content.py

from zope import schema
from plone.directives import form

from .contenttree import SubsectionUUIDSourceBinder


class IExamples(form.Schema):

    profileref = schema.Choice(title=u"Profile",
                                description=u"Select the profile",
                                source=SubsectionUUIDSourceBinder(
                                   portal_type='UserProfile',
                                   whitelist_types=('UserProfile', ),
                                )
                            )

    org = schema.List(title=u"Organisation",
                                description=u"Select organisation", 
                                value_type=schema.Choice(
                                    source=SubsectionUUIDSourceBinder(
                                        portal_type='Organisation',
                                        subsection="/orgs"
                                    )
                                )
                            )

contenttree.py

from Products.CMFCore.utils import getToolByName
from plone.formwidget.contenttree import UUIDSourceBinder
from plone.formwidget.contenttree.widget import ContentTreeBase
from zope.schema.vocabulary import SimpleTerm

ContentTreeBase.show_all_content_types = False


class SubsectionUUIDSourceBinder(UUIDSourceBinder):
    
    def __init__(self, *args, **kwargs):
        self.subsection = kwargs.get("subsection", "")
        self.portal_types =kwargs.get("whitelist_types")
        super(SubsectionUUIDSourceBinder, self).__init__(*args, **kwargs)
    
    def __call__(self, context):
        UUIDSource = super(SubsectionUUIDSourceBinder, self).__call__(context)
        
        try:
            portal = getToolByName(context, "portal_url").getPortalObject()
        except AttributeError:
            # We aren't rooted in a Plone site, so we can't specialise our path
            # This happens when instantiating a vocabulary in the form internals
            # and is never used to show to users, so we can skip display-only logic
            return UUIDSource
        
        path = '/'.join(portal.getPhysicalPath()) + self.subsection
        UUIDSource.navigation_tree_query = {'path': {'query':path}}
        if self.portal_types is not None:
            UUIDSource.navigation_tree_query['portal_type'] = self.portal_types
        return UUIDSource