32 lines
1.2 KiB
Python
32 lines
1.2 KiB
Python
from functools import partial
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from itertools import groupby
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from operator import attrgetter
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from django.forms.models import ModelChoiceIterator, ModelChoiceField
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class GroupedModelChoiceIterator(ModelChoiceIterator):
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def __init__(self, field, groupby):
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self.groupby = groupby
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super().__init__(field)
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def __iter__(self):
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if self.field.empty_label is not None:
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yield ("", self.field.empty_label)
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queryset = self.queryset
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# Can't use iterator() when queryset uses prefetch_related()
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if not queryset._prefetch_related_lookups:
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queryset = queryset.iterator()
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for group, objs in groupby(queryset, self.groupby):
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yield (group, [self.choice(obj) for obj in objs])
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class GroupedModelChoiceField(ModelChoiceField):
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def __init__(self, *args, choices_groupby, **kwargs):
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if isinstance(choices_groupby, str):
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choices_groupby = attrgetter(choices_groupby)
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elif not callable(choices_groupby):
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raise TypeError('choices_groupby must either be a str or a callable accepting a single argument')
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self.iterator = partial(GroupedModelChoiceIterator, groupby=choices_groupby)
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super().__init__(*args, **kwargs)
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