- From: Paul Prescod <paul@prescod.net>
- Date: Thu, 18 Apr 2002 09:45:48 -0700
- To: Graham Klyne <GK@ninebynine.org>
- CC: www-tag@w3.org
Graham Klyne wrote: > > At 12:34 AM 4/18/02 -0700, Paul Prescod wrote: > > > - an operation that is idempotent: has no further side effects if repeated > > > after it has been performed once > > > >The HTTP specification uses the term idempotent to mean idempotent. > > > >http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html#sec9.1.2 > > > >PUT is safe but not idempotent. > > Yup, what it says there is exactly what I meant. And according to that > reference, PUT is idempotent. Sorry, I meant to say "PUT is idempotent but not safe." >... > The section immediately preceding the one you cite mentions "actions they > might take which may have an unexpected significance to themselves or > others" -- in a web context, it seems to me that any action which changes > what is visible on the web is potentially significant, hence my attempt to > characterize it in terms of visible side effects. What if following a link on the Web had the semantic "inject patient with drug". That may not have visible side effects but is still a serious, dangerous side effect. Conversely, incrementing a page hit counter is not dangerous but IS web-visible. Paul Prescod
Received on Thursday, 18 April 2002 12:45:03 UTC