问题
So I have a Django project that doesn't use a database (the 'DATABASES' setting is commented out). I chose to use Django as there's a chance I will need the database functionality in the future. Anyway, I've been working on and off of tbhis project for a couple of months with no problems. I'm running Linux Mint and have had no troubles using the python manage.py runserver command so far.
Well, today I fired up the app and started the local server with no problems. I then tried to open the app in my browser and received the rather hideous error message:
Traceback (most recent call last):
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/contrib/sessions/backends/base.py", line 170, in _get_session
return self._session_cache
AttributeError: 'SessionStore' object has no attribute '_session_cache'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/core/handlers/base.py", line 87, in get_response
response = middleware_method(request)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/contrib/auth/middleware.py", line 34, in process_request
if user and hasattr(user, 'get_session_auth_hash'):
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/utils/functional.py", line 224, in inner
self._setup()
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/utils/functional.py", line 357, in _setup
self._wrapped = self._setupfunc()
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/contrib/auth/middleware.py", line 23, in <lambda>
request.user = SimpleLazyObject(lambda: get_user(request))
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/contrib/auth/middleware.py", line 11, in get_user
request._cached_user = auth.get_user(request)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/contrib/auth/__init__.py", line 151, in get_user
user_id = request.session[SESSION_KEY]
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/contrib/sessions/backends/base.py", line 49, in __getitem__
return self._session[key]
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/contrib/sessions/backends/base.py", line 175, in _get_session
self._session_cache = self.load()
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/contrib/sessions/backends/db.py", line 21, in load
expire_date__gt=timezone.now()
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/manager.py", line 92, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/query.py", line 351, in get
num = len(clone)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/query.py", line 122, in __len__
self._fetch_all()
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/query.py", line 966, in _fetch_all
self._result_cache = list(self.iterator())
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/query.py", line 265, in iterator
for row in compiler.results_iter():
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/sql/compiler.py", line 700, in results_iter
for rows in self.execute_sql(MULTI):
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/sql/compiler.py", line 775, in execute_sql
sql, params = self.as_sql()
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/sql/compiler.py", line 100, in as_sql
out_cols, s_params = self.get_columns(with_col_aliases)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/sql/compiler.py", line 246, in get_columns
col_aliases)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/sql/compiler.py", line 328, in get_default_columns
r = '%s.%s' % (qn(alias), qn2(column))
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/sql/compiler.py", line 62, in __call__
r = self.connection.ops.quote_name(name)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/backends/dummy/base.py", line 18, in complain
raise ImproperlyConfigured("settings.DATABASES is improperly configured. "
django.core.exceptions.ImproperlyConfigured: settings.DATABASES is improperly configured. Please supply the ENGINE value. Check settings documentation for more details.
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/contrib/sessions/backends/base.py", line 170, in _get_session
return self._session_cache
AttributeError: 'SessionStore' object has no attribute '_session_cache'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/lib/python3.3/wsgiref/handlers.py", line 137, in run
self.result = application(self.environ, self.start_response)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/contrib/staticfiles/handlers.py", line 64, in __call__
return self.application(environ, start_response)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/core/handlers/wsgi.py", line 187, in __call__
response = self.get_response(request)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/core/handlers/base.py", line 199, in get_response
response = self.handle_uncaught_exception(request, resolver, sys.exc_info())
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/core/handlers/base.py", line 236, in handle_uncaught_exception
return debug.technical_500_response(request, *exc_info)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/views/debug.py", line 91, in technical_500_response
html = reporter.get_traceback_html()
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/views/debug.py", line 349, in get_traceback_html
c = Context(self.get_traceback_data(), use_l10n=False)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/views/debug.py", line 307, in get_traceback_data
frames = self.get_traceback_frames()
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/views/debug.py", line 465, in get_traceback_frames
'vars': self.filter.get_traceback_frame_variables(self.request, tb.tb_frame),
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/views/debug.py", line 232, in get_traceback_frame_variables
cleansed[name] = self.cleanse_special_types(request, value)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/views/debug.py", line 187, in cleanse_special_types
if isinstance(value, HttpRequest):
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/utils/functional.py", line 224, in inner
self._setup()
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/utils/functional.py", line 357, in _setup
self._wrapped = self._setupfunc()
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/contrib/auth/middleware.py", line 23, in <lambda>
request.user = SimpleLazyObject(lambda: get_user(request))
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/contrib/auth/middleware.py", line 11, in get_user
request._cached_user = auth.get_user(request)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/contrib/auth/__init__.py", line 151, in get_user
user_id = request.session[SESSION_KEY]
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/contrib/sessions/backends/base.py", line 49, in __getitem__
return self._session[key]
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/contrib/sessions/backends/base.py", line 175, in _get_session
self._session_cache = self.load()
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/contrib/sessions/backends/db.py", line 21, in load
expire_date__gt=timezone.now()
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/manager.py", line 92, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/query.py", line 351, in get
num = len(clone)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/query.py", line 122, in __len__
self._fetch_all()
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/query.py", line 966, in _fetch_all
self._result_cache = list(self.iterator())
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/query.py", line 265, in iterator
for row in compiler.results_iter():
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/sql/compiler.py", line 700, in results_iter
for rows in self.execute_sql(MULTI):
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/sql/compiler.py", line 775, in execute_sql
sql, params = self.as_sql()
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/sql/compiler.py", line 100, in as_sql
out_cols, s_params = self.get_columns(with_col_aliases)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/sql/compiler.py", line 246, in get_columns
col_aliases)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/sql/compiler.py", line 328, in get_default_columns
r = '%s.%s' % (qn(alias), qn2(column))
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/models/sql/compiler.py", line 62, in __call__
r = self.connection.ops.quote_name(name)
File "/home/peter/.virtualenvs/vis_it/lib/python3.3/site-packages/django/db/backends/dummy/base.py", line 18, in complain
raise ImproperlyConfigured("settings.DATABASES is improperly configured. "
django.core.exceptions.ImproperlyConfigured: settings.DATABASES is improperly configured. Please supply the ENGINE value. Check settings documentation for more details.
[28/Nov/2014 13:18:54] "GET / HTTP/1.1" 500 59
I've not touched the app since I last worked on it and it was working fine then. I really have no idea what this is talking about as I have no caches implemented and am not using a database... I've asked a few colleges who are familiar with Django and have no idea what this is either. Any Ideas? I've also tried setting DATABASES to an empty dict {} on the advice of a post online but to no effect. At a bit of a loss.
EDIT: Thought I should mention that in the interim since I last touched this project, I've since started and set up a new Django project that does use a database. Is it possible that this project is somehow cached and breaking the one I'm currently trying to work on?
EDIT2: I should point out that this webapp is currently live and working at http://mrcagney-maps.com. The code is exactly the same (having not touched it since I last pushed to the server). Really weird.
回答1:
The error AttributeError: 'SessionStore' object has no attribute '_session_cache' can stem from the database not having a django_session table. However, since you are not using a table, you would need to make sure that you don't have the 'django.contrib.sessions.middleware.SessionMiddleware' in your MIDDLEWARE_CLASSES in the project's settings file. If it is in there, it will look for a database table which stores the sessions, causing the above error.
回答2:
Here is what worked for me. Since there is no databases in your application. Admin page looks for the database be it default. So first lets create the default databases.
Shut down your servers and run
python manage.py makemigrations
python manage.py migrate
Now create the admin or superuser for your application. Fill username and password.
python manage.py createsuperuser
Now restart your server and go the admin page
python manage.py runserver
来源：https://stackoverflow.com/questions/27180353/django-project-looking-for-attribute-session-cache