On Fri, Mar 10, 2017 at 4:12 PM, Alessandro Molina <alessandro.mol...@gmail.com> wrote: > > > On Fri, Mar 10, 2017 at 3:40 PM, mike bayer <mike...@zzzcomputing.com> > wrote: >> >> If this is truly, "unexpected error but we need to do things", perhaps you >> can use before_flush() to memoize the details you need for a restore inside >> of session.info. >> >> An event hook can be added but it would need to be carefully considered >> what the specific use case for this hook is. For example I'm not sure >> "before_rollback()" is really what this should be, it likely should be "on >> flush exception" similar to how engine does it. > > > My specific need is related to https://github.com/amol-/depot/issues/36 > > DEPOT allows loading files associated to database data. > In case of a rollback DEPOT deletes the files that got uploaded. > > That works in case of `.flush()` + `.rollback()` because it gathers the > history of the entity and the changed files in `before_flush`, but if a > rollback is issued without a flush it currently lacks an event from which it > can get the state of the objects and their history before the rollback. >
Could you collect the necessary data using the before_attach or after_attach events, rather than before_flush? Simon -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at https://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
