Idempotency keys

Corvis has no built-in support for idempotency keys (storing the response of a request identified by an Idempotency-Key header and replaying it if it arrives again).

Alternative

It can be built with existing pieces:

• An interceptor reads the header with ctx.request(), looks up a stored response and, if there is none, runs next.handle() and stores the result.
• To store responses within a single process, CacheManager works (see Caching). If you have several instances, store the key in the database with a unique constraint (#[unique] on a corvis-orm model), so two simultaneous requests are not both executed.