REST API Design pattern briefly breakdown

Y1. Understand RESTful Principles

API Design pattern methods calling 

REST (Representational State Transfer) is an architectural style for designing networked applications. The key principles include:

• Statelessness: Every request from a client to a server must contain all the information the server needs to fulfill the request. No session is stored on the server.
• Client-Server Architecture: The client and server are independent; the client interacts with the API, and the server processes requests.
• Uniform Interface: A consistent and standardized way of interacting with resources via HTTP methods (GET, POST, PUT, DELETE, etc.).
• Layered System: The system can be composed of layers that abstract away complexity (e.g., a proxy or load balancer).
• Cacheability: Responses should be explicitly labeled as cacheable or non-cacheable to improve performance.

2. Define Resources

Resources are the main entities that clients interact with. Each resource should have a unique URI.

• A resource might represent a data entity such as a user, product, or order.
• URIs should be descriptive and follow a consistent pattern. For example:
  • /users (get all users)
  • /users/{id} (get a specific user)
  • /products (get all products)
  • /products/{id} (get a specific product)

3. Use HTTP Methods Correctly

REST APIs rely on standard HTTP methods to perform operations:

• GET: Retrieve data from the server (does not modify data).
• POST: Create new resources.
• PUT: Update an existing resource.
• DELETE: Remove a resource.
• PATCH: Partially update an existing resource.

4. Design URI Structure

• Keep URIs simple and meaningful.
• Use nouns (representing entities), not verbs (verbs are already represented by HTTP methods).
• Example of a good URI design:
  • /users: List all users
  • /users/123: Get the user with ID 123
  • /orders/567/items: Get items in order 567

5. Handle HTTP Status Codes

HTTP status codes indicate the result of a request. Here are some common ones:

• 200 OK: The request was successful.
• 201 Created: The resource was successfully created.
• 400 Bad Request: The request is malformed or invalid.
• 401 Unauthorized: Authentication is required.
• 403 Forbidden: The client does not have permission.
• 404 Not Found: The resource was not found.
• 500 Internal Server Error: An error occurred on the server side.

6. Use Query Parameters for Filtering, Sorting, and Pagination

• Filtering: To filter resources based on certain fields, use query parameters. For example, to get users older than 25:
  • /users?age=25
• Sorting: To sort the results, use a query parameter like sort:
  • /users?sort=name (sort by name)
• Pagination: Limit the number of resources returned, often combined with offset or page parameters:
  • /users?page=1&limit=20

7. Handle Authentication and Authorization

REST APIs often require authentication to restrict access to certain resources. Common methods include:

• Token-based Authentication (JWT): Pass a token in the header of each request to identify the client.
• OAuth 2.0: Used for delegated access (i.e., logging in via another service, like Google or Facebook).
• Basic Authentication: Sending username and password in the request header (less secure and discouraged in modern applications).

8. Provide Descriptive Responses

• Include a response body with relevant data in JSON or XML format.
• Include metadata where necessary (e.g., pagination details, message). Example response for a user:

{
  "idC"l 123,
  "name:"vijay chauhan",
  "email": "vijay.chauhan@example.com"
}

9. Versioning Your API

APIs can change over time, so it's important to have a versioning strategy.

• URL Versioning: Include the version number in the URL.
  • /v1/users
• Header Versioning: Use request headers to specify the version.
  • Accept: application/vnd.myapi.v1+json

10. Error Handling

Provide clear and consistent error messages with HTTP status codes. Example of an error response:

json
{
  "error": "User not found",
  "message": "The user with ID 123 does not exist."
}

Example of a RESTful API Design

Here’s a simple example of a RESTful API for a Books resource:

GET /books - Retrieves a list of all books.

GET /books/{id} - Retrieves details of a specific book by its ID.

POST /books - Creates a new book.

PUT /books/{id} - Updates an existing book.

DELETE /books/{id} - Deletes a specific book.

Query Parameters:

• /books?author=J.K. Rowling - Filter books by author.
• /books?limit=10&page=2 - Pagination of results.