What is HTTP? | HTTP explained in 6 minutes

Summary

HTTP, or HyperText Transfer Protocol, is the fundamental set of rules that powers the web. It operates within the Client-Server Model, where browsers (clients) send requests to servers that host websites. The script explains the components of an HTTP request and response, including methods like GET, POST, and DELETE, as well as status codes like 200 OK and 404 Not Found. It also delves into the layers beneath HTTP, such as the Transport and Physical layers. Understanding HTTP helps demystify how the internet works, making it easier to troubleshoot and interact with web data.

Takeaways

• 😀 HTTP stands for HyperText Transfer Protocol, which is the set of rules for transferring hypertext (text with links, images, tables, etc.) over the internet.
• 😀 The Client-Server Model explains how HTTP works: the browser (client) makes requests to a server, which processes the request and sends back a response (like a webpage).
• 😀 HTTP Requests use methods (verbs) like GET, POST, PUT, PATCH, and DELETE to specify what action is being performed on the data. GET retrieves data, POST sends data, PUT and PATCH update data, and DELETE removes data.
• 😀 The HTTP request consists of a start line (method, path, and version), headers (e.g., Content-Type), and sometimes a body (especially for POST requests).
• 😀 HTTP Responses also have a start line, including the protocol version, status code (e.g., 200 OK for success, 404 for not found), headers, and a response body with the requested content.
• 😀 HTTP Status Codes are essential for understanding the outcome of requests. Codes starting with '2' are success codes (e.g., 200 OK), '4' indicates client errors (e.g., 404 Not Found), and '5' signals server errors.
• 😀 The response body contains the actual content returned by the server, such as HTML, images, or data. For some actions like saving a document, there may be no body, only a status code like 204 No Content.
• 😀 HTTP operates within the Application Layer of the internet protocol stack, while the Transport Layer (e.g., TCP) handles the communication between the client and server.
• 😀 The internet has multiple layers, with HTTP at the top (Application Layer), followed by the Transport Layer (TCP), and the Physical Layer (hardware like cables and routers) beneath it.
• 😀 For hands-on learning, you can inspect HTTP requests and responses directly in your browser using Developer Tools (available in Chrome, Firefox, Edge, etc.). This allows you to see the exact data being sent and received during web browsing.
• 😀 For further reading on HTTP, the Mozilla Foundation provides an excellent overview of how HTTP works, including detailed explanations and resources.

Q & A

What does HTTP stand for?

HTTP stands for HyperText Transfer Protocol. It's a set of rules for transferring hypertext, which includes text, images, and links, across the internet.

What is the Client-Server Model in HTTP?

The Client-Server Model in HTTP refers to how a client (like a web browser) sends requests to a server (like a website host), which processes the request and sends back a response.

What are the key HTTP request methods and their functions?

The main HTTP request methods are: GET (to retrieve data), POST (to send data), PUT (to fully update data), PATCH (to partially update data), and DELETE (to remove data).

What is the structure of an HTTP request?

An HTTP request consists of a start line (method, path, version), headers (key-value pairs providing additional information), and an optional body (data being sent, especially for POST requests).

How does the HTTP response differ from the request?

The HTTP response includes a start line (version, status code, reason), headers (information about the response), and a body (the actual content, such as HTML), whereas the request initiates the process.

What does a 404 status code mean in HTTP?

A 404 status code means 'Not Found'. It indicates that the server couldn't find the resource that was requested.

What is the role of headers in HTTP requests and responses?

Headers in HTTP requests and responses provide additional details about the content being transferred, such as the type of content (e.g., text, image), encoding, and caching instructions.

What is the significance of the HTTP response body?

The HTTP response body contains the actual content being sent back to the client, such as a webpage or media file. It's optional depending on the request and status code.

How can you inspect HTTP requests and responses in your browser?

To inspect HTTP requests and responses, open Developer Tools in your browser (using F12 or right-click → Inspect), then go to the 'Network' tab to view all interactions between your browser and the server.

What are the layers beneath HTTP and how do they work together?

Beneath HTTP, we have the Transport Layer (which uses protocols like TCP to ensure data is transferred correctly) and the Physical Layer (the hardware and infrastructure that move the data across the network).