Dynamic views

Description

How to programmatically change the active view of a Plone content item

Introduction

Dynamic views are views which the content editor can choose for his or her content from the Display… drop-down menu in the green edit frame.

By default, Plone comes with dynamic views for:

• Folder listing

• Summary

• Photo album

• etc.

The default view can be also a content item picked from the folder.

Available content item types can be managed from the: Site Setup Control Panel -> Content Settings (site.com/@@content-controlpanel) -> Select your new type from the drop down menu -> Click the “Can be used as default page” checkbox.

Permission for changing the view template of an item

A user needs the Modify view template permission to use the dynamic view dropdown. If you want to restrict this ability, grant or revoke this permission as appropriate.

This can be useful for some content types like Dexterity ones, where dynamic views are enabled by default, and the easiest way to disable them is using this permission.

Default dynamic views

Plone supports a few dynamic views for folders out of the box:

• Summary view (folder_summary_view)

• Tabular view (folder_tabular_view)

• Album view (atct_album_view)

• Listing (folder_listing)

• Full view (folder_full_view)

These are defined in portal_types information for the Folder content type and mapped to the Display menu all over in ZCML using browser:menuItem as described below.

Newly created folders have this dynamic view applied:

• Products.CMFPlone/skins/plone_content/folder_summary_view.pt (a non-view based old style Zope 2 page template)

More info

• Overriding views

Creating a dynamic view

Here are instructions how to create your own dynamic view.

There is also an example product Listless view, which provides “no content listing” view for Folder content types.

Registering a dynamic view menu item

In order to be able to register dynamic views, your content type must support them.

To do this, the content type should subclass Products.CMFDynamicViewFTI.browserdefault.BrowserDefaultMixin.

Then, you need to register a dynamic view menu item with the corresponding view in your configure.zcml:

<browser:menuItem
        for="Products.ATContentTypes.interface.IATFolder"
        menu="plone_displayviews"
        title="Product listing"
        action="@@product_listing"
        description="List folder contents as product summary view"
        />

Note

Products.ATContentTypes uses a non-standard name for the interfaces package. There, it is interface, while all other packages use interfaces.

The view must be listed in portal_types for the content type. In this case, we should enable it for Archetypes folders using the following GenericSetup XML: profiles/default/types/Folder.xml.

Note that you don’t need to copy the whole Folder.xml / Topic.xml from Products/CMFPlone/profiles/default/types. Including the changed view_methods in the XML code is enough.

You can also change this through portal_types in the Management Interface.

Note

view_methods must not have the @@view signature in their method name.

<?xml version="1.0"?>
<object name="Folder"
    xmlns:i18n="http://xml.zope.org/namespaces/i18n"
    i18n:domain="plone"
    meta_type="Factory-based Type Information with dynamic views" >
    <property name="view_methods" purge="False">
        <!-- We retrofit these new views for Folders in portal_types info -->
        <element value="product_listing"/>
    </property>
</object>

Also, if you want Collections to have this listing, you need to add the following profiles/default/types/Topic.xml.

<?xml version="1.0"?>
<object name="Topic"
    xmlns:i18n="http://xml.zope.org/namespaces/i18n"
    i18n:domain="plone"
    meta_type="Factory-based Type Information with dynamic views" >
    <property name="view_methods">
        <element value="folder_listing"/>
        <element value="folder_summary_view"/>
        <element value="folder_tabular_view"/>
        <element value="atct_album_view"/>
        <element value="atct_topic_view"/>

        <!-- We retrofit these new views for Folders in portal_types info -->
        <element value="product_listing"/>

    </property>
</object>

Working around broken default view

If you manage to:

• Create a new view

• set it to the default as a folder

• and this view has a bug

… you cannot access the folder anymore, because you are taken to the broken view stack trace instead instead of rendering the green edit menubar.

The fix is to reset the view by browsing to the select_default_view directly. Access your folder like this:

http://servername/plonesite/folder/select_default_view

Checking that your view is available

Products.CMFDynamicViewFTI.browserdefault.BrowserDefaultMixin.getAvailableLayouts() returns the list of known layouts in the following format:

[('folder_summary_view', 'Summary view'),
('folder_tabular_view', 'Tabular view'),
('atct_album_view', 'Thumbnail view'),
('folder_listing', 'Standard view'),
('product_listing', u'Product listing')]

To see if your view is available, check it against the ids from that result:

layout_ids = [id for id, title in self.portal.folder.getAvailableLayouts() ]
self.assertTrue("product_list" in layout_ids)

Getting active layout

>>> self.portal.folder.getLayout()
'atct_album_view'

Changing default view programmatically

self.portal.folder.setLayout("product_listing")

Default page

The default page is a content item chosen to be displayed when the visitor arrives at a URL without any subpages or views selected.

This is useful if you are doing the folder listing manually and you want to replace the default view.

The default_page helper view can be used to manipulate default pages.

Getting the default page:

# Filter out default content
container = self.getListingContainer()
default_page_helper = getMultiAdapter(
        (container, self.request), name='default_page')

# Return content object which is the default page or None if not set
default_page = default_page_helper.getDefaultPage(container)

Another example how to use this:

from Products.CMFCore.interfaces import IFolderish

def hasTabs(self):
    """Determine whether the page itself, or default page, in the case
    of folders, has setting showTabs set true.

    Show tab setting defined in dynamicpage.py.
    """

    page = self.context

    try:
        if IFolderish.providedBy(self.context):
            folder = self.context
            default_page_helper = getMultiAdapter(
                    (folder, self.request), name='default_page')
            page_name = default_page_helper.getDefaultPage(folder)
            page = folder[page_name]
    except:
        pass

    tabs = getattr(page, "showTabs", False)

    return tabs

Todo

Bare except?

Setting the default page can be done by calling the setDefaultPage on the folder, passing id of the default page:

folder.setDefaultPage("my_content_id")

More information can be found in

• https://github.com/plone/plone.app.layout/blob/master/plone/app/layout/globals/context.py

• https://github.com/plone/plone.app.layout/blob/master/plone/app/layout/navigation/defaultpage.py

Disabling dynamic views

Add to your content type class:

def canSetDefaultPage(self):
    """
    Override BrowserDefaultMixin because default page stuff doesn't make
    sense for topics.
    """
    return False

Setting a view using marker interfaces

If you need to have a view for few individual content items only, it is best to do this using marker interfaces.

Create a marker interface in python:

from zope.interface import Interface

class IMyMarkerInterface(Interface):
    """Used to create a specific view for a generic content type"""

Register the marker interface with ZCML, see marker interfaces:

<interface interface="my.package.interfaces.IMyMarkerInterface" />

Register the view against a marker interface:

<browser:page
  class="my.package.browser.views.MySpecificView"
  for="my.package.interfaces.IMyMarkerInterface"
  layer="my.package.interfaces.IBrowserLayer"
  name="my-custom-view"
  permission="zope2.View"
  template="view.pt"
/>

• Assign this marker interface to a content item using the Management Interface, via the Interfaces tab or with Python code:

from my.package.interfaces import IMyMarkerInterface
from plone import api
from Products.Five.utilities.interfaces import IMarkerInterfaces

portal = api.portal.get()
folder = portal['my-folder']
adapter = IMarkerInterfaces(folder)
adapter.update(add=(IMyMarkerInterface, ))

• If the view should be the default view for that given object, add a layout property with value my-custom-view. To do the same with python, see Changing default view programmatically.

Migration script from default view to another

Below is a script snippet which allows you to change the default view for all folders to another type. You can execute the script through the Management Interface as a Python script.

Script code:

from StringIO import StringIO

orignal = 'fancy_zoom_view'
target = 'atct_album_view'
for brain in context.portal_catalog(portal_type="Folder"):
    obj = brain.getObject()
    if getattr(obj, "layout", None) == orignal:
        print "Updated:" + obj.absolute_url()
        obj.setLayout(target)
return printed

This will allow you to migrate from collective.fancyzoom to Plone 4’s default album view or Products.PipBox.

Method aliases

Method aliases allow you to redirect basic actions (view, edit) to content type specific views. Aliases are configured in portal_types.

Other resources

• https://plone.org/documentation/how-to/how-to-create-and-set-a-custom-homepage-template-using-generic-setup

• Products.CMFDynamicViewFTI on GitHub