How is an HTTP request performed?

URL Parsing: The browser analyzes the entered URL to determine the protocol, domain, and path.
DNS Query: The browser sends a request to resolve the domain name to an IP address using the Domain Name System (DNS).
Establishing TCP Connection: After obtaining the IP address, the browser establishes a TCP connection with the server on the specified port (usually 80 for HTTP, 443 for HTTPS).
Sending HTTP Request: The browser forms and sends an HTTP request, which includes the method (GET, POST, etc.), path, headers (e.g., User-Agent, Accept), and possibly a body (for POST requests).
Server Processes Request: The server receives the request, processes it, and generates an HTTP response.
Sending HTTP Response: The server sends the HTTP response back to the browser. The response includes a status code (200 OK, 404 Not Found, etc.), headers, and a body (e.g., HTML document, image).
Parsing and Rendering: The browser receives the response, parses it (e.g., HTML), and begins rendering the content on the screen. During rendering, additional HTTP requests may be made to fetch resources (CSS, JavaScript, images).
Closing TCP Connection: After data exchange is complete, the TCP connection may be closed (depending on the HTTP version and server settings).

Example of an HTTP request structure (GET):

GET /index.html HTTP/1.1
Host: example.com
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Accept-Encoding: gzip, deflate, br
Connection: keep-alive

Example of an HTTP response structure (200 OK):

HTTP/1.1 200 OK
Date: Tue, 01 Jun 2021 12:00:00 GMT
Server: Apache/2.4.41 (Unix)
Content-Type: text/html; charset=UTF-8
Content-Length: 1234

<!DOCTYPE html>
<html>
<head>
    <title>Sample Page</title>
</head>
<body>
    <h1>Hello, World!</h1>
</body>
</html>