- From: Slein, Judith A <JSlein@crt.xerox.com>
- Date: Wed, 2 Dec 1998 17:04:20 -0500
- To: "'Jim Davis'" <jdavis@parc.xerox.com>, w3c-dist-auth@w3.org
Jim, Thanks for reviewing the draft. > -----Original Message----- > From: Jim Davis [mailto:jdavis@parc.xerox.com] > Sent: Wednesday, December 02, 1998 3:16 PM > To: w3c-dist-auth@w3.org > Subject: Comments on ACR draft of 10 Nov 1998 > > > 1. (3.3.1) I suggest we use the existing Destination header instead of > introducting a new header Ref-Target. Destination is > currently used with > COPY and MOVE. Good idea. Then the corresponding property would be DAV:destination. OK? > 2. (3.3.1) I agree that Hide-Target seems pointless. The > draft already > explains why. Let's get rid of it. This issue is on the agenda for Orlando. > 3. (3.8) says that PUT with a redirect reference returns a > 302 (as do GET > and HEAD) but also that is "MUST include an entity body for > display to users". > > I think this is a mistake for the following reasons > > a) Internationalization. What language would you use for > the message? > > b) Modularity. It's up to the user's browser to interpret > Web protocol > messages. For example, my browser warns me when I am > accepting a cookie, > when I am submitting a form via email, when I am leaving a > secure area, and > when I am about to send a message that is misspelled, has bad > grammar, or > might indicate intent to monopolize the market. ;-). It > should and could > also warn me if a PUT returns 302, rather than just blindly > re-doing it. > > The protocol should be kept simple. it should convey sufficient > information that a well written program can take reasonable action. > There is no need to burden server implementors with creating > a message that > will rarely if ever do any good. Agreed, all good arguments. This just reflected my confusion in trying to think about these down-level cases. I'm still confused about OPTIONS. If we assume the rules will be the same as for PUT, down-level clients will redirect to the target resource based on the headers. But a reference-aware client might really want to get OPTIONS for the reference rather than its target. There would be no way to do this, unless maybe we introduce a new request header. Should I do that? I'm pretty sure that OPTIONS is the only one of the HTTP methods where this is a problem -- GET and HEAD already returned all the information there is about the reference with the 302, and PUT and POST don't make sense to apply to references. > > 4. (3.11) I don't believe the rationale that the > DAV:references property > will be "much more efficient for the client to retrieve" that a DASL > search. Indeed, I expect the underlying implementation to be > identical > (that is, a DASL search for all references whose target is T will be > implemented by reading the DAV:references property of T.) > > On the other hand, it is likely the expected initial version > of DASL won't > be able to search structured values, and hence would not be > able to search > the references property. In any case, the references > property seems more > natural to me, and does not add to the cost of the protocol > (compared to > any other approach with the same functionality) On the agenda for Orlando. > 5. (4.3.1) The first sentence would be better if it read > > When a resource is created (e.g., by PUT or MKCOL) its position in the > parent collection can be set with the new Position header. > > because the current sentence omits MKCOL, and would have to > be modified if > any new method was added to WebDAV. I can make this change. I tried in the formal definitions of the headers (Section 5) to list all the methods that the header can be used with -- you're thinking that this is also a bad idea? I can try to replace each list with a conceptual description of the set of methods. (Any method that creates a new resource, etc.) > > 6. (5.6) I don't think the Resource-Type entity header should > be supported. > As the draft notes, this would only be needed if one can > create a reference > with LOCK, or change resource type with MOVE or COPY. > > a) I don't think the LOCK case is important. Normally, once > a reference > is created, there's nothing more to be done. I suppose a > client might want > to create a reference then add some properties, but is this > case important > enough to justify the additional complexity of the > Resource-Type header? > > Also, I don't see any reason from the protocol that one could > not do a LOCK > followed by a MKREF. Locking a non-existing resource creates a null > resource. The protocol says that MKREF overwrites the > resource. So what's > the problem? > > Also, can one currently LOCK foo followed by MKCOL foo? (If > not, that's > perhaps a problem for the mainline WebDAV spec, not ACR.) > > b) We certainly should *not* allow clients to *change* a > resource type > (with MOVE or COPY). I agree with all of your points. Unless others disagree, I'll get rid of the Resource-Type header. (The DAV spec does allow MKCOL to be applied to a locked null resource. If I read the spec correctly, the locked null resource has a DAV:resourcetype of empty until MKCOL gets applied, when the value of DAV:resourcetype would change to DAV:collection.) > > 7. (5.9, DAV-Collections header). Why can't we use > additional values of > the DAV header in Options to convey this? Note also that the > versioning > draft proposes a more general way to indicate the DAV > extensions supported, > namely the Verify-Extensions header. If we can't use the DAV > header, we > should at least pick up the same header that the versioning > team is using. > Well, I was trying to follow the Versioning model, but didn't entirely get it. The DAV-Collections header is analogous to the Versioning-Support header. Then I guess I need to add a new value DAV:collections for Verify-Extensions. > best regards > > Jim > > > ------------------------------------ > http://www.parc.xerox.com/jdavis/ > 650-812-4301 > Judith A. Slein Xerox Corporation jslein@crt.xerox.com (716)422-5169 800 Phillips Road 105/50C Webster, NY 14580
Received on Wednesday, 2 December 1998 16:59:57 UTC