* Henri Sivonen <[EMAIL PROTECTED]> [2005-05-05 18:35+0300] > > On May 5, 2005, at 16:24, Walter Underwood wrote: > > >--On May 5, 2005 8:07:15 AM -0500 Mark Pilgrim <[EMAIL PROTECTED]> > >wrote: > >> > >>Not to be flippant, but we have one that's widely available. It's > >>called the Expires header. > > > >You need the information outside of HTTP. To quote from the RSS spec > >for ttl: > > > > This makes it possible for RSS sources to be managed by a > >file-sharing > > network such as Gnutella. > > > >Caching information is about knowing when your client cache is stale, > >regardless of how you got the feed. > > Virtually everyone with IP connectivity can do HTTP, and HTTP has the > Expires header. If this feature is important to you, why would you > switch to a transfer protocol that doesn't have the feature? (I am not > claiming anything about the actual Gnutella features.) To me, the "what > if the feed is not over HTTP" argumentation seems theoretical > over-generalization.
+1 FWIW various P2P/filesharing protocols use HTTP, eg. Kazaa and others make use of HTTP's ability to request a byte range, handy if you're requesting chunks of the same file from different servers. Those who care to have HTTP header semantics show up in other environments can do various things (eg. reflect into an XML namespace). But it doesn't seem to me to be core business of the AtomPub WG to do this work... [googles a bit] OK it looks like Gnutella also uses HTTP for the file download part of it's protocol, fwiw. (including Range: header) http://www9.limewire.com/developer/gnutella_protocol_0.4.pdf Dan
