Express body-parser With Examples

ExpressJS body-parser is a body parsing middleware which parses incoming request bodies.

You can use body-parser module when you need to parse form data sent by a user by submitting a web form, to parse JSON payloads in REST APIs.

Installing body-parser

You can install body-parser module by using the following command.

npm install body-parser

Parsers in body-parser

This module provides the following parsers-

JSON body parser- For parsing JSON. Though there is a built-in middleware express.json() which can do the same task.
URL-encoded form body parser- Parses urlencoded bodies (form data - application/x-www-form-urlencoded)
Raw body parser- Parses request body as a Buffer
Text body parser- Parses request body as a string

body-parser middleware example with ExpressJS

In the example there is a form which has name and email inputs and submit button to submit the form.

This form is parsed using body-parser in a POST request. There is another route for JSON parser.

views\person.html

<!DOCTYPE html>
<html>
<head>
    <title>Person Form</title>
</head>
<body>
    <form action="/savePerson" method="post">
        <label for="name">Enter Name</label>
        <input type="text" name="name">
        <br/>
        <label for="email">Enter email</label>
        <input type="text" name="email">
        <br/>
        <button type="submit">Submit</button>
    </form>
</body>

The example uses express.Router() to create modular route definitions.

routes\routes.js

There are 3 route definitions. First is get request for rendering the html file for root path.

There is a POST request for the route '/savePerson' which uses bodyParser.urlencoded()

There is a POST request for the route '/api/Person' which uses bodyParser.json()

const express = require('express');
const path = require('path');
const router = express.Router();

router.get('/', (req, res) => {
    const view = path.join(__dirname, '..', 'views', 'person.html');
    res.sendFile(view);
})

router.post('/savePerson', (req, res) => {
    const name = req.body.name;
    console.log(name);
    const email = req.body.email;
    console.log(email);
    res.send('<h3>Your name is ' + name + ' and email is ' + email + '</h3>');
})

router.post('/api/Person', (req, res) => {
    const name = req.body.name;
    console.log(name);
    const email = req.body.email;
    console.log(email);
    // Then Logic to save Person data

    res.status(201).send("Data Saved Successfully");

})

module.exports = router;

app.js

This is the file where route definitions are imported. You'll import 'body-parser' too to parse the request body.

const express = require('express');

const appRoutes = require('./routes/route')

const bodyParser = require('body-parser'); 

const app = express();
const port = 3000;

// parse application/x-www-form-urlencoded
app.use(bodyParser.urlencoded({extended: true}));

// parse application/json
app.use(bodyParser.json())

// routes
app.use(appRoutes);
//Server
app.listen(port, () => {
    console.log(`Example app listening on port ${port}`)
})

Run the application using the following command

node app.js

If application starts successfully access the URL localhost:3000 which should render a form.

On submitting the form

In the console you should see the logs too

node app.js
Example app listening on port 3000
TestUser
TestUser@tu.com

For the other route you can use Postman to create a POST request with the JSON body.

{
    "name": "Suresh",
    "email": "suresh@su.com"
}

That's all for the topic Express body-parser With Examples. If something is missing or you have something to share about the topic please write a comment.

You may also like

KnpCode

June 4, 2024