**Course Title:** Modern Python Programming: Best Practices and Trends **Section Title:** Web Development with Python **Topic:** Building RESTful APIs with Flask/Django **Introduction** In this topic, we will explore the process of building RESTful APIs using two popular Python frameworks: Flask and Django. Representational State of Resource (REST) is an architectural style for designing networked applications. RESTful APIs are designed to take advantage of existing protocols, reducing the need for additional infrastructure. They are also stateless, meaning that each request contains all the information necessary to complete the request. **RESTful API Design Principles** Before we dive into building RESTful APIs with Flask and Django, let's cover some key design principles: 1. **Resource-based**: Everything in REST is a resource (e.g., users, orders, products). 2. **Client-server architecture**: Separate the client from the server. 3. **Stateless**: Each request contains all the information necessary to complete the request. 4. **Cacheable**: Responses from the server should be cacheable by the client. 5. **Uniform interface**: The API follows a uniform interface (e.g., HTTP methods, URI). 6. **Layered system**: The API follows a layered system (e.g., authentication, encryption). **Building a RESTful API with Flask** Flask is a lightweight Python web framework that is ideal for building small to medium-sized web applications. Here's a step-by-step guide to building a RESTful API with Flask: 1. **Install Flask**: `pip install flask` 2. **Create a new Flask app**: `flask new my_app` 3. **Create a new route**: `app.route('/api/users', methods=['GET'])` 4. **Define a function to handle the request**: `def get_users(): return jsonify([{'id': 1, 'name': 'John Doe'}])` 5. **Return the data in JSON format**: `return jsonify([{'id': 1, 'name': 'John Doe'}])` Here's a more complete example: ```python from flask import Flask, jsonify, request app = Flask(__name__) @app.route('/api/users', methods=['GET']) def get_users(): users = [{'id': 1, 'name': 'John Doe'}, {'id': 2, 'name': 'Jane Doe'}] return jsonify(users) @app.route('/api/users/<int:user_id>', methods=['GET']) def get_user(user_id): user = {'id': user_id, 'name': 'John Doe'} return jsonify(user) if __name__ == '__main__': app.run(debug=True) ``` **Building a RESTful API with Django** Django is a high-level Python web framework that is ideal for building complex web applications. Here's a step-by-step guide to building a RESTful API with Django: 1. **Install Django**: `pip install django` 2. **Create a new Django project**: `django-admin startproject my_project` 3. **Create a new Django app**: `python manage.py startapp my_app` 4. **Create a new model**: `python manage.py makemigrations && python manage.py migrate` 5. **Define a view to handle the request**: `from rest_framework import status from rest_framework.response import Response from rest_framework.views import APIView` Here's a more complete example: ```python from django.shortcuts import render from rest_framework import status from rest_framework.response import Response from rest_framework.views import APIView from .models import User from .serializers import UserSerializer class UserList(APIView): def get(self, request): users = User.objects.all() serializer = UserSerializer(users, many=True) return Response(serializer.data) class UserDetail(APIView): def get(self, request, pk): user = User.objects.get(pk=pk) serializer = UserSerializer(user) return Response(serializer.data) ``` **Conclusion** In this topic, we covered the principles of building RESTful APIs and built a simple example with Flask and Django. Remember to follow RESTful API design principles and use tools like Postman to test your APIs. **What to do next?** 1. **Practice building RESTful APIs**: Try building a RESTful API with Flask and Django. 2. **Read the official documentation**: Read the official documentation for Flask and Django to learn more about building RESTful APIs. 3. **Use Postman to test your APIs**: Use Postman to test your RESTful APIs and ensure they are working correctly. **Leave a comment or ask for help**: If you have any questions or need help with this topic, please leave a comment below. **Next topic**: Connecting to databases using SQLAlchemy (Flask) or Django ORM. **Recommended reading**: * [Flask Documentation](https://flask.palletsprojects.com/en/2.0.x/) * [Django Documentation](https://docs.djangoproject.com/en/4.0/) * [RESTful API Tutorial](https://flask-restful.readthedocs.io/en/latest/quickstart.html)