1. Introduction

This tutorial aims to provide a practical understanding of HTTP methods and how to use them in REST APIs. By the end of this guide, you will be familiar with various HTTP methods, when and how to use them appropriately.

What you will learn:
- Understanding HTTP methods
- Best practices for using HTTP methods
- Practical examples of using HTTP methods in REST APIs

Prerequisites:
Basic knowledge of HTTP and REST APIs is required for this tutorial. Familiarity with a programming language such as JavaScript will be helpful but not mandatory.

2. Step-by-Step Guide

HTTP methods indicate the desired action to be performed on the resource identified by the given URI. These methods are also known as verbs. The primary or most-used HTTP methods are POST, GET, PUT, DELETE.

2.1 GET Method

The GET method is used to retrieve data from a server. It is safe and idempotent, meaning that it can be called any number of times without changing the server's state.

Best Practice:
Do not use GET method if the request changes the state or performs any transaction.

GET /users/123

2.2 POST Method

The POST method is used to send data to a server to create a new resource. It is not idempotent.

Best Practice:
Use POST method when you want to add a new resource.

POST /users

2.3 PUT Method

The PUT method is used to update an existing resource. It is idempotent.

Best Practice:
Use PUT when you want to modify a single resource, which is already a part of resources collection.

PUT /users/123

2.4 DELETE Method

The DELETE method is used to delete a resource. It is idempotent.

Best Practice:
Use DELETE when you want to remove a specific resource.

DELETE /users/123

3. Code Examples

Below is an example of using these HTTP methods in a RESTful API designed with Express in Node.js.

// Importing express
const express = require('express');

// Initializing express
const app = express();

// GET method route
app.get('/users', function (req, res) {
  // Fetch users from database here
  res.send('GET request to the /users');
});

// POST method route
app.post('/users', function (req, res) {
  // Add new user to database here
  res.send('POST request to the /users');
});

// PUT method route
app.put('/users/:id', function (req, res) {
  // Update user in database here
  res.send(`PUT request to /users/${req.params.id}`);
});

// DELETE method route
app.delete('/users/:id', function (req, res) {
  // Delete user from database here
  res.send(`DELETE request to /users/${req.params.id}`);
});

// Server listening
app.listen(3000, function () {
  console.log('Example app listening on port 3000!');
});

4. Summary

In this tutorial, we've covered the basic HTTP methods used in REST APIs: GET, POST, PUT, and DELETE, along with their best practices. Remember, it's important to choose the correct method according to the operation you want to perform on the server.

Next Steps:
To further your understanding, learn more about other HTTP methods like PATCH, HEAD, OPTIONS, and how to use them in REST APIs.

Additional Resources:
- MDN Web Docs - HTTP methods
- REST API Tutorial

5. Practice Exercises

1. Create a REST API that uses all the HTTP methods for a resource of your choice.
2. Modify the above API to handle errors and edge cases.
3. Create a REST API that uses other HTTP methods like PATCH, HEAD, OPTIONS.

Tips for Further Practice:
Try to implement these methods in different programming languages and frameworks, such as Python with Flask or Django, Ruby with Rails, etc. This will help you understand how these methods are implemented in different contexts.