Site Manager APIs


The API returns the module-scope global registry:

>>> from zope.component.interfaces import IComponentLookup
>>> from zope.component.globalregistry import base
>>> from zope.component import getGlobalSiteManager
>>> gsm = getGlobalSiteManager()
>>> gsm is base

The registry implements the IComponentLookup interface:

>>> IComponentLookup.providedBy(gsm)

The same registry is returned each time we call the function:

>>> getGlobalSiteManager() is gsm

Callable objects that support being overridden

We don’t know anything about the default service manager, except that it is an IComponentLookup.

>>> from zope.component import getSiteManager
>>> from zope.component.interfaces import IComponentLookup
>>> IComponentLookup.providedBy(getSiteManager())

Calling getSiteManager() with no args is equivalent to calling it with a context of None.

>>> getSiteManager() is getSiteManager(None)

If the context passed to getSiteManager() is not None, it is adapted to IComponentLookup and this adapter returned. So, we create a context that can be adapted to IComponentLookup using the __conform__ API.

Let’s create the simplest stub-implementation of a site manager possible:

>>> sitemanager = object()

Now create a context that knows how to adapt to our newly created site manager.

>>> from zope.component.tests.examples import ConformsToIComponentLookup
>>> context = ConformsToIComponentLookup(sitemanager)

Now make sure that the getSiteManager() API call returns the correct site manager.

>>> getSiteManager(context) is sitemanager

Using a context that is not adaptable to IComponentLookup should fail.

>>> getSiteManager(sitemanager)
Traceback (most recent call last):
ComponentLookupError: ('Could not adapt', <instance Ob>,
<InterfaceClass zope...interfaces.IComponentLookup>)