> Don't do that, and this problem evaporates.
Don't do that, and you solved nothing.
Either I'm missing what you mean, or half the comments here are missing the point of idempotency.
Let's say your server received this request twice within one minute:
{
items: [ { id: 123, amount: 1 } ],
creditCardInfo: { ... }
}
How can you tell from the server if that's a retry (think e.g. some reverse proxy crashed and the first request timed out, but the payment already went through to the user's CC)... or if the user just trying to purchase another item 123 because they forgot they needed 2?
There is simply no way to make the requests idempotent without an idempotency key. The only way to tell both situations apart is to key the requests by some UID. The HTTP verb is irrelevant.
Did I misunderstand what you meant?
