I know HTTP PUT is an idempotent request that store something at a specific URI, according to the definition (quoted from the rfc)
The PUT method requests that t
If the Request-URI refers to an already existing resource, the enclosed entity SHOULD be considered as a modified version of the one residing on the origin server. If the Request-URI does not point to an existing resource, and that URI is capable of being defined as a new resource by the requesting user agent, the origin server can create the resource with that URI.