CODEWITHSUNDEEP
djangodjango-formsdjango-views
Przemek Lach
Przemek Lach

Reputation: 1538

Modify UpdateView Form Data Before Presenting To User

I'm using a CreateView and UpdateView for managing saving and updating. Before my data is saved I need combine 3 form fields into one field for storing it in my model. Basically, I'm taking a longitude, latitude, and range and converting it to a single value that is stored in my database. In my ModelForm I create the extra fields that I need and remove the one field that I don't:

class FilterForm(ModelForm):
    lat = forms.FloatField()
    lgt = forms.FloatField()
    range = forms.FloatField()

    class Meta:
        model = AdFilter
        fields = ['title', 'tags', 'start_date', 'end_date', 'start_time', 'end_time', 'week_days', 'ad']

To create new I implement form_valid() in order to combine the longitude, latitude, and range and store it in my model correctly:

class FilterCreate(CreateView):
    form_class = FilterForm
    template_name = 'filter_form.html'

    @method_decorator(login_required)
    def dispatch(self, *args, **kwargs):
        return super(FilterCreate, self).dispatch(*args, **kwargs)

    def form_valid(self, form):
        new_filter = form.save(commit=False)
        new_filter.creator = self.request.user

        utm_coordinates = utm.from_latlon(float(form.data['lat']), float(form.data['lgt']))
        center = geos.Point(utm_coordinates[0], utm_coordinates[1])
        broadcast_area_geometry = center.buffer(float(form.data['range']))

        # Set the right SRID
        utm_epsg = int('326' + str(utm_coordinates[2]))
        broadcast_area_geometry.srid = utm_epsg

        new_filter.filter_geometry = broadcast_area_geometry
        new_filter.save()

        return super(FilterCreate, self).form_valid(new_filter)

This all works fine. Now I'm trying to do the opposite of what form_valid() does in my UpdateView for the situation when someone gets the form. So I need to go from my single model value and create a longitude, latitude, and range values. I tried doing this inside get_context_data() but I've only been able to figure out how to add fields and not how to modify existing ones.

This seems like a very common problem but I can't seem to find an example of how to implement this. Maybe I'm looking in the wrong place.

Upvotes: 0

Views: 1011

Answers (1)

Daniel Roseman
Daniel Roseman

Reputation: 599600

You probably want to override the get_initial method to provide default values. The method should return a dictionary mapping field names to their default values.

Upvotes: 1

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