#---- 8< ----- myproj/myproj/forms/base.py -----
"""
Base classes for forms
"""
from formencode.schema import Schema

class FilteringSchema(Schema):
    """
    Schema that gets around the of toscawidgets in tg1 having
    self passed as a field.
    """
    # TODO: Get rid of this when we upgrade to tg2
    filter_extra_fields = True
    allow_extra_fields = True

#----- 8< ------- myproj/myproj/forms/site.py
"""
Tosca widgets form for a CMS Site
"""

from toscawidgets.api import WidgetsList, CSSSource, JSSource
from toscawidgets.widgets.forms import TableForm, TextField, HiddenField
from toscawidgets.widgets.forms.validators import UnicodeString, Int
from toscawidgets.js import js_function
from cms.forms.base import FilteringSchema

# Lil' chunk o' CSS for tasty eye-candy ;)
# External css files can be wrapped with CSSLink
css = CSSSource("""
label.required, .fielderror {
    font-weight: bold;
    color: red;
};
""")


# We define the source for some JS functions we're going to interface
# External js files can be wrapped with JSLink
functions = JSSource("""
var focus_element = function (elem) {
    var elem = document.getElementById(elem);
    elem.focus(); elem.select();
    }; 
    """,
    )

alert = js_function('alert')
focus_element = js_function('focus_element')


class SiteForm(TableForm):
    class fields(WidgetsList):
        clientId = HiddenField(validator=Int())
        siteId   = HiddenField(validator=Int())
        newSite  = HiddenField()
        url      = TextField(validator=UnicodeString(not_empty=True))
        title    = TextField(validator=UnicodeString(not_empty=True))
        notes    = TextField(validator=UnicodeString())

    validator = FilteringSchema()

    # allow adding js calls dynamically for a request
    include_dynamic_js_calls = True

    css = [css]
    javascript = [functions]

    def update_params(self, d):
        super(SiteForm, self).update_params(d)
        # Focus and select the 'title' field on the form
        # The adapter we just wrote lets us pass formfields as parameters and
        # the right thing will be done.
        if not d.error:
            self.add_call(focus_element(d.c.title))
        else:
            self.add_call( alert('The form contains invalid data\n%s'% unicode(d.error)))

#--------- 8< -------- Somewhere in your controllers
from cms.forms.site import SiteForm

class SuperController(controllers.Controller):

    siteForm = SiteForm();

    @expose(template="cms.templates.editSite")
    @require(in_group("manager"))
    def editSite(self, clientId=None, siteId=None, url=None, title=None, notes=None, newSite=None, tg_errors=None, tg_exceptions=None, tg_source=None):
        """
        Shows a form for editing the info of a site
        """
        # We are just showing the edit form
        if not siteId:
            return {
                'newSite': True,
                'client': Client.query.get(clientId),
                'form': self.siteForm,
            }
        else:
            return {
                'newSite': False,
                'site': Site.query.get_by(id=siteId),
                'form': self.siteForm,
            }

    @error_handler(editSite)
    @validate(siteForm)
    @expose()
    def saveSite(self, siteId=None, url=None, title=None, notes=None, newSite=None, clientId=None):
        """
        Where the site form posts to
        """
        if newSite:
            # Make a new site
            client = Client.query.get(clientId)
            site = Site(client=client, url=url, title=title, notes=notes)
        else:
            # Editing an existing site
            site = Site.query.get(siteId)
            if clientId != site.client.id:
                site.client = Client.query.get(clientId)
            site.url = url
            site.title = title
            site.notes = notes
        site.save()
        session.commit()
        return self.showSite(site=site)
---------8< ------- in the template (I'm using genshi)
    <div id="editSite" py:if="not newSite">
      ${form.display(
        action="saveSite",
        value=dict(
          newSite=newSite,
          siteId=site.id,
          siteTitle=site.title,
          siteURL=site.url,
          siteNotes=site.notes,
        ),
      )}
    </div>
    <div id="newSite" py:if="newSite">
      ${form.display(
          action="saveSite",
          value=dict(
            newSite=newSite,
            clientId=client.id,
          ),
       )}
    </div>