A variation on my previous z3c.form example

Another example of form logic, adding to the one discussed in my previous post.

Here is the idea: If you need a more flexible solution for your use case, you can inherit directly from z3c.form.form.Form.
Let’s say you want the form to be used for both adding contact information (making sure later that this only works when the user is authenticated) and sending a mail message to the site administrator. A site feedback form that will at the same time be used to populate your database of contacts.

Your form class could be defined as follows (I’m skipping the imports part):

# my.example/my/example/browser.py

class ContactForm(z3c.form.form.Form):
    """ Contact Form """
    fields = z3c.form.field.Fields(interfaces.IContactData)
    message_field = z3c.form.field.Fields(schema.TextLine(__name__ = 'message',
                                                          title=u"Message",
                                                          required=False)
                                          )
    fields += message_field

    ignoreContext = True

    @z3c.form.button.buttonAndHandler(u'Send', name='send')
    def handle_send(self, action):
        data, errors = self.extractData()
        if errors:
            self.status = z3c.form.form.EditForm.formErrorsMessage
            return

        # Add the contact data, if not in yet
        id = data['firstname'] + data['lastname']
        id = zope.component.queryUtility(IIDNormalizer).normalize(id)

        if id not in self.context.objectIds():
            self._name = id
            contact = MyContact(self._name, **data)
            self.context[self._name] = contact

        # Do something else, e.g. send the message to the site admin.
        # Complete the code as needed...
        message = data['message']
        print "Message from %s %s (%s):\n%s" % (data['firstname'], data['lastname'], data['email'], data['message'])

        # Redirect
        self.request.RESPONSE.redirect(self.context.absolute_url())

The main points of the used pattern:

• You define the fields for the form ; new fields can be added to the already defined list (based on the IContactData schema in interfaces.py) using the “+” operator.
• You define your specific form button(s) and handler method(s). In the case of a standard AddForm, there is already a handle_add() defined for the “add” button for you.
• Also, you need to set the form attribute ‘ignoreContext’ to True, so that the form has the same behaviour as an AddForm, i.e. it does not have to get/set data on attributes on the context. Note that by default, an AddForm has this attribute set to True, and an EditForm has it set to False.

Now, the final touch with the wrapping view…

class ContactFormView(base.FormWrapper):

    form = ContactForm
    label= "Contact Form"

… and its configuration:

<configure
    xmlns="http://namespaces.zope.org/zope"
    xmlns:browser="http://namespaces.zope.org/browser"
    xmlns:five="http://namespaces.zope.org/five"
    i18n_domain="my.example" >

    <browser:page
        for="Products.CMFPlone.Portal.PloneSite"
        name="contact_form"
        class=".browser.ContactFormView"
        permission="zope2.View"
        />

</configure>

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Possibly related posts: (automatically generated)

• Updating your form code to latest version of plone.z3cform
• Using z3c.form for our forms in Plone
• More on using the EditForm
• Auto-Numbering InfoPath Forms