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Chained select box widget for Django framework using AJAX requests.

Project description

This library is inspired by django-chained-selectbox from s-block (https://github.com/s-block/django-chained-selectbox).

It serves chained select box widget for Django framework using AJAX requests for chaining select boxes together. The values change depending on the parent value.

Previous mentioned library was intended for use in Django admin only. The new library has frontend functionality, improved existing instance data initialization and new ChainedModelChoiceField. It also uses custom TestClient which is able pass request.user variable into AJAX view if user is logged in. It is very useful if you need to filter result queryset by user permissions for example.

Tested on Django 1.4.5.

Requirements

  • Django
  • jQuery

Installation

  1. Install python library using pip: pip install django-clever-selects
  2. Add clever_selects to INSTALLED_APPS in your Django settings file
  3. Add clever_selects_extras to your {% load %} statement and put {% clever_selects_js_import %} tag before closing </body> element. It is important to load clever-selects.js file after body content, so do not put it in the <head></head>!

Usage

Forms

Form must inherit from ChainedChoicesMixin (or from ChainedChoicesForm / ChainedChoicesModelForm, depends on your needs) which loads the options when there is already an instance or initial data:

from clever_selects.form_fields import ChainedChoiceField
from clever_selects.forms import ChainedChoicesForm


class SimpleChainForm(ChainedChoicesForm):
    first_field = ChoiceField(choices=(('', '------------'), (1, '1'), (2, '2'), (3, '3'), (4, '4'), (5, '5'), ))
    second_field = ChainedChoiceField(parent_field='first_field', ajax_url=reverse_lazy('ajax_chained_view'))


class MultipleChainForm(ChainedChoicesForm):
    first_field = ChoiceField(choices=(('', '------------'), (6, 6), (7, 7), (8, 8), (9, 9), (10, 10), ))
    second_field = ChainedChoiceField(parent_field='first_field', ajax_url=reverse_lazy('ajax_chained_view'))
    third_field = ChainedChoiceField(parent_field='second_field', ajax_url=reverse_lazy('ajax_chained_view'))
    fourth_field = ChainedChoiceField(parent_field='third_field', ajax_url=reverse_lazy('ajax_chained_view'))
    fifth_field = ChainedChoiceField(parent_field='fourth_field', ajax_url=reverse_lazy('ajax_chained_view'))


class ModelChainForm(ChainedChoicesModelForm):
    brand = forms.ModelChoiceField(queryset=CarBrand.objects.all(), required=True,
        empty_label=_(u'Select a car brand'))
    model = ChainedModelChoiceField(parent_field='brand', ajax_url=reverse_lazy('ajax_chained_models'),
        empty_label=_(u'Select a car model'), model=BrandModel, required=True)
    engine = forms.ChoiceField(choices=([('', _('All engine types'))] + Car.ENGINES), required=False)
    color = ChainedChoiceField(parent_field='model', ajax_url=reverse_lazy('ajax_chained_colors'),
        empty_label=_(u'Select a car model'), required=False)

    class Meta:
        model = Car

Notice that ajax URLs could differ of each field for different purposes. See example project for more use cases.

In order to pre-populate child fields, the form can need to have access to the current user. This can be done by passing the user to the kwargs of the form’s __init__() method in the form’s view. The ChainedSelectFormViewMixin takes care of this for you.:

class CreateCarView(ChainedSelectFormViewMixin, CreateView)
    template_name = "create_car.html"
    form_class = ModelChainForm
    model = Car

Views

Ajax call is made whenever the parent field is changed. You must set up the ajax URL to return json list of lists:

class AjaxChainedView(BaseDetailView):
    """
    View to handle the ajax request for the field options.
    """

    def get(self, request, *args, **kwargs):
        field = request.GET.get('field')
        parent_value = request.GET.get("parent_value")

        vals_list = []
        for x in range(1, 6):
            vals_list.append(x*int(parent_value))

        choices = tuple(zip(vals_list, vals_list))

        response = HttpResponse(
            json.dumps(choices, cls=DjangoJSONEncoder),
            mimetype='application/javascript'
        )
        add_never_cache_headers(response)
        return response

Or you can use ChainedSelectChoicesView class helper like this:

class AjaxChainedView(ChainedSelectChoicesView):
    def get_choices(self):
        vals_list = []
        for x in range(1, 6):
            vals_list.append(x*int(self.parent_value))
        return tuple(zip(vals_list, vals_list))

or like this:

class AjaxChainedView(ChainedSelectChoicesView):
    def get_child_set(self):
        return ChildModel.object.filter(parent_id=self.parent_value)

Don’t forget to update your urls.py:

url(r'^ajax/custom-chained-view-url/$', AjaxChainedView.as_view(), name='ajax_chained_view'),

Authors

Library is by Erik Telepovsky from Pragmatic Mates. See our other libraries.

Project details


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