Martijn Faassen wrote: > > Hi there, > > I'm investigating ways to make an ORM-mapped instance read-only, > dependent the value of a particular attribute (database backed or not). > If an object has a certain state, I want to prevent normal users from > making a modification. Other objects connected to the same session > should be editable however. > > I've tried to figure out various possibilities, but none of them seem > entirely satisfactory: > > * I could use AttributeExtension that checks the 'readonly' attribute > and if so, raises an exception when modification is attempted. As far as > I can see I'd need to manually define an AttributeExtension for *all* > attributes, and I'd just like to do this once per mapped class at most. > > * It may be possible to use MapperExtension and modify before_update > somehow. This is a bit late however - I'd prefer an exception to be > raised as soon as someone tries to modify an attribute. > > * I could proxy the whole instance with a security proxy, along the > lines of zope.security, which could then do the checks. I'd like to > avoid security proxies if I can get away with it however. I'd prefer it > if the objects that came back from session.query() were already > configured to do read-only checks. > > * I could try to use some form of row-level security on the database > level. MySQL, the database I'm working with, doesn't have such feature > as far as I'm aware, however. Also this'd be warning the developer a bit > late - I'd prefer if it happened directly when modifying the attribute. > > Does anyone have any clues as to what a good implementation strategy > would be?
did you try implementing __getattribute__() ? --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
