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Re: LDAP Enhancement Style Guide

At 01:56 PM 3/31/2001 -0800, Rob Weltman wrote:
Bruce Greenblatt wrote:
>
> I have been requested to publish an update of this draft. So, attached is
> an update of my "LDAP Enhancement Style Guide" internet draft. Please
> publish it as an update to draft-greenblatt-ldapextstyle-00.txt. Several
> comments were received on the previous edition, and have been
> incorporated. Many thanks to those who responded, especially Kurt Z! Thanks,
>
> Bruce Greenblatt

Interesting about control extensibility. My first draft on the proxy auth control didn't include extensibility hooks. It only specified the fields required by the control as conceived. A couple of people suggested that perhaps in the future it could be extended to passing other credential fields, so I changed its value contents to a SEQUENCE in the second revision. Then other people (well-known within LDAPEXT) said no, that's wrong. An extension should result in a new control, rather than additional fields in an existing control. So a subsequent revision reverted to just specifying a single non-extensible credentials field.

OK. If you allow for new fields in the control, and the meaning of the control doesn't change, why should you have to get a new OID and a new control. I think that it is appropriate to allow for future extensibility. If the client puts a field in a control that the server doesn't know about, how is that any different than the client putting a control in an operation that the server doesn't know about?


  Your draft says:

"The definition of a control SHOULD be defined in such a manner that
it is extensible.  For extensibility, extra binary fields SHOULD be
built into the definition.  In ASN.1, use of a SEQUENCE is helpful."

Has there been a change in the opinion generally among the LDAP luminaries on extensibility in controls, or are the opinions strongly divergent?

Probably the latter, if past experience is any judgement. In any case, it's only my opinion, and it's only a SHOULD. I'm sure that there are some situations in which the allowance for extensibility is inappropriate. That's why its a SHOULD and not a MUST.


Rob


>
> ==============================================
> Bruce Greenblatt, Ph. D.
> Directory Tools and Application Services, Inc.
> http://www.directory-applications.com
>
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==============================================
Bruce Greenblatt, Ph. D.
Directory Tools and Application Services, Inc.
http://www.directory-applications.com