308 lines
13 KiB
Python
308 lines
13 KiB
Python
from __future__ import unicode_literals
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import logging
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import sys
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import types
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import warnings
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from django import http
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from django.conf import settings
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from django.core import signals
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from django.core.exceptions import (
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MiddlewareNotUsed, PermissionDenied, SuspiciousOperation,
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)
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from django.db import connections, transaction
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from django.http.multipartparser import MultiPartParserError
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from django.urls import get_resolver, set_urlconf
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from django.utils import six
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from django.utils.deprecation import RemovedInDjango20Warning
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from django.utils.encoding import force_text
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from django.utils.module_loading import import_string
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from django.views import debug
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logger = logging.getLogger('django.request')
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class BaseHandler(object):
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# Changes that are always applied to a response (in this order).
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response_fixes = [
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http.conditional_content_removal,
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]
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def __init__(self):
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self._request_middleware = None
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self._view_middleware = None
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self._template_response_middleware = None
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self._response_middleware = None
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self._exception_middleware = None
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def load_middleware(self):
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"""
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Populate middleware lists from settings.MIDDLEWARE_CLASSES.
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Must be called after the environment is fixed (see __call__ in subclasses).
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"""
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self._view_middleware = []
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self._template_response_middleware = []
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self._response_middleware = []
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self._exception_middleware = []
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request_middleware = []
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for middleware_path in settings.MIDDLEWARE_CLASSES:
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mw_class = import_string(middleware_path)
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try:
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mw_instance = mw_class()
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except MiddlewareNotUsed as exc:
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if settings.DEBUG:
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if six.text_type(exc):
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logger.debug('MiddlewareNotUsed(%r): %s', middleware_path, exc)
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else:
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logger.debug('MiddlewareNotUsed: %r', middleware_path)
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continue
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if hasattr(mw_instance, 'process_request'):
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request_middleware.append(mw_instance.process_request)
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if hasattr(mw_instance, 'process_view'):
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self._view_middleware.append(mw_instance.process_view)
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if hasattr(mw_instance, 'process_template_response'):
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self._template_response_middleware.insert(0, mw_instance.process_template_response)
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if hasattr(mw_instance, 'process_response'):
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self._response_middleware.insert(0, mw_instance.process_response)
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if hasattr(mw_instance, 'process_exception'):
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self._exception_middleware.insert(0, mw_instance.process_exception)
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# We only assign to this when initialization is complete as it is used
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# as a flag for initialization being complete.
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self._request_middleware = request_middleware
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def make_view_atomic(self, view):
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non_atomic_requests = getattr(view, '_non_atomic_requests', set())
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for db in connections.all():
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if (db.settings_dict['ATOMIC_REQUESTS']
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and db.alias not in non_atomic_requests):
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view = transaction.atomic(using=db.alias)(view)
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return view
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def get_exception_response(self, request, resolver, status_code, exception):
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try:
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callback, param_dict = resolver.resolve_error_handler(status_code)
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# Unfortunately, inspect.getargspec result is not trustable enough
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# depending on the callback wrapping in decorators (frequent for handlers).
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# Falling back on try/except:
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try:
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response = callback(request, **dict(param_dict, exception=exception))
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except TypeError:
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warnings.warn(
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"Error handlers should accept an exception parameter. Update "
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"your code as this parameter will be required in Django 2.0",
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RemovedInDjango20Warning, stacklevel=2
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)
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response = callback(request, **param_dict)
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except Exception:
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signals.got_request_exception.send(sender=self.__class__, request=request)
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response = self.handle_uncaught_exception(request, resolver, sys.exc_info())
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return response
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def get_response(self, request):
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"Returns an HttpResponse object for the given HttpRequest"
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# Setup default url resolver for this thread, this code is outside
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# the try/except so we don't get a spurious "unbound local
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# variable" exception in the event an exception is raised before
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# resolver is set
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urlconf = settings.ROOT_URLCONF
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set_urlconf(urlconf)
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resolver = get_resolver(urlconf)
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# Use a flag to check if the response was rendered to prevent
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# multiple renderings or to force rendering if necessary.
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response_is_rendered = False
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try:
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response = None
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# Apply request middleware
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for middleware_method in self._request_middleware:
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response = middleware_method(request)
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if response:
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break
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if response is None:
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if hasattr(request, 'urlconf'):
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# Reset url resolver with a custom URLconf.
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urlconf = request.urlconf
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set_urlconf(urlconf)
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resolver = get_resolver(urlconf)
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resolver_match = resolver.resolve(request.path_info)
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callback, callback_args, callback_kwargs = resolver_match
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request.resolver_match = resolver_match
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# Apply view middleware
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for middleware_method in self._view_middleware:
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response = middleware_method(request, callback, callback_args, callback_kwargs)
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if response:
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break
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if response is None:
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wrapped_callback = self.make_view_atomic(callback)
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try:
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response = wrapped_callback(request, *callback_args, **callback_kwargs)
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except Exception as e:
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response = self.process_exception_by_middleware(e, request)
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# Complain if the view returned None (a common error).
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if response is None:
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if isinstance(callback, types.FunctionType): # FBV
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view_name = callback.__name__
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else: # CBV
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view_name = callback.__class__.__name__ + '.__call__'
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raise ValueError("The view %s.%s didn't return an HttpResponse object. It returned None instead."
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% (callback.__module__, view_name))
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# If the response supports deferred rendering, apply template
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# response middleware and then render the response
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if hasattr(response, 'render') and callable(response.render):
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for middleware_method in self._template_response_middleware:
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response = middleware_method(request, response)
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# Complain if the template response middleware returned None (a common error).
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if response is None:
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raise ValueError(
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"%s.process_template_response didn't return an "
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"HttpResponse object. It returned None instead."
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% (middleware_method.__self__.__class__.__name__))
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try:
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response = response.render()
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except Exception as e:
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response = self.process_exception_by_middleware(e, request)
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response_is_rendered = True
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except http.Http404 as exc:
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logger.warning('Not Found: %s', request.path,
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extra={
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'status_code': 404,
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'request': request
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})
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if settings.DEBUG:
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response = debug.technical_404_response(request, exc)
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else:
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response = self.get_exception_response(request, resolver, 404, exc)
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except PermissionDenied as exc:
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logger.warning(
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'Forbidden (Permission denied): %s', request.path,
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extra={
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'status_code': 403,
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'request': request
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})
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response = self.get_exception_response(request, resolver, 403, exc)
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except MultiPartParserError as exc:
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logger.warning(
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'Bad request (Unable to parse request body): %s', request.path,
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extra={
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'status_code': 400,
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'request': request
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})
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response = self.get_exception_response(request, resolver, 400, exc)
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except SuspiciousOperation as exc:
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# The request logger receives events for any problematic request
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# The security logger receives events for all SuspiciousOperations
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security_logger = logging.getLogger('django.security.%s' %
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exc.__class__.__name__)
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security_logger.error(
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force_text(exc),
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extra={
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'status_code': 400,
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'request': request
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})
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if settings.DEBUG:
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return debug.technical_500_response(request, *sys.exc_info(), status_code=400)
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response = self.get_exception_response(request, resolver, 400, exc)
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except SystemExit:
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# Allow sys.exit() to actually exit. See tickets #1023 and #4701
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raise
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except Exception: # Handle everything else.
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# Get the exception info now, in case another exception is thrown later.
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signals.got_request_exception.send(sender=self.__class__, request=request)
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response = self.handle_uncaught_exception(request, resolver, sys.exc_info())
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try:
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# Apply response middleware, regardless of the response
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for middleware_method in self._response_middleware:
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response = middleware_method(request, response)
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# Complain if the response middleware returned None (a common error).
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if response is None:
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raise ValueError(
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"%s.process_response didn't return an "
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"HttpResponse object. It returned None instead."
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% (middleware_method.__self__.__class__.__name__))
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response = self.apply_response_fixes(request, response)
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except Exception: # Any exception should be gathered and handled
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signals.got_request_exception.send(sender=self.__class__, request=request)
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response = self.handle_uncaught_exception(request, resolver, sys.exc_info())
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response._closable_objects.append(request)
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# If the exception handler returns a TemplateResponse that has not
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# been rendered, force it to be rendered.
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if not response_is_rendered and callable(getattr(response, 'render', None)):
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response = response.render()
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return response
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def process_exception_by_middleware(self, exception, request):
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"""
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Pass the exception to the exception middleware. If no middleware
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return a response for this exception, raise it.
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"""
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for middleware_method in self._exception_middleware:
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response = middleware_method(request, exception)
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if response:
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return response
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raise
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def handle_uncaught_exception(self, request, resolver, exc_info):
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"""
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Processing for any otherwise uncaught exceptions (those that will
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generate HTTP 500 responses). Can be overridden by subclasses who want
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customised 500 handling.
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Be *very* careful when overriding this because the error could be
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caused by anything, so assuming something like the database is always
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available would be an error.
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"""
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if settings.DEBUG_PROPAGATE_EXCEPTIONS:
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raise
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logger.error('Internal Server Error: %s', request.path,
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exc_info=exc_info,
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extra={
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'status_code': 500,
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'request': request
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}
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)
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if settings.DEBUG:
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return debug.technical_500_response(request, *exc_info)
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# If Http500 handler is not installed, re-raise last exception
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if resolver.urlconf_module is None:
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six.reraise(*exc_info)
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# Return an HttpResponse that displays a friendly error message.
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callback, param_dict = resolver.resolve_error_handler(500)
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return callback(request, **param_dict)
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def apply_response_fixes(self, request, response):
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"""
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Applies each of the functions in self.response_fixes to the request and
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response, modifying the response in the process. Returns the new
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response.
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"""
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for func in self.response_fixes:
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response = func(request, response)
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return response
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