django1/django/core/handler.py

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import os
from django.utils import httpwrappers
# NOTE: do *not* import settings (or any module which eventually imports
# settings) until after CoreHandler has been called; otherwise os.environ
# won't be set up correctly (with respect to settings).
class ImproperlyConfigured(Exception):
pass
class CoreHandler:
def __init__(self):
self._request_middleware = self._view_middleware = self._response_middleware = None
def __call__(self, req):
# mod_python fakes the environ, and thus doesn't process SetEnv. This fixes that
os.environ.update(req.subprocess_env)
# now that the environ works we can see the correct settings, so imports
# that use settings now can work
from django.conf import settings
from django.core import db
# if we need to set up middleware, now that settings works we can do it now.
if self._request_middleware is None:
self.load_middleware()
try:
request = self.get_request(req)
response = self.get_response(req.uri, request)
finally:
db.db.close()
# Apply response middleware
for middleware_method in self._response_middleware:
response = middleware_method(request, response)
# Convert our custom HttpResponse object back into the mod_python req.
httpwrappers.populate_apache_request(response, req)
return 0 # mod_python.apache.OK
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 = []
for middleware_path in settings.MIDDLEWARE_CLASSES:
dot = middleware_path.rindex('.')
mw_module, mw_classname = middleware_path[:dot], middleware_path[dot+1:]
try:
mod = __import__(mw_module, '', '', [''])
except ImportError, e:
raise ImproperlyConfigured, 'Error importing middleware %s: "%s"' % (mw_module, e)
try:
mw_class = getattr(mod, mw_classname)
except AttributeError:
raise 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)
def get_request(self, req):
"Returns an HttpRequest object for the given mod_python req object"
from django.core.extensions import DjangoRequest
return DjangoRequest(req)
def get_response(self, path, request):
"Returns an HttpResponse object for the given HttpRequest"
from django.core import db, exceptions, urlresolvers
from django.core.mail import mail_admins
from django.conf.settings import DEBUG, INTERNAL_IPS, ROOT_URLCONF
# Apply request middleware
for middleware_method in self._request_middleware:
response = middleware_method(request)
if response:
return response
conf_module = __import__(ROOT_URLCONF, '', '', [''])
resolver = urlresolvers.RegexURLResolver(conf_module.urlpatterns)
try:
callback, param_dict = resolver.resolve(path)
# Apply view middleware
for middleware_method in self._view_middleware:
response = middleware_method(request, callback, param_dict)
if response:
return response
return callback(request, **param_dict)
except exceptions.Http404:
if DEBUG:
return self.get_technical_error_response(is404=True)
else:
resolver = urlresolvers.Error404Resolver(conf_module.handler404)
callback, param_dict = resolver.resolve()
return callback(request, **param_dict)
except db.DatabaseError:
db.db.rollback()
if DEBUG:
return self.get_technical_error_response()
else:
subject = 'Database error (%s IP)' % (request.META['REMOTE_ADDR'] in INTERNAL_IPS and 'internal' or 'EXTERNAL')
message = "%s\n\n%s" % (self._get_traceback(), request)
mail_admins(subject, message, fail_silently=True)
return self.get_friendly_error_response(request, conf_module)
except exceptions.PermissionDenied:
return httpwrappers.HttpResponseForbidden('<h1>Permission denied</h1>')
except: # Handle everything else, including SuspiciousOperation, etc.
if DEBUG:
return self.get_technical_error_response()
else:
subject = 'Coding error (%s IP)' % (request.META['REMOTE_ADDR'] in INTERNAL_IPS and 'internal' or 'EXTERNAL')
message = "%s\n\n%s" % (self._get_traceback(), request)
mail_admins(subject, message, fail_silently=True)
return self.get_friendly_error_response(request, conf_module)
def get_friendly_error_response(self, request, conf_module):
"""
Returns an HttpResponse that displays a PUBLIC error message for a
fundamental database or coding error.
"""
from django.core import urlresolvers
resolver = urlresolvers.Error404Resolver(conf_module.handler500)
callback, param_dict = resolver.resolve()
return callback(request, **param_dict)
def get_technical_error_response(self, is404=False):
"""
Returns an HttpResponse that displays a TECHNICAL error message for a
fundamental database or coding error.
"""
error_string = "<pre>There's been an error:\n\n%s</pre>" % self._get_traceback()
responseClass = is404 and httpwrappers.HttpResponseNotFound or httpwrappers.HttpResponseServerError
return responseClass(error_string)
def _get_traceback(self):
"Helper function to return the traceback as a string"
import sys, traceback
return '\n'.join(traceback.format_exception(*sys.exc_info()))
def handler(req):
return CoreHandler()(req)