HTTP Requests and Responses

When exchanging data between a web browser (client) and a web server on the internet, a protocol called HTTP (HyperText Transfer Protocol) is used.

When the web browser sends a Request to the web server, the web server returns a Response for that request.

An HTTP Request refers to a message sent from the web browser to the web server.

For instance, when opening a specific web page or sending user-input data to the web server, the web browser sends an HTTP request to that web server.

The most basic types of requests include:

• GET: Requests data from the server. For example, it is used when loading a web page or image.

• POST: Sends data to the server to process a resource based on the submitted data. For example, it is used when submitting a web form.

A request can include an address (URL), a request method (e.g., GET, POST), headers (e.g., metadata about the request and cookies), and a request body (data sent with a POST request).

Copy
# Sending an HTTP request using the requests library
import requests 

url = 'http://example.com' # URL of the web page to request
response = requests.get(url) # Sending a GET request

print(response.text)  # Output the HTML content of the web page

An HTTP Response is a message sent by the web server to the client in response to a request.

This response includes a status code indicating the success/failure of the request, server information, and data returned from the server.

Examples of status codes are:

• 200 OK: Indicates that the request was successfully processed.

• 404 Not Found: Indicates that the requested resource could not be found.

• 500 Internal Server Error: Indicates that an internal server error occurred.

A response can also include headers and a body.

The headers provide metadata about the response (e.g., content type), and the body contains the actual returned data (HTML document, image, etc.).

Copy
# Receiving an HTTP response using the requests library
import requests

url = 'http://example.com'
response = requests.get(url)

print(response.status_code)  # Output the status code
print(response.headers)  # Output the response headers
print(response.text)  # Output the response body

1. Request: When a user enters a URL in the address bar of a web browser and presses enter, the browser sends an HTTP request to the web server for that URL.

2. Processing: The web server processes the request and returns the requested data and web page as an HTTP response to the client.

3. Response: The browser parses the response result and renders the contents of the web page on the screen.

Click the Run Code button on the right side of the screen to see the results of crawling or modify the code!