dolmen.field 0.3

Generic Formlib fields

The dolmen.field package provides additional generic fields to extend zope.schema.

Configuration fields

The configuration fields are used for description and constraints, to impose a consistent schema and data model.

GlobalClass

GlobalClass is a field requiring a valid Interface class. It can be used for factories and other components that need to store an interface with the possibility to check and verify the consistency of the given value:

>>> from zope.interface import Interface
>>> from dolmen.field import GlobalClass, IClassField

>>> class IDummy(Interface):
...     def shall_fail():
...         pass

>>> class Dummy(object):
...     pass

Of course, it must be a valid interface:

>>> field = GlobalClass(
...             title=u'a class field',
...             schema=object
...             )
Traceback (most recent call last):
...
WrongType: <type 'object'> is not a valid Interface

The interface will be used to validate the class:

>>> field = GlobalClass(
...             title=u'a class field',
...             schema=IDummy
...             )

>>> field.schema
<InterfaceClass dolmen.field.tests.IDummy>
>>> IClassField.providedBy(field)
True

We make sure the interface attribute is not touched:

>>> print field.interface
None

In a first time, we make sure the class implements the needed interface:

>>> field._validate(Dummy)
Traceback (most recent call last):
...
ConstraintNotSatisfied: <class 'dolmen.field.tests.Dummy'> does not implement <InterfaceClass dolmen.field.tests.IDummy>

>>> from zope.interface import classImplements
>>> classImplements(Dummy, IDummy)
>>> IDummy.implementedBy(Dummy)
True

Then the interface acts as a strict validator:

>>> field._validate(Dummy)
Traceback (most recent call last):
...
BrokenImplementation: An object has failed to implement interface <InterfaceClass dolmen.field.tests.IDummy>
<BLANKLINE>
The shall_fail attribute was not provided.
<BLANKLINE>

>>> Dummy.shall_fail = lambda x: u'not'
>>> field._validate(Dummy) is None
True

Changelog

0.3 (2009-10-25)

• Refactored the field to use the ‘schema’ attribute instead of ‘interface’. The attribute name ‘interface’ was conflicting with other fields manipulating packages.

• Now using a README.txt instead of inline doctests, for more readability.

0.2 (2009-06-09)

• Initial Pypi release

0.1 (2009-05-03)

• Internal release