Question

我试图将我的模型之一中的字段限制为特定组的所有用户的选择。另一个字段具有所有注册用户的选择。在外壳中可以正常工作：

>>> from django.contrib.auth.models import User, Group
>>> all_users = User.objects.all()
>>> all_users
<QuerySet [<User: somedude>, <User: test>, <User: testma>]>
>>> tm_users = User.objects.filter(groups__name='Testmanager')
>>> tm_users
<QuerySet [<User: somedude>, <User: testma>]>

但是如果我在模型中输入相同的代码：

class TestPlan(models.Model):

    all_users = User.objects.all()
    all_user_choices = ((x.username, x.get_full_name()) for x in all_users)
    tm_users = User.objects.filter(groups__name='Testmanager')
    tm_user_choices = ((x.username, x.get_full_name()) for x in tm_users)
    tp_title = models.CharField(max_length=200, verbose_name='Title')
    tp_manager = models.CharField(max_length=100, blank=True,
                                 verbose_name='Test Manager',
                                  choices=tm_user_choices)
    tp_tester = models.CharField(max_length=100, blank=True,
                                 verbose_name='Tester',
                                 choices=all_user_choices)


    def __str__(self):
        return f'{self.tp_title}'

我得到的堆栈跟踪对我来说没有什么帮助：

O:\somedude\Documents\Python\Django\testcases>manage.py makemigrations
Traceback (most recent call last):
  File "O:\somedude\Documents\Python\Django\testcases\manage.py", line 15, in <module>
    execute_from_command_line(sys.argv)
  File "C:\Program Files\Python36\lib\site-packages\django\core\management\__init__.py", line 381, i
n execute_from_command_line
    utility.execute()
  File "C:\Program Files\Python36\lib\site-packages\django\core\management\__init__.py", line 357, i
n execute
    django.setup()
  File "C:\Program Files\Python36\lib\site-packages\django\__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "C:\Program Files\Python36\lib\site-packages\django\apps\registry.py", line 112, in populate
    app_config.import_models()
  File "C:\Program Files\Python36\lib\site-packages\django\apps\config.py", line 198, in import_mode
ls
    self.models_module = import_module(models_module_name)
  File "C:\Program Files\Python36\lib\importlib\__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "O:\somedude\Documents\Python\Django\testcases\testman\models.py", line 68, in <module>
    class TestPlan(models.Model):
  File "O:\somedude\Documents\Python\Django\testcases\testman\models.py", line 70, in TestPlan
    tm_users = User.objects.filter(groups__name='Testmanager')
  File "C:\Program Files\Python36\lib\site-packages\django\db\models\manager.py", line 82, in manage
r_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "C:\Program Files\Python36\lib\site-packages\django\db\models\query.py", line 844, in filter
    return self._filter_or_exclude(False, *args, **kwargs)
  File "C:\Program Files\Python36\lib\site-packages\django\db\models\query.py", line 862, in _filter
_or_exclude
    clone.query.add_q(Q(*args, **kwargs))
  File "C:\Program Files\Python36\lib\site-packages\django\db\models\sql\query.py", line 1263, in ad
d_q
    clause, _ = self._add_q(q_object, self.used_aliases)
  File "C:\Program Files\Python36\lib\site-packages\django\db\models\sql\query.py", line 1287, in _a
dd_q
    split_subq=split_subq,
  File "C:\Program Files\Python36\lib\site-packages\django\db\models\sql\query.py", line 1164, in bu
ild_filter
    lookups, parts, reffed_expression = self.solve_lookup_type(arg)
  File "C:\Program Files\Python36\lib\site-packages\django\db\models\sql\query.py", line 1028, in so
lve_lookup_type
    _, field, _, lookup_parts = self.names_to_path(lookup_splitted, self.get_meta())
  File "C:\Program Files\Python36\lib\site-packages\django\db\models\sql\query.py", line 1365, in na
mes_to_path
    if field.is_relation and not field.related_model:
  File "C:\Program Files\Python36\lib\site-packages\django\utils\functional.py", line 37, in __get__

    res = instance.__dict__[self.name] = self.func(instance)
  File "C:\Program Files\Python36\lib\site-packages\django\db\models\fields\related.py", line 94, in
 related_model
    apps.check_models_ready()
  File "C:\Program Files\Python36\lib\site-packages\django\apps\registry.py", line 137, in check_mod
els_ready
    raise AppRegistryNotReady("Models aren't loaded yet.")
django.core.exceptions.AppRegistryNotReady: Models aren't loaded yet.

O:\somedude\Documents\Python\Django\testcases>

当我执行User.objects.all（）时它可以工作，但是当我尝试按组过滤用户时它就会失败。我真的不知道我在做什么错。这是错误还是功能？

Answer 1

您可能必须覆盖save方法和clean方法：

from django.core.exceptions import ValidationError

def clean(self):
    if self.tp_manager and not self.tp_manager.groups.filter(name='Testmanager').exists():
        raise ValidationError({'tp_manager': 'ValidationError Msg'})

def save(self, *args, **kwargs):
    self.full_clean()
    return super().save(*args, **kwargs)

Django文档：https://docs.djangoproject.com/en/2.0/ref/models/instances/#django.db.models.Model.clean

否则，您可以使用ModelForm并编写一个清理函数来实施验证检查。

如果要使用表格，则可以轻松处理动态选择。

class TestPlanForm(forms.ModelForm):

def __init__(self, *args, **kwargs):
    super().__init__(*args, **kwargs)
    tm_users = User.objects.filter(groups__name='Testmanager')
    tm_user_choices = ((x.username, x.get_full_name()) for x in tm_users)
    self.fields['tp_manager'].choices = tm_user_choices

class Meta:
    model = TestPlan
    fields = '__all__'

Answer 2

“ choices”字段属性不能是动态的，必须是静态集，例如：

MONTH_CHOICES = (
    ("JANUARY", "January"),
    ("FEBRUARY", "February"),
    ("MARCH", "March"),
    # ....
    ("DECEMBER", "December"),
)

如果需要此限制，则可以使用“ django形式”或“ DRF序列化器”逻辑来验证这种情况。

Answer 3

虽然我没有找到原始问题的答案，但已经解决了潜在的问题。这样做的方法是将模型字段定义为外键：

class TestPlan(models.Model):
    tp_title = models.CharField(max_length=200, verbose_name='Title')
    tp_manager = models.ForeignKey(User, on_delete=models.SET_NULL,
                    blank=True, null=True, verbose_name='Test Manager',
                    limit_choices_to={'groups__name': 'Testmanager'},
                    related_name='testmanager_set')
    tp_tester = models.ForeignKey(User, on_delete=models.SET_NULL,
                                  blank=True, null=True, verbose_name='Tester')

limit_choices_to参数的作用与原始帖子中的User.objects.filter（groups__name ='Testmanager'）相同。由于我现在在同一模型上有两个外键字段，因此需要related_name参数。

将组的所有用户添加为模型字段中的选项

3 个答案: