import sys from django import http from django.core import signals from django.utils.encoding import force_unicode class BaseHandler(object): # Changes that are always applied to a response (in this order). response_fixes = [ http.fix_location_header, http.conditional_content_removal, http.fix_IE_for_attach, http.fix_IE_for_vary, ] def __init__(self): self._request_middleware = self._view_middleware = self._response_middleware = 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__). """ from django.conf import settings from django.core import exceptions self._request_middleware = [] self._view_middleware = [] self._response_middleware = [] self._exception_middleware = [] for middleware_path in settings.MIDDLEWARE_CLASSES: try: dot = middleware_path.rindex('.') except ValueError: raise exceptions.ImproperlyConfigured, '%s isn\'t a middleware module' % middleware_path mw_module, mw_classname = middleware_path[:dot], middleware_path[dot+1:] try: mod = __import__(mw_module, {}, {}, ['']) except ImportError, e: raise exceptions.ImproperlyConfigured, 'Error importing middleware %s: "%s"' % (mw_module, e) try: mw_class = getattr(mod, mw_classname) except AttributeError: raise exceptions.ImproperlyConfigured, 'Middleware module "%s" does not define a "%s" class' % (mw_module, mw_classname) try: mw_instance = mw_class() except exceptions.MiddlewareNotUsed: 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_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) def get_response(self, request): "Returns an HttpResponse object for the given HttpRequest" from django.core import exceptions, urlresolvers from django.conf import settings # Apply request middleware for middleware_method in self._request_middleware: response = middleware_method(request) if response: return response # Get urlconf from request object, if available. Otherwise use default. urlconf = getattr(request, "urlconf", settings.ROOT_URLCONF) resolver = urlresolvers.RegexURLResolver(r'^/', urlconf) try: callback, callback_args, callback_kwargs = resolver.resolve( request.path_info) # Apply view middleware for middleware_method in self._view_middleware: response = middleware_method(request, callback, callback_args, callback_kwargs) if response: return response try: response = callback(request, *callback_args, **callback_kwargs) except Exception, e: # If the view raised an exception, run it through exception # middleware, and if the exception middleware returns a # response, use that. Otherwise, reraise the exception. for middleware_method in self._exception_middleware: response = middleware_method(request, e) if response: return response raise # Complain if the view returned None (a common error). if response is None: try: view_name = callback.func_name # If it's a function except AttributeError: view_name = callback.__class__.__name__ + '.__call__' # If it's a class raise ValueError, "The view %s.%s didn't return an HttpResponse object." % (callback.__module__, view_name) return response except http.Http404, e: if settings.DEBUG: from django.views import debug return debug.technical_404_response(request, e) else: try: callback, param_dict = resolver.resolve404() return callback(request, **param_dict) except: try: return self.handle_uncaught_exception(request, resolver, sys.exc_info()) finally: receivers = signals.got_request_exception.send(sender=self.__class__, request=request) except exceptions.PermissionDenied: return http.HttpResponseForbidden('

Permission denied

') except SystemExit: # Allow sys.exit() to actually exit. See tickets #1023 and #4701 raise except: # Handle everything else, including SuspiciousOperation, etc. # Get the exception info now, in case another exception is thrown later. exc_info = sys.exc_info() receivers = signals.got_request_exception.send(sender=self.__class__, request=request) return self.handle_uncaught_exception(request, resolver, exc_info) 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. """ from django.conf import settings from django.core.mail import mail_admins if settings.DEBUG_PROPAGATE_EXCEPTIONS: raise if settings.DEBUG: from django.views import debug return debug.technical_500_response(request, *exc_info) # When DEBUG is False, send an error message to the admins. subject = 'Error (%s IP): %s' % ((request.META.get('REMOTE_ADDR') in settings.INTERNAL_IPS and 'internal' or 'EXTERNAL'), request.path) try: request_repr = repr(request) except: request_repr = "Request repr() unavailable" message = "%s\n\n%s" % (self._get_traceback(exc_info), request_repr) mail_admins(subject, message, fail_silently=True) # Return an HttpResponse that displays a friendly error message. callback, param_dict = resolver.resolve500() return callback(request, **param_dict) def _get_traceback(self, exc_info=None): "Helper function to return the traceback as a string" import traceback return '\n'.join(traceback.format_exception(*(exc_info or sys.exc_info()))) def apply_response_fixes(self, request, response): """ Applies each of the functions in self.response_fixes to the request and response, modifying the response in the process. Returns the new response. """ for func in self.response_fixes: response = func(request, response) return response def get_script_name(environ): """ Returns the equivalent of the HTTP request's SCRIPT_NAME environment variable. If Apache mod_rewrite has been used, returns what would have been the script name prior to any rewriting (so it's the script name as seen from the client's perspective), unless DJANGO_USE_POST_REWRITE is set (to anything). """ from django.conf import settings if settings.FORCE_SCRIPT_NAME is not None: return force_unicode(settings.FORCE_SCRIPT_NAME) # If Apache's mod_rewrite had a whack at the URL, Apache set either # SCRIPT_URL or REDIRECT_URL to the full resource URL before applying any # rewrites. Unfortunately not every webserver (lighttpd!) passes this # information through all the time, so FORCE_SCRIPT_NAME, above, is still # needed. script_url = environ.get('SCRIPT_URL', u'') if not script_url: script_url = environ.get('REDIRECT_URL', u'') if script_url: return force_unicode(script_url[:-len(environ.get('PATH_INFO', ''))]) return force_unicode(environ.get('SCRIPT_NAME', u''))