django1/django/core/handlers/base.py

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from django.utils import httpwrappers
class BaseHandler:
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:
dot = middleware_path.rindex('.')
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, 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
# Reset query list per request.
db.db.queries = []
# Apply request middleware
for middleware_method in self._request_middleware:
response = middleware_method(request)
if response:
return response
resolver = urlresolvers.RegexURLResolver(r'^/', ROOT_URLCONF)
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
try:
response = callback(request, **param_dict)
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:
raise ValueError, "The view %s.%s didn't return an HttpResponse object." % (callback.__module__, callback.func_name)
return response
except exceptions.Http404, e:
if DEBUG:
return self.get_technical_error_response(is404=True, exception=e)
else:
callback, param_dict = resolver.resolve404()
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): %s' % ((request.META.get('REMOTE_ADDR') in INTERNAL_IPS and 'internal' or 'EXTERNAL'), getattr(request, 'path', ''))
message = "%s\n\n%s" % (self._get_traceback(), request)
mail_admins(subject, message, fail_silently=True)
return self.get_friendly_error_response(request, resolver)
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): %s' % ((request.META.get('REMOTE_ADDR') in INTERNAL_IPS and 'internal' or 'EXTERNAL'), getattr(request, 'path', ''))
try:
request_repr = repr(request)
except:
request_repr = "Request repr() unavailable"
message = "%s\n\n%s" % (self._get_traceback(), request_repr)
mail_admins(subject, message, fail_silently=True)
return self.get_friendly_error_response(request, resolver)
def get_friendly_error_response(self, request, resolver):
"""
Returns an HttpResponse that displays a PUBLIC error message for a
fundamental database or coding error.
"""
from django.core import urlresolvers
callback, param_dict = resolver.resolve500()
return callback(request, **param_dict)
def get_technical_error_response(self, is404=False, exception=None):
"""
Returns an HttpResponse that displays a TECHNICAL error message for a
fundamental database or coding error.
"""
if is404:
from django.conf.settings import ROOT_URLCONF
from django.utils.html import escape
html = ['<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">']
html.append('<html><head><title>Error 404</title>')
# Explicitly tell robots not to archive this, in case this slips
# onto a production site.
html.append('<meta name="robots" content="NONE,NOARCHIVE" />')
html.append('</head><body><h1>Error 404</h1>')
try:
tried = exception.args[0]['tried']
except (IndexError, TypeError):
if exception.args:
html.append('<p>%s</p>' % escape(exception.args[0]))
else:
html.append('<p>Using the URLconf defined in <code>%s</code>, Django tried these URL patterns, in this order:</p>' % ROOT_URLCONF)
html.append('<ul>%s</ul>' % ''.join(['<li><code>%s</code></li>' % escape(t).replace(' ', '&nbsp;') for t in tried]))
html.append("<p>The current URL, <code><strong>%r</strong></code>, didn't match any of these.</p>" % exception.args[0]['path'])
html.append("<hr /><p>You're seeing this error because you have <code>DEBUG = True</code> in your Django settings file. Change that to <code>False</code>, and Django will display a standard 404 page.</p>")
html.append('</body></html>')
return httpwrappers.HttpResponseNotFound('\n'.join(html))
else:
output = "There's been an error:\n\n%s" % self._get_traceback()
return httpwrappers.HttpResponseServerError(output, mimetype='text/plain')
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()))