nested colander schema and validation

[Andi Balke]

hi, 

i sat on this problem for 10 hours now and i have no idea anymore. if anyone could give me  a hint, i would really appreciate that. 

story: i created a schema for a custom widget, wich renders, the form works, all fine so far. 

problem: i need to create a nested schema so i can access ``children`` in my custom widget to transmit more than only one filed. i had different variations of schemas so far, which all kinda work - e.g. render - but on validation my problem is i cannot access the POST data of the children in my parent-schema.

now i just wanted to see if i can access them at least in a custom validator (http://deformdemo.repoze.org/interfield/), nope. also the preparer just doesn't work on the parent-schema. 

here is all relevant code, maybe someone spots an error. 

thanks, andi

class curry(object):

    """

    class to curry a methods together with fewer arguments.

    @see: http://code.activestate.com/recipes/52549-curry-associating-parameters-with-a-function/

    """

    def __init__(self, fun, *args, **kwargs):

        self.fun = fun

        self.pending = args[:]

        self.kwargs = kwargs.copy()

    def __call__(self, *args, **kwargs):

        if kwargs and self.kwargs:

            kw = self.kwargs.copy()

            kw.update(kwargs)

        else:

            kw = kwargs or self.kwargs

        return self.fun(*(self.pending + args), **kw)

@colander.deferred

def create_LocationPickerWidget(node, kw):

    """

    callable to create the widget with a deferred paramater, here

    "request"

    gets applied by ``colander.Schema.bind(request=self.request)``

    """

    request = kw["request"]

    return LocationPickerWidget(request)

class Location(colander.MappingSchema):

    location_search = colander.SchemaNode(

        colander.String(),

        name = "location_string.location_search",

        validator=colander.Length(min=1),

    )

    location_point = colander.SchemaNode(

        colander.String(),

        name = "location_string.location_point",

        widget = deform.widget.HiddenWidget(),

        validator=colander.Length(min=1),

    )

class LocationPicker(colander.MappingSchema):

    """

    schema only for a step in the form to choose a location

    @see http://docs.pylonsproject.org/projects/colander/en/latest/manipulation.html

    """

    location_string = Location(

        widget=create_LocationPickerWidget,

    )

    @classmethod

    def prepare_location(cls, fieldname, value):

        """

        deform preparer to convert a form submitted location in a real

        location.

        appended below

        """

        if log.isEnabledFor(logging.WARN):

            _out = StringIO()

            pprint(value, stream=_out)

            log.warn("%s.%s @%s value: %s", __name__, cls.__name__, fieldname, _out.getvalue())

        if value:

            lat, lng = value.split(',')

            position = WKTSpatialElement('POINT({0} {1})'.format(lat, lng))

            return position

        return value

# adding a preparer to the mapping node will not work

LocationPicker.location_string.preparer =\

        curry(LocationPicker.prepare_location, "XX_location_string_XX")

# those work

Location.location_search.preparer =\

        curry(LocationPicker.prepare_location, "location_search")

Location.location_point.preparer =\

        curry(LocationPicker.prepare_location, "location_point")

[Andi Balke]

hi, 

the solution to get the nested fields applied correctly lies in the template::

    <input type="hidden" name="__start__" value="${field.name}:mapping"/>

    <div tal:repeat="tup subfields">

        <div tal:replace="structure rndr(tup[1].widget.template, field=tup[1], cstruct=tup[0],

                      parent=field)"/>

    </div>

    <input type="text"

           name="${item_field.name}"

           value="${cstruct['location_search']}"

           tal:attributes="size field.widget.size;

                           class field.widget.css_class"

           id="${item_field.oid}" />

    <input type="hidden" name="__end__" value="${field.name}:mapping"/>

cheers, andi