Browser view for folders, and for other types

Plone Support Add-on Development
1

In my AJAX navigation add-on (PyPI package and Github present but currently not up-to-date) I have "@@ajax-nav" browser views which are intended to be different for

  • folders
  • all other content types.

(currently almost only Archetypes-based data).
However, with this ZCML:

<browser:page
   name="ajax-nav"
   for="Products.ATContentTypes.interfaces.IATContentType"
   class=".AjaxnavBaseBrowserView"
   permission="zope2.View"
   />

<browser:page
   name="ajax-nav"
   for="Products.ATContentTypes.interfaces.IATFolder"
   class=".folder.AjaxnavBrowserView"
   permission="zope2.View"
   />

... I get a zope.configuration.xmlconfig.ZopeXMLConfigurationError:

ZopeXMLConfigurationError: File "/opt/zope/common/eggs/Products.CMFPlone-4.3.3-py2.7.egg/Products/CMFPlone/configure.zcml", line 98.4-102.10
ZopeXMLConfigurationError: File "/opt/zope/instances/unitracc-devel/src/visaplan.plone.ajaxnavigation/src/visaplan/plone/ajaxnavigation/configure.zcml", line 30.2-30.30
ZopeXMLConfigurationError: File "/opt/zope/instances/unitracc-devel/src/visaplan.plone.ajaxnavigation/src/visaplan/plone/ajaxnavigation/views/configure.zcml", line 17.2-22.7
TypeError: multiple bases have instance lay-out conflict

Now what should I do, i.e.: What would be "best practice"?

  • Detect folders at runtime?
  • Is there a common non-folder interface to use?
  • Use a special layer for folder objects?
  • Any other options?
2

Maybe if helps if you use the interfaces from Products.CMFCore, as listed under common interfaces in the Plone documentation at: https://docs.plone.org/develop/addons/components/interfaces.html

Products.CMFCore.interfaces.IContentish

All content items on the site. In the site root, this interface excludes Zope objects like acl_users (the user folder) and portal_skins which might otherwise appear in the item listing when you iterate through the root content.

Products.CMFCore.interfaces.IFolderish

All folders in the site.

Here a folder also has both IContentish and IFolderish, but the error you get hints at some low level clash in the class inheritance tree when you use the Archetypes Interfaces.

3

Thank you; indeed I was wondering which set of interfaces to use.