Can a template in a CMF skin be overridden by a Zope 3 browser:page?

Question

I'm trying to override a view provided by a CMF skin layer with a <browser:page ... having the same name= attribute. Is this possible in Plone, or can browser views only override other browser views?

Answer 1

(This is a bit late, but what the hell)

CMF Skin layers override browser views. That is why you have to put @@ in front of a browserview's name in an URL, i.e to disambiguate it and make sure that the browserview is called instead of the CMF skin layer template.

So in short, if you put @@ in front, the browserview will override, otherwise not.

i.e:

localhost:8080/Plone/@@myview 

overrides:

localhost:8080/Plone/myview

To overcome this, override the template in your CMF skin layer and tal:define the View variable to point to your @@myview. You can then still access the BrowserViews methods from the CMF skin layer template.

Answer 2

By default, the CMF skins mechanism looks in portal_skins before looking up a view. You can change this by customising the IPublishTraverse adapter. It's a bit evil, but this may work (tested in Plone 3 - I'm not 100% sure what the default behaviour is in Plone 4):

from zope.component import adapts, queryMultiAdapter
from zope.publisher.interfaces.browser import IBrowserRequest 

from Acquisition import aq_base
from ZPublisher.BaseRequest import DefaultPublishTraverse
from Products.CMFCore.Skinnable import SKINDATA, SkinnableObjectManager

from thread import get_ident

_MARKER = object()

class SkinnableTraverser(DefaultPublishTraverse):
    adapts(SkinnableObjectManager, IBrowserRequest)

    def publishTraverse(self, request, name):
        """Let the default traverser do its job, but if the thing that was
        returned was from a skin layer and there's a view with
        the same name, let the view win.
        """

        gotten = super(SkinnableTraverser, self).publishTraverse(request, name) 

        if not name.startswith('_') and not name.startswith('aq_'):
            sd = SKINDATA.get(get_ident())
            if sd is not None:
                ob, skinname, ignore, resolve = sd
                if resolve.get(name, None) is aq_base(gotten):
                    # This was retrieved as a skin resource
                    # Check if it could've been a view also

                    view = queryMultiAdapter((self.context, request), name=name)
                    if view is not None:
                        return view.__of__(self.context)

        return gotten

You need to register this with:

<adapter factory=".skins.SkinnableTraverser" />

Possibly in an overrides.zcml. Another option would be to use a more specific marker interface on the request, e.g. one installed via the browserlayer.xml import step.

Martin

Answer 3

I am not sure about it, but what you can do for fast is to try it with "custom" folder from plone_skins.

You can also try "Alternative" way from http://plone.org/documentation/kb/applying-a-custom-view-to-a-specific-folder