The z3c.breadcrumb package provides base classes for breadcrumb
implementations. It allows you to write adapters for each content object which
provides it’s own rule for providing the breadcrumb name, url and selection.
Let’s do some imports we will use later.
IBreadcrumb
Let’s define a interface and a content object.
>>> class IOffice(zope.interface.Interface):
... """Office interface."""
>>> class Office(contained.Contained):
... zope.interface.implements(IOffice)
... def __init__(self, label):
... self.label = label
... self.activeURL = True
>>> office = Office(u'Zope Foundation')
>>> office.__name__ = u'ZF'
There is a generic breadcrumb implementation which is registered by
default. If we do not implement a custom IBreadcrumb the generic adapter will
return the title or __name__ of the item. Let’s register the default
adapter, this is normaly done in configure.zcml:
>>> zope.component.provideAdapter(browser.GenericBreadcrumb)
And see what we get:
>>> request = TestRequest()
>>> breadcrumb = zope.component.getMultiAdapter((office, request),
... interfaces.IBreadcrumb)
>>> breadcrumb.name
u'ZF'
We can also implement a custom IBreadcrumb adapter and provide another
name for the breadcrumb name:
>>> class BreadcrumbForOffice(object):
... zope.interface.implements(interfaces.IBreadcrumb)
... zope.component.adapts(IOffice, IHTTPRequest)
...
... def __init__(self, context, request):
... self.context = context
... self.request = request
...
... @property
... def name(self):
... return self.context.label
...
... @property
... def url(self):
... return absoluteURL(self.context, self.request)
...
... @property
... def activeURL(self):
... return self.context.activeURL
Let’s register the custom IBreadcrumb adapter for IOffice:
>>> zope.component.provideAdapter(BreadcrumbForOffice)
And check the new breadcrumb name:
>>> breadcrumb = zope.component.getMultiAdapter((office, request),
... interfaces.IBreadcrumb)
>>> breadcrumb.name
u'Zope Foundation'
IBreadcrumbs
There is also a IBreadcrumbs adapter which knows how to collect breadcrumb
informations for each item he traverses. We need to setup a little bit
infrastucture:
>>> root = rootFolder
>>> root['office'] = office
Register the IBreadcrumbs adapter:
>>> zope.component.provideAdapter(browser.Breadcrumbs,
... (zope.interface.Interface, zope.interface.Interface),
... interfaces.IBreadcrumbs)
Now we can collect breadcrumbs for our items. You can see the url is correct
and the label Zope Foundation is collected by the custom IBreadcrumb
adapter:
>>> breadcrumb = zope.component.getMultiAdapter((office, request),
... interfaces.IBreadcrumbs)
>>> list(breadcrumb.crumbs)
[{'url': 'http://127.0.0.1',
'activeURL': True,
'name': 'top'},
{'url': 'http://127.0.0.1/office',
'activeURL': True,
'name': u'Zope Foundation'}]
>>> breadcrumb.__parent__ is office
True
Default breadcrumbs stops on virtual host root
>>> request._vh_root = office
>>> list(breadcrumb.crumbs)
[{'url': 'http://127.0.0.1', 'activeURL': True, 'name': u'Zope Foundation'}]
Actually i don’t understand what is this for? Stephan, Roger?
>>> browser.CustomNameBreadcrumb('office')
<class 'z3c.breadcrumb.browser.CustomNameBreadcrumb('office')'>