Body Parser

What is Body Parser?

Body Parser is a middleware of Node JS used to handle HTTP POST request. Body Parser can parse string based client request body into JavaScript Object which we can use in our application.

What Body Parser Do?

1. Parse the request body into JS Object ( if content-type is application/JSON) or a HTML Form data where MIME type is application/x-www-form-urlencoded.
2. Put above JS Object in req.body so that middleware can use the data.

Install Body Parser

API

To include body-parser in our application, use following code. The bodyParser object has two methods, bodyParser.json() and bodyParser.urlencoded(). The data will be available in req.body property.

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

req.body

req.body contains data ( in key-value form ) submitted in request body. The default value is undefined.

req.json

   
    const express=require('express');
    const app=express();
    
    const bodyParser=require('body-parser'); 
    // parse application/json 
    app.use(bodyParser.json());  
    
    app.post('post',(req,res)=>{
        console.log(req.body);
        res.json(req.body);
    });

Form Data

Use bodyParser to parse HTML Form Data received through HTTP POST method. Create a separate HTML Form with inputs. Use name attributes in all input controls. Set the method (in html form ) to POST and action to path of Post request.

   
    const express=require('express');
    const app=express();
    
    const bodyParser=require('body-parser'); 
    // parse application/x-www-form-urlencoded
    app.use(bodyParser.urlencoded({ extended: false })); 
    
    app.post('formdata',(req,res)=>{
        console.log(req.body);
        res.json(req.body);
    });

 
    <form method="post" action="127.0.0.01:3000/formdata">
        <input type="text" name="username" required>
        <input type="password" name="userpass" required>
        <button>Send</button>
    <form>