fields.py 文件源码

def create_slug(self, model_instance, add):
        # get fields to populate from and slug field to set
        if not isinstance(self._populate_from, (list, tuple)):
            self._populate_from = (self._populate_from, )
        slug_field = model_instance._meta.get_field(self.attname)

        if add or self.overwrite:
            # slugify the original field content and set next step to 2
            slug_for_field = lambda lookup_value: self.slugify_func(self.get_slug_fields(model_instance, lookup_value))
            slug = self.separator.join(map(slug_for_field, self._populate_from))
            start = 2
        else:
            # get slug from the current model instance
            slug = getattr(model_instance, self.attname)
            # model_instance is being modified, and overwrite is False,
            # so instead of doing anything, just return the current slug
            return slug

        # strip slug depending on max_length attribute of the slug field
        # and clean-up
        self.slug_len = slug_field.max_length
        if self.slug_len:
            slug = slug[:self.slug_len]
        slug = self._slug_strip(slug)
        original_slug = slug

        if self.allow_duplicates:
            setattr(model_instance, self.attname, slug)
            return slug

        return super(AutoSlugField, self).find_unique(
            model_instance, slug_field, self.slug_generator(original_slug, start))