**Course Title:** API Development: Design, Implementation, and Best Practices **Section Title:** Designing RESTful APIs **Topic:** Design a RESTful API for a simple application. (Lab topic) **Objective:** By the end of this lab, you will have a comprehensive understanding of how to design a RESTful API for a simple application. You will learn how to apply the concepts and principles of RESTful API design to a real-world scenario. **Overview:** In this lab, we will design a RESTful API for a simple e-commerce application that allows customers to view products, place orders, and view order history. We will apply the principles and best practices learned in previous topics to create a robust and scalable API. **Step 1: Define the Requirements** Before designing the API, we need to define the requirements of the application. Let's assume the application has the following features: * View products * Place orders * View order history * Register and login users **Step 2: Identify the Resources** Based on the requirements, we can identify the following resources: * Products * Orders * Users **Step 3: Define the Endpoints** Using the resources identified, we can define the following endpoints: * GET /products: Retrieve a list of products * GET /products/{id}: Retrieve a specific product by ID * POST /orders: Place a new order * GET /orders: Retrieve a list of orders for the authenticated user * GET /orders/{id}: Retrieve a specific order by ID * POST /users: Register a new user * POST /users/login: Login an existing user **Step 4: Define the Request and Response Bodies** * GET /products: + Request Body: None + Response Body: List of products in JSON format * GET /products/{id}: + Request Body: None + Response Body: Specific product in JSON format * POST /orders: + Request Body: Order details in JSON format (e.g., product ID, quantity) + Response Body: Order confirmation in JSON format * GET /orders: + Request Body: None + Response Body: List of orders for the authenticated user in JSON format * GET /orders/{id}: + Request Body: None + Response Body: Specific order in JSON format * POST /users: + Request Body: User details in JSON format (e.g., name, email, password) + Response Body: User confirmation in JSON format * POST /users/login: + Request Body: User credentials in JSON format (e.g., email, password) + Response Body: User authentication token in JSON format **Step 5: Define the HTTP Methods** Based on the endpoints, we can define the following HTTP methods: * GET: Retrieve resources * POST: Create new resources **Step 6: Define the Status Codes** Based on the endpoints, we can define the following status codes: * 200 OK: Successful response * 201 Created: New resource created * 400 Bad Request: Invalid request * 401 Unauthorized: Authentication required * 404 Not Found: Resource not found **Example API Documentation:** You can use tools like Swagger or API Blueprint to create API documentation. Here's an example using Swagger: ```yaml openapi: 3.0.0 info: title: E-commerce API description: API for e-commerce application version: 1.0.0 paths: /products: get: summary: Retrieve a list of products tags: [Products] responses: '200': description: List of products content: application/json: schema: type: array items: $ref: '#/components/schemas/Product' '404': description: Products not found /products/{id}: get: summary: Retrieve a specific product by ID tags: [Products] parameters: - in: path name: id schema: type: string required: true description: Product ID responses: '200': description: Specific product content: application/json: schema: $ref: '#/components/schemas/Product' '404': description: Product not found /orders: post: summary: Place a new order tags: [Orders] requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/Order' responses: '201': description: Order confirmation content: application/json: schema: $ref: '#/components/schemas/OrderConfirmation' '400': description: Invalid order components: schemas: Product: type: object properties: id: type: string name: type: string price: type: number Order: type: object properties: productId: type: string quantity: type: integer OrderConfirmation: type: object properties: orderId: type: string message: type: string ``` **Conclusion:** In this lab, we designed a RESTful API for a simple e-commerce application. We applied the principles and best practices learned in previous topics to create a robust and scalable API. **Additional Resources:** * Swagger: <https://swagger.io/> * API Blueprint: <https://apiblueprint.org/> **Leave a comment or ask for help:** If you have any questions or need further clarification on any of the steps, please leave a comment below. **What's next:** In the next topic, we will learn about setting up a development environment using Node.js, Express, or Flask. This lab has provided you with hands-on experience in designing a RESTful API for a simple application. You have applied the principles and best practices learned in previous topics to create a robust and scalable API.