Body-parser middleware in Node.js

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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