Python Classroom notes 08/May/2025

HTTP(s)

• HTTP has request and response
• Request has
  • url/endpoint
  • headers: these are key value pairs sent along with request
  • body:
  • Action/Verb/Method:
    • GET: Select
    • PUT: Update (all)
    • PATCH: update (few)
    • POST: Create
    • DELETE: Delete
• Response
  • Status Code: Refer Here
    • 1xx: Information
    • 2xx: Success
    • 3xx: Redirection
    • 4xx: client side errors
    • 5xx: Server side errors
  • headers
  • body

Exercise:

1. Write a python code to send sms
2. Write python code to find temperature of hyderabad tomorrow Refer Here

Sending HTTP Requests

• Python has a pypi library requests and Refer Here for using requests library

import requests
url = "https://fakestoreapi.com/products/1"
response = requests.get(url)
if response.status_code == 200:
    print(response.content)

• Generally all APIs are documented which give us how to use apis. The standard is OpenAPI

REST API

• This is an architecural pattern to build APIs
• Refer Here for RESTAPI docs

REST API Principles

Principle	Description
Uniform Interface	Standardizes interactions between client and server using consistent resource identification, representations, and HTTP methods (GET, POST, PUT, DELETE)[1][4][7].
Client-Server Separation	Separates client and server concerns, allowing each to evolve independently as long as the interface is unchanged[1][3][4][7].
Statelessness	Each request from client to server must contain all necessary information; no session state is stored on the server[1][3][4][7].
Cacheable	Responses must define whether they are cacheable to improve performance and scalability[1][3][4][7].
Layered System	The API architecture can include multiple layers (e.g., intermediaries, proxies) without clients knowing about them[1][3][4][7].
Code on Demand (optional)	Servers can provide executable code (like JavaScript) to clients, extending client functionality when needed[1][4][7].

Would you like examples of how these principles are applied in real-world APIs?

Citations:
[1] https://restfulapi.net
[2] https://daily.dev/blog/restful-api-design-best-practices-guide-2024
[3] https://www.ibm.com/think/topics/rest-apis
[4] https://blog.dreamfactory.com/rest-apis-an-overview-of-basic-principles
[5] https://aws.amazon.com/what-is/restful-api/
[6] https://learn.microsoft.com/en-us/azure/architecture/best-practices/api-design
[7] https://about.gitlab.com/blog/2024/10/18/guide-to-rest-api/
[8] https://www.postman.com/api-platform/api-design/
[9] https://www.getambassador.io/blog/7-rest-api-design-best-practices
[10] https://upsun.com/blog/restful-api-design-principles/
[11] https://www.mulesoft.com/api/rest/what-is-rest-api-design
[12] https://codewithmukesh.com/blog/restful-api-best-practices-for-dotnet-developers/
[13] https://blog.postman.com/rest-api-examples/
[14] https://www.freecodecamp.org/news/rest-api-best-practices-rest-endpoint-design-examples/
[15] https://swagger.io/resources/articles/best-practices-in-api-design/
[16] https://www.youtube.com/watch?v=8XK2o5MfxkE
[17] https://stackoverflow.blog/2020/03/02/best-practices-for-rest-api-design/

Lets Design a REST API for Job Portal

• Identify Nouns which generally become Resources
  • User
  • Employer
  • Job
  • Account
• On Each Resource (Noun) define Actions
  • Actions Account:
    • Register
    • UnRegister
  • User
  • Job
  • Employer
• URI (Uniform Resource Identifier)
  • /Users
    • Get: Get all users
    • POST: Create a user with a body (json)
  • /Users/1
    • Get user with id 1
    • PUT: update the user information for a user with id 1

REST API Creation – Server

• We find nouns and verbs and create a API with docs
• In python, we can acheive creating this with many libraries but we will be using fastapi.
• Other options:
  • Django-restful
  • flask

Rest API Usage – Client

• On a larger note
  • Web stores (Reactjs/angularjs)
  • Mobile/Desktop App
  • Custom Tools:
    • from code
    • from cli
• For using a Rest API we need API Docs (Swagger/OpenAPI)

References

• APIs
  • Refer Here
  • Refer Here

Getting started with fastapi

• Refer Here for fastapi official docs
• Create a virtual environment and install fastapi

pip install "fastapi[standard]"

• code which i have written

from fastapi import FastAPI

app = FastAPI(
    title="Hello-api",
    summary="Learning FastAPI",
    version="0.0.1")

@app.get("/")
def home():
    return { "message": "hello" }

@app.get("/square/{number}")
def square(number: int):
    return {
        "result" : number ** 2
    }