Body-parser middleware in Node.js

Difficulty Level : Hard
Last Updated : 13 May, 2020

Body-parser is the Node.js body parsing middleware. It is responsible for parsing the incoming request bodies in a middleware before you handle it.

Installation of body-parser module:

You can visit the link to Install body-parser module. You can install this package by using this command.
```
npm install body-parser
```
After installing body-parser you can check your body-parser version in command prompt using the command.
```
npm version body-parser
```
After that, you can just create a folder and add a file, for example, index.js. To run this file you need to run the following command.
```
node index.js
```

Filename: SampleForm.ejs

<!DOCTYPE html>
<html>
  
<head>
    <title>Body-Parser Module Demo</title>
</head>
  
<body>
    <h1>Demo Form</h1>
  
    <form action="saveData" method="POST">
        <pre>
            Enter your Email    : <input type="text"
                                name="email"> <br>
                                  
            <input type="submit" value="Submit Form"> 
        </pre>
    </form>
</body>
  
</html>

Filename: index.js

const bodyparser = require('body-parser')
const express = require("express")
const path = require('path')
const app = express()
   
var PORT = process.env.port || 3000
  
// View Engine Setup
app.set("views", path.join(__dirname))
app.set("view engine", "ejs")
  
// Body-parser middleware
app.use(bodyparser.urlencoded({extended:false}))
app.use(bodyparser.json())
   
app.get("/", function(req, res){
    res.render("SampleForm")
});
   
app.post('/saveData', (req, res) => {
    console.log("Using Body-parser: ", req.body.email)
})
   
app.listen(PORT, function(error){
    if (error) throw error
    console.log("Server created Successfully on PORT", PORT)
})

Steps to run the program:

The project structure will look like this:
Make sure you have installed ‘view engine’ like I have used “ejs” and also installed express and body-parser module using following commands:
```
npm install express
npm install ejs
npm install body-parser
```
Run index.js file using below command:
```
node index.js
```
Now Open browser and type the below URL and you will see the Demo Form as shown below:
```
http://localhost:3000/
```
Now submit the form and then you will see the following output:
But if we do not use this body-parser middle, then while parsing, error will occur as show below:

So this is how you can use body-parser module for parsing incoming request bodies in a middleware before you handle it.

My Personal Notes

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