Handling GET and POST Requests Tutorial

1. Introduction

Brief Explanation of the Tutorial's Goal:

In this tutorial, we will be exploring how to handle GET and POST requests in Express.js. Our goal is to understand the basics of these two HTTP methods and how to use them effectively in our Express applications.

What You Will Learn:

By the end of this tutorial, you will be able to:
- Understand what GET and POST requests are.
- Handle GET and POST requests in Express.js.
- Use GET to retrieve data from the server.
- Use POST to send data to the server.

Prerequisites:

Before starting with this tutorial, it would be helpful if you have:
- Basic knowledge of JavaScript.
- Familiarity with Node.js & Express.js.
- A development environment set up with Node.js.

2. Step-by-Step Guide

Detailed Explanation of Concepts:

HTTP (Hypertext Transfer Protocol) is the primary means of communicating data on the web. HTTP works as a request-response protocol between a client and server.

A client (a web browser) sends an HTTP request to the server and then the server sends an HTTP response to the client. The response contains status information about the request and may also contain the requested content.

GET and POST are two different types of HTTP methods.

• GET is used to request data from a specified resource.
• POST is used to send data to a server to create/update a resource.

Clear Examples with Comments:

GET Request:

app.get('/', function(req, res) {
  res.send('This is a GET request');
});

POST Request:

app.post('/', function(req, res) {
  res.send('This is a POST request');
});

Best Practices and Tips:

• GET requests should be used only to retrieve data.
• POST requests can send large amount of data and it's secured because the data sent is in the body.

3. Code Examples

Code Example 1:

Handling GET requests in Express.js

const express = require('express');
const app = express();
app.get('/', function(req, res) {
  res.send('Hello World!');
});
app.listen(3000, function() {
  console.log('App is listening on port 3000!');
});

In the above example, we create an Express application, set up a GET route for the root URL ("/"), and start the server on port 3000.

Code Example 2:

Handling POST requests in Express.js

const express = require('express');
const app = express();
app.post('/', function(req, res) {
  res.send('Got a POST request');
});
app.listen(3000, function() {
  console.log('App is listening on port 3000!');
});

In this example, we set up a POST route for the root URL ("/"). When a POST request is made to this URL, the server responds with "Got a POST request".

4. Summary

• We've learned what GET and POST requests are, and how to handle them in Express.js.
• GET is used to retrieve data, while POST is used to send data to the server.
• Remember to use the right HTTP method for the right job.

5. Practice Exercises

Exercise 1:

Create an Express app that handles GET requests at "/user" and returns a list of users.

Exercise 2:

Extend the above app to handle POST requests at "/user" that adds a new user to the list.

For further practice, try handling PUT and DELETE requests. These methods are used to update and delete resources, respectively.