HTTP

The Hypertext Transfer Protocol (HTTP) is an application-layer protocol used for transmitting hypermedia documents, such as HTML. It is the foundation of data communication on the World Wide Web. HTTP follows a client-server model where the client makes requests and the server sends responses.

Key Concepts of HTTP

Client-Server Model: HTTP operates on a client-server model where the client (usually a web browser) sends requests to the server, and the server responds with the requested resources.
Stateless Protocol: HTTP is stateless, meaning each request from a client to a server is independent, and the server does not retain any state information between requests.
Methods: HTTP defines several request methods to indicate the desired action to be performed on the identified resource.

HTTP Methods

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: Replaces all current representations of the target resource with the request payload.
DELETE: Deletes the specified resource.
HEAD: Asks for a response identical to a GET request, but without the response body.
OPTIONS: Describes the communication options for the target resource.
PATCH: Applies partial modifications to a resource.

HTTP Status Codes

1xx (Informational): Request received, continuing process.
2xx (Success): The action was successfully received, understood, and accepted.
- 200 OK: The request has succeeded.
- 201 Created: The request has been fulfilled and resulted in a new resource being created.
3xx (Redirection): Further action needs to be taken to complete the request.
- 301 Moved Permanently: The resource has been moved to a new URL permanently.
- 302 Found: The resource has been found at a different URL temporarily.
4xx (Client Error): The request contains bad syntax or cannot be fulfilled.
- 400 Bad Request: The server could not understand the request due to invalid syntax.
- 401 Unauthorized: The client must authenticate itself to get the requested response.
- 404 Not Found: The server can not find the requested resource.
5xx (Server Error): The server failed to fulfill a valid request.
- 500 Internal Server Error: The server has encountered a situation it doesn't know how to handle.
- 503 Service Unavailable: The server is not ready to handle the request.

For more detailed information on HTTP status codes, refer to the HTTP(S) Status Codes topic.

Example: Making HTTP Requests Using Python's `requests` Library

Here is an example of making HTTP requests using Python's requests library:

import requests

# GET request
response = requests.get('https://api.example.com/data')
print(response.status_code)
print(response.json())

# POST request
data = {'key': 'value'}
response = requests.post('https://api.example.com/data', json=data)
print(response.status_code)
print(response.json())

# PUT request
data = {'key': 'new_value'}
response = requests.put('https://api.example.com/data/1', json=data)
print(response.status_code)
print(response.json())

# DELETE request
response = requests.delete('https://api.example.com/data/1')
print(response.status_code)

Relevant Switches and Parameters

Common `requests` Methods

requests.get(url, params=None, **kwargs): Sends a GET request.
requests.post(url, data=None, json=None, **kwargs): Sends a POST request.
requests.put(url, data=None, **kwargs): Sends a PUT request.
requests.delete(url, **kwargs): Sends a DELETE request.

Understanding HTTP and its associated methods and status codes is crucial for implementing and troubleshooting web services.

Last modified: 14 December 2024