dolmen.forms.crud 1.0

CRUD forms and actions for `dolmen.content`

dolmen.forms.crud is a module which helps developers create their C.R.U.D forms using Grok, zeam.form and dolmen.content. It provides a collection of base classes to add, edit, and access content. It provides adapters to customize the fields of a form.

Adding view

dolmen.forms.crud provides an abstraction for the ‘adding’ action. It allows pluggability at the container level and handles naming and persistence. More explicitly, it’s a named adapter that will query the add form, check the constraints, choose a name (using a INameChooser) and finally, if everything went smoothly, add it on the context.

A base adding view is registered out-of-the-box as a named traversable adapter called ‘add’. It uses the following pattern: ++add++factory_name. factory_name must be the name of a dolmen.content.IFactory component.

Let’s first create a container in which we’ll test the adding view:

>>> import dolmen.content
>>> from dolmen.forms.crud.tests import Sietch

>>> sietch = Sietch()
>>> dolmen.content.IContent.providedBy(sietch)
True

>>> from zope.site.hooks import getSite
>>> root = getSite()
>>> root['sietch'] = sietch

With the container created, the adding view should be available and operational. Let’s have a quick overview:

>>> from zope.component import getMultiAdapter
>>> from zope.publisher.browser import TestRequest
>>> request = TestRequest()
>>> addingview = getMultiAdapter((sietch, request), name='add')
>>> addingview
<dolmen.forms.crud.addview.Adder object at ...>

The adding view component explicitly checks the security requirement on the factory. To test that behavior, we set up two accounts. ‘zope.manager’ has all the permissions granted while ‘zope.manfred’ only has the ‘zope.View’ credentials. Our factory explicitly requires a ‘zope.ManageContent’ permission to be called. Let’s try to access it with Manfred:

>>> import zope.security.management as security
>>> from zope.security.testing import Principal, Participation

>>> manager = Principal('zope.manager', 'Manager')
>>> manfred = Principal('zope.manfred', 'Manfred')

>>> security.newInteraction(Participation(manfred))
>>> addingview.traverse('fremen', [])
Traceback (most recent call last):
...
Unauthorized: <class 'dolmen.forms.crud.tests.Fremen'> requires the 'zope.ManageContent' permission.

>>> security.endInteraction()

Manfred is not authorized, however Manager should successfully be able to access the addingview:

>>> security.newInteraction(Participation(manager))
>>> addingview.traverse('fremen', [])
Traceback (most recent call last):
...
NotFound: Object: <dolmen.forms.crud.tests.Sietch object at ...>, name: 'fremen'

The adding view is available for our item. Though, as we have no add form registered, a NotFound error will be raised if we try to access our current factory.

Let’s create and register a very basic generic crud add form:

>>> import dolmen.forms.crud as crud
>>> class AddForm(crud.Add):
...     '''Generic add form.
...     '''

>>> import grokcore.component
>>> grokcore.component.testing.grok_component('addform', AddForm)
True

>>> addform = addingview.traverse('fremen', [])
>>> addform
<dolmen.forms.crud.tests.AddForm object at ...>

Our AddForm is returned as we traverse toward the factory ‘fremen’.

Perfect. Our adding view is ready to be used. Before testing the AddForm itself, let’s have a try at the add method:

>>> from dolmen.forms.crud.tests import Fremen

>>> naib = Fremen()
>>> added_item = addingview.add(naib)
>>> added_item
<dolmen.forms.crud.tests.Fremen object at ...>

The created content is correctly located and persisted:

>>> added_item.__name__
u'Fremen'
>>> added_item.__parent__ is sietch
True

As a matter of fact, a IAdding component should always be locatable. Conveniently, you can access the location information:

>>> addingview.__parent__
<dolmen.forms.crud.tests.Sietch object at ...>
>>> addingview.__name__
u''

The add method checks if the constraints are respected. If the container has defined restrictions or if some interface contract is violated, we get an error:

>>> from dolmen.forms.crud.tests import Harkonnen

>>> rabban = Harkonnen()
>>> addingview.add(rabban)
Traceback (most recent call last):
...
InvalidItemType: (<...Sietch object at ...>, <...Harkonnen object at ...>, (<InterfaceClass dolmen.forms.crud.tests.IDesertWarrior>,))

The add method of the adding view can be called from the AddForm to delegate the adding operation. The generic adding view already handles the common operations such as naming and persistence.

Generic forms

dolmen.forms.crud provides a set of ready-to-use base classes that will auto-generate forms based on dolmen.content schemas.

dolmen.forms.crud forms are layout aware (see megrok.layout for more info). Therefore, we need to register a basic layout in order to render our forms:

>>> from grokcore.layout import Layout
>>> from zope.interface import Interface

>>> class GenericLayout(Layout):
...     grokcore.component.context(Interface)
...
...     def render(self):
...         return self.view.content()

>>> grokcore.component.testing.grok_component('layout', GenericLayout)
True

The context of the tests is our previously created content:

>>> naib
<dolmen.forms.crud.tests.Fremen object at ...>
>>> naib.__parent__
<dolmen.forms.crud.tests.Sietch object at ...>

Create

The add form implementation is tightly tied to the adding view. As the add form behavior has been mostly covered above, we’ll only test the presence of the fields and the label on the form itself:

>>> addform = addingview.traverse('fremen', [])
>>> addform
<dolmen.forms.crud.tests.AddForm object at ...>

>>> print addform.label
Add: Fremen Warrior

>>> addform.fields.keys()
['title', 'water']

>>> addform.updateForm()
>>> for action in addform.actions: print action
<AddAction Add>
<CancelAction Cancel>

>>> security.endInteraction()

Update

An edit form can be registered simply by sublassing the Edit base class:

>>> class EditForm(crud.Edit):
...     '''Generic edit form.
...     '''

>>> grokcore.component.testing.grok_component('editform', EditForm)
True

By default, the registered name of an Edit form is ‘edit’:

>>> grokcore.component.name.bind().get(EditForm)
'edit'

This form registered, we can check if all the fields are ready to be edited:

>>> post = TestRequest(form={
...     'form.field.water': '25',
...     'form.field.title': u'Stilgar',
...     'form.action.update': u'Update'},
...     REQUEST_METHOD='POST',
...     )

>>> security.newInteraction(post)

>>> editform = getMultiAdapter((naib, post), name='edit')
>>> editform
<dolmen.forms.crud.tests.EditForm object at ...>

>>> editform.updateForm()
>>> for action in editform.actions: print action
<UpdateAction Update>
<CancelAction Cancel>

>>> editform.fields.keys()
['title', 'water']

The values should now be set:

>>> naib.title
u'Stilgar'
>>> naib.water
25

>>> security.endInteraction()

Read

A special kind of form allows you display your content:

>>> class DefaultView(crud.Display):
...     '''Generic display form.
...     '''

>>> grokcore.component.testing.grok_component('display', DefaultView)
True

>>> security.newInteraction(TestRequest())

>>> view = getMultiAdapter((naib, request), name='defaultview')
>>> view
<dolmen.forms.crud.tests.DefaultView object at ...>

The Display form removes the ‘title’ from the list of fields. This particular attribute is used directly by the template:

>>> view.fields.keys()
['water']

A display form has no actions:

>>> len(view.actions)
0

dolmen.forms.crud provides a very basic template for that form. As we can see, the title attribute is used as the HTML header (h1) of the page:

>>> print view()
<form action="http://127.0.0.1" method="post"
      enctype="multipart/form-data">
  <h1>Stilgar</h1>
  <div class="fields">
    <div class="field">
        <label class="field-label" for="form-field-water">Number water gallons owned</label>
        <span class="field-required">(required)</span>
        <br />
      25
    </div>
  </div>
</form>

>>> security.endInteraction()

Delete

A delete form is a simple form with no fields, that only provides a ‘confirm’ action:

>>> class DeleteForm(crud.Delete):
...     '''Generic delete form.
...     '''

>>> grokcore.component.testing.grok_component('delete_form', DeleteForm)
True

>>> deleteform = getMultiAdapter((naib, request), name='deleteform')
>>> deleteform
<dolmen.forms.crud.tests.DeleteForm object at ...>

>>> deleteform.updateForm()
>>> for action in deleteform.actions: print action
<DeleteAction Delete>
<CancelAction Cancel>

>>> len(deleteform.fields)
0

When confirmed, the form tries to delete the object:

>>> post = TestRequest(form={
...     'form.action.delete': u'Delete'},
...     REQUEST_METHOD='POST',
...     )

>>> security.newInteraction(post)

>>> list(sietch.keys())
[u'Fremen']

>>> deleteform = getMultiAdapter((naib, post), name='deleteform')
>>> deleteform.updateForm()

>>> from zope.i18n import translate
>>> translate(deleteform.status, context=post)
u'The object has been deleted.'

>>> list(sietch.keys())
[]

>>> deleteform.response.getStatus()
302
>>> deleteform.response.getHeader('location')
'http://127.0.0.1/sietch'

>>> security.endInteraction()

Generic forms without Dublin Core

Tests run above where using a content defining a title, let’s verify it still works with bare contents.

>>> sietch = root['sietch']

Create

Form customization

To customize forms, the usual solution is to subclass them and to work with the subclass. dolmen.forms.crud proposes a new component to customize your forms. Defined by the IFieldsCustomization interface, it’s an adapter that allows you to interact at the field level.

In a IFieldsCustomization, the customization happens at the __call__ level. The forms, while they update the objects fields, query a IFieldsCustomization adapter and call it, giving the fields as an argument.

Let’s implement an example:

>>> class RemoveWater(crud.FieldsCustomizer):
...    grokcore.component.adapts(Fremen, crud.Add, None)
...
...    def __call__(self, fields):
...       """Alters the form fields"""
...       return fields.omit('water')

>>> from zope.interface import verify
>>> verify.verifyClass(crud.IFieldsCustomization, RemoveWater)
True

We can now register and test the customization:

>>> grokcore.component.testing.grok_component('removewater', RemoveWater)
True

>>> security.newInteraction(Participation(manager))

>>> addform = addingview.traverse('fremen', [])
>>> for field in addform.fields: print field
<TextLineField Name of the warrior>

One important thing is noticeable here : the ‘RemoveWater’ adapter was registered for the ‘Fremen’ component. To be able to lookup the registery for suitable adapters, the add form uses a special lookup function : dolmen.forms.crud.utils.queryClassMultiAdapter.

We can test a more complex example, returning a brand new instance of Fields:

>>> import dolmen.forms.base
>>> from dolmen.forms.crud.utils import getSchemaFields

>>> class AddFieldToView(crud.FieldsCustomizer):
...    grokcore.component.adapts(Fremen, crud.Display, None)
...
...    def __call__(self, fields):
...       """Returns a new instance of Fields.
...       """
...       schema = dolmen.content.get_schema(self.context)
...       if schema:
...           return dolmen.forms.base.Fields(*schema)
...       return dolmen.forms.base.Fields()

>>> grokcore.component.testing.grok_component('viewer', AddFieldToView)
True

Checking the fields, we should get all the fields defined by the Fremen schema:

>>> view = getMultiAdapter((naib, request), name='defaultview')
>>> view.fields.keys()
['title', 'water']

>>> security.endInteraction()

Events and field updates

When using the generic dolmen.forms.crud forms, some events are triggered for you. They represent the lifecycle of the manipulated object.

To check on all the events triggered, we can set up a simple event logging list and a generic handler:

>>> from zope.component import provideHandler
>>> from zope.lifecycleevent import IObjectModifiedEvent
>>> logger = []

>>> def event_logger(object, event):
...   logger.append(event)

>>> provideHandler(event_logger, (Fremen, IObjectModifiedEvent))

Editing events

Let’s have the same introspection check with the edit form:

>>> logger = []

We provide data for the update:

>>> request = TestRequest(form={
...     'form.field.water': '10',
...     'form.field.title': u'Sihaya',
...     'form.action.update': u'Update'},
...     REQUEST_METHOD='POST',
...     )

>>> security.newInteraction(request)

>>> chani = Fremen()
>>> root['chani'] = chani

>>> editform = getMultiAdapter((chani, request), name='edit')
>>> editform.updateForm()

We check the trigged events:

>>> for event in logger: print event
<...ObjectModifiedEvent object at ...>

In depth, we can check if the updated fields are correctly set in the event’s descriptions:

>>> for desc in logger[0].descriptions:
...   print "%r: %s" % (desc.interface, desc.attributes)
<InterfaceClass dolmen.forms.crud.tests.IDesertWarrior>: ('water', 'title')

>>> chani.title
u'Sihaya'
>>> chani.water
10

>>> security.endInteraction()

Field update

dolmen.forms.base provides the description of a new component that can be used to atomize the updating process of an object: IFieldUpdate. An implementation is available in dolmen.forms.crud, using an event handler, listening on ObjectModifiedEvent and ObjectCreatedEvent:

>>> updates = []

>>> from zope.schema import TextLine
>>> from zope.component import adapter, provideAdapter
>>> from zope.interface import implementer
>>> from dolmen.forms.base import IFieldUpdate

>>> @implementer(IFieldUpdate)
... @adapter(Fremen, TextLine)
... def updated_textfield(context, field):
...    updates.append((context, field))

>>> provideAdapter(updated_textfield, name="updatetext")

Using an add form, the IFieldUpdate adapters should be called during an objects creation:

>>> request = TestRequest(form={
...     'form.field.title': u'Liet',
...     'form.action.add': u'Add'},
...     REQUEST_METHOD='POST',
...     )

>>> request.setPrincipal(manager)
>>> interaction = security.newInteraction(request)

>>> desert = root['desert'] = dolmen.content.Container()
>>> addingview = getMultiAdapter((desert, request), name='add')
>>> addform = addingview.traverse('fremen', [])
>>> addform.updateForm()

>>> kynes = desert['Fremen']
>>> kynes
<dolmen.forms.crud.tests.Fremen object at ...>
>>> kynes.title
u'Liet'

>>> print updates
[(<dolmen.forms.crud.tests.Fremen object at ...>,
<zope.schema._bootstrapfields.TextLine object at ...>)]

>>> security.endInteraction()

We can do the same thing for the edit form:

>>> updates = []

>>> request = TestRequest(form={
...     'form.field.water': '50',
...     'form.field.title': u'Imperial weather specialist',
...     'form.action.update': u'Update'},
...     REQUEST_METHOD='POST',
...     )

>>> request.setPrincipal(manager)
>>> security.newInteraction(request)

>>> editform = getMultiAdapter((kynes, request), name='edit')
>>> editform.updateForm()

>> kynes.title
u'Imperial weather specialist'

>>> updates
[(<dolmen.forms.crud.tests.Fremen object at ...>, <zope.schema._bootstrapfields.TextLine object at ...>)]

Updating a field without a registered IFieldUpdate adapter shouldn’t do anything:

>>> updates = []

 >>> request = TestRequest(form={
 ...     'form.field.water': '40',
 ...     'form.action.update': u'Update'},
 ...     REQUEST_METHOD='POST',
 ...     )

 >>> editform = getMultiAdapter((kynes, request), name='edit')
 >>> editform.updateForm()

 >>> updates
 []

Changelog

1.0 (2012-10-24)

• Fixed the dependencies and the testing, echoing the changes in the related packages.

1.0b5 (2011-02-16)

• We now use the new get_schema util function from dolmen.content to get the schema value. This allows a normalized way to deal with schema retrieval.

1.0b4 (2011-02-16)

• Corrected event triggering that used to fail if the IContent object had no schema defined.

1.0b3 (2011-02-14)

• Added a util function that returns a Fields instance, given a form, a context and a list of omitted fields’ name.

• Objects or classes with no schema are now supported.

• We now use the getContent method of the form to get the Edit, Display, Delete forms’ context.

1.0b2 (2011-02-14)

• Adapted to echo the latest dolmen.content changes.

• title is now obtained thanks to DCDescriptiveProperties from zope.dublincore (for the labels).

• Adapted the tests for the latest zeam.form.base changes.

1.0b1 (2010-07-13)

• Using latest dolmen.content changes, to display a sane form label.

• Added correct translations.

• Forms mode are now using mode markers.

1.0a3 (2010-06-25)

• Added missing translations (french)

• Actions now use the form getContent method, to get the proper form content. In addition, the content is now tested, to handle DataManagers. Import fix : the Delete action now behaves properly.

• Using the latest version of dolmen.forms.base with improved errors handling and data processing and notification.

1.0a2 (2010-06-05)

• Added the CancelAction to the input forms.

• Fixed a bug where the errors where not set correctly on submission failure.

1.0a1 (2010-06-03)

• The package is now using zeam.form instead of z3c.form.

• Added internationalization (French, English)

• The IObjectInitializedEvent has been removed, as we are now using dolmen.content >= 0.3.1. It has been replaced by a simple IObjectAddedEvent. The IFieldUpdate triggers have been modified accordingly.

0.4.0 (2010-02-22)

• Cleaned dependencies and tests. The package is now 100% zope.app free.

0.3.0 (2009-11-02)

• Removed dependencies on zope.app.container.

• Upgraded to use ZTK versions (1.0dev).

0.2.1 (2009-11-02)

• The Delete form is now using class level messages for success and failure.

• Updated tests to cover the deletion bug.

• Corrected the redirection URL after a delete action.

0.2.0 (2009-11-02)

• Added a DeleteForm

• Added titles to all the forms

• Corrected double nextURL method in the EditForm.

0.1.0 (2009-10-26)

• Initial release