273 lines
8.2 KiB
Python
273 lines
8.2 KiB
Python
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# -*- coding: utf-8 -*-
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"""
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Select2 Widgets based on https://github.com/applegrew/django-select2.
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These components are responsible for rendering
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the necessary HTML data markups. Since this whole
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package is to render choices using Select2 JavaScript
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library, hence these components are meant to be used
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with choice fields.
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Widgets are generally of two types:
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1. **Light** --
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They are not meant to be used when there
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are too many options, say, in thousands.
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This is because all those options would
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have to be pre-rendered onto the page
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and JavaScript would be used to search
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through them. Said that, they are also one
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the most easiest to use. They are a
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drop-in-replacement for Django's default
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select widgets.
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2. **Heavy** --
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They are suited for scenarios when the number of options
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are large and need complex queries (from maybe different
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sources) to get the options.
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This dynamic fetching of options undoubtedly requires
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Ajax communication with the server. Django-Select2 includes
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a helper JS file which is included automatically,
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so you need not worry about writing any Ajax related JS code.
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Although on the server side you do need to create a view
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specifically to respond to the queries.
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Heavy widgets have the word 'Heavy' in their name.
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Light widgets are normally named, i.e. there is no
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'Light' word in their names.
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"""
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from copy import copy
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from itertools import chain
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from django import forms
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from django.conf import settings
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from django.core import signing
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from django.forms.models import ModelChoiceIterator
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from django.urls import reverse_lazy
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DEFAULT_SELECT2_JS = '//cdnjs.cloudflare.com/ajax/libs/select2/4.0.3/js/select2.min.js'
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DEFAULT_SELECT2_CSS = '//cdnjs.cloudflare.com/ajax/libs/select2/4.0.3/css/select2.min.css'
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__all__ = ['Select2Widget', 'Select2MultipleWidget', 'Select2TagWidget',
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'HeavySelect2Widget', 'HeavySelect2MultipleWidget', 'HeavySelect2TagWidget',
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'AdminSelect2Widget', 'AdminSelect2MultipleWidget', 'AdminHeavySelect2Widget',
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'AdminHeavySelect2MultipleWidget']
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class Select2Mixin(object):
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"""
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The base mixin of all Select2 widgets.
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This mixin is responsible for rendering the necessary
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data attributes for select2 as well as adding the static
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form media.
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"""
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def build_attrs(self, base_attrs, extra_attrs=None):
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"""Add select2 data attributes."""
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attrs = super(Select2Mixin, self).build_attrs(base_attrs, extra_attrs)
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if self.is_required:
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attrs.setdefault('data-allow-clear', 'false')
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else:
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attrs.setdefault('data-allow-clear', 'true')
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attrs.setdefault('data-placeholder', '')
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attrs.setdefault('data-minimum-input-length', 0)
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if 'class' in attrs:
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attrs['class'] += ' django-select2'
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else:
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attrs['class'] = 'django-select2'
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return attrs
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def optgroups(self, name, value, attrs=None):
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"""Add empty option for clearable selects."""
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if not self.is_required and not self.allow_multiple_selected:
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self.choices = list(chain([('', '')], self.choices))
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return super(Select2Mixin, self).optgroups(name, value, attrs=attrs)
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@property
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def media(self):
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"""
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Construct Media as a dynamic property.
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.. Note:: For more information visit
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https://docs.djangoproject.com/en/1.8/topics/forms/media/#media-as-a-dynamic-property
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"""
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return forms.Media(
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js=[settings.SELECT2_JS_URL, 'django_select2.js'],
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css={'screen': [settings.SELECT2_CSS_URL]},
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)
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class AdminSelect2Mixin(Select2Mixin):
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@property
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def media(self):
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return forms.Media(
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js=['admin/js/jquery.init.js', settings.SELECT2_JS_URL, 'django_select2.js'],
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css={'screen': [settings.SELECT2_CSS_URL]},
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)
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class Select2TagMixin(object):
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"""Mixin to add select2 tag functionality."""
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def build_attrs(self, base_attrs, extra_attrs=None):
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"""Add select2's tag attributes."""
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extra_attrs = extra_attrs or {}
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extra_attrs.setdefault('data-minimum-input-length', 1)
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extra_attrs.setdefault('data-tags', 'true')
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extra_attrs.setdefault('data-token-separators', [",", " "])
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return super(Select2TagMixin, self).build_attrs(base_attrs, extra_attrs)
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class Select2Widget(Select2Mixin, forms.Select):
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"""
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Select2 drop in widget.
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Example usage::
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class MyModelForm(forms.ModelForm):
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class Meta:
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model = MyModel
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fields = ('my_field', )
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widgets = {
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'my_field': Select2Widget
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}
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or::
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class MyForm(forms.Form):
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my_choice = forms.ChoiceField(widget=Select2Widget)
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"""
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pass
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class Select2MultipleWidget(Select2Mixin, forms.SelectMultiple):
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"""
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Select2 drop in widget for multiple select.
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Works just like :class:`.Select2Widget` but for multi select.
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"""
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pass
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class Select2TagWidget(Select2TagMixin, Select2Mixin, forms.SelectMultiple):
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"""
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Select2 drop in widget for for tagging.
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Example for :class:`.django.contrib.postgres.fields.ArrayField`::
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class MyWidget(Select2TagWidget):
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def value_from_datadict(self, data, files, name):
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values = super(MyWidget, self).value_from_datadict(data, files, name):
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return ",".join(values)
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"""
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pass
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class HeavySelect2Mixin(Select2Mixin):
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"""Mixin that adds select2's ajax options."""
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def __init__(self, attrs=None, choices=(), **kwargs):
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self.choices = choices
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if attrs is not None:
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self.attrs = attrs.copy()
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else:
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self.attrs = {}
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self.data_view = kwargs.pop('data_view', None)
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self.data_url = kwargs.pop('data_url', None)
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if not (self.data_view or self.data_url):
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raise ValueError('You must ether specify "data_view" or "data_url".')
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def get_url(self):
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"""Return url from instance or by reversing :attr:`.data_view`."""
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if self.data_url:
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return self.data_url
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return reverse_lazy(self.data_view)
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def build_attrs(self, base_attrs, extra_attrs=None):
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"""Set select2's ajax attributes."""
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attrs = super(HeavySelect2Mixin, self).build_attrs(base_attrs, extra_attrs)
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# encrypt instance Id
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self.widget_id = signing.dumps(id(self))
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attrs['data-field_id'] = self.widget_id
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attrs.setdefault('data-ajax--url', self.get_url())
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attrs.setdefault('data-ajax--cache', "true")
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attrs.setdefault('data-ajax--type', "GET")
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attrs.setdefault('data-minimum-input-length', 2)
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attrs['class'] += ' django-select2-heavy'
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return attrs
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def format_value(self, value):
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result = super(HeavySelect2Mixin, self).format_value(value)
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if isinstance(self.choices, ModelChoiceIterator):
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chosen = copy(self.choices)
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chosen.queryset = chosen.queryset.filter(pk__in=[
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int(i) for i in result if isinstance(i, int) or i.isdigit()
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])
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self.choices = set(chosen)
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return result
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class HeavySelect2Widget(HeavySelect2Mixin, forms.Select):
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"""
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Select2 widget with AJAX support.
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Usage example::
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class MyWidget(HeavySelectWidget):
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data_view = 'my_view_name'
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or::
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class MyForm(forms.Form):
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my_field = forms.ChoicesField(
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widget=HeavySelectWidget(
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data_url='/url/to/json/response'
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)
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)
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"""
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pass
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class HeavySelect2MultipleWidget(HeavySelect2Mixin, forms.SelectMultiple):
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"""Select2 multi select widget similar to :class:`.HeavySelect2Widget`."""
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pass
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class HeavySelect2TagWidget(Select2TagMixin, HeavySelect2MultipleWidget):
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"""Select2 tag widget."""
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pass
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class AdminSelect2Widget(AdminSelect2Mixin, Select2Widget):
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pass
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class AdminSelect2MultipleWidget(AdminSelect2Mixin, Select2MultipleWidget):
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pass
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class AdminHeavySelect2Widget(AdminSelect2Mixin, HeavySelect2Widget):
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pass
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class AdminHeavySelect2MultipleWidget(AdminSelect2Mixin, HeavySelect2MultipleWidget):
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pass
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