task4-rest-api

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🚀 Task 4: Building a REST API with Flask

📌 Objective

The objective of this task is to create a RESTful API using Python's Flask framework that performs CRUD (Create, Read, Update, Delete) operations on user data. The API uses in-memory storage (a simple list) for managing users and supports HTTP methods: POST, GET, PUT, and DELETE.

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🛠 Tools Used

• Language: Python
• Framework: Flask
• API Testing Tool: Postman
• IDE: VS Code
• Platform: Localhost (127.0.0.1:5000)

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📂 Project Structure

task-4-rest-api/ ├── app.py # Flask application ├── README.md └── screenshots/ # Postman API testing screenshots ├── post-create-user.png ├── get-all-users.png ├── put-update-user.png └── delete-user.png

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🔥 Features

• Add new users using POST /users
• Get a list of all users using GET /users
• Update a specific user by ID using PUT /users/
• Delete a user by ID using DELETE /users/
• JSON responses with meaningful status codes
• Handles both lowercase and capitalized JSON keys ("name" or "Name")

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⚙ How to Run This Project

1. Open terminal and install Flask:

pip install flask

2. Run the Flask app:

python app.py

3. Open Postman and test the API using:

http://127.0.0.1:5000/

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🧠 Code Explanation (Line by Line)

Importing Modules:
We start by importing Flask and its required classes: Flask, request, and jsonify to create and handle web routes and responses.

Initializing App:
We create a Flask app instance using app = Flask(name).

In-Memory Database:
We define a Python list users = [] which stores user dictionaries containing id, name, and email.

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POST /users – Add New User

• This route accepts JSON data via POST.
• It checks for either lowercase or capitalized keys (name or Name, email or Email).
• If either field is missing, it returns a 400 Bad Request.
• Otherwise, it creates a user, assigns an incremental ID, and appends it to the list.
• Returns 201 Created with user data.

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GET /users – Get All Users

• Returns the entire list of users.
• Responds with 200 OK.

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GET /users/ – Get User by ID

• Accepts a user ID as a path parameter.
• Searches for the user with that ID.
• If found, returns the user data.
• If not found, returns 404 Not Found.

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PUT /users/ – Update User

• Accepts user ID and JSON payload.
• Checks if the user exists.
• Updates name or email if present in the payload (case-insensitive).
• Returns updated user with 200 OK.

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DELETE /users/ – Delete User

• Accepts user ID as a parameter.
• Removes the user from the list if they exist.
• Responds with confirmation message and 200 OK.

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✅ API Endpoints Summary

Method	Endpoint	Description
POST	/users	Create a new user
GET	/users	Get all users
GET	/users/	Get a user by ID
PUT	/users/	Update user by ID
DELETE	/users/	Delete user by ID

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📸 Screenshots

All API requests were successfully tested in Postman.

Method	Screenshot
✅ POST - Create User
✅ GET - All Users
✅ PUT - Update User
✅ DELETE - Remove User

Each screenshot clearly displays:

• Correct request URL and method
• Proper headers and JSON body
• Successful status codes (200 OK, 201 Created)
• Valid JSON responses

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Conclusion

• 💡 Fully working REST API using Flask
• 🔄 Supports all HTTP methods with complete CRUD functionality
• 💬 User-friendly error messages and validations
• 🧠 Accepts both name/Name and email/Email inputs for flexibility
• 📸 Well-documented Postman results with proof screenshots
• 🧾 Professionally written README.md with full explanations
• 💻 Clean, maintainable, and scalable Python code

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👨‍💻 Developer Info

Name: Rohith K N
Internship: Python Development (1 Month)
Task Number: Task 4 - REST API using Flask
Date: June 2025
Goal: Top 10 out of 200 interns ✨

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