SAValidation 0.4.1
Active Record like validation on SQLAlchemy declarative model objects
License: BSD

SAValidation
############

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Introduction
------------

SAValidation facilitates Active Record like validation on SQLAlchemy declarative model
objects.

You can install the `in-development version
<https://github.com/blazelibs/sqlalchemy-validation/archive/master.zip#egg=savalidation-dev>`_
of savalidation with ``easy_install savalidation==dev``.

The home page is currently the `GitHub repository
<https://github.com/blazelibs/sqlalchemy-validation>`_.

Usage Example
-------------

The following is a snippet from the examples.py file:

.. code-block:: python

    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)

.. code-block:: bash

    # create a virtualenv
    # activate the virtualenv

    $ pip install -e git+git://github.com/blazelibs/sqlalchemy-validation.git@master#egg=savalidation
    $ pip install nose
    $ cd src/savalidation/savalidation
    $ nosetests

Questions & 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:

* `Sqlalchemy Validations <http://code.google.com/p/sqlalchemy-validations/>`_
* `Elixir <http://elixir.ematia.de/apidocs/elixir.html>`_

Current Status
--------------

The code itself seems stable, but the API may change in the future.


Change Log
----------


0.4.1 released 2016-11-23
=========================

* fixed Python versions listed for package
* fixed a broken link in the readme to the Elixir project
* updated CircleCI setup and added AppVeyor

0.4.0 released 2016-06-10
=========================

* added support for Python 3.4+ (thanks to Jiří Bireš)
* set up continuous integration on Circle CI
* coverage reports through CodeCov

0.3.2 released 2016-04-20
=========================

* validate precision and scale of numeric column values

0.3.1 released 2016-02-23
=========================

* fix formencode compatibility, supports formencode 1.2 and 1.3

0.3.0 released 2014-09-30
=========================

* fix bug with .validates_constraints() and Text column types
* watch_session() is no longer needed, SQLAlchemy >= 0.7.6 required
* now beta quality: been used in production a long time, but not used widely

0.2.1 released 2013-05-15
=========================

* fixed issue #6 - adjustment to the version of python-dateutil required.

0.2.0 released 2012-10-24
=========================

This release contains some **BC BREAKS**.

* internal API cleaned up
* refactored to use SQLAlchemy (SA) events, we are now compatable with & require
  SA >= 0.7
* CHANGE: if using SA < 0.7.6, savalidation.watch_session() must be called with each
  instance of your session IF the savalidation module is being instantiated
  before your session is created.
* CHANGE: the validator API has changed.  If you have created custom validators
  you will need to look at the changes in validators.py.
* the Formencode state object sent to a validator's method has changed the
  "instance" attribute to be "entity."
* add before_flush() helper to decorate entity instance methods
* got rid of after_flush validation.  Instead, before_insert/before_update events
    can now be used to validate non-nullable foreign keys.
* got rid of validation support for a column's default and server_default
    values (b/c it required after_flush validation)
* formencode schemas are now only created once per class, not per instance,
    boosting performance.

0.1.5 released 2011-06-11
=========================

* fix 0.1.4 release which didn't include version file

0.1.4 released 2011-06-11
=========================

* change python-dateutil dependence to < 2.0, 2.x is for python 3

0.1.3 released 2011-05-19
=========================

* change SQLAlchemy requirement so the latest package < 0.7 is installed