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Re: BIND forest question

From: <jamsden@us.ibm.com>
Date: Tue, 13 Apr 1999 16:17:59 -0400
To: w3c-dist-auth@w3.org
Message-ID: <85256752.006F81B8.00@d54mta03.raleigh.ibm.com>


Interesting problem. To review: we start out with the following collections
and resources (no links or aliases)

C1
  |_ C2
         |_ R.html

Now we bind A to C1. We get:

A --> C1
            |_ C2
                   |_ R.html

Now one could ask, what are the members of A? Seems like it would have to
be C2 as we traverse the alias A to the resource it is bound to in order to
figure out what it is.

Next we bind A/B to C2.

    A -->  C1
A/B -->    |_ C2
                        |_ R.html

I'm not sure what this means. In what context is A/B bound to C2? Or is it
bound to C1/C2? What is C2 by itself other than a member of C1? If I ask
what are the members of A again, what do I get? C2? B? C2 and B? In other
words, creating aliases must be done in the context of collection
semantics. We could treat A/B as an alias, not a path name containing two
entries. Then A still contains C2, and A/B contains R.html. This looks a
little funny  though because unless you know A/B is an alias bound to
something, you don't get the expected semantics i.e., that A contains B.

I think BIND must be done in the context of a parent collection, just like
PUT of MKCOL. So binding A/B to C2 would have to enter the alias B as a
member of C1. Now C1 contains C2 and B where B is an alias of C2. So C1
contains two URLs referencing the same resource.

Finally, introduce another alias for C2, X

    A      -->  C1
A/B, X -->    |_ C2
                             |_ R.html

So the members of X are R.html. I don't think there is a binding from
X/R.html to R.html, only a binding from X to C1/C2. When resolving the
binding we get C2 which has member R.html making X appear to contain
R.html.






"Jim Davis" <jdavis@coursenet.com> on 04/13/99 02:05:30 PM

To:   w3c-dist-auth@w3.org
cc:    (bcc: Jim Amsden/Raleigh/IBM)

Subject:  BIND forest question




(This is exactly the same issue as the one Yaron raised earlier, about
whether creating a direct reference creates a forest of new references,
except expressed in terms of binding.)

Suppose you have two existing collections, C1, and C2, where C1 contains
C2, and the
name bound to C1 is A/, and the name bound to C2 is A/B/, and that
collection C2 contains R.html.  Then we have the following mapping from
names to resources

URL            resource
A/               C1
A/B/            C2
A/B/R.html   R

Now suppose one binds the name X to C2

A/               C1
A/B/            C2
A/B/R.html   R
X/                C2

Does this also create a binding for X/R.html to R?

If Yes, does this impose an unreasonable storage burden on the server?
(Perhaps not.  The bindings for the "contents" of collection C2 are stored
with C2, not with the name X/)

if No, then what does a server do with X/R.html?
Received on Tuesday, 13 April 1999 16:18:14 GMT

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