On 26 Nov 2007, at 18:17 , Chris Withers wrote:
Philipp von Weitershausen wrote:
Yes. It returns the one and only global registry.

Am I right in thinking the global registry is _only_ used if no context is supplied?
No. One should never have to supply an explicit context.

Surely that's only the case if you're using zope's traversal stuff?


I'm guessing that if you are, you either need to stick with the one global registry or manage either ISites or IComponentLookup's yourself?

Not sure what you mean by "if you are".

If so, how come it's not called getGlobalComponentRegistry?

Because component registries used to be called site managers and we can't just change the API at this point anymore.

Well, getGlobalComponentRegistry could be added as an alternate spelling and people could be encouraged to use it ;-)
Feel free to submit a patch :)

It's entertaining to get asked to submit a patch *and* told you're not doing anything that belongs on the -dev list in the same email ;-)

Touche ;)

There seems to be comments suggesting getSiteManager is deprecated, but maybe I'm not getting exactly what is being deprecated...
It's not deprecated at all. If it were, it would say so in the code and emit a deprecation warning when you try to use it.

What's line 37 of component._api on about then?

# SiteManager API. This needs to get deprecated eventually.

It says *eventually*  :)

and by "Site" you mean "something implementing IComponentRegistry"?
No, something implementing ISite, which defines a setSiteManager and getSiteManager for setting and retrieving an IComponentRegistry.

Are you sure you don't mean ISiteManager, which is marked as being deprecated and to be removed in 2007...

Yes, I'm sure I mean ISite.

If you mean a different ISite, where is it defined?

zope.app.component.interfaces. Well, it moved to zope.location.interfaces recently in order to reduce the amount of interdependencies between the eggs, but it's still available w/o deprecation from zope.app.component.interfaces.

(and I'm guessing there is an ISite somewhere, as I could find no definition of setSiteManager, but how does IComponentArchitecture's getSiteManager relate to that of ISite?)

zope.component.getSiteManager() will return whichever component registry is active. site.getSiteManager() will return the local component registry that has been associated with site (which provides ISite).

I'm guessing the adapter to IComponentLookup is what implements the search up the object graph to find an IComponentRegistry?
Yes, but that's rarely used (only when you pass an explicit context which we almost never do).

I think I'm misreading the code in _api then. It looks to me that most things use getSiteManager (even though the comment says it needs to be deprecated) which always appears to return either the global registry or do an IComponentLookup adaptation. If no explicit context is supplied, how does anything other than the global registry end up getting used?

getSiteManager is "overloaded" from zope.app.component. See hooks.py. Yay for indirection :).

Normally, during traversal, an event subscriber reacts to ISites being traversed and remembers the site's component registry in a thread-local variable. getSiteManager() will then return whatever is in the thread-local variable, and therefore getUtility, getMultiAdapter, etc., will use that local registry.
If so, where do I find that adapter implementation(s)?
See zope.app.component (also for the subscriber stuff mentioned above).

I spent quite a while looking and didn't spot them. Where exactly?

A quick look through zope.app.component/configure.zcml reveals that the subscriber is in site.py. The rest of the machinery is in hooks.py.

(also bear in mind that I don't really want to use any of zope.app...)

Fair enough.

...however, I'm interested in the mechanics of how zope.component handles multiple component registries, in particular how registries are added to and removed from the set of registries that are searched hen looking for a component and some other bits and pieces.
Which is the *use* of Zope, not the *development* of Zope.

I'm not really sure why you're quibling over this but I'm quite happy to move this discussion to zope3-users if you're prefer and then move it back to zope-dev if it turns out I need to do *development* of Zope (such as the patch you requested above ;-) )

I guess I'm nitpicking. I would just like to stress the focus of the zope-dev list. And regarding the patch, I've encouraged people to submit patches on zope3-users before, too ;).

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