Subject: etag in untagged production of If header

From: Jim Davis <[email-masked]>
Date: Sat, 12 Sep 1998 11:14:40 PDT

The no-tagged production of an If header is to be applied to every resource
to which the method is applied.  This production can contain both state
tokens and etags.  I understand why the no-tagged production is useful when
it contains a state token.  Many distinct resources can be in the same
state.  I do not understand why this production can contain an etag.
Unlike a state token, an etag can match at most one resource, and the only
way a client could have an etag in the first place is by already knowing
the resource.  So it would always be possible for the client to use the
tagged production.

Can someone provide an example of when it would ever make sense to include
an etag in such a production?

The only reason I can think of is to allow the client to transmit slightly
fewer bytes on the wire.

I am not calling for any changes in the protocol or documentation, but
would like to know whether I missed something.

Jim

------------------------------------
http://www.parc.xerox.com/jdavis/
650-812-4301

---

From: Jim Amsden <[email-masked]>
Date: Mon, 14 Sep 1998 19:19:49 -0400

My interpretation of the No-tag-list production in an If header is that is is
used for those cases where the condition (a list of state tokens and/or e-tags)
applies to the (single) target resource of the request method, no other
resource is effected. The Tagged-list production is for methods that effect
more than one resource and therefore need to provide matching conditions for
each.

---

From: Yaron Goland <[email-masked]>
Date: Tue, 15 Sep 1998 00:26:29 -0700

I could also probably come up with some fairly convoluted example where you
could use an untagged If header with an e-tag on a Depth Infinity method but
that would be besides the point. The real point is that we generally don't
ban something unless we have a reason to. Since we didn't have a compelling
reason to keep e-tags out of untagged lists and there is occasion that they
could actually be useful in an untagged list, we decided to just allow them.

			Yaron

> -----Original Message-----
> From: Jim Amsden [mailto:[email-masked]]
> Sent: Monday, September 14, 1998 4:20 PM
> To: [email-masked]
> Subject: Re: etag in untagged production of If header
> 
>