==============
dolmen.content
==============
The package `dolmen.content` is a convenient way to define content
types.
.. contents::
About
=====
Content types usually have several attributes defined in a
schema and a name. In addition, they often need security to control the
creation or the modification (update, deletion, etc.). This is what
provides `dolmen.content`, with an easy-to-use set of grok directives.
Example
=======
A `dolmen.content` content is declared as a simple class. Some
directives are available to define your content: `name`, `schema` and
`factory`. To have detailed information about these directives, please
have a look at the package tests.
Defining the content
--------------------
Let's demonstrate the package's features with a simple and
non-exhaustive test::
>>> import dolmen.content
>>> from zope import schema
>>> from zope.interface import Interface
>>> class IContentSchema(Interface):
... text = schema.Text(title=u"A body text", default=u"N/A")
>>> class MyContent(dolmen.content.Content):
... """A very simple content
... """
... dolmen.content.schema(IContentSchema)
... dolmen.content.name("a simple content type")
Schema
------
The content can now be instanciated. As we can see here, the object is
effectively providing the schema, even without grokking::
>>> MyContent.text
<zope.schema.fieldproperty.FieldProperty object at ...>
>>> IContentSchema.implementedBy(MyContent)
True
>>> obj = MyContent()
>>> obj.text
u'N/A'
The content can also be instanciated providing initial values::
>>> obj = MyContent(text=u"This is a nice text !")
>>> obj.text
u'This is a nice text !'
Even though the schema has been applied and the content type
boostrapped, the content type is not yet complete::
>>> obj.__content_type__
Traceback (most recent call last):
...
AttributeError: 'MyContent' object has no attribute '__content_type__'
To get all the features of a `dolmen.content` Content, we need to
register our component : we need to grok it.
Grokking
--------
We register our component::
>>> from grokcore.component import testing
>>> testing.grok_component('mycontent', MyContent)
True
An additional information is now available::
>>> obj.__content_type__
u'a simple content type'
The grokking process also allowed an automatic registration of a very
convenient factory as an utility.
Factory
-------
When the content is grokked, a factory is registered, using the
full module and class dotted names. It allows us to query and
instanciate the content easily::
>>> from zope.component import getUtility
>>> factory = getUtility(dolmen.content.IFactory,
... name="dolmen.content.MyContent")
>>> factory
<dolmen.content.factoring.Factory object at ...>
The factory will create your content type for you, when called::
>>> obj = factory()
>>> obj
<dolmen.content.MyContent object at ...>
>>> obj.text
u'N/A'
>>> obj = factory(text=u"This is as easy as it seems.")
>>> obj
<dolmen.content.MyContent object at ...>
>>> obj.text
u'This is as easy as it seems.'
Security
--------
The created content type has a basic security declaration. We can
retrieve the value of the permission protecting the content type by
using the `require` directive::
>>> dolmen.content.require.bind().get(obj)
'zope.ManageContent'
Please note that this security declaration is _not_ used anywhere in
`dolmen.content`. It's provided as a convenient way to declare a
permission at the content type level. The factory does not check this
permission. If you need a permission checker at the factory level,
please provide your own factory : see the tests module, factory
folder, for examples.
Changelog
=========
0.7.1 (2011-02-16)
------------------
* Added util function to retrieve the schema from a component. This
deals with the martian new handling of baseclasses. `get_schema`
should return the `schema` directive default value, even if called
on a baseclass that does not define `schema`.
0.7 (2011-02-11)
----------------
This version is a major breakdown and is not backward compatible with
the previous ones:
* `BaseContent` no longer exists. It has been merged with `Content`.
* The `IBaseContent` interface is gone.
* There are no longer any schema defined by default.
* ``dolmen.content`` contents no longer provide a dublincore `title`
property and are no longer "attribute annotatable" by default.
0.6.2 (2011-02-10)
------------------
* Fixed inheritance bug: the properties of the parent classes were
overriden, if defined in the schema. This has been solved by
deferring the schema treatment in the class advisor and by using
'hasattr' instead of checking the class __dict__.
0.6.1 (2011-02-02)
------------------
* Cleaned up the ZCML declarations, to be sure it includes all the
needed dependencies.
0.6 (2010-11-06)
----------------
* Cleaned up dependencies. ``zope.formlib`` is no longer used.
* The code has been updated to work with the latest ``martian`` and
``grokcore.component``.
* The `__content_type__` property is now a unicode string. This will
convert the given name to unicode or die trying.
0.5.1 (2010-07-13)
------------------
* Added `zope` domain translation for the `Title` label of the
`IBaseContent` interface.
0.5 (2010-07-13)
----------------
* Default factory now provides a valid `IFactory`
implementation. Added tests to fix that.
* Changed the policy of the `__content_type__` attribute
computation. Tests have been added to prevent any changes and
regression.
* Added an util function to fetch the content type of an object or
class.
* The `IFactory` interface now allows empty `title` and `description`,
in accordance with the base value of the generic factory and
directives.
0.4 (2010-07-13)
----------------
* Factories now provide a name and a description, in addition to the
title. These attributes, by default, fetch the generated class
directives' values.
* Updated tests and improved the coverage.
* The factories `name` attribute no longer returns a cooked i18n
value, but the `name` directive's value of the generated
class. The form has to take care of its own title now.
0.3.1 (2010-02-22)
------------------
* Corrected a very important bug in the models instanciation. The
simple instanciation was causing an infinite loop due to imports
having the same name than the module classes. This is fixed and tests
have been added to test this simple case and avoid regression.
0.3 (2010-02-08)
----------------
* Using the new `grokcore.content` package, allowing to cut the `grok`
dependency.
* The `BaseContent` now sets a default `require` value at
`zope.ManageContent`. This permission is _NOT_ used, it's just a
convenient directive to implement your own security check.
* Dependencies have been cut down. `zope.app` packages are no longer
used. The tests module has been rewritten for a cleaner and clearer
read.
* Directive `icon` has been removed. The functionality will be
implemented in a standalone package. ATTENTION, this might break
your existing code !
* Directive `schema` now works without grokking, using a
`zope.interface` class advisor. This allows a flexible
bootstrapping, even in non-grokked code.
0.2.2 (2009-09-25)
------------------
* Using the last `dolmen.field` version with a bug fix.
0.2.1 (2009-09-20)
------------------
* Added tests and cleaned the testing module.
0.2 (2009-09-04)
----------------
* Added an OrderedContainer base class.
0.1 (2009-09-01)
----------------
* Initial release