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# Copyright 2012 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
# 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.
Utility methods for working with WSGI servers redux
from oslo_log import log as logging
import webob.dec
import webob.exc
from neutron.api import api_common
from neutron.common import utils
from neutron import wsgi
LOG = logging.getLogger(__name__)
class Request(wsgi.Request):
def Resource(controller, faults=None, deserializers=None, serializers=None,
"""Represents an API entity resource and the associated serialization and
deserialization logic
default_deserializers = {'application/json': wsgi.JSONDeserializer()}
default_serializers = {'application/json': wsgi.JSONDictSerializer()}
format_types = {'json': 'application/json'}
action_status = action_status or dict(create=201, delete=204)
default_deserializers.update(deserializers or {})
default_serializers.update(serializers or {})
deserializers = default_deserializers
serializers = default_serializers
faults = faults or {}
def resource(request):
route_args = request.environ.get('wsgiorg.routing_args')
if route_args:
args = route_args[1].copy()
args = {}
# NOTE(jkoelker) by now the controller is already found, remove
# it from the args if it is in the matchdict
args.pop('controller', None)
fmt = args.pop('format', None)
action = args.pop('action', None)
content_type = format_types.get(fmt,
language = request.best_match_language()
deserializer = deserializers.get(content_type)
serializer = serializers.get(content_type)
if request.body:
args['body'] = deserializer.deserialize(request.body)['body']
# Routes library is dumb and cuts off everything after last dot (.)
# as format. At the same time, it doesn't enforce format suffix,
# which combined makes it impossible to pass a 'id' with dots
# included (the last section after the last dot is lost). This is
# important for some API extensions like tags where the id is
# really a tag name that can contain special characters.
# To work around the Routes behaviour, we will attach the suffix
# back to id if it's not one of supported formats (atm json only).
# This of course won't work for the corner case of a tag name that
# actually ends with '.json', but there seems to be no better way
# to tackle it without breaking API backwards compatibility.
if fmt is not None and fmt not in format_types:
args['id'] = '.'.join([args['id'], fmt])
revision_number = api_common.check_request_for_revision_constraint(
if revision_number is not None:
controller._collection, args['id'], revision_number)
method = getattr(controller, action)
result = method(request=request, **args)
except Exception as e:
mapped_exc = api_common.convert_exception_to_http_exc(e, faults,
if hasattr(mapped_exc, 'code') and 400 <= mapped_exc.code < 500:'%(action)s failed (client error): %(exc)s',
{'action': action, 'exc': mapped_exc})
LOG.exception('%(action)s failed: %(details)s',
'action': action,
'details': utils.extract_exc_details(e),
raise mapped_exc
status = action_status.get(action, 200)
body = serializer.serialize(result)
# NOTE(jkoelker) Comply with RFC2616 section 9.7
if status == 204:
content_type = ''
body = None
return webob.Response(request=request, status=status,
# NOTE(blogan): this is something that is needed for the transition to
# pecan. This will allow the pecan code to have a handle on the controller
# for an extension so it can reuse the code instead of forcing every
# extension to rewrite the code for use with pecan.
setattr(resource, 'controller', controller)
setattr(resource, 'action_status', action_status)
return resource