Tag: ztk

Last minute information for remote Sprinters for the Zope Resurrection Sprint

As the Zope Resurrection sprint is approaching, it seems useful to share some information on the schedule for the three days in Halle. As we have also some sprinters, who can not join on site, but might want to join remotely, a few key facts might come in handy.

Etherpad

There is the Etherpad, where the current list of topics is collected. Most of the stories we are going to tackle will be based on this list. In case you have something to add, or are interested in a specific topic in particular, it is a good idea to add your thoughts before the start of the sprint.

IRC Channel

During the sprint we will communicate via the #sprint channel on irc.freenode.net, so additional information and questions can be placed there.

Google Hangout

As the sprint is also intended to foster discussions about the future of Zope, we want to encourage as many people as possible to join. Therefore, we have a hangout where we will meet.

Scheduled Discussions

At the moment we plan the following session:

  • Wednesday 2016-09-28 10:00 CEST, duration 1 h: Introduction to WSGI in Zope 4 by Hanno Schlichting (hannosh) + discussion
  • Wednesday 2016-09-28 14:00 CEST, duration 2 h: Discussion about through-the web (TTW) pattern and the underlying RestrictedPython
  • Thursday 2016-09-29 10:00 CEST, duration 0.5 h: Discussion about the necessity and future of ZTK
  • Friday 2016-09-30 14:00 CEST, duration 1 h: Discussion about the Zope 5

So in case you want to contribute remotely to the sprint, please join us on one of the three ways.

 

Custom widgets in zope.formlib

zope.formlib has the ability to customize the used widget like this:

class KeywordsManagementForm(five.formlib.formbase.SubPageForm):
    form_fields = zope.formlib.form.Fields(IKeywords)
    form_fields['keywords'].custom_widget = KWSelectWidgetFactory

I do not like this approach for two reasons:

  • the widget has to be set manually every time the specific field is used
  • there is no easy way to get a display widget if the form or field is not editable for the user

Defining a new schema field and registering the widget for this field seems a bit heavy, so I came up with providing a marker interface on the field:

class IHaveSelectableKeywords(zope.interface.Interface):
    """Marker interface to get a special keywords widget."""

class IKeywords(zope.interface.Interface):
    keywords = zope.schema.List(
        title = _("Edit Keywords"),
        value_type = zope.schema.Choice(
            vocabulary=u"uc.keywords.Keywords"))
    zope.interface.alsoProvides(keywords, IHaveSelectableKeywords)

I registered the edit widget and display widget for the IHaveSelectableKeywords interface, so the custom widget does not have to be set in the form like this (edit widget):

<adapter
   for=".IHaveSelectableKeywords
        zope.publisher.interfaces.browser.IBrowserRequest"
 provides="zope.app.form.browser.interfaces.ISimpleInputWidget"
 factory=".KWSelectWidgetFactory"
 permission="zope.Public" />

Get a zc.sourcefactory to implement an interface

zc.sourcefactory is very handy to easily create a source (zope.schema.interfaces.IIterableSource to be precise) with corresponding titles and tokens for its contents. Every now and then a source requires an explicit interface. For zc.sourcefactory the following code snippet helps:

class IMySource(zope.schema.interfaces.IIterableSource):
    """my source"""

class MySource(
    zc.sourcefactory.contextual.BasicContextualSourceFactory):
    """The source factory."""

    class source_class(
        zc.sourcefactory.source.FactoredContextualSource):
        """This class is being instanciated by the factory.

        It *must* be called source_class.
        """
        zope.interface.implements(IMySource)

    def getValues(self, context):
        …

Of course it is also possible to declare the source_class separately from the source factory and reference it. But since its sole purpose is to hold an implements declaration, I’m fine with defining it inline.