HTTP Basics

What is HTTP?

HTTP (HyperText Transfer Protocol) is the foundation of any data exchange on the Web. It is a protocol used for transmitting hypertext requests and information on the internet. HTTP follows a request-response protocol in the client-server computing model.

HTTP Methods

HTTP defines a set of request methods to indicate the desired action to be performed for a given resource:

GET: Requests a representation of the specified resource. Requests using GET should only retrieve data.
POST: Submits data to be processed to a specified resource.
PUT: Updates a current resource with new data.
DELETE: Deletes the specified resource.
HEAD: Asks for a response identical to that of a GET request, but without the response body.
OPTIONS: Used to describe the communication options for the target resource.
PATCH: Applies partial modifications to a resource.

HTTP Status Codes

HTTP responses include status codes to indicate the success or failure of the request. They are grouped into five classes:

1xx (Informational): Request received, continuing process.
2xx (Successful): The request was successfully received, understood, and accepted.
3xx (Redirection): Further action needs to be taken to complete the request.
4xx (Client Error): The request contains bad syntax or cannot be fulfilled.
5xx (Server Error): The server failed to fulfill an apparently valid request.

Example: Basic HTTP Request and Response

Let's see a simple example of an HTTP GET request and the corresponding response.

HTTP GET Request

GET /index.html HTTP/1.1
Host: www.example.com
Connection: close

HTTP Response

HTTP/1.1 200 OK
Date: Mon, 27 Jun 2024 12:28:53 GMT
Server: Apache/2.4.1 (Unix)
Last-Modified: Tue, 15 Nov 2023 12:45:26 GMT
Content-Length: 362
Content-Type: text/html
Connection: Closed




    Example Page


    Hello, World!
    This is a simple HTML document.