Source code for horizon.middleware

# 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 json
import logging
import time

from django.conf import settings  # noqa
from django.contrib.auth import REDIRECT_FIELD_NAME  # noqa
from django.contrib.auth.views import redirect_to_login  # noqa
from django.contrib import messages as django_messages
from django import http
from django.http import HttpResponseRedirect  # noqa
from django import shortcuts
from django.utils.encoding import iri_to_uri  # noqa
from django.utils import timezone
from django.utils.translation import ugettext_lazy as _  # noqa

from horizon import exceptions
from horizon.utils import functions as utils

LOG = logging.getLogger(__name__)


class HorizonMiddleware(object):
    """ The main Horizon middleware class. Required for use of Horizon. """
[docs] logout_reason = None def process_request(self, request): """ Adds data necessary for Horizon to function to the request. """
[docs] # Activate timezone handling tz = request.session.get('django_timezone') if tz: timezone.activate(tz) # Check for session timeout try: timeout = settings.SESSION_TIMEOUT except AttributeError: timeout = 1800 last_activity = request.session.get('last_activity', None) timestamp = int(time.time()) request.horizon = {'dashboard': None, 'panel': None, 'async_messages': []} if (isinstance(last_activity, int) and (timestamp - last_activity) > timeout): request.session.pop('last_activity') response = HttpResponseRedirect( '%s?next=%s' % (settings.LOGOUT_URL, request.path)) self.logout_reason = _("Session timed out.") utils.add_logout_reason(request, response, self.logout_reason) return response request.session['last_activity'] = timestamp def process_exception(self, request, exception): """
[docs] Catches internal Horizon exception classes such as NotAuthorized, NotFound and Http302 and handles them gracefully. """ if isinstance(exception, (exceptions.NotAuthorized, exceptions.NotAuthenticated)): auth_url = settings.LOGIN_URL next_url = iri_to_uri(request.get_full_path()) if next_url != auth_url: field_name = REDIRECT_FIELD_NAME else: field_name = None login_url = request.build_absolute_uri(auth_url) response = redirect_to_login(next_url, login_url=login_url, redirect_field_name=field_name) if request.is_ajax(): response_401 = http.HttpResponse(status=401) response_401['X-Horizon-Location'] = response['location'] return response_401 return response # 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) def process_response(self, request, response): """
[docs] 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, extra_tags in queued_msgs: getattr(django_messages, tag)(request, message, extra_tags) if response['location'].startswith(settings.LOGOUT_URL): redirect_response = http.HttpResponse(status=401) # This header is used for handling the logout in JS redirect_response['logout'] = True if self.logout_reason is not None: utils.add_logout_reason( request, redirect_response, self.logout_reason) else: redirect_response = http.HttpResponse() # Copy cookies from HttpResponseRedirect towards HttpResponse for cookie_name, cookie in response.cookies.iteritems(): cookie_kwargs = dict(( (key, value) for key, value in cookie.iteritems() if key in ('max_age', 'expires', 'path', 'domain', 'secure', 'httponly') and value )) redirect_response.set_cookie( cookie_name, cookie.value, **cookie_kwargs) 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'] = json.dumps(queued_msgs) return response