CS API Development & Integration 2

Question 1

A client sends a PUT request to /api/users/42 with a complete user object. What behavior does REST semantics prescribe?

Accepted Answer

Replace the entire resource at that URI with the supplied representation

Answer

PUT is defined as a full replacement of the resource at the target URI, while PATCH is used for partial updates.

Question 2

An API returns HTTP 429 to a client. What is the client expected to do?

Accepted Answer

Slow down and retry after the interval indicated by the Retry-After header

Answer

Status 429 Too Many Requests signals rate limiting, and the client should back off, typically honoring the Retry-After header.

Question 3

Which OAuth 2.0 grant type is recommended for a single-page application authenticating a user in 2020s best practice?

Accepted Answer

Authorization code flow with PKCE

Answer

The authorization code flow with PKCE replaced the implicit grant as the secure standard for public clients like SPAs.

Question 4

In a REST API, which practice best supports safe retries of a payment creation request over an unreliable network?

Accepted Answer

Requiring the client to send an idempotency key with the POST request

Answer

An idempotency key lets the server detect and deduplicate retried POST requests so the payment is only created once.

Question 5

A mobile app must fetch a user's name, their last 5 orders, and each order's shipping status, but the REST API requires three separate round trips. Which technology directly addresses this over-fetching and multiple-request problem?

Accepted Answer

GraphQL

Answer

GraphQL lets clients request exactly the nested data they need in a single query, avoiding multiple REST round trips.

(CS) Computer Science Practice Test

(CS) Computer Science Practice Test

CS API Development & Integration 2