Extend Plone-Controlpanel Form - plone

Question

Is it possible to extend the Controlpanel-View with each addon?
For Example
ca.db.core -> Makes basic fieldset/tab for DB Connection Settings
ca.db.person -> If installed, Adds to the "core" settings a new fieldset/tab for Person specific fields/settings
ca.db.schema -> If installed, also adds an new fieldset/tab for schema.org Fields

Answer 1

Yes it's possible, I once discussed this problem with a guy, who wrote the bda.plone.shop addon.
They faced the same problem, and solved it by using a ContextProxy object, which puts the different schema definitions together in one proxy object.
Using a proxy is IMHO a hack, but I don't know a better solution.
The proxy, tries to get/set a attribute from a list of schemas.
Be aware, you need to handle conflicting names, means if you have the same field name in more than one schema.
class ContextProxy(object):
def __init__(self, interfaces):
self.__interfaces = interfaces
alsoProvides(self, *interfaces)
def __setattr__(self, name, value):
if name.startswith('__') or name.startswith('_ContextProxy__'):
return object.__setattr__(self, name, value)
registry = getUtility(IRegistry)
for interface in self.__interfaces:
proxy = registry.forInterface(interface)
try:
getattr(proxy, name)
except AttributeError:
pass
else:
return setattr(proxy, name, value)
raise AttributeError(name)
def __getattr__(self, name):
if name.startswith('__') or name.startswith('_ContextProxy__'):
return object.__getattr__(self, name)
registry = getUtility(IRegistry)
for interface in self.__interfaces:
proxy = registry.forInterface(interface)
try:
return getattr(proxy, name)
except AttributeError:
pass
raise AttributeError(name)
Now you need to use the proxy in your ControlPanel form.
I assume you're using the RegistryEditForm from plone.registry:
class SettingsEditForm(controlpanel.RegistryEditForm):
schema = ISettings
label = _(u"Settings")
description = _(u"")
# IMPORTANT Note 1 - This is where you hook in your proxy
def getContent(self):
interfaces = [self.schema] # Base schema from ca.db.core
interfaces.extend(self.additionalSchemata) # List of additional schemas
return ContextProxy(interfaces)
# IMPORTANT Note 2 - You may get the additional schemas dynamically to extend the Settings Form. For example by name (startswith...)
# In this case they have a separate interface, which marks the relevant interfaces.
#property
def additionalSchemata(self):
registry = getUtility(IRegistry)
interface_names = set(record.interfaceName for record
in registry.records.values())
for name in interface_names:
if not name:
continue
interface = None
try:
interface = resolve(name)
except ImportError:
# In case of leftover registry entries of uninstalled Products
continue
if ISettingsProvider.providedBy(interface):
yield interface
...
You can find the full code here