From 05c888ffb843ba3eff06cd07b3cef5bbb513a54f Mon Sep 17 00:00:00 2001 From: Florian Apolloner Date: Mon, 2 May 2016 12:37:49 -0400 Subject: [PATCH] Refs #26601 -- Refactored BaseHandler to prepare for new-style middleware. --- django/core/handlers/base.py | 212 +++++++++++++-------------------- django/middleware/exception.py | 78 ++++++++++++ 2 files changed, 164 insertions(+), 126 deletions(-) create mode 100644 django/middleware/exception.py diff --git a/django/core/handlers/base.py b/django/core/handlers/base.py index 93b8f04cac9..65cb59357ca 100644 --- a/django/core/handlers/base.py +++ b/django/core/handlers/base.py @@ -5,18 +5,14 @@ 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.core.exceptions import MiddlewareNotUsed from django.db import connections, transaction -from django.http.multipartparser import MultiPartParserError -from django.urls import get_resolver, set_urlconf +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.encoding import force_text from django.utils.module_loading import import_string from django.views import debug @@ -31,6 +27,7 @@ class BaseHandler(object): self._template_response_middleware = None self._response_middleware = None self._exception_middleware = None + self._middleware_chain = None def load_middleware(self): """ @@ -38,12 +35,13 @@ class BaseHandler(object): 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 = [] - request_middleware = [] + handler = self._legacy_get_response for middleware_path in settings.MIDDLEWARE_CLASSES: mw_class = import_string(middleware_path) try: @@ -57,7 +55,7 @@ class BaseHandler(object): continue if hasattr(mw_instance, 'process_request'): - request_middleware.append(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'): @@ -67,9 +65,11 @@ class BaseHandler(object): if hasattr(mw_instance, 'process_exception'): self._exception_middleware.insert(0, mw_instance.process_exception) + 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._request_middleware = request_middleware + self._middleware_chain = handler def make_view_atomic(self, view): non_atomic_requests = getattr(view, '_non_atomic_requests', set()) @@ -100,121 +100,11 @@ class BaseHandler(object): return response def get_response(self, request): - "Returns an HttpResponse object for the given HttpRequest" + """Return an HttpResponse object for the given HttpRequest.""" + # Setup default url resolver for this thread + set_urlconf(settings.ROOT_URLCONF) - # 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()) + response = self._middleware_chain(request) try: # Apply response middleware, regardless of the response @@ -228,13 +118,13 @@ class BaseHandler(object): % (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 = 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 response_is_rendered and callable(getattr(response, 'render', None)): + if not getattr(response, 'is_rendered', True) and callable(getattr(response, 'render', None)): response = response.render() if response.status_code == 404: @@ -245,6 +135,64 @@ class BaseHandler(object): 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 @@ -284,3 +232,15 @@ class BaseHandler(object): # 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 diff --git a/django/middleware/exception.py b/django/middleware/exception.py new file mode 100644 index 00000000000..437a82cf265 --- /dev/null +++ b/django/middleware/exception.py @@ -0,0 +1,78 @@ +from __future__ import unicode_literals + +import logging +import sys + +from django.conf import settings +from django.core import signals +from django.core.exceptions import PermissionDenied, SuspiciousOperation +from django.http import Http404 +from django.http.multipartparser import MultiPartParserError +from django.urls import get_resolver, get_urlconf +from django.utils.encoding import force_text +from django.views import debug + +logger = logging.getLogger('django.request') + + +class ExceptionMiddleware(object): + """ + Convert selected exceptions to HTTP responses. + + For example, convert Http404 to a 404 response either through handler404 + or through the debug view if settings.DEBUG=True. To ensure that + exceptions raised by other middleware are converted to the appropriate + response, this middleware is always automatically applied as the outermost + middleware. + """ + def __init__(self, get_response, handler=None): + from django.core.handlers.base import BaseHandler + self.get_response = get_response + self.handler = handler or BaseHandler() + + def __call__(self, request): + try: + response = self.get_response(request) + except Http404 as exc: + if settings.DEBUG: + response = debug.technical_404_response(request, exc) + else: + response = self.handler.get_exception_response(request, get_resolver(get_urlconf()), 404, exc) + + except PermissionDenied as exc: + logger.warning( + 'Forbidden (Permission denied): %s', request.path, + extra={'status_code': 403, 'request': request}, + ) + response = self.handler.get_exception_response(request, get_resolver(get_urlconf()), 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.handler.get_exception_response(request, get_resolver(get_urlconf()), 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.handler.get_exception_response(request, get_resolver(get_urlconf()), 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.handler.__class__, request=request) + response = self.handler.handle_uncaught_exception(request, get_resolver(get_urlconf()), sys.exc_info()) + + return response