Express.js Restful API
ExpressJS- Restful API
- API stands for Application Programming Interface.
- APIs are mechanisms that enable two software components to communicate with each other using a set of definitions and protocols.
- REST here stands for Representational Transfer state.
Let us create API using Express. Install the cookie parser using Command:
npm install cookie-parser
In app.js
var express = require('express');
var bodyParser = require('body-parser');
var multer = require('multer');
var upload = multer();
var cookieParser = require('cookie-parser')
var app = express();
app.use(cookieParser());
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
app.use(upload.array());
//Require the Router we defined in movies.js
var movies = require('./books.js');
//Use the Router on the sub route /movies
app.use('/books', movies);
app.listen(3000);
In books.js, All the crud operations including GET, POST, PUT, and DELETE in the below code.
var express = require('express');
var router = express.Router();
var books = [
{id: 101, name: "Words of Radiance",Author:"Brandon Sanderson", year: 2014, rating: 4.75},
{id: 102, name: "Harry Potter and the Deathly Hallows",Author:"J.K.Rowling", year: 2007, rating: 4.62},
{id: 103, name: "Becoming",Author:"Michelle Obama", year: 2018, rating: 4.49},
{id: 104, name: "The Help",Author:"Kathryn Stockett", year: 2009, rating: 4.47},
];
// fetch the data using ID using get http method
router.get('/:id([0-9]{3,})', function(req, res){
var currbook = books.filter(function(book){
if(book.id == req.params.id){
return true;
}
});
if(currbook.length == 1){
res.json(currbook[0])
} else {
res.status(404); //Set status to 404 as book was not found
res.json({message: "Not Found"});
}
});
// Adding details of book using POST
router.post('/', function(req, res){
//Check if all fields are provided and are valid:
if(!req.body.name ||
!req.body.year.toString().match(/^[0-9]{4}$/g) ||
!req.body.Author.toString().match(/^[0-9]\.[0-9]$/g)||
!req.body.rating.toString().match(/^[0-9]\.[0-9]$/g)){
res.status(400);
res.json({message: "Bad Request"});
} else {
var newId = books[books.length-1].id+1;
books.push({
id: newId,
name: req.body.name,
Author:req.body,author,
year: req.body.year,
rating: req.body.rating
});
res.json({message: "New book created.", location: "/books/" + newId});
}
});
// Editing details using PUT method
router.put('/:id', function(req, res) {
//Check if all fields are provided and are valid:
if(!req.body.name ||
!req.body.year.toString().match(/^[0-9]{4}$/g) ||
!req.body.rating.toString().match(/^[0-9]\.[0-9]$/g) ||
!req.params.id.toString().match(/^[0-9]{3,}$/g)){
res.status(400);
res.json({message: "Bad Request"});
} else {
//Gets us the index of book with given id.
var updateIndex = books.map(function(book){
return book.id;
}).indexOf(parseInt(req.params.id));
if(updateIndex === -1){
//book not found, create new
books.push({
id: req.params.id,
name: req.body.name,
Author:req.body.author,
year: req.body.year,
rating: req.body.rating
});
res.json({
message: "New book created.", location: "/books/" + req.params.id});
} else {
//Update existing book
books[updateIndex] = {
id: req.params.id,
name: req.body.name,
Author:req.body.author,
year: req.body.year,
rating: req.body.rating
};
res.json({message: "book id " + req.params.id + " updated.",
location: "/books/" + req.params.id});
}
}
});
// Deleting Details of books using Id
router.delete('/:id', function(req, res){
var removeIndex = books.map(function(book){
return book.id;
}).indexOf(req.params.id); //Gets us the index of book with given id.
if(removeIndex === -1){
res.json({message: "Not found"});
} else {
books.splice(removeIndex, 1);
res.send({message: "book id " + req.params.id + " removed."});
}
});
module.exports = router;
Run the server using the command:
node app.js
We will check whether our APIs work properly or not using Postman. Postman is an API platform for building and using APIs. Download Postman using the link: https://www.postman.com/downloads/
- Verifying GET method API using Postman
