Django 1.11循环导入错误及URL路径不匹配问题求助

Hey there, let's work through your two Django 1.11 issues—circular imports and the frustrating "current path doesn't match" URL error. I'll break down practical fixes for each below.

First: Resolving Circular Imports #

Circular imports pop up when two modules try to import from each other at the top level. Here are the most reliable fixes for Django projects:

• Delay imports to inside functions/methods
  Instead of importing a module at the top of your file, move the import statement inside the function that actually uses it. This avoids the upfront loop:

  # Bad: Circular import risk at top level
  from myapp.views import MyView
  
  def my_function():
      # ...
  

  # Good: Import only when needed
  def my_function():
      from myapp.views import MyView
      # Use MyView here
  

• Extract shared code to a separate module
  If two modules are importing each other to access shared logic (like constants, utility functions, or base classes), move that code into a new module (e.g., myapp/utils.py or myapp/core.py). Both original modules can import from this shared file without creating a loop.

• Use string references for Django model relationships
  When defining ForeignKey, ManyToManyField, etc., use a string like 'app_name.ModelName' instead of importing the model directly. Django resolves this lazily, skipping the circular import:

  # Instead of:
  from otherapp.models import OtherModel
  class MyModel(models.Model):
      other = models.ForeignKey(OtherModel, on_delete=models.CASCADE)
  
  # Do this:
  class MyModel(models.Model):
      other = models.ForeignKey('otherapp.OtherModel', on_delete=models.CASCADE)
  

Second: Fixing the "Current Path Doesn't Match" URL Error #

This error means the URL you're requesting doesn't align with any pattern in your URLconf. Let's check the most common culprits:

• Verify your root URLconf includes
  Double-check that you've correctly included your app's URLs in the project's urls.py—no typos in the path, regex, or namespace:

  # Project urls.py
  from django.conf.urls import url, include
  
  urlpatterns = [
      url(r'^myapp/', include('myapp.urls')),  # Confirm regex and app name are correct
  ]
  

• Check app-level URL patterns
  Ensure your app's urls.py has valid regex patterns. Common mistakes include missing trailing slashes (Django's APPEND_SLASH setting might handle this, but not always), incorrect capture groups, or typos in view names:

  # App urls.py
  from django.conf.urls import url
  from . import views
  
  urlpatterns = [
      url(r'^$', views.home, name='home'),  # Matches /myapp/
      url(r'^detail/(?P<id>\d+)/$', views.detail, name='detail'),  # Matches /myapp/detail/123/
  ]
  

• Confirm the requested URL matches exactly
  Django's URL matching is case-sensitive and exact (unless your regex uses wildcards). If you're requesting http://localhost:8000/myapp/Detail/123/ but your pattern uses detail, it won't match. Also, check for extra slashes or missing path segments.

• Check named URL usage
  If you're using reverse() or template {% url %} tags, make sure you're passing the correct arguments and using the right namespace (if set in include()). A missing or incorrect argument can generate a non-existent URL, triggering the error.

Your Traceback for Reference #

Traceback (most recent call last):
File "C:\Python3\envs\myDjangoEnv\lib\site-packages\django\utils\autoreload.py", line 228, in wrapper
fn(*args, **kwargs)
File "C:\Python3\envs\myDjangoEnv\lib\site-packages\django\core\management\commands\runserver.py", line 124, in inner_run
self.check(display_num_errors=True)
File "C:\Python3\envs\myDjangoEnv\lib\site-packages\django\core\management\base.py", line 359, in check
include_deployment_checks=include...

内容的提问来源于stack exchange，提问作者Elijah Lewis