Explain the principles of building web application…

Web application architecture using REST is built on REST principles (Representational State Transfer), which ensure simplicity, scalability, and component independence.

Main principles:

Resource-oriented: all objects (users, products, orders, etc.) are represented as resources with unique URIs.
Use of standard HTTP methods:
- GET — retrieve a resource
- POST — create a new resource
- PUT — update a resource
- DELETE — delete a resource
HTTP status codes to inform about the request result (e.g., 200 OK, 404 Not Found, 201 Created).
Statelessness: the server does not store client state between requests.

Example:

Suppose there is a web application for task management.

Get list of tasks: GET /tasks
Get a specific task: GET /tasks/{id}
Create a task: POST /tasks with request body containing task data
Update a task: PUT /tasks/{id} with updated data
Delete a task: DELETE /tasks/{id}

In Python with Flask, it might look like this:

from flask import Flask, request, jsonify
app = Flask(__name__)
tasks = {}

@app.route('/tasks', methods=['GET'])
def get_tasks():
    return jsonify(list(tasks.values()))

@app.route('/tasks/<int:task_id>', methods=['GET'])
def get_task(task_id):
    task = tasks.get(task_id)
    if task:
        return jsonify(task)
    return '', 404

@app.route('/tasks', methods=['POST'])
def create_task():
    data = request.json
    task_id = len(tasks) + 1
    tasks[task_id] = {'id': task_id, 'name': data['name']}
    return jsonify(tasks[task_id]), 201

@app.route('/tasks/<int:task_id>', methods=['PUT'])
def update_task(task_id):
    if task_id not in tasks:
        return '', 404
    data = request.json
    tasks[task_id].update(data)
    return jsonify(tasks[task_id])

@app.route('/tasks/<int:task_id>', methods=['DELETE'])
def delete_task(task_id):
    if task_id in tasks:
        del tasks[task_id]
        return '', 204
    return '', 404

if __name__ == '__main__':
    app.run()

This approach simplifies interaction between client and server, making the API understandable and standardized.

Explain the principles of building web application architecture using REST, providing specific examples.