HTTP Basics

HTTP (Hypertext Transfer Protocol) is the foundation of web communication. Understanding HTTP is essential for effective web scraping.

How the Web Works

When you visit a website:

1. Your browser sends an HTTP request to a server
2. The server processes the request
3. The server sends back an HTTP response
4. Your browser renders the response (usually HTML)

HTTP Methods

The most common HTTP methods:

Method	Purpose	Use in Scraping
GET	Retrieve data	Most common - fetching pages
POST	Submit data	Form submissions, searches
PUT	Update data	Rarely used in scraping
DELETE	Delete data	Rarely used in scraping

HTTP Status Codes

Status codes tell you if your request succeeded:

HTTP Headers

Headers provide metadata about requests and responses:

Request Headers

Response Headers

Query Parameters

URLs can include parameters to filter or modify requests:

Request Body (POST Data)

POST requests include data in the body:

Practical Example

Let's trace a complete HTTP transaction:

Key Takeaways

• HTTP is a request-response protocol
• GET fetches data; POST submits data
• Status codes indicate success (2xx) or failure (4xx, 5xx)
• Headers carry metadata (User-Agent, cookies, content type)
• Query parameters filter/modify GET requests
• Understanding HTTP helps debug scraping issues