On Fri, Jul 30, 2010 at 07:13:47AM +0200, Tom Coetser wrote:
> I would like to use a validator with a PickleCol like this:
>
> ---------------- cut ---------------------------------------------------------
> from formencode import validators
>
> class PTValidator(validators.FancyValidator):
>
> def validate_python(self, value, state):
> # Do validation on value here before storing it in the db
> print "value:", value
>
>
> class PT(SQLObject):
> pickled = PickleCol(validator=PTValidator)
>
> ---------------- cut ---------------------------------------------------------
>
> The problem is that (it seems) value is already pickled by the time it is
> passed to the PTValidator.validate_pyton() method.
>
> Can anyone give me some example/advise on how to use validators on a pickle
> column and being able to **validate** the value being stored only, but still
> leaving SQLObject to deal with the pickling/unpickling?
This is the way:
from formencode import compound
class PT(SQLObject):
pickled = PickleCol()
socol = PT.sqlmeta.columns['pickled']
validator = socol.validator
socol.validator = compound.All.join(PTValidator(), validator)
PTValidator.from_python will be called first, before String/BLOB/Pickle
conversion; and PTValidator.to_python will be called last, after
unPickle/BLOB/String conversion.
And you raised an interesting question. Some user-supplied validators
need to be run in "normal" (current) order - from_python called last, after
all conversions, and to_python first. For example, I use a special
validator in a CurrencyCol, and I certainly want its from_python get data
after all decimal conversions.
But some columns require a different order. Perhaps I need to add an
additional validator ("before_validator"? "validator2"?) so user-supplied
validator will be inserted into the other end of the list of validators.
Oleg.
--
Oleg Broytman http://phd.pp.ru/ [email protected]
Programmers don't die, they just GOSUB without RETURN.
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