shell 中的错误：未声明显式 app_label 且不在 INSTALLED_APPS 中的应用程序中

Posted 2023-04-14

【中文标题】shell 中的错误：未声明显式 app_label 且不在 INSTALLED_APPS 中的应用程序中

【英文标题】：Error in shell: doesn't declare an explicit app_label and isn't in an application in INSTALLED_APPS

【发布时间】：2018-03-31 21:14:15

【问题描述】：

我第一次尝试 Django。阅读“Django 1.11 的两勺”一书。伟大的阅读。只有脚本经验和 Python 新手，我正在尽最大努力遵循书籍标准。

使用“cookiecutter-django”启动的项目制作了一个带有 TimeStampedModel 的简单地址应用程序进行实验。

适用于 makemigrations、migrate、admin 和 runserver。没问题，它就像一个魅力。

但是，我想在 csv 导入和绑定到表单上尝试本书示例，但我想从 shell 运行它进行测试。

以下内容可能过于冗长，但我不确定如何继续。

python manage.py shell --settings=config.settings.local

导入所需代码时出现错误（任何其他形式或模型得到相同的结果）：

In [1]: from address.forms import add_csv_postarea
---------------------------------------------------------------------------
RuntimeError                              Traceback (most recent call last)
<ipython-input-1-f253686866ed> in <module>()
----> 1 from address.forms import add_csv_postarea

~/projects/myproject/myproject/address/forms.py in <module>()
      5 from django import forms
      6 
----> 7 from .models import PostArea, Address
      8 
      9 

~/projects/myproject/myproject/address/models.py in <module>()
      7 
      8 
----> 9 class Country(TimeStampedModel):
     10     """ ISO 3166 Country codes
     11         https://en.wikipedia.org/wiki/ISO_3166-1

~/.virtualenvs/myproject/lib/python3.6/site-packages/django/db/models/base.py in __new__(cls, name, bases, attrs)
    116                         "Model class %s.%s doesn't declare an explicit "
    117                         "app_label and isn't in an application in "
--> 118                         "INSTALLED_APPS." % (module, name)
    119                     )
    120 

RuntimeError: Model class address.models.Country doesn't declare an explicit app_label and isn't in an application in INSTALLED_APPS.

上面提到的模型还没有实现，但是如果我把模型注释掉，下一个模型 PostArea 也会有同样的问题。

这是我的相关设置：

配置/设置/base.py

...
# Apps specific for this project go here.
LOCAL_APPS = [
    # custom users app
    'myproject.users.apps.UsersConfig',

    # Your stuff: custom apps go here
    'myproject.core', # Containing the abstract class TimeStampedModel
    'myproject.address', # including the address and PostArea models
]
...

配置/urls.py

urlpatterns = [
    ...
    # Your stuff: custom urls includes go here
    url(r'^address/', include('myproject.address.urls', namespace='address')),

我的项目/地址/forms.py

import csv

from django.utils.six import StringIO

from django import forms

from .models import PostArea, Address


class AddressForm(forms.ModelForm):

    class Meta:

        model = Address
        fields = ['line1', 'line2', 'post_area']


class PostAreaForm(forms.ModelForm):

    class Meta:

        model = PostArea
        fields = ['code', 'name']


def add_csv_postarea(rows):
    """ Two Scoops of Django 1.11 - page 167
        Importing Postal addresses from a CSV file

        Data source: https://data.norge.no/data/posten-norge/postnummer-i-norge
    """

    rows = StringIO(rows)

    records_added = 0
    errors = []

    # Generate a dict per row, overriding the first CSV row missing keys
    for row in csv.DictReader(rows, fieldnames=('code', 'name')):

        # Bind the row to PostAreaForm
        form = PostAreaForm(row)
        # Check to see if the row is valid
        if form.is_valid():
            # Row data is valid so save the record.
            form.save()
            records_added += 1
        else:
            errors.append(form.errors)

    return records_added, errors

我的项目/地址/models.py

import uuid as uuid_lib

from django.db import models
from django.urls import reverse

from core.models import TimeStampedModel


class Country(TimeStampedModel):
    """ ISO 3166 Country codes
        https://en.wikipedia.org/wiki/ISO_3166-1
    """
    iso_2 = models.CharField(max_length=2, null=False)
    iso_3 = models.CharField(max_length=3, null=False)
    iso_numeric = models.CharField(max_length=3, null=False)
    name_gb = models.CharField(max_length=30)
    name_no = models.CharField(max_length=30)

    def __str__(self):
        return self.iso_2

    class Meta:
        verbose_name = "Country"
        verbose_name_plural = "Countries"


class PostArea(TimeStampedModel):
    """ Norwegian PostArea code and are
        Foreign keys linking connected municipals
    """

    code = models.CharField(max_length=12)
    name = models.CharField(max_length=200)

    def __str__(self):
        return self.code

    class Meta:
        verbose_name = "Postal area"
        verbose_name_plural = "Postal Areas"


class Address(TimeStampedModel):
    """ Reusable Entities Addresses with relations to
            - PostArea
            - Country
    """

    uuid = models.UUIDField(
        primary_key=True,
        default=uuid_lib.uuid4(),
        editable=False
    )
    line1 = models.CharField(max_length=100)
    line2 = models.CharField(max_length=100, blank=True)
    post_area = models.ForeignKey(
        PostArea,
        on_delete=models.PROTECT,
        null=True,
    )

    def __str__(self):
        return self.line1

    def post_name_callable(self):
        return self.post_area.name

    def get_absolute_url(self):
        return reverse('address:detail', kwargs='pk': self.uuid)

    class Meta:
        verbose_name = "Address"
        verbose_name_plural = "Addresses"

【问题讨论】：

您的导入似乎不一致。您同时拥有myproject.address 和from address.forms。如果您在任何地方都使用myproject.address，它可能会解决问题。

感谢 @Alasdair 在 shell 中使用 from myproject.address.forms import add_csv_postarea 解决了这个问题。我是新来的 - 我怎样才能给你学分？

@henningb 你只能给出答案。由于他是评论，因此您可以对此表示赞同。您也可以回答自己的问题并接受它，以便下一个出现的人可以轻松找到它。或者您可以要求 Alasdair 发表他的评论作为答案并接受该评论。

@henningb 我已将其添加为答案，如果它解决了您的问题，您可以接受它。

【参考方案1】：

在您的INSTALLED_APPS 中，您已包含myproject.address。因此，您应该使用 myproject.address 而不是 address 进行导入。

例如，改变，

from address.forms import add_csv_postarea

到

from myproject.address.forms import add_csv_postarea

我不确定为什么您的项目布局允许您导入与 myproject 和 myproject.address 相同的模块。在 Django 的早期，这样做很容易导致奇怪的错误，但是在 Django 1.4 中更改了默认项目布局以避免这种方式。

【讨论】：

谢谢！ @alasdair 我差点把头发拉出来。如此简单，但很难弄清楚:-)