- Author:
- crucialfelix
- Posted:
- February 12, 2009
- Language:
- Python
- Version:
- 1.0
- Score:
- 2 (after 2 ratings)
sorry, this is a duplicate post, original is here:
http://www.djangosnippets.org/snippets/690/
no way to delete snippets
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 | import re
from django.template.defaultfilters import slugify
def unique_slugify(instance, value, slug_field_name='slug', queryset=None,
slug_separator='-'):
"""
Calculates a unique slug of ``value`` for an instance.
``slug_field_name`` should be a string matching the name of the field to
store the slug in (and the field to check against for uniqueness).
``queryset`` usually doesn't need to be explicitly provided - it'll default
to using the ``.all()`` queryset from the model's default manager.
"""
slug_field = instance._meta.get_field(slug_field_name)
current_slug = getattr(instance, slug_field.attname)
slug_len = slug_field.max_length
# Sort out the initial slug. Chop its length down if we need to.
slug = slugify(value)
if slug_len:
slug = slug[:slug_len]
slug = _slug_strip(slug, slug_separator)
original_slug = slug
# Create a queryset, excluding the current instance.
if not queryset:
queryset = instance.__class__._default_manager.all()
if instance.pk:
queryset = queryset.exclude(pk=instance.pk)
# Find a unique slug. If one matches, at '-2' to the end and try again
# (then '-3', etc).
next = 2
while not slug or queryset.filter(**{slug_field_name: slug}):
slug = original_slug
end = '-%s' % next
if slug_len and len(slug) + len(end) > slug_len:
slug = slug[:slug_len-len(end)]
slug = _slug_strip(slug, slug_separator)
slug = '%s%s' % (slug, end)
next += 1
setattr(instance, slug_field.attname, slug)
return slug
def _slug_strip(value, separator=None):
"""
Cleans up a slug by removing slug separator characters that occur at the
beginning or end of a slug.
If an alternate separator is used, it will also replace any instances of
the default '-' separator with the new separator.
"""
if separator == '-' or not separator:
re_sep = '-'
else:
re_sep = '(?:-|%s)' % re.escape(separator)
value = re.sub('%s+' % re_sep, separator, value)
return re.sub(r'^%s+|%s+$' % (re_sep, re_sep), '', value)
|
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Comments
Thanks for this.
One bug I found:
line 29 should be changed to:
if queryset is None:
otherwise if the argument queryset is empty, it will be re-populated with all rows from the model, leading to slug being modified when it should of been left alone.
#
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