Site Manager APIs

zope.component.getGlobalSiteManager()

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
True

The registry implements the IComponentLookup interface:

>>> IComponentLookup.providedBy(gsm)
True

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

>>> getGlobalSiteManager() is gsm
True
zope.component.getSiteManager(context=None)

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())
True

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

>>> getSiteManager() is getSiteManager(None)
True

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
True

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>)

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