ianG wrote: > Hi all, > > I'm wrestling with a protocol error condition where an action has been > done already, the requester innocently asks for it to be done, and is > told that it is already done. Idempotency, in a nutshell. > > The problem with "already done" in an idempotent sense is that it is > both an error and a success.
But that's not what idempotent means. It means that the same transaction has the same attack - you can repeat it multiple times without worry. write(key, value) is idempotent (for the same key/value pair) add 1 to value is not an "already done" message is implicitly NOT idempotent (the more appropriate response is returning the value) - for example: read(key) -> 10 write(key,20) -> 20 write(key,20) -> 20 write(key,20) -> 20 is idempotent. Miles Fidelman -- In theory, there is no difference between theory and practice. In practice, there is. .... Yogi Berra _______________________________________________ p2p-hackers mailing list [email protected] http://lists.zooko.com/mailman/listinfo/p2p-hackers
