Jürgen Kartnaller wrote:
I've also tried to create the subfolders in a subscriber on
IObjectCreatedEvent, but this is equivalent to the previous attempt :
What I've understood is that the transaction that manages the folder
is not finished, and the IntId utility is not yet able to get a
connection on the ZODB. So I've tried to create an adapter to
IConnection for my subfolder, so that it can use the same connection
as the folder. But I couldn't. (however it might be possible?).
'NotYet' happens if the object in not connected to a database. The
connection to the database exists as soon as your object is added to the
object tree in zope. It is not related to a finished transaction.
That's not entirely true. The problem's origin is in
zope.app.keyreference. In order to give newly created objects an integer
id, the objects need to be adaptable to IKeyReference. The IKeyReference
adapter for persistnet objects wants access to the object's database
Now, if the object has already been persisted before in an *already
committed transaction*, it will have a _p_jar attribute. So, if the
transaction were in fact finished, the IKeyReference adapter could take
the object's _p_jar attribute right away.
But since the transaction isn't over yet and the object was just
created, it has no _p_jar attribute, so the IKeyReference adapter does a
bit of guessing. It walks up the __parent__ hierarchy and figures that
if the newly created object is part of a container somewhere, it will be
persisted in the same database. So it takes the container's _p_jar. This
is the reason why IKeyReference wants an intact __parent__ hierarchy for
newly created objects.
The simple solution is to create the subfolders AFTER the folder has
been eventually ADDED with the add method. So in the AddForm, I've
replaced the create() method with a createAndAdd method. In this
method, I've just created my folder, called add to add it, then only I
could create the subfolders and add them to the folder.
You can also do this using an event handler for ObjectAddedEvent on your
Folder. In this case you do not need to touch any code in your form.
Yes, this is what I'd recommend. A handler for an ObjectAddedEvent will
always see the object already as part of the object hierarchy (which is,
after all, what ObjectAddedEvent is about).
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