I discovered the sqlalchemy.orm.validates decorator, which executes when I want it to (on attribute assignment) so I got out my hacksaw and tried to make it work in one fell swoop... implementing automatic UTC assignment for all UTCEnforcedDateTime columns.
I'm not comfortable with it yet... but a mostly-inclusive demo code snippet is here: http://pastebin.com/wB4BLzax Where I intend to do that last bit of hackery (utcConversionList and __sa_validators__ work) by introspecting through a large number of classes (all having the TableDefMixin) and looking for UTCEnforcedDateTime Column definitions that should be added to the utcConversionList for the class. Method tbd there, but not important. Although it is doing what I want it to do ("hands off" UTC assignment where expected), I'm really not comfortable with it. It seems *highly* sketchy, quite indirect, and it seems like there must be a better way to simply set a default validator for a custom Column type. Is there? It would be much tidier to put the validator into the UTCEnforcedDateTime class. If not... can I rely on the direct setting of __sa_validators__ working in the future? Using the orm.validates decorator in each and every class is obviously the better choice for future compatibility, but if I want one-shot assignment as I do above, I can't use the orm.validates because it is too late to set __sa_validators__ directly as orm.validates does, and I needed to be brutal and go to the __dict__ directly. I expect there is a simple answer and all my hacking/exploration related to my posts above was pointless... except it has been highly educational to root through the SQLAlchemy implementation here. Tidbits learned include now understanding descriptors (never had cause to before), and learning about attrgetter and attrsetter. Stepping into the attribute assignment (InstrumentedAttribute.__set__) was highly confusing until reading up on those bits!! instance_state() and instance_dict() instantly returning was somewhat mysterious for a while! Thanks, Russ -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
