horizon/horizon/middleware.py

114 lines
4.6 KiB
Python

# 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 json
import logging
from django.conf import settings
from django.contrib.auth import REDIRECT_FIELD_NAME
from django.contrib.auth.views import redirect_to_login
from django.contrib import messages as django_messages
from django import http
from django import shortcuts
from django.utils.encoding import iri_to_uri
from django.utils import timezone
from horizon import exceptions
LOG = logging.getLogger(__name__)
class HorizonMiddleware(object):
""" The main Horizon middleware class. Required for use of Horizon. """
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': []}
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 = 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)
# 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'] = 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):
"""
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)
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'] = json.dumps(queued_msgs)
return response