django1/django/core/handlers/base.py

279 lines
12 KiB
Python

from __future__ import unicode_literals
import logging
import sys
import types
import warnings
from django.conf import settings
from django.core import signals
from django.core.exceptions import ImproperlyConfigured, MiddlewareNotUsed
from django.db import connections, transaction
from django.middleware.exception import ExceptionMiddleware
from django.urls import get_resolver, get_urlconf, set_urlconf
from django.utils import six
from django.utils.deprecation import RemovedInDjango20Warning
from django.utils.module_loading import import_string
from django.views import debug
logger = logging.getLogger('django.request')
class BaseHandler(object):
def __init__(self):
self._request_middleware = None
self._view_middleware = None
self._template_response_middleware = None
self._response_middleware = None
self._exception_middleware = None
self._middleware_chain = None
def load_middleware(self):
"""
Populate middleware lists from settings.MIDDLEWARE (or the deprecated
MIDDLEWARE_CLASSES).
Must be called after the environment is fixed (see __call__ in subclasses).
"""
self._request_middleware = []
self._view_middleware = []
self._template_response_middleware = []
self._response_middleware = []
self._exception_middleware = []
if settings.MIDDLEWARE is None:
warnings.warn(
"Old-style middleware using settings.MIDDLEWARE_CLASSES is "
"deprecated. Update your middleware and use settings.MIDDLEWARE "
"instead.", RemovedInDjango20Warning
)
handler = self._legacy_get_response
for middleware_path in settings.MIDDLEWARE_CLASSES:
mw_class = import_string(middleware_path)
try:
mw_instance = mw_class()
except MiddlewareNotUsed as exc:
if settings.DEBUG:
if six.text_type(exc):
logger.debug('MiddlewareNotUsed(%r): %s', middleware_path, exc)
else:
logger.debug('MiddlewareNotUsed: %r', middleware_path)
continue
if hasattr(mw_instance, 'process_request'):
self._request_middleware.append(mw_instance.process_request)
if hasattr(mw_instance, 'process_view'):
self._view_middleware.append(mw_instance.process_view)
if hasattr(mw_instance, 'process_template_response'):
self._template_response_middleware.insert(0, mw_instance.process_template_response)
if hasattr(mw_instance, 'process_response'):
self._response_middleware.insert(0, mw_instance.process_response)
if hasattr(mw_instance, 'process_exception'):
self._exception_middleware.insert(0, mw_instance.process_exception)
else:
handler = self._get_response
for middleware_path in reversed(settings.MIDDLEWARE):
middleware = import_string(middleware_path)
try:
mw_instance = middleware(handler)
except MiddlewareNotUsed as exc:
if settings.DEBUG:
if six.text_type(exc):
logger.debug('MiddlewareNotUsed(%r): %s', middleware_path, exc)
else:
logger.debug('MiddlewareNotUsed: %r', middleware_path)
continue
if mw_instance is None:
raise ImproperlyConfigured(
'Middleware factory %s returned None.' % middleware_path
)
if hasattr(mw_instance, 'process_view'):
self._view_middleware.insert(0, mw_instance.process_view)
if hasattr(mw_instance, 'process_template_response'):
self._template_response_middleware.append(mw_instance.process_template_response)
handler = mw_instance
handler = ExceptionMiddleware(handler, self)
# We only assign to this when initialization is complete as it is used
# as a flag for initialization being complete.
self._middleware_chain = handler
def make_view_atomic(self, view):
non_atomic_requests = getattr(view, '_non_atomic_requests', set())
for db in connections.all():
if db.settings_dict['ATOMIC_REQUESTS'] and db.alias not in non_atomic_requests:
view = transaction.atomic(using=db.alias)(view)
return view
def get_exception_response(self, request, resolver, status_code, exception):
try:
callback, param_dict = resolver.resolve_error_handler(status_code)
# Unfortunately, inspect.getargspec result is not trustable enough
# depending on the callback wrapping in decorators (frequent for handlers).
# Falling back on try/except:
try:
response = callback(request, **dict(param_dict, exception=exception))
except TypeError:
warnings.warn(
"Error handlers should accept an exception parameter. Update "
"your code as this parameter will be required in Django 2.0",
RemovedInDjango20Warning, stacklevel=2
)
response = callback(request, **param_dict)
except Exception:
signals.got_request_exception.send(sender=self.__class__, request=request)
response = self.handle_uncaught_exception(request, resolver, sys.exc_info())
return response
def get_response(self, request):
"""Return an HttpResponse object for the given HttpRequest."""
# Setup default url resolver for this thread
set_urlconf(settings.ROOT_URLCONF)
response = self._middleware_chain(request)
try:
# Apply response middleware, regardless of the response
for middleware_method in self._response_middleware:
response = middleware_method(request, response)
# Complain if the response middleware returned None (a common error).
if response is None:
raise ValueError(
"%s.process_response didn't return an "
"HttpResponse object. It returned None instead."
% (middleware_method.__self__.__class__.__name__))
except Exception: # Any exception should be gathered and handled
signals.got_request_exception.send(sender=self.__class__, request=request)
response = self.handle_uncaught_exception(request, get_resolver(get_urlconf()), sys.exc_info())
response._closable_objects.append(request)
# If the exception handler returns a TemplateResponse that has not
# been rendered, force it to be rendered.
if not getattr(response, 'is_rendered', True) and callable(getattr(response, 'render', None)):
response = response.render()
if response.status_code == 404:
logger.warning(
'Not Found: %s', request.path,
extra={'status_code': 404, 'request': request},
)
return response
def _get_response(self, request):
response = None
if hasattr(request, 'urlconf'):
urlconf = request.urlconf
set_urlconf(urlconf)
resolver = get_resolver(urlconf)
else:
resolver = get_resolver()
resolver_match = resolver.resolve(request.path_info)
callback, callback_args, callback_kwargs = resolver_match
request.resolver_match = resolver_match
# Apply view middleware
for middleware_method in self._view_middleware:
response = middleware_method(request, callback, callback_args, callback_kwargs)
if response:
return response
wrapped_callback = self.make_view_atomic(callback)
try:
response = wrapped_callback(request, *callback_args, **callback_kwargs)
except Exception as e:
response = self.process_exception_by_middleware(e, request)
# Complain if the view returned None (a common error).
if response is None:
if isinstance(callback, types.FunctionType): # FBV
view_name = callback.__name__
else: # CBV
view_name = callback.__class__.__name__ + '.__call__'
raise ValueError(
"The view %s.%s didn't return an HttpResponse object. It "
"returned None instead." % (callback.__module__, view_name)
)
# If the response supports deferred rendering, apply template
# response middleware and then render the response
elif hasattr(response, 'render') and callable(response.render):
for middleware_method in self._template_response_middleware:
response = middleware_method(request, response)
# Complain if the template response middleware returned None (a common error).
if response is None:
raise ValueError(
"%s.process_template_response didn't return an "
"HttpResponse object. It returned None instead."
% (middleware_method.__self__.__class__.__name__)
)
try:
response = response.render()
except Exception as e:
response = self.process_exception_by_middleware(e, request)
return response
def process_exception_by_middleware(self, exception, request):
"""
Pass the exception to the exception middleware. If no middleware
return a response for this exception, raise it.
"""
for middleware_method in self._exception_middleware:
response = middleware_method(request, exception)
if response:
return response
raise
def handle_uncaught_exception(self, request, resolver, exc_info):
"""
Processing for any otherwise uncaught exceptions (those that will
generate HTTP 500 responses). Can be overridden by subclasses who want
customised 500 handling.
Be *very* careful when overriding this because the error could be
caused by anything, so assuming something like the database is always
available would be an error.
"""
if settings.DEBUG_PROPAGATE_EXCEPTIONS:
raise
logger.error(
'Internal Server Error: %s', request.path,
exc_info=exc_info,
extra={'status_code': 500, 'request': request},
)
if settings.DEBUG:
return debug.technical_500_response(request, *exc_info)
# If Http500 handler is not installed, re-raise last exception
if resolver.urlconf_module is None:
six.reraise(*exc_info)
# Return an HttpResponse that displays a friendly error message.
callback, param_dict = resolver.resolve_error_handler(500)
return callback(request, **param_dict)
def _legacy_get_response(self, request):
response = None
# Apply request middleware
for middleware_method in self._request_middleware:
response = middleware_method(request)
if response:
break
if response is None:
response = self._get_response(request)
return response