- From: Jim Whitehead <ejw@ics.uci.edu>
- Date: 1998年11月13日 09:29:45 -0800
- To: Larry Masinter <masinter@parc.xerox.com>
- Cc: w3c-dist-auth@w3.org
- Message-ID: <000b01be0f2b34ドルf5ffe0$d115c380@galileo.ics.uci.edu>
Larry Masinter writes: > Urk! That wasn't what I was complaining about. The requirement I > don't understand is the requirement that a resource not appear > twice in a collection. I don't understand the reason for the requirement. > If I understood the reason for the requirement, then I might know > why it should be OK for the same 'resource' to appear in a collection > twice if that resource is named with different URLs. The requirement is intended to be: the same *URL* cannot appear more than once in the same collection. Multiple instances of the same *resource* are allowed. One rationale for this requirement is to avoid having to have "instance" identifiers for each URL in a collection, and to avoid handling ordering issues in the base specification. The other rationale for this requirement is that having multiple instances of the same URL in a collection just didn't make sense. For example, assuming multiple instances of the same URL are allowed in a collection, if there is a collection resource R, with URL http://www.example.com/collection/, and it has members: ./hello.html ./logo.gif ./hello.html That is, when accessed via URL http://www.example.com/collection/ the absolute form of the URLs of these members is: http://www.example.com/collection/hello.html http://www.example.com/collection/logo.gif http://www.example.com/collection/hello.html What does it mean to have ./hello.html twice? How can one of these duplicates be created? If one instance is deleted, the others must go away as well (or leave a dangling member of collection). This issue of having multiple instances of the same URL in a collection was discussed in the advanced collections specification as well, and the decision was made there too not to have multiple instances of the same URL in a collection. - Jim
Received on Friday, 13 November 1998 12:34:48 UTC