36 lines
1.2 KiB
Python
36 lines
1.2 KiB
Python
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import re
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from unicodedata import normalize
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from django.db import models
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class NaturalSortField(models.CharField):
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"""
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A custom model field specifically for storing a normalized unicode string,
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with removed starting articles, for use in natural sorting.
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Code is a modified version of 'django-naturalsortfield' by Nathan Reynolds:
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https://github.com/nathforge/django-naturalsortfield
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"""
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def __init__(self, for_field, **kwargs):
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self.for_field = for_field
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kwargs.setdefault('db_index', True)
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kwargs.setdefault('editable', False)
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kwargs.setdefault('max_length', 255)
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super(NaturalSortField, self).__init__(**kwargs)
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def pre_save(self, model_instance, add):
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return self.naturalize(getattr(model_instance, self.for_field))
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def naturalize(self, string):
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def naturalize_int_match(match):
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return '%08d' % (int(match.group(0)),)
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string = normalize('NFKD', string).encode('ascii', 'ignore').decode('ascii')
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string = string.lower()
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string = string.strip()
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string = re.sub(r'^(a|an|the)\s+', '', string)
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string = re.sub(r'\d+', naturalize_int_match, string)
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return string
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