text: # 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.
  import logging
  
  from django.conf import settings
  from django.contrib import auth
  from django.contrib.auth.decorators import login_required
  from django.contrib.auth import views as django_auth_views
  from django.contrib import messages
  from django import http as django_http
  from django import shortcuts
  from django.utils import functional
  from django.utils import http
  from django.utils.translation import ugettext_lazy as _
  from django.views.decorators.cache import never_cache
  from django.views.decorators.csrf import csrf_exempt
  from django.views.decorators.csrf import csrf_protect
  from django.views.decorators.debug import sensitive_post_parameters
  from keystoneauth1 import exceptions as keystone_exceptions
  import six
  
  from openstack_auth import exceptions
  from openstack_auth import forms
  from openstack_auth import plugin
  
  # This is historic and is added back in to not break older versions of
  # Horizon, fix to Horizon to remove this requirement was committed in
  # Juno
  from openstack_auth.forms import Login  # noqa:F401
  from openstack_auth import user as auth_user
  from openstack_auth import utils
  
  try:
      is_safe_url = http.is_safe_url
  except AttributeError:
      is_safe_url = utils.is_safe_url
  
  
  LOG = logging.getLogger(__name__)
  
  
  @sensitive_post_parameters()
  @csrf_protect
  @never_cache
  def login(request, template_name=None, extra_context=None, **kwargs):
      """Logs a user in using the :class:`~openstack_auth.forms.Login` form."""
  
      # If the user enabled websso and selects default protocol
      # from the dropdown, We need to redirect user to the websso url
      if request.method == 'POST':
          auth_type = request.POST.get('auth_type', 'credentials')
          if utils.is_websso_enabled() and auth_type != 'credentials':
              auth_url = request.POST.get('region')
              url = utils.get_websso_url(request, auth_url, auth_type)
              return shortcuts.redirect(url)
  
      if not request.is_ajax():
          # If the user is already authenticated, redirect them to the
          # dashboard straight away, unless the 'next' parameter is set as it
          # usually indicates requesting access to a page that requires different
          # permissions.
          if (request.user.is_authenticated and
                  auth.REDIRECT_FIELD_NAME not in request.GET and
                  auth.REDIRECT_FIELD_NAME not in request.POST):
              return shortcuts.redirect(settings.LOGIN_REDIRECT_URL)
  
      # Get our initial region for the form.
      initial = {}
      current_region = request.session.get('region_endpoint', None)
      requested_region = request.GET.get('region', None)
      regions = dict(getattr(settings, "AVAILABLE_REGIONS", []))
      if requested_region in regions and requested_region != current_region:
          initial.update({'region': requested_region})
  
      if request.method == "POST":
          form = functional.curry(forms.Login)
      else:
          form = functional.curry(forms.Login, initial=initial)
  
      if extra_context is None:
          extra_context = {'redirect_field_name': auth.REDIRECT_FIELD_NAME}
  
      extra_context['csrf_failure'] = request.GET.get('csrf_failure')
  
      if not template_name:
          if request.is_ajax():
              template_name = 'auth/_login.html'
              extra_context['hide'] = True
          else:
              template_name = 'auth/login.html'
  
      res = django_auth_views.login(request,
                                    template_name=template_name,
                                    authentication_form=form,
                                    extra_context=extra_context,
                                    **kwargs)
      # Save the region in the cookie, this is used as the default
      # selected region next time the Login form loads.
      if request.method == "POST":
          utils.set_response_cookie(res, 'login_region',
                                    request.POST.get('region', ''))
          utils.set_response_cookie(res, 'login_domain',
                                    request.POST.get('domain', ''))
  
      # Set the session data here because django's session key rotation
      # will erase it if we set it earlier.
      if request.user.is_authenticated:
          auth_user.set_session_from_user(request, request.user)
          regions = dict(forms.Login.get_region_choices())
          region = request.user.endpoint
          login_region = request.POST.get('region')
          region_name = regions.get(login_region)
          request.session['region_endpoint'] = region
          request.session['region_name'] = region_name
          expiration_time = request.user.time_until_expiration()
          threshold_days = getattr(
              settings, 'PASSWORD_EXPIRES_WARNING_THRESHOLD_DAYS', -1)
          if expiration_time is not None and \
                  expiration_time.days <= threshold_days:
              expiration_time = str(expiration_time).rsplit(':', 1)[0]
              msg = (_('Please consider changing your password, it will expire'
                       ' in %s minutes') %
                     expiration_time).replace(':', ' Hours and ')
              messages.warning(request, msg)
      return res
  
  
  @sensitive_post_parameters()
  @csrf_exempt
  @never_cache
  def websso(request):
      """Logs a user in using a token from Keystone's POST."""
      referer = request.META.get('HTTP_REFERER', settings.OPENSTACK_KEYSTONE_URL)
      auth_url = utils.clean_up_auth_url(referer)
      token = request.POST.get('token')
      try:
          request.user = auth.authenticate(request=request, auth_url=auth_url,
                                           token=token)
      except exceptions.KeystoneAuthException as exc:
          msg = 'Login failed: %s' % six.text_type(exc)
          res = django_http.HttpResponseRedirect(settings.LOGIN_URL)
          res.set_cookie('logout_reason', msg, max_age=10)
          return res
  
      auth_user.set_session_from_user(request, request.user)
      auth.login(request, request.user)
      if request.session.test_cookie_worked():
          request.session.delete_test_cookie()
      return django_http.HttpResponseRedirect(settings.LOGIN_REDIRECT_URL)
  
  
  def logout(request, login_url=None, **kwargs):
      """Logs out the user if he is logged in. Then redirects to the log-in page.
  
      :param login_url:
          Once logged out, defines the URL where to redirect after login
  
      :param kwargs:
          see django.contrib.auth.views.logout_then_login extra parameters.
  
      """
      msg = 'Logging out user "%(username)s".' % \
          {'username': request.user.username}
      LOG.info(msg)
  
      """ Securely logs a user out. """
      return django_auth_views.logout_then_login(request, login_url=login_url,
                                                 **kwargs)
  
  
  @login_required
  def switch(request, tenant_id, redirect_field_name=auth.REDIRECT_FIELD_NAME):
      """Switches an authenticated user from one project to another."""
      LOG.debug('Switching to tenant %s for user "%s".',
                (tenant_id, request.user.username))
  
      endpoint, __ = utils.fix_auth_url_version_prefix(request.user.endpoint)
      session = utils.get_session()
      # Keystone can be configured to prevent exchanging a scoped token for
      # another token. Always use the unscoped token for requesting a
      # scoped token.
      unscoped_token = request.user.unscoped_token
      auth = utils.get_token_auth_plugin(auth_url=endpoint,
                                         token=unscoped_token,
                                         project_id=tenant_id)
  
      try:
          auth_ref = auth.get_access(session)
          msg = 'Project switch successful for user "%(username)s".' % \
              {'username': request.user.username}
          LOG.info(msg)
      except keystone_exceptions.ClientException:
          msg = (
              _('Project switch failed for user "%(username)s".') %
              {'username': request.user.username})
          messages.error(request, msg)
          auth_ref = None
          LOG.exception('An error occurred while switching sessions.')
  
      # Ensure the user-originating redirection url is safe.
      # Taken from django.contrib.auth.views.login()
      redirect_to = request.GET.get(redirect_field_name, '')
      if not is_safe_url(url=redirect_to, host=request.get_host()):
          redirect_to = settings.LOGIN_REDIRECT_URL
  
      if auth_ref:
          user = auth_user.create_user_from_token(
              request,
              auth_user.Token(auth_ref, unscoped_token=unscoped_token),
              endpoint)
          auth_user.set_session_from_user(request, user)
          message = (
              _('Switch to project "%(project_name)s" successful.') %
              {'project_name': request.user.project_name})
          messages.success(request, message)
      response = shortcuts.redirect(redirect_to)
      utils.set_response_cookie(response, 'recent_project',
                                request.user.project_id)
      return response
  
  
  @login_required
  def switch_region(request, region_name,
                    redirect_field_name=auth.REDIRECT_FIELD_NAME):
      """Switches the user's region for all services except Identity service.
  
      The region will be switched if the given region is one of the regions
      available for the scoped project. Otherwise the region is not switched.
      """
      if region_name in request.user.available_services_regions:
          request.session['services_region'] = region_name
          LOG.debug('Switching services region to %s for user "%s".',
                    (region_name, request.user.username))
  
      redirect_to = request.GET.get(redirect_field_name, '')
      if not is_safe_url(url=redirect_to, host=request.get_host()):
          redirect_to = settings.LOGIN_REDIRECT_URL
  
      response = shortcuts.redirect(redirect_to)
      utils.set_response_cookie(response, 'services_region',
                                request.session['services_region'])
      return response
  
  
  @login_required
  def switch_keystone_provider(request, keystone_provider=None,
                               redirect_field_name=auth.REDIRECT_FIELD_NAME):
      """Switches the user's keystone provider using K2K Federation
  
      If keystone_provider is given then we switch the user to
      the keystone provider using K2K federation. Otherwise if keystone_provider
      is None then we switch the user back to the Identity Provider Keystone
      which a non federated token auth will be used.
      """
      base_token = request.session.get('k2k_base_unscoped_token', None)
      k2k_auth_url = request.session.get('k2k_auth_url', None)
      keystone_providers = request.session.get('keystone_providers', None)
  
      if not base_token or not k2k_auth_url:
          msg = _('K2K Federation not setup for this session')
          raise exceptions.KeystoneAuthException(msg)
  
      redirect_to = request.GET.get(redirect_field_name, '')
      if not is_safe_url(url=redirect_to, host=request.get_host()):
          redirect_to = settings.LOGIN_REDIRECT_URL
  
      unscoped_auth_ref = None
      keystone_idp_id = getattr(
          settings, 'KEYSTONE_PROVIDER_IDP_ID', 'localkeystone')
  
      if keystone_provider == keystone_idp_id:
          current_plugin = plugin.TokenPlugin()
          unscoped_auth = current_plugin.get_plugin(auth_url=k2k_auth_url,
                                                    token=base_token)
      else:
          # Switch to service provider using K2K federation
          plugins = [plugin.TokenPlugin()]
          current_plugin = plugin.K2KAuthPlugin()
  
          unscoped_auth = current_plugin.get_plugin(
              auth_url=k2k_auth_url, service_provider=keystone_provider,
              plugins=plugins, token=base_token)
  
      try:
          # Switch to identity provider using token auth
          unscoped_auth_ref = current_plugin.get_access_info(unscoped_auth)
      except exceptions.KeystoneAuthException as exc:
          msg = 'Switching to Keystone Provider %s has failed. %s' \
                % (keystone_provider, (six.text_type(exc)))
          messages.error(request, msg)
  
      if unscoped_auth_ref:
          try:
              request.user = auth.authenticate(
                  request=request, auth_url=unscoped_auth.auth_url,
                  token=unscoped_auth_ref.auth_token)
          except exceptions.KeystoneAuthException as exc:
              msg = 'Keystone provider switch failed: %s' % six.text_type(exc)
              res = django_http.HttpResponseRedirect(settings.LOGIN_URL)
              res.set_cookie('logout_reason', msg, max_age=10)
              return res
          auth.login(request, request.user)
          auth_user.set_session_from_user(request, request.user)
          request.session['keystone_provider_id'] = keystone_provider
          request.session['keystone_providers'] = keystone_providers
          request.session['k2k_base_unscoped_token'] = base_token
          request.session['k2k_auth_url'] = k2k_auth_url
          message = (
              _('Switch to Keystone Provider "%(keystone_provider)s"'
                'successful.') % {'keystone_provider': keystone_provider})
          messages.success(request, message)
  
      response = shortcuts.redirect(redirect_to)
      return response
  