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18. Web & API

What is REST API?​

Junior

Answer: REST (Representational State Transfer) is an architectural style for designing networked applications. It relies on a stateless, client-server, cacheable communications protocol — and in virtually all cases, the HTTP protocol is used. Read more: What is REST API?

What are the main HTTP methods used in REST?​

Junior

Answer:

  • GET: Retrieve a resource.
  • POST: Create a new resource.
  • PUT: Update/replace an existing resource.
  • PATCH: Partially update an existing resource.
  • DELETE: Delete a resource.
  • OPTIONS: Describe the communication options for the target resource.
  • HEAD: Same as GET but returns only the headers (no body).

What is the difference between GET and POST?​

Junior

Answer:

  • GET: Data is sent in the URL. Used for retrieving data.
  • POST: Data is sent in the request body. Used for submitting data.

What are HTTP Status Codes? Give examples.​

Junior

Answer:

  • 200 OK: Success.
  • 201 Created: Resource successfully created.
  • 400 Bad Request: Client error.
  • 401 Unauthorized: User not authenticated.
  • 403 Forbidden: User authenticated but not allowed.
  • 404 Not Found: Resource not found.
  • 500 Internal Server Error: Server error.

What does "stateless" mean in the context of REST?​

Middle

Answer: Each request from a client to a server must contain all the information necessary to understand and process the request. The server does not store any client context between requests.

SOAP vs REST​

Middle

Answer:

  • SOAP: Protocol-based, uses XML, rigid structure, good for security and ACID compliance.
  • REST: Architectural style, uses JSON/XML, flexible, lightweight, and uses standard HTTP.

REST vs JSON-RPC​

Middle

Answer:

  • REST: Resource-oriented, uses HTTP methods (GET, POST, etc.) and status codes.
  • JSON-RPC: Method-oriented, usually uses POST to a single endpoint with a JSON payload specifying the method and parameters.

Can you implement your own HTTP method like POSTAWESOME instead of POST? Would it be in compliance with REST?​

Middle

Answer: Technically, yes, you can define and use custom HTTP methods. The HTTP protocol allows for extension, and most web servers and clients can be configured to handle them. However, it would not be fully in compliance with the Uniform Interface constraint of REST. REST emphasizes a standardized set of methods (the standard HTTP verbs) to ensure interoperability, predictability, and to leverage existing web infrastructure (like caches and proxies) that only understand standard methods. Using POSTAWESOME would break these benefits and make your API harder to consume.