django1/django/core/handlers/base.py

287 lines
12 KiB
Python

from __future__ import unicode_literals
import logging
import sys
import types
import warnings
from django import http
from django.conf import settings
from django.core import signals
from django.core.exceptions import (
MiddlewareNotUsed, PermissionDenied, SuspiciousOperation,
)
from django.db import connections, transaction
from django.http.multipartparser import MultiPartParserError
from django.urls import get_resolver, set_urlconf
from django.utils import six
from django.utils.deprecation import RemovedInDjango20Warning
from django.utils.encoding import force_text
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
def load_middleware(self):
"""
Populate middleware lists from settings.MIDDLEWARE_CLASSES.
Must be called after the environment is fixed (see __call__ in subclasses).
"""
self._view_middleware = []
self._template_response_middleware = []
self._response_middleware = []
self._exception_middleware = []
request_middleware = []
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'):
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)
# We only assign to this when initialization is complete as it is used
# as a flag for initialization being complete.
self._request_middleware = request_middleware
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):
"Returns an HttpResponse object for the given HttpRequest"
# Setup default url resolver for this thread, this code is outside
# the try/except so we don't get a spurious "unbound local
# variable" exception in the event an exception is raised before
# resolver is set
urlconf = settings.ROOT_URLCONF
set_urlconf(urlconf)
resolver = get_resolver(urlconf)
# Use a flag to check if the response was rendered to prevent
# multiple renderings or to force rendering if necessary.
response_is_rendered = False
try:
response = None
# Apply request middleware
for middleware_method in self._request_middleware:
response = middleware_method(request)
if response:
break
if response is None:
if hasattr(request, 'urlconf'):
# Reset url resolver with a custom URLconf.
urlconf = request.urlconf
set_urlconf(urlconf)
resolver = get_resolver(urlconf)
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:
break
if response is None:
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
if 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)
response_is_rendered = True
except http.Http404 as exc:
if settings.DEBUG:
response = debug.technical_404_response(request, exc)
else:
response = self.get_exception_response(request, resolver, 404, exc)
except PermissionDenied as exc:
logger.warning(
'Forbidden (Permission denied): %s', request.path,
extra={'status_code': 403, 'request': request},
)
response = self.get_exception_response(request, resolver, 403, exc)
except MultiPartParserError as exc:
logger.warning(
'Bad request (Unable to parse request body): %s', request.path,
extra={'status_code': 400, 'request': request},
)
response = self.get_exception_response(request, resolver, 400, exc)
except SuspiciousOperation as exc:
# The request logger receives events for any problematic request
# The security logger receives events for all SuspiciousOperations
security_logger = logging.getLogger('django.security.%s' % exc.__class__.__name__)
security_logger.error(
force_text(exc),
extra={'status_code': 400, 'request': request},
)
if settings.DEBUG:
return debug.technical_500_response(request, *sys.exc_info(), status_code=400)
response = self.get_exception_response(request, resolver, 400, exc)
except SystemExit:
# Allow sys.exit() to actually exit. See tickets #1023 and #4701
raise
except Exception: # Handle everything else.
# Get the exception info now, in case another exception is thrown later.
signals.got_request_exception.send(sender=self.__class__, request=request)
response = self.handle_uncaught_exception(request, resolver, sys.exc_info())
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, resolver, 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 response_is_rendered 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 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)