Source code for horizon.middleware

# vim: tabstop=4 shiftwidth=4 softtabstop=4

# Copyright 2012 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# All Rights Reserved.
#
# Copyright 2012 Nebula, Inc.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.
"""
Middleware provided and used by Horizon.
"""

import logging

from django import http
from django import shortcuts
from django.contrib import messages as django_messages
from django.contrib.auth import REDIRECT_FIELD_NAME
from django.core.urlresolvers import reverse
from django.utils import timezone
from django.utils.encoding import iri_to_uri

from horizon import exceptions
from horizon.openstack.common import jsonutils


LOG = logging.getLogger(__name__)


[docs]class HorizonMiddleware(object): """ The main Horizon middleware class. Required for use of Horizon. """
[docs] def process_request(self, request): """ Adds data necessary for Horizon to function to the request. """ # Activate timezone handling tz = request.session.get('django_timezone') if tz: timezone.activate(tz) request.horizon = {'dashboard': None, 'panel': None, 'async_messages': []}
[docs] def process_exception(self, request, exception): """ Catches internal Horizon exception classes such as NotAuthorized, NotFound and Http302 and handles them gracefully. """ if isinstance(exception, (exceptions.NotAuthorized, exceptions.NotAuthenticated)): auth_url = reverse("login") next_url = iri_to_uri(request.get_full_path()) if next_url != auth_url: param = "?%s=%s" % (REDIRECT_FIELD_NAME, next_url) redirect_to = "".join((auth_url, param)) else: redirect_to = auth_url # TODO(gabriel): Find a way to display an appropriate message to # the user *on* the login form... if request.is_ajax(): response_401 = http.HttpResponse(status=401) response_401['X-Horizon-Location'] = redirect_to return response_401 return shortcuts.redirect(redirect_to) # If an internal "NotFound" error gets this far, return a real 404. if isinstance(exception, exceptions.NotFound): raise http.Http404(exception) if isinstance(exception, exceptions.Http302): # TODO(gabriel): Find a way to display an appropriate message to # the user *on* the login form... return shortcuts.redirect(exception.location)
[docs] def process_response(self, request, response): """ Convert HttpResponseRedirect to HttpResponse if request is via ajax to allow ajax request to redirect url """ if request.is_ajax(): queued_msgs = request.horizon['async_messages'] if type(response) == http.HttpResponseRedirect: # Drop our messages back into the session as per usual so they # don't disappear during the redirect. Not that we explicitly # use django's messages methods here. for tag, message in queued_msgs: getattr(django_messages, tag)(request, message) redirect_response = http.HttpResponse() redirect_response['X-Horizon-Location'] = response['location'] return redirect_response if queued_msgs: # TODO(gabriel): When we have an async connection to the # client (e.g. websockets) this should be pushed to the # socket queue rather than being sent via a header. # The header method has notable drawbacks (length limits, # etc.) and is not meant as a long-term solution. response['X-Horizon-Messages'] = jsonutils.dumps(queued_msgs) return response