This content originally appeared on DEV Community and was authored by Eric The Coder
Here is a series of articles that will allow you to create backend applications with NodeJS + Express.
This series is the continuation of my series on the basics of NodeJS. If you don't have basic knowledge of NodeJS read this series first: Introduction to NodeJS
Node.js is today a must, so it is essential for a developer to master it.
So I will publish a new article about every two days and little by little you will learn everything there is to know about Node.js + Espress
To not miss anything follow me on twitter: https://twitter.com/EricTheCoder_
CRUD API
Now that we know the basics concept, it's time to build real CRUD API (create, read, update, delete)
We will build all those CRUD routes:
Create: POST /api/products
Read all: GET /api/products
Read: GET /api/product/1
Update: PUT /api/products/1
Delete: DELETE /api/products/1
Return status
With a CRUD API you can return data but also status code.
Here is a list of some status code and there meaning
res.status(200) // Ok
res.status(201) // Created
res.status(204) // No content
res.status(400) // Bad request
res.status(401) // Unauthorized
res.status(403) // Forbidden
res.status(404) // Not found
res.status(500) // Server error
Create a file name data.js and copy/paste this code
const products = [
{ id: 1, name: 'iPhone', price: 800 },
{ id: 2, name: 'iPad', price: 650 },
{ id: 3, name: 'iWatch', price: 750 }
]
module.exports = products
Load data and start the server
const express = require('express')
const app = express()
const products = require('./data.js')
app.listen(5000, () => {
console.log('server is listening on port 5000')
})
Create: POST /api/products
app.use(express.json()) // parse json body content
app.post('/api/products', (req, res) => {
const newProduct = {
id: products.length + 1,
name: req.body.name,
price: req.body.price
}
products.push(newProduct)
res.status(201).json(newProduct)
})
The app.use(express.json) is a middleware that take JSON content and create related req.body properties. (ex. req.body.name and req.body.price)
The res.status(201).json(newProduct) set the return response status to 201 (created) and also return the newProduct data in JSON format.
Read all: GET /api/products
app.get('/api/products', (req, res) => {
res.json(products)
})
Read: GET /api/product/1
app.get('/api/products/:productID', (req, res) => {
const id = Number(req.params.productID)
const product = products.find(product => product.id === id)
if (!product) {
return res.status(404).send('Product not found')
}
res.json(product)
})
As seen in part 2, first we retrieved the productID from the route parameter.
Then we check if this product exist and send a response accordingly.
res.json(product) send the product in JSON format with a 200 ok status code.
Update: PUT /api/products/1
app.use(express.json()) // parse json body content
app.put('/api/products/:productID', (req, res) => {
const id = Number(req.params.productID)
const index = products.findIndex(product => product.id === id)
if (index === -1) {
return res.status(404).send('Product not found')
}
const updatedProduct = {
id: products[index].id,
name: req.body.name,
price: req.body.price
}
products[index] = updatedProduct
res.status(200).json('Product updated')
})
Delete: DELETE /api/products/1
app.use(express.json()) // parse json body content
app.delete('/api/products/:productID', (req, res) => {
const id = Number(req.params.productID)
const index = products.findIndex(product => product.id === id)
if (index === -1) {
return res.status(404).send('Product not found')
}
products.splice(index,1)
res.status(200).json('Product deleted')
})
Conclusion
That's all for today, follow me on twitter: https://twitter.com/EricTheCoder_ to be notified of the publication of the next article (within two days).
This content originally appeared on DEV Community and was authored by Eric The Coder
Eric The Coder | Sciencx (2021-10-30T11:34:59+00:00) NodeJS + Express part 4: CRUD API. Retrieved from https://www.scien.cx/2021/10/30/nodejs-express-part-4-crud-api/
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