Dieter Maurer <dieter@handshake.de> wrote:
Christian Heimes wrote at 2005-4-1 22:28 +0200:
... You want to bind some actions to the transaction system because you want to execute some code at the end of the first phase of the 2 phase commit.
I do not think that Florent wants to execute things at the end or in the first commit phase. Instead, he wants to execute something *BEFORE* this phase.
Yes, wherever it's inserted, I want to do additional processing before everything is finalized, and in some cases I want to be able to abort the transaction, and to create and change objects in the ZODB.
Hooking into the transaction machinery of ZODB is very easy. Write your own DateManager implementing the IDateManager interface and register it into the current transaction using get_transaction.register(DM).
For your use case overwrite the tpc_vote() method of the data manager to do the indexing at the boundary between the two phases.
This will not work for Florent's use case, at least not in the current ZODB (for Zope 2.7).
Reason:
The transaction freezes the set of objects it processes in the commit *BEFORE* the first commit phase.
Therefore, no "tpc_vote" is allowed to modify any persistent object. Failure to do so leads to extremely nasty persistency errors (the object is marked changed but no transaction knows about it -- no change to this object in the future will get persisted until a restart).
Ah, that was what I was afraid of, but I was assured it was not the case. I'll have to reread that transaction code... and maybe readd the low-tech post-publishing hook I was thinking of. Thanks Dieter, Florent -- Florent Guillaume, Nuxeo (Paris, France) CTO, Director of R&D +33 1 40 33 71 59 http://nuxeo.com fg@nuxeo.com