I asked this question on the HTTP mailing list and was told that idempotency does not include return codes. Meaning, you are free to return HTTP 204 the first time a resource is deleted, and HTTP 404 at a later time, so long as the subsequent request does not change the server state. While it …
In more simple terms: Pure deterministic function: The output is based entirely, and only, on the input values and nothing else: there is no other (hidden) input or state that it relies on to generate its output. There are no side-effects or other output. Impure deterministic function: As with a deterministic function that is a …
This question is very similar to Implementing secure, unique “single-use” activation URLs in ASP.NET (C#). My answer there is close to your scheme, with a few issues pointed out – such as short period of validity, handling double signups, etc. Your use of a cryptographic nonce is also important, that many tend to skip over …
An idempotent function can cause idempotent side-effects. A pure function cannot. For example, a function which sets the text of a textbox is idempotent (because multiple calls will display the same text), but not pure. Similarly, deleting a record by GUID (not by count) is idempotent, because the row stays deleted after subsequent calls. (additional …
As HTTP requests in a stateless system should be independent, the results of one request should not be dependent on a previous request. Consider what should happen if two users did a DELETE on the same resource simultaneously. It makes sense for the second request to get a 404. The same should be true if …
In computing, an idempotent operation is one that has no additional effect if it is called more than once with the same input parameters. For example, removing an item from a set can be considered an idempotent operation on the set. In mathematics, an idempotent operation is one where f(f(x)) = f(x). For example, the …