¿Cómo funciona HTTP?

What is HTTP and how do we use it on the front-end?

When developing web applications, understanding how to handle HTTP requests is fundamental for communication between the front-end and the servers. HTTP (Hypertext Transfer Protocol) is the protocol for making data requests and sending information between clients and servers. In practice, HTTP methods are used using the fetch function in JavaScript to interact with APIs.

How do fetch requests work?

When we use fetch, we are requesting a server to provide us with information that we can then handle and display in the DOM. Using fetch, we make a request to an API, which often returns data in JSON format. Using fetch is a way to make HTTP requests asynchronously, which allows us to improve the user experience by loading data without interrupting the flow of the application.

fetch('https://jsonplaceholder.typicode.com/posts').then(response => response.json()).then(data => console.log(data));

This code performs a GET request to an example API that returns dummy information.

What do HTTP status codes mean?

When making HTTP requests, it is crucial to interpret the status codes that accompany them, since they tell us the result of the requested operation:

• 200 OK: The request was successful.
• 404 Not Found: The requested resource has not been found.
• 500 Internal Server Error: An error has occurred on the server.

Knowing these codes helps us to diagnose problems and understand the communication between the client and the server.

How to check requests and responses in the browser?

The browser offers development tools that facilitate the monitoring of HTTP requests. The "Network" tab allows us to observe:

• The requests to HTML, JavaScript and CSS.
• The URL to which the request is made.
• The status of the response obtained, such as a 200 OK.
• The loading speed of the resources.

By accessing the "Network" tab, we can determine the success of our requests and understand what happens with each request that is made, strengthening our knowledge of data management in web applications.

Practical example of interaction with an API

Let's imagine that we are generating information from an API using fetch. We can drill down and work with the returned information to, for example, obtain user details and display them in our application.

When fetch is executed, the API is queried and, using promises(then), we handle the response. If the request is successful, we get a JSON object with the data:

fetch('https://jsonplaceholder.typicode.com/posts').then(response => response.json()).then(data => { // Data is processed to display titles, users, etc. data.forEach(post => { console.log(post.title); }); });

This basic structure demonstrates how we can extend the functionality of fetch to suit the needs of our application.

Understanding HTTP and fetch gives us control over the front-end interactions with the server, allowing us to optimize the development process and providing a more efficient and dynamic user experience. Keep exploring and experimenting with different scenarios to expand your skills!