[英]Django models slug mixin with unique constraint handling
我在使用SlugField
的models.py
中有三個模型Book
、 Part
、 Chapter
。
對於Book
class,我在自定義save
方法中編寫了一個 slug 處理程序,用於檢查 object 是否與slug
一起存在。 當它這樣做時,它會通過向它附加一個count
來使其獨一無二。
如何將Book
中的塊重寫為SlugMixin
以便我可以用於模型的 rest?
models.py
...
class SlugMixin(models.Model):
slug = models.SlugField(max_length=50, unique=True)
class Meta:
abstract = True
class Book(models.Model):
title = models.CharField(max_length=50)
slug = models.SlugField(max_length=50, unique=True)
def save(self, *args, **kwargs):
if not self.pk and not self.slug:
slug = slugify(self.title, allow_unicode=True)
slug_exists = True
counter = 1
self.slug = slug
while slug_exists:
try:
slug_exists = Book.objects.get(slug=slug)
if slug_exists:
slug = self.slug + '_' + str(counter)
counter += 1
except Book.DoesNotExist:
self.slug=slug
break
class Part(models.Model):
book = models.ForeignKey(Book, on_delete=models.CASCADE, related_name='parts')
title = models.CharField(max_length=30)
slug = models.SlugField(max_length=30, unique=True)
class Chapter(models.Model):
part = models.ForeignKey(Part, on_delete=models.CASCADE, related_name='chapters')
title = models.CharField(max_length=40)
slug = models.SlugField(max_length=40, unique=True)
...
這個怎么樣
SLUG_LENGTH = 50
def get_unique_slug(model_instance):
slugify_title = slugify(model_instance.title, allow_unicode=True)
if len(slugify_title) > SLUG_LENGTH:
slug = slugify_title[:SLUG_LENGTH]
else:
slug = slugify_title
slug_copy = slug
num = 1
while model_instance.__class__.objects.filter(slug=slug).exists():
number_attached_slug = '{}-{}'.format(slug_copy, num)
if len(number_attached_slug) > SLUG_LENGTH:
trimmed_slug = slug_copy[:-(num + 1)] # adding 1 because there is hyphen in the slug
slug = '{}-{}'.format(trimmed_slug, num)
else:
slug = number_attached_slug
num += 1
return slug
class SomeLogicKlass:
def save(self, *args, **kwargs):
if not self.slug:
self.slug = get_unique_slug(self)
super().save(*args, **kwargs)
def __str__(self):
return self.slug
class Book(SomeLogicKlass, models.Model):
...
class Part(SomeLogicKlass, models.Model):
...
注意:確保SLUG_LENGTH
的值與models.SlugField(...)
的max_length
相同
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