text: # Copyright 2011-2016 OpenStack Foundation
  # All Rights Reserved.
  #
  #    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 webob
  
  from oslo_config import cfg
  from oslo_context import context
  from oslo_log import log as logging
  from oslo_middleware import request_id
  from oslo_serialization import jsonutils
  
  from glare.common import policy
  from glare.common import wsgi
  from glare.i18n import _
  
  context_opts = [
      cfg.BoolOpt('allow_anonymous_access', default=False,
                  help=_('Allow unauthenticated users to access the API with '
                         'read-only privileges. This only applies when using '
                         'ContextMiddleware.'))
  ]
  
  CONF = cfg.CONF
  CONF.register_opts(context_opts)
  
  
  LOG = logging.getLogger(__name__)
  
  
  class RequestContext(context.RequestContext):
      """Stores information about the security context for Glare.
  
      Stores how the user accesses the system, as well as additional request
      information.
      """
  
      def __init__(self, service_catalog=None, **kwargs):
          super(RequestContext, self).__init__(**kwargs)
          self.service_catalog = service_catalog
          # check if user is admin using policy file
          if kwargs.get('is_admin') is None:
              self.is_admin = policy.check_is_admin(self)
  
      def to_dict(self):
          d = super(RequestContext, self).to_dict()
          d.update({
              'service_catalog': self.service_catalog,
          })
          return d
  
      @classmethod
      def from_dict(cls, values):
          return cls(**values)
  
      def to_policy_values(self):
          values = super(RequestContext, self).to_policy_values()
          values['is_admin'] = self.is_admin
          values['read_only'] = self.read_only
          return values
  
  
  class ContextMiddleware(wsgi.Middleware):
  
      def __init__(self, app):
          super(ContextMiddleware, self).__init__(app)
  
      def process_request(self, req):
          """Convert authentication information into a request context
  
          Generate a RequestContext object from the available
          authentication headers and store on the 'context' attribute
          of the req object.
  
          :param req: wsgi request object that will be given the context object
          :raises: webob.exc.HTTPUnauthorized: when value of the
                                              X-Identity-Status  header is not
                                              'Confirmed' and anonymous access
                                              is disallowed
          """
          if req.headers.get('X-Identity-Status') == 'Confirmed':
              req.context = self._get_authenticated_context(req)
          elif CONF.allow_anonymous_access:
              req.context = self._get_anonymous_context()
          else:
              raise webob.exc.HTTPUnauthorized()
  
      @staticmethod
      def _get_anonymous_context():
          """Anonymous user has only Read-Only grants"""
          return RequestContext(read_only=True, is_admin=False)
  
      @staticmethod
      def _get_authenticated_context(req):
          headers = req.headers
          service_catalog = None
          if headers.get('X-Service-Catalog') is not None:
              catalog_header = headers.get('X-Service-Catalog')
              try:
                  service_catalog = jsonutils.loads(catalog_header)
              except ValueError:
                  raise webob.exc.HTTPInternalServerError(
                      _('Invalid service catalog json.'))
          kwargs = {
              'service_catalog': service_catalog,
              'request_id': req.environ.get(request_id.ENV_REQUEST_ID),
          }
          return RequestContext.from_environ(req.environ, **kwargs)
  
  
  class UnauthenticatedContextMiddleware(wsgi.Middleware):
      """Process requests and responses when auth is turned off at all."""
  
      def process_request(self, req):
          """Create a context without an authorized user.
  
          When glare deployed as public repo everybody is admin
          without any credentials.
          """
          req.context = RequestContext(is_admin=True)
  