dolmen.app.breadcrumbs 0.2

Breadcrumbs navigation for Dolmen applications.

dolmen.app.breadcrumbs provides a breadcrumbs navigation for the Dolmen applications. It registers a viewlet to render the links.

Getting started

To test the breadcrumbs’ features, we need to create some content. We used here dolmen.content contents, as our breadcrumbs’ behavior works only for IBaseContent objects:

>>> import dolmen.content
>>> from grokcore.component import testing

>>> class Container(dolmen.content.Container):
...    dolmen.content.name('A dummy container')

>>> testing.grok_component('container', Container)
True

We now create our contents in an hypothetical application:

>>> from zope.component.hooks import getSite

>>> app = getSite()
>>> app['cave'] = Container()
>>> app['cave']['pot'] = Container()

To finish, we create a view. As we use a viewlet, we need a view to display something:

>>> import grokcore.view

>>> class simpleView(grokcore.view.View):
...   grokcore.view.context(dolmen.content.IBaseContent)
...   def render(self):
...     return u'For test purposes'

>>> testing.grok_component('simpleview', simpleView)
True

Adapting

The component that allows to build URLs and Breadcrumbs is a multi adapter providing the IAbsoluteUrl interface. let’s have a closer look:

>>> from zope.component import getMultiAdapter
>>> from zope.publisher.browser import TestRequest
>>> from zope.traversing.browser.interfaces import IAbsoluteURL

>>> request = TestRequest()
>>> url = getMultiAdapter((app['cave'], request), IAbsoluteURL)

>>> url
<dolmen.app.breadcrumbs.url.DescriptiveAbsoluteURL object at ...>

>>> from zope.interface.verify import verifyObject
>>> verifyObject(IAbsoluteURL, url)
True

>>> url()
'http://127.0.0.1/cave'

>>> url.breadcrumbs()
({'url': 'http://127.0.0.1', 'name': ''},
 {'url': 'http://127.0.0.1/cave', 'name': u'cave'})

Rendering

Now, we have some contents in our application. We can call our view and render the viewlet using its manager.

>>> from dolmen.app.layout import master
>>> from dolmen.app.breadcrumbs import Breadcrumbs

>>> view = getMultiAdapter((app['cave'], request), name="simpleview")
>>> view
<simpleView object at ...>

The Breadcrumbs viewlet is registered for the dolmen.app.layout.Top manager:

>>> manager = master.Top(app['cave'], request, view)
>>> viewlet = Breadcrumbs(app['cave'], request, view, manager)
>>> viewlet
<dolmen.app.breadcrumbs.crumbs.Breadcrumbs object at ...>

Our contents have no title yet. If we render the viewlet, it uses the location in the parent (__name__):

>>> viewlet.update()
>>> print viewlet.render()
<div id="breadcrumb">
  <span class="you-are-here">You are here:</span>
  <span class="crumb">
    <a href="http://127.0.0.1/cave">cave</a>
  </span>
</div>

If we set a title, it uses the title:

>>> app['cave'].title = u"My cave with a fireplace"

>>> viewlet.update()
>>> print viewlet.render()
<div id="breadcrumb">
  <span class="you-are-here">You are here:</span>
  <span class="crumb">
    <a href="http://127.0.0.1/cave">My cave with a fireplace</a>
  </span>
</div>

It works with all kind of objects although the title will only be used for objects providing dolmen.content.IBaseContent:

>>> app['cave']['pot']['bone'] = object()
>>> bone = app['cave']['pot']['bone']
>>> viewlet = Breadcrumbs(bone, request, view, manager)

>>> viewlet.update()
>>> print viewlet.render()
<div id="breadcrumb">
  <span class="you-are-here">You are here:</span>
  <span class="crumb">
    <a href="http://127.0.0.1/cave">My cave with a fireplace</a>
    <span class="breadcrumb-separator">&rarr;</span>
  </span>
  <span class="crumb">
    <a href="http://127.0.0.1/cave/pot">pot</a>
    <span class="breadcrumb-separator">&rarr;</span>
  </span>
  <span class="crumb">
    <a href="http://127.0.0.1/cave/pot/bone">bone</a>
  </span>
</div>

If the object is not locatable, we raise a TypeError:

>>> unlocatable = Container()
>>> viewlet = Breadcrumbs(unlocatable, request, view, manager)
>>> viewlet.update()
Traceback (most recent call last):
...
TypeError: There isn't enough context to get URL information. This is probably due to a bug in setting up location information.

Changelog

0.2 (2010-02-26)

• The Breadcrumbs now uses an adaptation to the zope.dublincore IDCDescriptiveProperties interface in order to provide a name. The base multi adapter is registered for zope.location ILocation. Therefore, the Breadcrumbs is no longer limited to dolmen.content IBaseContent components.

• The dependencies have been greatly cleaned. We are now using a Grok 1.1rc1 version of the ZTK. We no longer depend on zope.app packages.

• Updated the IAbsoluteUrl component to match the changes in zope.traversing. The View has been removed and replace by a simple MultiAdapter providing IAbsoluteUrl.

0.1 (2009-11-08)

• Initial release