[Zope] ExtFile/ExtImage in Zope2 2.13 and Transaction Manager
jcea at jcea.es
Sat Nov 16 03:49:16 CET 2013
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I did some tests a year ago about upgrading to 2.13.19. I use
ExtFile/ExtImage extensively and I had to patch it a bit.
I hit the problem that ExtFile tries to import "from Shared.DC.ZRDB.TM
import TM". Messing around a bit, I solved the issue installing
"Products.ZSQLMethods" product (via
this is not working with 2.13.21. I am getting tons of upgrade
warnings about zope packages.
The documentation for "Products/ExtFile/TM.py" says this:
TMRegistry and ProxyTM
Persistent objects (ExtFiles) need to participate in ZODB transactions.
ExtFiles perform all operations using temporary files which are saved on
commit or deleted on abort.
- - TransactionManagers (TM) must not be persistent themselves, i.e. must
not have a _p_jar attribute.
- - We have to make sure the ExtFile's _abort is called *before* the ZODB
destroys the attributes of the persistent object.
- - ProxyTM is a subclass of TM.TM that keeps a (hard) reference to the
(wrapped) persistent object it manages. Calls to _begin, _finish, and
_abort are forwarded to the target object.
- - TMRegistry is a module-level container for ProxyTMs. It creates and
holds ProxyTMs keyed by (target_id, thread_id).
- - ExtFiles implement _finish and _abort and register with the machinery
by calling TM.register(self).
- - On commit (or abort) the ProxyTM notifies its target object and removes
itself from the registry.
- - We manipulate the transaction's _resources attribute directly. This is
to guarantee the ProxyTM is processed before other resources. There may
be a way to achieve this using official APIs only, but I can't seem to
How can I solve this?. Is there any product similar to
ExtFile/ExtImage? I can program Python if somebody guides me around
the zope2 internal details...
Jesús Cea Avión _/_/ _/_/_/ _/_/_/
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