Introduction
SAValidation facilitates Active Record like validation on SQLAlchemy declarative model objects.
You can install the in-development version
of savalidation with easy_install savalidation==dev.
The home page is currently the bitbucket repository.
Usage Example
The following is a snippet from the examples.py file:
from datetime import datetime
import formencode
import sqlalchemy as sa
import sqlalchemy.ext.declarative as sadec
import sqlalchemy.sql as sasql
import sqlalchemy.orm as saorm
from savalidation import ValidationMixin, watch_session
import savalidation.validators as val
engine = sa.create_engine('sqlite://')
#engine.echo = True
meta = sa.MetaData()
Base = sadec.declarative_base(metadata=meta)
Session = saorm.scoped_session(
saorm.sessionmaker(
bind=engine,
autoflush=False
)
)
sess = Session
class Family(Base, ValidationMixin):
__tablename__ = 'families'
# SA COLUMNS
id = sa.Column(sa.Integer, primary_key=True)
createdts = sa.Column(sa.DateTime, nullable=False, default=datetime.now, server_default=sasql.text('CURRENT_TIMESTAMP'))
updatedts = sa.Column(sa.DateTime, onupdate=datetime.now)
name = sa.Column(sa.Unicode(75), nullable=False, unique=True)
reg_num = sa.Column(sa.Integer, nullable=False, unique=True)
status = sa.Column(sa.Unicode(15), nullable=False, default=u'active', server_default=u'active')
# VALIDATION
STATUS_CHOICES = (
('active', 'Active'),
('inactive', 'Inactive'),
('moved', 'Moved'),
)
# will validate nullability and string types
val.validates_constraints()
val.validates_one_of('status', [k for k, v in STATUS_CHOICES])
#OTHER
def __str__(self):
return '<Family id=%s, name=%s>' % (self.id, self.name)
class Person(Base, ValidationMixin):
__tablename__ = 'people'
id = sa.Column(sa.Integer, primary_key=True)
createdts = sa.Column(sa.DateTime, nullable=False, server_default=sasql.text('CURRENT_TIMESTAMP'))
updatedts = sa.Column(sa.DateTime, onupdate=datetime.now)
name_first = sa.Column(sa.Unicode(75), nullable=False)
name_last = sa.Column(sa.Unicode(75), nullable=False)
family_role = sa.Column(sa.Unicode(20), nullable=False)
nullable_but_required = sa.Column(sa.Unicode(5))
ROLE_CHOICES = (
('father', 'Father'),
('mother', 'Mother'),
('child', 'Child'),
)
val.validates_constraints(exclude='createdts')
val.validates_presence_of('nullable_but_required')
val.validates_choices('family_role', ROLE_CHOICES)
class ReverseConverter(formencode.api.FancyValidator):
def _to_python(self, value, state):
if not isinstance(value, basestring):
raise formencode.Invalid('Must be a string type', value, state)
# this reverse a string or list...yah, I know, it looks funny
return value[::-1]
validates_reverse = val.formencode_factory(ReverseConverter)
converts_reverse = val.formencode_factory(ReverseConverter, sv_convert=True)
class ConversionTester(Base, ValidationMixin):
__tablename__ = 'conversion_testers'
id = sa.Column(sa.Integer, primary_key=True)
val1 = sa.Column(sa.String(25))
val2 = sa.Column(sa.String(25))
val3 = sa.Column(sa.String(25))
val4 = sa.Column(sa.String(25))
validates_reverse('val1')
validates_reverse('val2', sv_convert=True)
converts_reverse('val3')
converts_reverse('val4', sv_convert=False)See more examples in the tests directory of the distribution.
Installing & Testing Source
(this is one way, there are others)
# create a virtualenv
# activate the virtualenv
$ pip install -e "hg+http://bitbucket.org/blazlibs/sqlalchemy-validation#egg=savlidation-dev"
$ pip install nose
$ cd src/savalidation/savalidation
$ nosetestsQuestions & Comments
Please visit: http://groups.google.com/group/blazelibs
Known Issues
Final values that get set on an ORM mapped object attributes through relationships, the default or onupdate column parameters, and possibly others are not availble at the time validation is done.
In some cases, this can be caught after the flush (before commit) when those values become available on the ORM object.
Unfortunately, that is of limited value in the case where the the value that slipped through violates a DB constraint. In that case, a true DB exception will be raised.
Dependencies
- SQLAlchemy > 0.7.6
- FormEncode
- python-dateutil (for date/time converters)
- Nose (if you want to run the tests)
Credits
This project borrows code and ideas from:
Current Status
The code itself seems stable, but the API may change in the future.
