[Zope3-dev] Principal Folder How-To

[Garrett Smith]

Roger Ineichen wrote:
> Hi Garrett
> 
> Behalf Of Garrett Smith
>> Sent: Sunday, February 20, 2005 10:27 PM
>> To: Stefan Marti; zope3-dev at zope.org
>> Subject: RE: [Zope3-dev] Principal Folder How-To
>> 
>> Make sure you register the PAU as providing IAuthentication (it's a
>> number of interfaces down in the list, so not obvious that you must
>> choose it).
> 
> Can you tell me why we offer more the one (the right) inteface?
> Is there a use case for to register a utility providing another
> interface then the interface which was the utility developed for?

You can register a utility as providing more than one interface. This is
more theory than practice though.

> I think this is the most confusing part in the utility registration.

I agree.

> My uderstanding of the (only) use case is:
> 
> I place a local utility like PAU in the service space (default or
> tool) because I like to have local version of PAU where I can use.
> 
> If I like to register the PAU providing another Interface nothing is
> using the PAU and I have to write a application which lookup the
> PAU under this(another) interface.
> 
> Or I'm wrong?

You're right. It reflects the underlying architecture, which requires a
lot of knowledge by the user. I don't think many people like it :)

There was an attempt to solve some of these problems with the 'tools'
concept, but I don't use that view and can't offer an opinion. Obviously
we need to do some more work.

Maybe this is a good sprint topic -- who's gonna be in DC around March
19th?

 -- Garrett