ExpressRESTfulAPI

Building a RESTful API using Express JS. Eg: CRUD functions to manipulate Genres table in a Movies database.

Resources

• Node.JS https://nodejs.org
• Express http://expressjs.com/
• npm
  • nodemon - to watch for changes in files and automatically restart the node process (for development)
  • Joi - to perform input validation

Steps

• Install Node.JS
• Install Express and load Express in the application
• Install Joi and load it in the application
• To pass JSON object with the body of the request, we need to use express.json() in the top
  • app.use(express.json());

Load Express and Joi

const Joi = require('joi');
const express = require('express');
const app = express();

Listen to a given port

const port = process.env.PORT  ||  3000;    
app.listen(port, () =>  console.log(`Listening to port ${port}...`));

Function to validate input

function validateGenre(genre){
    const schema  = {
	    name: Joi.string().required()
    };
    return Joi.validate(genre, schema);
}

Sample data array

const  genres  = [    
    {id:1, name:  'Drama'},    
    {id:2, name:  'Thriller'},    
    {id:3, name:  'Comedy'},    
    {id:4, name:  'Adventure'}    
];

Methods

GET (Get all items)

app.get('/api/genres', (req,res) => {       
    res.send(genres);    
});

GET (Get item by id)

app.get('/api/genres/:id', (req,res) => {  
    const  genre  =  genres.find(g  =>  g.id  ===  parseInt(req.params.id));    
    if(!genre) res.status(404).send('The Genre not found!');    
    res.send (genre);
});

POST (Add new item)

app.post('/api/genres',(req,res) => {
    const { error } =  validateGenre(req.body);    
    if(error) return  res.status(400).send(error.details[0].message);    
    const  genre  = {   
	    id:  genres.length  +  1,
	    name:  req.body.name    
    };  
    genres.push(genre);
    res.send(genre);
});

PUT (Edit an existing item)

app.put('/api/genres/:id', (req,res) => { 
    const  genre  =  genres.find(g  =>  g.id  ===  parseInt(req.params.id));
    if(!genre) return  res.status(404).send('The Genre not found!');
    const { error } =  validateGenre(req.body);
    if(error) return  res.status(400).send(error.details[0].message);
    genre.name  =  req.body.name;
    res.send(genre);
});

DELETE (Edit an existing item)

app.delete('/api/genres/:id', (req,res)=>{
    const  genre  =  genres.find(g  =>  g.id  ===  parseInt(req.params.id));
    if(!genre) return  res.status(404).send('The Genre not found!');
    const  index  =  genres.indexOf(genre);
    genres.splice(index, 1);
    res.send(genre);
});