implementing Plone subsites with p4a.subtyper

p4a.subtyper to the rescue

Implementing it is dead easy:

Add p4a.subtyper to your buildout.cfg eggs and zcml sections:

eggs =
    Plone
    p4a.subtyper
    ...

zcml =
     p4a.subtyper
     ...

In your types product, or wherever you want your custom code to live, add a new module adapters:

# mkdir adapters
# touch adapters/_init_.py

In this module, create a new file section.py with the following contents:

import p4a.subtyper.interfaces
import zope.interface
import zope.app.content.interfaces
import zope.component

from plone.app.layout.navigation.interfaces import INavigationRoot

class IPlain(zope.interface.Interface):
    "A marker interface that allows subtyping reset"

zope.interface.alsoProvides(IPlain,
                            zope.app.content.interfaces.IContentType)

class Section(object):
    zope.interface.implements(p4a.subtyper.interfaces.IPortalTypedFolderishDescriptor)
    title = u'Section'
    description = u'Website section that acts as a INavigationRoot'
    type_interface = INavigationRoot
    for_portal_type = 'Folder'

class Plain(object):
    zope.interface.implements(p4a.subtyper.interfaces.IPortalTypedFolderishDescriptor)
    title = u'Plain'
    description = u'Just a plain Folder that does NOT act as a INavigationRoot'
    type_interface = IPlain
    for_portal_type = 'Folder'

This creates two decorators we can use. One is the Section class that uses the vanilla INavigationRoot interface from plone.app.layout. The other one is a "no-op" Plain class using a custom marker interface whose only function is that it allows us to trick p4a.subtyper into removing the INavigationRoot marker interface. That is, convert a Section back into a plain Folder.

We need to hook this stuff up in zcml, obviously. Create adapters/configure.zcml:

<configure
    xmlns="http://namespaces.zope.org/zope"
    i18n_domain="my_site.types">

    <utility
        name="my_site.Section"
        factory=".section.Section"
        />

    <utility
        name="my_site.Plain"
        factory=".section.Plain"
        />

</configure>

Finally, hook up the adapters module in your types product configure.zcml:

   ...

   <include package=".adapters" />

   ...

That's it. Well, you know: re-run the buildout and re-start your instance.

site_url and navigation_root_url

However, you may have gotten more than you wanted to. Specifically, in an INavigationRoot context, the portal_logo links to the Section, not to the Site. Search is within the Section, not within the whole Site. Navigation is in the Section. The News portlet shows only news items from within the Section, not from the whole Site. You see where this is going.

That's the consistency thing the PLIP mentioned above was about.

It's easy to adjust this behaviour per viewlet/portlet though, so you can set up your site exactly how you want to. Key to this is portal_url, which you'll know about if you've ever customized a template.

portal_url is now deprecated, and replaced by two other url variables:

site_url

this is the "old" portal_url that refers to the toplevel Site

navigation_root_url

this is the "new" url that makes all the viewlets and portlets respect the INavigationRoot Section containment we've been talking about

making search global again

In my site, I want the search box to search the whole site, not just the INavigationRoot Section. That's very easy to achieve:

Copy the searchbox portlet template from plone.app.layout.viewlets.searchbox.pt into your browser directory.

In your browser/configure.zcml add the following lines:

    <browser:viewlet
       name="plone.searchbox"
       manager="plone.app.layout.viewlets.interfaces.IPortalHeader"
       class="plone.app.layout.viewlets.common.SearchBoxViewlet"
       template="searchbox.pt"
       permission="zope2.View"
       />

This keeps the generic python logic but overrides the template with your own.

Finally, customize the template by doing a search-and-replace: change all

${view/navigation_root_url}

into:

${view/site_url}

E presto, search is global again.

As you can see, it's now easy to mix-and-match INavigationRoot "section logic" with sitewide facilities.

For more advanced customizations, take a look at plone.app.layout.globals to see where portal_state does it's magic. And check out plone.app.layout.navigation.root for the actual implementation.

Kudos to Rocky Burt for writing p4a.subtyper and teaching me about it.