contributions.js file , the same codes in get , post requests I just changed the message , and this is the app.js file 

I added the contributionsR variable that's require the contributions.js route then I have used the method ' use ' to check if the URL is ' /contributions ' then redirect me to the contributions file .

And this is the result from the postman , sure after restart the server and write the /contributions it will apply the get method and this is the message 'List of contributions ' .

There is a problem , every time I restart the server to get the new changes , but what if I forget it ? 

The solution : 

We have a package called nodemon , this package will save and restart the server with every change it gets , to install it go to the CMD and type npm install nodemon --save-dev , and to understand what means this code just read this tutorial .

So the nodemon now is available in my project , I have installed it like a dev dependency because we need this version to develop , and now to start the server we don't need the manual method just type ' nodemon serverUtopian.js ' once , it will restart automatically .

This is the result when I send a get request with a specific ID 

And now I will try to change something in my code , save it and directly send a request without restarting the server to check if the nodemon really restart automatically the server or no ..

I just changed the message I added the word ' the ' and I have saved it , let's send a request without restarting the server and see the result 

the nodemon is already works , there is another method is to add the ' nodemon serverUtopian.js ' inside a script and with the command npm ' name script ' it will start automatically .

This is the package.JSON file , inside the scripts object we have the start attribute with the 'nodemon serverUtopian.js ' value , just we type npm start in the CMD and this is the result : 

It will be automatically , if you want to know more about this package just type nodemon -h it will give you more informations about using this package .

In order to fully understand the terms that I have used, you  should read past tutorials in which I have provided all about Node JS  and Node Package Manager .

Curriculum 

•  Node Js Tutorial Creating a REST API #01 What's the API and How To Build It 
•  Node Package Manager Tutorial What's The Semantic Versioning And How To Control It Also From The Package.Json File
•  Node Package Manager Tutorial How To Install And Uninstall Global And Local Packages And How To List Them
•  Node Package Manager Tutorial How To Get The NPM and How To Create The Package.JSON
•  Node Js Tutorial Select From Where , Order by , Delete and Limit Using Mysql Module
•  Node Js Tutorial Serve HTML Pages , Serve JSON Data , Connect And Insert Into DB Using Mysql Module
• Node Js Tutorial How To Create Read And Write Stream Manually And Automatically For Big Files
• Node Js Tutorial Read , Write and Edit files and directories by fs module
• Node JS Tutorial How To Use Event Emitter By Events Module

Proof of Work Done 

https://github.com/alexendre-maxim/routesUtopian