import sys from google.appengine._internal.django import http from google.appengine._internal.django.core import signals from google.appengine._internal.django.utils.encoding import force_unicode from google.appengine._internal.django.utils.importlib import import_module 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 google.appengine._internal.django.conf import settings from google.appengine._internal.django.core import exceptions self._view_middleware = [] self._response_middleware = [] self._exception_middleware = [] request_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_module(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'): 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) # 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 get_response(self, request): "Returns an HttpResponse object for the given HttpRequest" from google.appengine._internal.django.core import exceptions, urlresolvers from google.appengine._internal.django.conf import settings try: try: # Setup default url resolver for this thread. urlconf = settings.ROOT_URLCONF urlresolvers.set_urlconf(urlconf) resolver = urlresolvers.RegexURLResolver(r'^/', urlconf) # Apply request middleware for middleware_method in self._request_middleware: response = middleware_method(request) if response: return response if hasattr(request, "urlconf"): # Reset url resolver with a custom urlconf. urlconf = request.urlconf urlresolvers.set_urlconf(urlconf) resolver = urlresolvers.RegexURLResolver(r'^/', urlconf) 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 google.appengine._internal.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. receivers = signals.got_request_exception.send(sender=self.__class__, request=request) return self.handle_uncaught_exception(request, resolver, sys.exc_info()) finally: # Reset URLconf for this thread on the way out for complete # isolation of request.urlconf urlresolvers.set_urlconf(None) 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 google.appengine._internal.django.conf import settings from google.appengine._internal.django.core.mail import mail_admins if settings.DEBUG_PROPAGATE_EXCEPTIONS: raise if settings.DEBUG: from google.appengine._internal.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) # If Http500 handler is not installed, re-raise last exception if resolver.urlconf_module is None: raise exc_info[1], None, exc_info[2] # 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 google.appengine._internal.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 Web server (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''))