YAFOWIL is a form library for Python. This is its Plone Integration package

Overview

yafowil.plone offers different levels of integration for Plone:

• wraps the Zope Request to fullfill YAFOWIL expectations
• combines and registers CSS and JavScript Resources
• a YAFOWIL theme for the widgets
• macros following Plone default markup for fields, labels, ...
• Plone specific widgets
• l10n/i18n integration
• base forms for use in views (Python and YAML based)
• autoform features (still experimental): - generates forms from zope.schema and schema annotations - works as drop-in replacement for z3c.form - full add/edit lifecycle for Plone content forms. - optional immediate content create feature on add

Functionality

Resources Integration with GenericSetup

Addon widgets may provide custom javascripts, CSS, images and so on.

This package registers the directories containing these assets as resource directories. Thus they can be accessed from the webbrowser. The registration schema is ++resource++MODULENAME/....

The "YAFOWIL Form Library" GenericSetup profile registers all resources related to so called "resource groups" in the CSS and Javascript registries.

This resource groups must be enabled explicitly(!). The resource groups configuration happens via the portal registry.

You need to provide a Generic setup profile containing a registry.xml with the resource groups configuration, e.g.:

<!-- yafowil.widget.array -->
<record name="yafowil.widget.array.common">
  <field type="plone.registry.field.Bool">
    <title>Array widget common resources</title>
  </field>
  <value>True</value>
</record>

The record name maps to the YAFOWIL resource group name.

Take a look into registry.xml of the yafowil.plone:profiles/demoresources profile for more examples.

The YAFOWIL autoform profile registers a bunch of addons and may be used a a reference.

Integration with Translation

The package adds an translation method for Zope2 i18n messages. It's added using by defining a global preprocessor

Request wrapper

This package registers a global preprocessor for YAFOWIL. It wraps the Zope2 request by an own request instance providing the behavior expected by YAFOWIL.

File Uploads provided by Zope2 as ZPublisher.HTTPRequest.Fileupload objects are turned into a python dict with the keys:

file

file-like object to read data from

filename

submitted name of the upload

mimetype

type of the upload

headers

all headers

original

keeps the original ZPublisher.HTTPRequest.Fileupload object

Base Forms

This package ships with base forms to be extended.

The following form base classes are available:

yafowil.plone.form.BaseForm

does not define a `__call__` method: define a template in ZCML or a __call__ method. It provides a method named `render_form` which processes and renders the form.

yafowil.plone.form.Form

renders the naked form on __call__.

yafowil.plone.form.YAMLBaseForm

similar to BaseForm above. Expects properties form_template pointing to a YAML file and message_factory providing the message factory used for YAML message strings.

yafowil.plone.form.YAMLForm

similar to YAMLBaseForm renders the naked YAML form on __call__.

An in practice implementation may look like:

from yafowil.base import factory
from yafowil.plone.form import Form

class MyForm(Form):
    action_resource = '@@view_name_callable_by_browser'

    def prepare(self):
        form = factory(
            'form',
            name='myform',
            props={
                'action': self.form_action,
            })

        # form widgets creation here...

        self.form = form

Convenience code for creating YAML forms:

from zope.i18nmessageid import MessageFactory
from yafowil.plone.form import YAMLBaseForm

class MyYAMLForm(YAMLBaseForm):
    action_resource = '@@view_name_callable_by_browser'
    form_template = 'package.name:forms/myform.yaml'
    message_factory = MessageFactory('package.name')

Form classes inherit from Products.Five.BrowserPage, thus they must be registered via ZCML browser:page directive:

<browser:page
  for="*"
  name="form_registration_name"
  class=".forms.MyYAMLForm"
  template="myyamlform.pt"
  permission="cmf.ModifyPortalContent"
/>

Forms build with this base form classes need a template in order to insert such a form in a layout. It must be called inside a wrapper template `myform.yaml`:

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"
      xmlns:tal="http://xml.zope.org/namespaces/tal"
      xmlns:metal="http://xml.zope.org/namespaces/metal"
      xmlns:i18n="http://xml.zope.org/namespaces/i18n"
      lang="en"
      metal:use-macro="context/main_template/macros/master"
      i18n:domain="package.name">
  <body>
    <metal:content-core fill-slot="content-core">
      <metal:block define-macro="content-core">
        <tal:form replace="structure view/render_form" />
      </metal:block>
    </metal:content-core>
  </body>
</html>

When not using one of the BaseForms, the CSS/JS resources for YAFOWIL are not loaded automatically.

Add the following lines in order to load it:

from Products.CMFPlone.resources import add_bundle_on_request

...

class MyViewWithYafowil(BrowserView):

def __init__(self, context, request):
    super(MyViewWithYafowil, self).__init__(context, request)
    add_bundle_on_request(request, 'yafowil')

CSRF Protection

To write into the database in Plone a CSRF protection authenticator key must be provided as a hidden form field. This can be done by adding a plumbing behavior to the forms created as above.

from plumber import plumbing
from yafowil.plone.form import BaseForm
from yafowil.plone.form import CSRFProtectionBehavior

...

@plumbing(CSRFProtectionBehavior)
class ImportForm(BaseForm):
    """Form with CSRF protection"""

Autoform

EXPERIMENTAL:

Autoform features are not feature complete yet and can be considered as late alpha/early beta in YAFOWL 4.x. We plan to move it to a stable state in the 4.x series. With lots of care, it can be used in production.

YAFOWIL can be used as an drop-in replacement for the z3c.form based and plone.autoform generated forms.

Installation

There is a profile called YAFOWIL Autoform (in XML: yafowil.plone:autoform). By installing the profile, all needed to enable YAFOWIL rendered forms is installed. To finally activate autoform rendering for a content-type, one of the provided YAFOWIL Autoform behaviors has to be activated on the content-type.

Basic Functionality

YAFOWIL offers a layer to read z3c.form zope.schema annotations and build forms from this information.

Furthermore it offers an own zope.schema annotations named factory and factory_callable to build rich custom YAFOWIL forms without any z3c.form references.

Examples can be found within the bda.plone.yafowil_autoform_example behavior

Usage as z3c.form drop-in replacement

There are two behaviors available.

YAFOWIL forms from content-type schemas

Basic configuration with almost same behavior as z3c.form rendered types. Main difference: All widgets and processing is done through YAFOWIL. Also, a temporary non-persistent add-context is created and used (opposed to the container as add context in Dexterity).

YAFOWIL forms from content-type schemas with persistent add context

Work the same as the basic one above, but a persistent add context is created. I.e., this enables users to upload content in a container just created by the add form. On cancel the persistent object is removed. To enable removal of stalled content (because user closed browser or similar) an index is added to track the state of the content. This immediate creation feature is similar to the one in (but completely independent from) the addon collective.immediatecreate.

Detailed Documentation

If you're interested to dig deeper: The detailed YAFOWIL documentation is available. Read it and learn how to create your example application with YAFOWIL.

Source Code

The sources are in a GIT DVCS with its main branches at github.

We'd be happy to see many forks and pull-requests to make YAFOWIL even better.

Contributors

• Jens W. Klein <jens [at] bluedynamics [dot] com>
• Peter Holzer <hpeter [at] agitator [dot] com>
• Benjamin Stefaner <bs [at] kleinundpartner [dot] at>
• Robert Niederreiter <rnix [at] squarewave [dot] at>