Embedding PloneFormGen forms

Description

PloneFormGen forms may be rendered from other templates, viewlets, and portlets.

Warning

This feature requires Plone 3.0 or later to work out of the box. You can make it work in Plone 2.5 by turning on the PLONE_25_PUBLISHER_MONKEYPATCH config option, which applies a monkey patch to the Zope publisher exception hook based on some code included in Plone 3.

Caveat: This feature should be considered beta quality. I've written code that takes advantage of it, and you shouldn't be afraid of it, but take care to test thoroughly. There may be certain types of contexts for rendering the form with implications that I haven't taken into consideration.

To insert the form into an arbitrary template, use the 'embedded' browser view:

<tal:block tal:replace="structure path/to/form/@@embedded"/>

If you are including the form on a page that features another form, you'll probably need to set a prefix on the 'embedded' view to disambiguate submissions:

<tal:block tal:define="form nocall:path/to/form/@@embedded;
                   dummy python:form.setPrefix('mypfg')"
       tal:replace="structure form"/>

Or if you are using a view class, you could define a method like:

from Products.CMFCore.utils import getToolByName
def render_form(self):
    portal = getToolByName(self.context, 'portal_url').getPortalObject()
    form_view = portal.restrictedTraverse('path/to/form/@@embedded')
    form_view.prefix = 'mypfg'
    return form_view()

(Note that restrictedTraverse expects a path relative to the object you are calling it on, with no initial slash.) And then in the associated template:

<tal:block tal:replace="structure view/render_form"/>

By default the embedded form uses the current URL as the form's 'action' parameter. When the form is rendered upon submission, it will perform validation, run the normal action adapters, and redirect to the success page as normal. If you want to submit to the form's real location or somewhere else, you can override the action by setting the 'action' attribute on the 'embedded' view.

Known limitation: Embedded forms have no way of injecting javascript or CSS into the page head like their standalone counterparts.