So it seems we are in agreement. By adding the ability to support an arbitrary list of headers in the digest, we make Digest usable by DAV and everyone else. Yaron > -----Original Message----- > From: John Franks [SMTP:john@math.nwu.edu] > Sent: Wednesday, December 31, 1997 11:40 AM > To: Yaron Goland > Cc: 'ietf-http-wg@w3.org'; http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com > Subject: Re: FW: Digest mess > > > > > > > The main thing I hate about Digest is: > > > > > > A) Can't digest arbitrary headers. > > > > > > This is a big deal for groups like WebDAV where new headers are being > > > introduced which contain critical command information. For example the > > > depth header specifies if a command applies to a single resource or a > > > collection of resources. The destination header specifies the > destination > > > of a move or copy. Changing these headers would have a profound effect > on > > > the meaning of the method. > > > > > > As you probably know from the discussion in this group the difficulty > with digesting headers is that proxies may modify them. Proxies > may add headers which were not originally present, may change them, > or may "canonicalize" them. All of these features would ruin a > digest. > > It has proven difficult if not impossible to have the specification > require that proxies not change all the headers people would like > digested. My guess is that it is futile to try to specify a set of > headers which must always be digested and must not be changed by > proxies. At least the discussion so far has not shown anything like a > consensus on this. > > On the other hand I agree that digesting arbitrary headers is highly > desirable. Painful though it may be in terms of bandwidth, the only > way I think this can be done is by replicating all the relevant origin > server headers in a field of the Authentication-info header. Proxies > are required not to touch the Authentication-info header. > > This "origin-header" field would have a value which is a quoted string > consisting of the concatenation (with some separator) of the complete > headers which the sender wants digested. This string would be included > in the material digested to form the entity-digest. > > This would have the advantage of being extensible as any new headers > are added. > > I am not sure what a good separator would be; colon might not work > too well. Also I don't know what to do about headers containing > quotation marks. Perhaps something like %-escapes for colons, quotes > and percents in the headers being concatenated and colon as separator? > > John Franks > john@math.nwu.edu > > > > > >Received on Wednesday, 31 December 1997 15:30:14 UTC
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