Django 在安装 cors-headers 后尝试运行服务器时出错

Question

So I'm trying to make a Django back-end for my project. It's my first time doing something like this, so when I got a CORS error (CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.) I Googled what to do. After doing the steps following the documentation, I've got the following error when trying to run 'python manage.py runserver'.

    C:\Users\Bence\Documents\Programozás-tanulás\web50\final project\benefactum>python manage.py runserver
Watching for file changes with StatReloader
Exception in thread django-main-thread:
Traceback (most recent call last):
  File "C:\Python310\lib\threading.py", line 1009, in _bootstrap_inner
    self.run()
  File "C:\Python310\lib\threading.py", line 946, in run
    self._target(*self._args, **self._kwargs)
  File "C:\Users\Bence\AppData\Roaming\Python\Python310\site-packages\django\utils\autoreload.py", line 64, in wrapper
    fn(*args, **kwargs)
  File "C:\Users\Bence\AppData\Roaming\Python\Python310\site-packages\django\core\management\commands\runserver.py", line 115, in inner_run
    autoreload.raise_last_exception()
  File "C:\Users\Bence\AppData\Roaming\Python\Python310\site-packages\django\utils\autoreload.py", line 87, in raise_last_exception
    raise _exception[1]
  File "C:\Users\Bence\AppData\Roaming\Python\Python310\site-packages\django\core\management\__init__.py", line 381, in execute
    autoreload.check_errors(django.setup)()
  File "C:\Users\Bence\AppData\Roaming\Python\Python310\site-packages\django\utils\autoreload.py", line 64, in wrapper
    fn(*args, **kwargs)
  File "C:\Users\Bence\AppData\Roaming\Python\Python310\site-packages\django\__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "C:\Users\Bence\AppData\Roaming\Python\Python310\site-packages\django\apps\registry.py", line 114, in populate
    app_config.import_models()
  File "C:\Users\Bence\AppData\Roaming\Python\Python310\site-packages\django\apps\config.py", line 300, in import_models
    self.models_module = import_module(models_module_name)
  File "C:\Python310\lib\importlib\__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 883, in exec_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "C:\Python310\lib\site-packages\corsheaders\models.py", line 4, in <module>
    from .signals import check_request_enabled  # noqa
  File "C:\Python310\lib\site-packages\corsheaders\signals.py", line 5, in <module>
    check_request_enabled = django.dispatch.Signal(
TypeError: Signal.__init__() got an unexpected keyword argument 'providing_args'

I've done the following steps, following the documentation:

1. Installing it from pip (pip install django-cors-headers)
2. I've added 'corsheaders' to the INSTALLED_APPS (in settings.py)
3. Adding "corsheaders.middleware.CorsMiddleware", "django.middleware.common.CommonMiddleware" to MIDDLEWARE (in settings.py, putting them as high as possible as per document recommendation)
4. Added CORS_ALLOW_ALL_ORIGINS = True

Is the problem even related to me adding cors-headers? I'm only assuming, because it was working before I did. Any help would be greatly appreciated!

Answer 1

Answer:

Go to your Python installation folder -> Lib -> site-packages -> corsheaders -> signal.py file. (for me it was C:\Python310\Lib\site-packages\corsheaders\signal.py)

I solved the issue by changing the file to the following:

from django.dispatch import Signal

# Return Truthy values to enable a specific request.
# This allows users to build custom logic into the request handling
check_request_enabled = Signal()

More details and smarter explanation: https://github.com/django-notifications/django-notifications/issues/322

Answer 2

The providing_args kwarg was removed in Django 4.0.

It's impossible for this to happen if you have properly installed django-cors-headers 3.10.1, since this was fixed in 3.3 . In addition, the line in your traceback does not exist in version 3.10.1 of the library .

1. Make sure you don't have multiple different versions of the library installed, eg one within a virtualenv and one outside it (you clearly seem to have one outside a virtualenv).
   • In fact, you seem to have two Python 3.10 installations altogether, one in AppData\Roaming\Python\Python310 and one in C:\Python310 . You will want to clean that up first.
2. If you aren't using virtualenvs, please start using them to separate the dependencies of your different projects from one another.