plone.app.linkintegrity

Overview

This package implement link integrity checking in Plone. It makes use of the zope3 event system in order to modify Plone itself as little as possible.

Features

This package handles deleting an item in the Plone-User-interface (i.e. deleting items in the view folder_contents via Actions / Delete).

Whenever an object that is referred to by another one via an <a> or <img> tag is going to be deleted, a confirmation form is presented to the user. The same applies to content referenced via a relation field and indexed in the zc.relation catalog, like via the related items behavior. They can then decide to indeed delete the object, breaching link integrity of the site or first edit the objects that link to the item in question.

For relations set in a textfield, the isRelated reference is used. For these references, plone.app.linkintegrity also handles modifications, if a content related via isRelated is modified. For all other related content, other mechanisms handle updates. One such handler can be found in plone.app.relationfield.

Changes in 3.0

• Linkintegrity-relations are no longer stored in reference_catalog of Products.Archetypes. Instead it used zc.relation.
• No longer intercept the request on manage_deleteObjects. This means that deleting with other methods (like manage_deleteObjects, plone.api.content.delete, ttw in the ZMI) no longer warns about linkintegrity-breaches. It now simply adds information about linkintegrity-breaches in the user-interface.
• LinkIntegrityNotificationException is not longer thrown anywhere.

Refresh the linkintegrity site status

In the case you'll need to update/refresh the linkintegrity status of the whole site, you can call the @@updateLinkIntegrityInformation view.

It can be really slow operation.

Customization

On object created, added, modified events the modifiedContent handler is called. This handler adapts an IRetriever object if found. The package comes with two general adapters for Dexterity and Archetypes. You can easily write custom adapters implementing the IRetriever interface for your contenttype. Look at the retriever module in this package for examples.

API

To check if there would be breaches when deleting one or more objects you can use the follwing code:

from plone import api
portal = api.portal.get()
view = api.content.get_view(
    'delete_confirmation_info',
    portal,
    self.request)
breaches = view.get_breaches([obj1, obj2])

get_breaches ignores breaches originating from any items that would also be deleted by deleting the items (and their chidlren if an item is a folder).

Each breach in breaches is a dictionary with a target (a dict with some info on the object to be deleted) and a list of sources. Each source is again a dict with uid, title, url and accessible (a boolean telling you if the user can access that source).

To check items for links in html-fields you can use the methods in plone.app.linkintegrity.utils:

utils.hasIncomingLinks(obj)

Test if an object is linked to by other objects.

utils.hasOutgoingLinks(obj)

Test if an object links to other objects.

utils.getIncomingLinks(obj, from_attribute)

Return a generator of incoming relations. from_attribute is optional and defaults to plone.app.linkintegrity.handlers.referencedRelationship. Is set to None, all references pointing to the object are searched.

utils.getOutgoingLinks(obj, from_attribute)

Return a generator of outgoing relations. from_attribute is optional and defaults to plone.app.linkintegrity.handlers.referencedRelationship. Is set to None, all references pointing from the object are searched.

utils.linkintegrity_enabled()

Test if linkintegrity-feature is enables for users.