我已经看到很多这样的错误，但是没有一个与我正在搜索的错误相匹配，因此请帮助我了解在将信号保存为Django时我在哪里出错。我知道该save方法正在无限运行，但是由于我是初学者，我如何才能停止在代码中执行？
from django.db import models
import random
import os
from .utils import unique_slug_generator
from django.db.models.signals import pre_save, post_save
class ProductQuerySet(models.query.QuerySet):
def active(self):
return self.filter(active=True)
def featured(self):
return self.filter(featured=True, active=True)
class ProductManager(models.Manager):
def get_queryset(self):
return ProductQuerySet(self.model, using=self._db)
def all(self):
return self.get_queryset().active()
def features(self):
return self.get_queryset().featured()
def get_by_id(self, id):
qs=self.get_queryset().filter(id=id)
if qs.count() ==1:
return qs.first()
return None
# Create your models here.
class Product(models.Model):
title = models.CharField(max_length=120)
slug = models.SlugField(blank=True, unique=True)
description = models.TextField()
price = models.DecimalField(decimal_places=2, max_digits=20, default=39.99)
image = models.ImageField(upload_to='products/', null=True, blank=True)
featured = models.BooleanField(default=False)
active = models.BooleanField(default=True)
objects=ProductManager()
def __str__(self):
return self.title
def __unicode__(self):
return self.title
def product_pre_save_receiver(sender, instance, *args, **kwargs):
if not instance.slug:
instance.slug = unique_slug_generator(instance)
pre_save.connect(product_pre_save_receiver, sender=Product)
这可能是model.py
from django.utils.text import slugify
import random
import string
def random_string_generator(size=10, chars=string.ascii_lowercase+string.digits):
return ''.join(random.choice(chars) for _ in range(size))
def unique_slug_generator(instance, new_slug=None):
if new_slug is not None:
slug = new_slug
else:
slug = slugify(instance.title)
klass = instance.__class__
qs_exists = klass.objects.filter(slug=slug).exists()
if qs_exists:
ne_slug = "{slug}-{randstr}".format(
slug=slug,
randstr=random_string_generator(size=4)
)
return unique_slug_generator(instance, new_slug=new_slug)
return slug
这是我的utils.py
堆栈跟踪
System check identified no issues (0 silenced).
April 20, 2020 - 16:27:28
Django version 3.0.5, using settings 'ecommerce.settings'
Starting development server at http://127.0.0.1:8000/
Quit the server with CTRL-BREAK.
Internal Server Error: /admin/products/product/add/
Traceback (most recent call last):
File "C:\ProgramData\Anaconda3\lib\site-packages\django\core\handlers\exception.py", line 34, in inner
response = get_response(request)
File "C:\ProgramData\Anaconda3\lib\site-packages\django\core\handlers\base.py", line 115, in _get_response
response = self.process_exception_by_middleware(e, request)
File "C:\ProgramData\Anaconda3\lib\site-packages\django\core\handlers\base.py", line 113, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "C:\ProgramData\Anaconda3\lib\site-packages\django\contrib\admin\options.py", line 607, in wrapper
return self.admin_site.admin_view(view)(*args, **kwargs)
File "C:\ProgramData\Anaconda3\lib\site-packages\django\utils\decorators.py", line 130, in _wrapped_view
response = view_func(request, *args, **kwargs)
File "C:\ProgramData\Anaconda3\lib\site-packages\django\views\decorators\cache.py", line 44, in _wrapped_view_func
response = view_func(request, *args, **kwargs)
File "C:\ProgramData\Anaconda3\lib\site-packages\django\contrib\admin\sites.py", line 231, in inner
return view(request, *args, **kwargs)
File "C:\ProgramData\Anaconda3\lib\site-packages\django\contrib\admin\options.py", line 1638, in add_view
return self.changeform_view(request, None, form_url, extra_context)
File "C:\ProgramData\Anaconda3\lib\site-packages\django\utils\decorators.py", line 43, in _wrapper
return bound_method(*args, **kwargs)
File "C:\ProgramData\Anaconda3\lib\site-packages\django\utils\decorators.py", line 130, in _wrapped_view
response = view_func(request, *args, **kwargs)
File "C:\ProgramData\Anaconda3\lib\site-packages\django\contrib\admin\options.py", line 1522, in changeform_view
return self._changeform_view(request, object_id, form_url, extra_context)
File "C:\ProgramData\Anaconda3\lib\site-packages\django\contrib\admin\options.py", line 1565, in _changeform_view
self.save_model(request, new_object, form, not add)
File "C:\ProgramData\Anaconda3\lib\site-packages\django\contrib\admin\options.py", line 1081, in save_model
obj.save()
File "C:\ProgramData\Anaconda3\lib\site-packages\django\db\models\base.py", line 746, in save
force_update=force_update, update_fields=update_fields)
File "C:\ProgramData\Anaconda3\lib\site-packages\django\db\models\base.py", line 771, in save_base
update_fields=update_fields,
File "C:\ProgramData\Anaconda3\lib\site-packages\django\dispatch\dispatcher.py", line 175, in send
for receiver in self._live_receivers(sender)
File "C:\ProgramData\Anaconda3\lib\site-packages\django\dispatch\dispatcher.py", line 175, in <listcomp>
for receiver in self._live_receivers(sender)
File "F:\Ecom\DjangoEcommerce\products\models.py", line 69, in product_pre_save_receiver
instance.slug = unique_slug_generator(instance)
File "F:\Ecom\DjangoEcommerce\products\utils.py", line 22, in unique_slug_generator
return unique_slug_generator(instance, new_slug=new_slug)
File "F:\Ecom\DjangoEcommerce\products\utils.py", line 22, in unique_slug_generator
return unique_slug_generator(instance, new_slug=new_slug)
File "F:\Ecom\DjangoEcommerce\products\utils.py", line 22, in unique_slug_generator
return unique_slug_generator(instance, new_slug=new_slug)
[Previous line repeated 920 more times]
File "F:\Ecom\DjangoEcommerce\products\utils.py", line 16, in unique_slug_generator
qs_exists = klass.objects.filter(slug=slug).exists()
File "C:\ProgramData\Anaconda3\lib\site-packages\django\db\models\query.py", line 777, in exists
return self.query.has_results(using=self.db)
File "C:\ProgramData\Anaconda3\lib\site-packages\django\db\models\sql\query.py", line 537, in has_results
return compiler.has_results()
File "C:\ProgramData\Anaconda3\lib\site-packages\django\db\models\sql\compiler.py", line 1121, in has_results
return bool(self.execute_sql(SINGLE))
File "C:\ProgramData\Anaconda3\lib\site-packages\django\db\models\sql\compiler.py", line 1138, in execute_sql
sql, params = self.as_sql()
File "C:\ProgramData\Anaconda3\lib\site-packages\django\db\models\sql\compiler.py", line 490, in as_sql
extra_select, order_by, group_by = self.pre_sql_setup()
File "C:\ProgramData\Anaconda3\lib\site-packages\django\db\models\sql\compiler.py", line 51, in pre_sql_setup
self.setup_query()
File "C:\ProgramData\Anaconda3\lib\site-packages\django\db\models\sql\compiler.py", line 42, in setup_query
self.select, self.klass_info, self.annotation_col_map = self.get_select()
File "C:\ProgramData\Anaconda3\lib\site-packages\django\db\models\sql\compiler.py", line 218, in get_select
select.append((RawSQL(sql, params), alias))
File "C:\ProgramData\Anaconda3\lib\site-packages\django\db\models\expressions.py", line 711, in __init__
output_field = fields.Field()
File "C:\ProgramData\Anaconda3\lib\site-packages\django\db\models\fields\__init__.py", line 156, in __init__
if isinstance(choices, collections.abc.Iterator):
File "C:\ProgramData\Anaconda3\lib\abc.py", line 139, in __instancecheck__
return _abc_instancecheck(cls, instance)
RecursionError: maximum recursion depth exceeded in comparison
答案 0 :(得分：2)
我建议您尝试使用while循环而不是递归，因为这比递归有效得多，并且不会影响程序堆栈。
也许是这样的：
def unique_slug_generator(instance, new_slug=None):
if new_slug is not None:
slug = new_slug
else:
slug = slugify(instance.title)
klass = instance.__class__
while True:
if not klass.objects.filter(slug=slug).exists():
return slug
slug = "{slug}-{randstr}".format(
slug=slug,
randstr=random_string_generator(size=4)
)