[Zope-dev] add optional "folder" argument to ZClass.createInObjectManager() ?

[Bruce Perens]

Hi,

I propose to add an optional argument to ZClass.createInObjectManager() that
specifies the ObjectManager instance in which the newly-created object will
reside.

Currently, the ObjectManager in which an object is to be created is found
through acquisition. This breaks when sub-objects are created in the
constructor of their container object. For example: I have a Purchase object
containing Item objects. In method PurchaseClass_add(), I create the Purchase
object using PurchaseClass.createInObjectManager(). That goes fine. Then I
create its contained objects using ItemClass().createInObjectManager().
Instead of going inside of the PurchaseObject, they go in the folder that
contains the PurchaseObject.

No manipulation of name spaces by <dtml-with> will change this - the
ObjectManager is found through acquisition, not the name space.

Currently, the only way out of this is to create an external method and
call _setObject() directly. You can't do it from DTML at all. I propose to
add a "folder" argument to createInObjectManager() so that the folder can be
specified directly. The modified method appears below, please compare it to
the version in ZClass.py .

I have a few questions about this:

1. Am I missing an easier or more elegant way to do this?
2. Would this circumvent security in some way?
3. Can I get this change, or something that has a similar effect, into a
   future version of Zope?

	Thanks

	Bruce

    def createInObjectManager(self, id, REQUEST, RESPONSE=None, folder=None):
        """
        Create Z instance. If called with a RESPONSE,
        the RESPONSE will be redirected to the management
        screen of the new instance's parent Folder. Otherwise,
        the instance will be returned.
        """
        i=mapply(self._zclass_, (), REQUEST)
        if not hasattr(i, 'id') or not i.id: i.id=id

        durl=None
	if folder is None:
            if hasattr(self, 'Destination'):
                d=self.Destination
                if d.im_self.__class__ is FactoryDispatcher:
                    folder=d()
        if folder is None: folder=self.aq_parent
        if not hasattr(folder,'_setObject'):
            folder=folder.aq_parent

        folder._setObject(id, i)

        if RESPONSE is not None:
            try: durl=self.DestinationURL()
            except: durl=REQUEST['URL3']
            RESPONSE.redirect(durl+'/manage_workspace')
        else:
            return folder._getOb(id)