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Re: Alias dereferencing

Michael Reiher wrote:
On Saturday 10 September 2005 09:29, you wrote:
Apparently, yes:
<draft-ietf-ldapbis-models, section 2.6>
      An alias entry shall have no subordinates, so that an alias entry
      is always a leaf entry.
</draft-ietf-ldapbis-models, section 2.6>

Hmm, too bad. Are there technical reasons for not supporting aliases which are no leaves? Actually that's something what I expect to work, from a users point of view. It's like filesystem symlinks that may only point to files, but not directories :) Anyway...
Well, one good technical reason is that only the Search operation provides a Deref option. Put another way, the Search operation is the only one intended to recognize aliases. And it's the only one that gives clients control over whether to dereference them or not.
Now, if I'd want to implement this, i.e. to a) transparently handle aliases

It would be a mistake to implement (a) since you'll have no way to specify when you want to Modify the alias entry itself, vs what the alias points to.
and b) support references to other backends.

It would be a mistake to implement (b); that is already the purpose of referrals.
What would be the best way?
The best thing to do would be to take a step back and think about something else for a while. Then read through the LDAP specs and gain an understanding of what facilities are already provided, and how to use them to your advantage. Some things to think about - why does your design require the use of aliases at all, why don't your applications already know the real DNs of the entries they need to operate on? Why does your design require the use of multiple backends?

Something else to think about - you should not be thinking about how to "fix" code that isn't broken, this shows a lack of understanding of the existing code. Trying to write new code before you understand the existing design and implementation is ... obviously a bad idea.

 -- Howard Chu
 Chief Architect, Symas Corp.  http://www.symas.com
 Director, Highland Sun        http://highlandsun.com/hyc
 OpenLDAP Core Team            http://www.openldap.org/project/