4572e6500a
Fixes bug #911663 The None, True, and False values are singletons. All variable *comparisons* to singletons should use 'is' or 'is not'. All variable *evaluations* to boolean should use 'if' or 'if not'. All Object type comparisons should use isinstance() instead of comparing types directly. Change-Id: Id5c797d3339d0d7015bac386088133540f0c0c9e
1037 lines
36 KiB
Python
1037 lines
36 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright 2011 OpenStack LLC.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""
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Utility methods for working with WSGI servers
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"""
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import logging
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import sys
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import eventlet.wsgi
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eventlet.patcher.monkey_patch(all=False, socket=True)
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import routes.middleware
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import webob.dec
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import webob.exc
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from lxml import etree
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from xml.dom import minidom
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from xml.parsers import expat
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from quantum.common import exceptions as exception
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from quantum.common import utils
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LOG = logging.getLogger('quantum.common.wsgi')
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class WritableLogger(object):
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"""A thin wrapper that responds to `write` and logs."""
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def __init__(self, logger, level=logging.DEBUG):
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self.logger = logger
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self.level = level
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def write(self, msg):
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self.logger.log(self.level, msg.strip("\n"))
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def run_server(application, port):
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"""Run a WSGI server with the given application."""
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sock = eventlet.listen(('0.0.0.0', port))
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eventlet.wsgi.server(sock, application)
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class Server(object):
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"""Server class to manage multiple WSGI sockets and applications."""
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def __init__(self, name, threads=1000):
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self.pool = eventlet.GreenPool(threads)
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self.name = name
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def start(self, application, port, host='0.0.0.0', backlog=128):
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"""Run a WSGI server with the given application."""
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socket = eventlet.listen((host, port), backlog=backlog)
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self.pool.spawn_n(self._run, application, socket)
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def wait(self):
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"""Wait until all servers have completed running."""
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try:
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self.pool.waitall()
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except KeyboardInterrupt:
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pass
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def _run(self, application, socket):
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"""Start a WSGI server in a new green thread."""
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logger = logging.getLogger('eventlet.wsgi.server')
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eventlet.wsgi.server(socket, application, custom_pool=self.pool,
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log=WritableLogger(logger))
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class Middleware(object):
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"""
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Base WSGI middleware wrapper. These classes require an application to be
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initialized that will be called next. By default the middleware will
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simply call its wrapped app, or you can override __call__ to customize its
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behavior.
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"""
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def __init__(self, application):
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self.application = application
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def process_request(self, req):
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"""
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Called on each request.
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If this returns None, the next application down the stack will be
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executed. If it returns a response then that response will be returned
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and execution will stop here.
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"""
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return None
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def process_response(self, response):
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"""Do whatever you'd like to the response."""
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return response
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@webob.dec.wsgify
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def __call__(self, req):
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response = self.process_request(req)
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if response:
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return response
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response = req.get_response(self.application)
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return self.process_response(response)
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class Request(webob.Request):
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def best_match_content_type(self):
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"""Determine the most acceptable content-type.
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Based on:
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1) URI extension (.json/.xml)
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2) Content-type header
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3) Accept* headers
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"""
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# First lookup http request
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parts = self.path.rsplit('.', 1)
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if len(parts) > 1:
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format = parts[1]
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if format in ['json', 'xml']:
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return 'application/{0}'.format(parts[1])
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#Then look up content header
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type_from_header = self.get_content_type()
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if type_from_header:
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return type_from_header
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ctypes = ['application/json', 'application/xml']
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#Finally search in Accept-* headers
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bm = self.accept.best_match(ctypes)
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return bm or 'application/json'
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def get_content_type(self):
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allowed_types = ("application/xml", "application/json")
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if not "Content-Type" in self.headers:
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LOG.debug(_("Missing Content-Type"))
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return None
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type = self.content_type
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if type in allowed_types:
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return type
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return None
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class ActionDispatcher(object):
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"""Maps method name to local methods through action name."""
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def dispatch(self, *args, **kwargs):
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"""Find and call local method."""
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action = kwargs.pop('action', 'default')
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action_method = getattr(self, str(action), self.default)
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return action_method(*args, **kwargs)
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def default(self, data):
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raise NotImplementedError()
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class DictSerializer(ActionDispatcher):
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"""Default request body serialization"""
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def serialize(self, data, action='default'):
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return self.dispatch(data, action=action)
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def default(self, data):
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return ""
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class JSONDictSerializer(DictSerializer):
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"""Default JSON request body serialization"""
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def default(self, data):
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return utils.dumps(data)
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class XMLDictSerializer(DictSerializer):
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def __init__(self, metadata=None, xmlns=None):
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"""
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:param metadata: information needed to deserialize xml into
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a dictionary.
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:param xmlns: XML namespace to include with serialized xml
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"""
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super(XMLDictSerializer, self).__init__()
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self.metadata = metadata or {}
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self.xmlns = xmlns
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def default(self, data):
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# We expect data to contain a single key which is the XML root.
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root_key = data.keys()[0]
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doc = minidom.Document()
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node = self._to_xml_node(doc, self.metadata, root_key, data[root_key])
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return self.to_xml_string(node)
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def to_xml_string(self, node, has_atom=False):
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self._add_xmlns(node, has_atom)
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return node.toxml('UTF-8')
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#NOTE (ameade): the has_atom should be removed after all of the
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# xml serializers and view builders have been updated to the current
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# spec that required all responses include the xmlns:atom, the has_atom
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# flag is to prevent current tests from breaking
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def _add_xmlns(self, node, has_atom=False):
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if self.xmlns is not None:
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node.setAttribute('xmlns', self.xmlns)
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if has_atom:
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node.setAttribute('xmlns:atom', "http://www.w3.org/2005/Atom")
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def _to_xml_node(self, doc, metadata, nodename, data):
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"""Recursive method to convert data members to XML nodes."""
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result = doc.createElement(nodename)
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# Set the xml namespace if one is specified
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# TODO(justinsb): We could also use prefixes on the keys
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xmlns = metadata.get('xmlns', None)
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if xmlns:
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result.setAttribute('xmlns', xmlns)
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#TODO(bcwaldon): accomplish this without a type-check
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if isinstance(data, list):
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collections = metadata.get('list_collections', {})
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if nodename in collections:
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metadata = collections[nodename]
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for item in data:
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node = doc.createElement(metadata['item_name'])
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node.setAttribute(metadata['item_key'], str(item))
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result.appendChild(node)
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return result
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singular = metadata.get('plurals', {}).get(nodename, None)
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if singular is None:
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if nodename.endswith('s'):
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singular = nodename[:-1]
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else:
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singular = 'item'
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for item in data:
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node = self._to_xml_node(doc, metadata, singular, item)
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result.appendChild(node)
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#TODO(bcwaldon): accomplish this without a type-check
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elif isinstance(data, dict):
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collections = metadata.get('dict_collections', {})
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if nodename in collections:
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metadata = collections[nodename]
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for k, v in data.items():
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node = doc.createElement(metadata['item_name'])
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node.setAttribute(metadata['item_key'], str(k))
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text = doc.createTextNode(str(v))
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node.appendChild(text)
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result.appendChild(node)
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return result
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attrs = metadata.get('attributes', {}).get(nodename, {})
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for k, v in data.items():
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if k in attrs:
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result.setAttribute(k, str(v))
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else:
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node = self._to_xml_node(doc, metadata, k, v)
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result.appendChild(node)
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else:
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# Type is atom
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node = doc.createTextNode(str(data))
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result.appendChild(node)
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return result
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def _create_link_nodes(self, xml_doc, links):
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link_nodes = []
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for link in links:
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link_node = xml_doc.createElement('atom:link')
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link_node.setAttribute('rel', link['rel'])
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link_node.setAttribute('href', link['href'])
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if 'type' in link:
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link_node.setAttribute('type', link['type'])
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link_nodes.append(link_node)
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return link_nodes
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def _to_xml(self, root):
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"""Convert the xml object to an xml string."""
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return etree.tostring(root, encoding='UTF-8', xml_declaration=True)
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class ResponseHeaderSerializer(ActionDispatcher):
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"""Default response headers serialization"""
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def serialize(self, response, data, action):
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self.dispatch(response, data, action=action)
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def default(self, response, data):
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response.status_int = 200
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class ResponseSerializer(object):
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"""Encode the necessary pieces into a response object"""
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def __init__(self, body_serializers=None, headers_serializer=None):
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self.body_serializers = {
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'application/xml': XMLDictSerializer(),
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'application/json': JSONDictSerializer(),
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}
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self.body_serializers.update(body_serializers or {})
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self.headers_serializer = headers_serializer or \
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ResponseHeadersSerializer()
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def serialize(self, response_data, content_type, action='default'):
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"""Serialize a dict into a string and wrap in a wsgi.Request object.
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:param response_data: dict produced by the Controller
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:param content_type: expected mimetype of serialized response body
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"""
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response = webob.Response()
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self.serialize_headers(response, response_data, action)
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self.serialize_body(response, response_data, content_type, action)
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return response
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def serialize_headers(self, response, data, action):
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self.headers_serializer.serialize(response, data, action)
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def serialize_body(self, response, data, content_type, action):
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response.headers['Content-Type'] = content_type
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if data is not None:
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serializer = self.get_body_serializer(content_type)
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response.body = serializer.serialize(data, action)
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def get_body_serializer(self, content_type):
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try:
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return self.body_serializers[content_type]
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except (KeyError, TypeError):
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raise exception.InvalidContentType(content_type=content_type)
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class TextDeserializer(ActionDispatcher):
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"""Default request body deserialization"""
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def deserialize(self, datastring, action='default'):
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return self.dispatch(datastring, action=action)
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def default(self, datastring):
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return {}
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class JSONDeserializer(TextDeserializer):
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def _from_json(self, datastring):
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try:
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return utils.loads(datastring)
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except ValueError:
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msg = _("cannot understand JSON")
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raise exception.MalformedRequestBody(reason=msg)
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def default(self, datastring):
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return {'body': self._from_json(datastring)}
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class XMLDeserializer(TextDeserializer):
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def __init__(self, metadata=None):
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"""
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:param metadata: information needed to deserialize xml into
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a dictionary.
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"""
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super(XMLDeserializer, self).__init__()
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self.metadata = metadata or {}
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def _from_xml(self, datastring):
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plurals = set(self.metadata.get('plurals', {}))
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try:
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node = minidom.parseString(datastring).childNodes[0]
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return {node.nodeName: self._from_xml_node(node, plurals)}
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except expat.ExpatError:
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msg = _("cannot understand XML")
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raise exception.MalformedRequestBody(reason=msg)
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def _from_xml_node(self, node, listnames):
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"""Convert a minidom node to a simple Python type.
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:param listnames: list of XML node names whose subnodes should
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be considered list items.
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"""
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if len(node.childNodes) == 1 and node.childNodes[0].nodeType == 3:
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return node.childNodes[0].nodeValue
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elif node.nodeName in listnames:
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return [self._from_xml_node(n, listnames) for n in node.childNodes]
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else:
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result = dict()
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for attr in node.attributes.keys():
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result[attr] = node.attributes[attr].nodeValue
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for child in node.childNodes:
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if child.nodeType != node.TEXT_NODE:
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result[child.nodeName] = self._from_xml_node(child,
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listnames)
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return result
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def find_first_child_named(self, parent, name):
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"""Search a nodes children for the first child with a given name"""
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for node in parent.childNodes:
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if node.nodeName == name:
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return node
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return None
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def find_children_named(self, parent, name):
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"""Return all of a nodes children who have the given name"""
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for node in parent.childNodes:
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if node.nodeName == name:
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yield node
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def extract_text(self, node):
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"""Get the text field contained by the given node"""
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if len(node.childNodes) == 1:
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child = node.childNodes[0]
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if child.nodeType == child.TEXT_NODE:
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return child.nodeValue
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return ""
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def default(self, datastring):
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return {'body': self._from_xml(datastring)}
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class RequestHeadersDeserializer(ActionDispatcher):
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"""Default request headers deserializer"""
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def deserialize(self, request, action):
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return self.dispatch(request, action=action)
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def default(self, request):
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return {}
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class RequestDeserializer(object):
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"""Break up a Request object into more useful pieces."""
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def __init__(self, body_deserializers=None, headers_deserializer=None):
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self.body_deserializers = {
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'application/xml': XMLDeserializer(),
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'application/json': JSONDeserializer(),
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}
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self.body_deserializers.update(body_deserializers or {})
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self.headers_deserializer = headers_deserializer or \
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RequestHeadersDeserializer()
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|
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def deserialize(self, request):
|
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"""Extract necessary pieces of the request.
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|
|
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:param request: Request object
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:returns tuple of expected controller action name, dictionary of
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keyword arguments to pass to the controller, the expected
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content type of the response
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"""
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action_args = self.get_action_args(request.environ)
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action = action_args.pop('action', None)
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action_args.update(self.deserialize_headers(request, action))
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action_args.update(self.deserialize_body(request, action))
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accept = self.get_expected_content_type(request)
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return (action, action_args, accept)
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|
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def deserialize_headers(self, request, action):
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return self.headers_deserializer.deserialize(request, action)
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def deserialize_body(self, request, action):
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try:
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content_type = request.best_match_content_type()
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except exception.InvalidContentType:
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LOG.debug(_("Unrecognized Content-Type provided in request"))
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return {}
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|
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if content_type is None:
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LOG.debug(_("No Content-Type provided in request"))
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return {}
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|
|
if not len(request.body) > 0:
|
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LOG.debug(_("Empty body provided in request"))
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return {}
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|
|
|
try:
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deserializer = self.get_body_deserializer(content_type)
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except exception.InvalidContentType:
|
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LOG.debug(_("Unable to deserialize body as provided Content-Type"))
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raise
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|
|
|
return deserializer.deserialize(request.body, action)
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|
|
|
def get_body_deserializer(self, content_type):
|
|
try:
|
|
return self.body_deserializers[content_type]
|
|
except (KeyError, TypeError):
|
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raise exception.InvalidContentType(content_type=content_type)
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|
|
|
def get_expected_content_type(self, request):
|
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return request.best_match_content_type()
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|
|
|
def get_action_args(self, request_environment):
|
|
"""Parse dictionary created by routes library."""
|
|
try:
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args = request_environment['wsgiorg.routing_args'][1].copy()
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except Exception:
|
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return {}
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|
|
try:
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del args['controller']
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except KeyError:
|
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pass
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|
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try:
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del args['format']
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except KeyError:
|
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pass
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|
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return args
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|
|
|
|
class Application(object):
|
|
"""Base WSGI application wrapper. Subclasses need to implement __call__."""
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|
|
|
@classmethod
|
|
def factory(cls, global_config, **local_config):
|
|
"""Used for paste app factories in paste.deploy config files.
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|
|
|
Any local configuration (that is, values under the [app:APPNAME]
|
|
section of the paste config) will be passed into the `__init__` method
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as kwargs.
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|
|
A hypothetical configuration would look like:
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|
|
[app:wadl]
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latest_version = 1.3
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paste.app_factory = nova.api.fancy_api:Wadl.factory
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|
|
which would result in a call to the `Wadl` class as
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|
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import quantum.api.fancy_api
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fancy_api.Wadl(latest_version='1.3')
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You could of course re-implement the `factory` method in subclasses,
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but using the kwarg passing it shouldn't be necessary.
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"""
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return cls(**local_config)
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def __call__(self, environ, start_response):
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r"""Subclasses will probably want to implement __call__ like this:
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@webob.dec.wsgify(RequestClass=Request)
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def __call__(self, req):
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# Any of the following objects work as responses:
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# Option 1: simple string
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res = 'message\n'
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# Option 2: a nicely formatted HTTP exception page
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res = exc.HTTPForbidden(detail='Nice try')
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# Option 3: a webob Response object (in case you need to play with
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# headers, or you want to be treated like an iterable, or or or)
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res = Response();
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res.app_iter = open('somefile')
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# Option 4: any wsgi app to be run next
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res = self.application
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# Option 5: you can get a Response object for a wsgi app, too, to
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# play with headers etc
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res = req.get_response(self.application)
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# You can then just return your response...
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return res
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# ... or set req.response and return None.
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req.response = res
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See the end of http://pythonpaste.org/webob/modules/dec.html
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for more info.
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"""
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raise NotImplementedError(_('You must implement __call__'))
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class Debug(Middleware):
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"""
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Helper class that can be inserted into any WSGI application chain
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to get information about the request and response.
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"""
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@webob.dec.wsgify
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def __call__(self, req):
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print ("*" * 40) + " REQUEST ENVIRON"
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for key, value in req.environ.items():
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print key, "=", value
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print
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resp = req.get_response(self.application)
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print ("*" * 40) + " RESPONSE HEADERS"
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for (key, value) in resp.headers.iteritems():
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print key, "=", value
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print
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resp.app_iter = self.print_generator(resp.app_iter)
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return resp
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@staticmethod
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def print_generator(app_iter):
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"""
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Iterator that prints the contents of a wrapper string iterator
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when iterated.
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"""
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print ("*" * 40) + " BODY"
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for part in app_iter:
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sys.stdout.write(part)
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sys.stdout.flush()
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yield part
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print
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class Router(object):
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"""
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WSGI middleware that maps incoming requests to WSGI apps.
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"""
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@classmethod
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def factory(cls, global_config, **local_config):
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"""
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Returns an instance of the WSGI Router class
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"""
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return cls()
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def __init__(self, mapper):
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"""
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Create a router for the given routes.Mapper.
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Each route in `mapper` must specify a 'controller', which is a
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WSGI app to call. You'll probably want to specify an 'action' as
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well and have your controller be a wsgi.Controller, who will route
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the request to the action method.
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Examples:
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mapper = routes.Mapper()
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sc = ServerController()
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# Explicit mapping of one route to a controller+action
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mapper.connect(None, "/svrlist", controller=sc, action="list")
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# Actions are all implicitly defined
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mapper.resource("network", "networks", controller=nc)
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# Pointing to an arbitrary WSGI app. You can specify the
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# {path_info:.*} parameter so the target app can be handed just that
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# section of the URL.
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mapper.connect(None, "/v1.0/{path_info:.*}", controller=BlogApp())
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"""
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self.map = mapper
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self._router = routes.middleware.RoutesMiddleware(self._dispatch,
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self.map)
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@webob.dec.wsgify
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def __call__(self, req):
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"""
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Route the incoming request to a controller based on self.map.
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If no match, return a 404.
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"""
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return self._router
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|
@staticmethod
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@webob.dec.wsgify
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def _dispatch(req):
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"""
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Called by self._router after matching the incoming request to a route
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and putting the information into req.environ. Either returns 404
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or the routed WSGI app's response.
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"""
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match = req.environ['wsgiorg.routing_args'][1]
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if not match:
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return webob.exc.HTTPNotFound()
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app = match['controller']
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return app
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|
|
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|
class Resource(Application):
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"""WSGI app that handles (de)serialization and controller dispatch.
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WSGI app that reads routing information supplied by RoutesMiddleware
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and calls the requested action method upon its controller. All
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controller action methods must accept a 'req' argument, which is the
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incoming wsgi.Request. If the operation is a PUT or POST, the controller
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method must also accept a 'body' argument (the deserialized request body).
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They may raise a webob.exc exception or return a dict, which will be
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serialized by requested content type.
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"""
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def __init__(self, controller, deserializer=None, serializer=None):
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"""
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:param controller: object that implement methods created by routes lib
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:param deserializer: object that can serialize the output of a
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controller into a webob response
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:param serializer: object that can deserialize a webob request
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into necessary pieces
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"""
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self.controller = controller
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self.deserializer = deserializer or RequestDeserializer()
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self.serializer = serializer or ResponseSerializer()
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# use serializer's xmlns for populating Fault generator xmlns
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xml_serializer = self.serializer.body_serializers['application/xml']
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if hasattr(xml_serializer, 'xmlns'):
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self._xmlns = xml_serializer.xmlns
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|
|
@webob.dec.wsgify(RequestClass=Request)
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def __call__(self, request):
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"""WSGI method that controls (de)serialization and method dispatch."""
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LOG.info("%(method)s %(url)s" % {"method": request.method,
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"url": request.url})
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try:
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action, args, accept = self.deserializer.deserialize(request)
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except exception.InvalidContentType:
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msg = _("Unsupported Content-Type")
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LOG.exception("InvalidContentType:%s", msg)
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return Fault(webob.exc.HTTPBadRequest(explanation=msg),
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self._xmlns)
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except exception.MalformedRequestBody:
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|
msg = _("Malformed request body")
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|
LOG.exception("MalformedRequestBody:%s", msg)
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return Fault(webob.exc.HTTPBadRequest(explanation=msg),
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self._xmlns)
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try:
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|
action_result = self.dispatch(request, action, args)
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except webob.exc.HTTPException as ex:
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|
LOG.info(_("HTTP exception thrown: %s"), unicode(ex))
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action_result = Fault(ex, self._xmlns)
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|
|
if isinstance(action_result, dict) or action_result is None:
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response = self.serializer.serialize(action_result,
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accept,
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action=action)
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else:
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response = action_result
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|
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try:
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|
msg_dict = dict(url=request.url, status=response.status_int)
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msg = _("%(url)s returned with HTTP %(status)d") % msg_dict
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|
except AttributeError, e:
|
|
msg_dict = dict(url=request.url, e=e)
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|
msg = _("%(url)s returned a fault: %(e)s" % msg_dict)
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|
|
|
LOG.info(msg)
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|
|
|
return response
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|
|
|
def dispatch(self, request, action, action_args):
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"""Find action-spefic method on controller and call it."""
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|
|
|
controller_method = getattr(self.controller, action)
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try:
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|
#NOTE(salvatore-orlando): the controller method must have
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# an argument whose name is 'request'
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|
return controller_method(request=request, **action_args)
|
|
except TypeError as exc:
|
|
LOG.exception(exc)
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|
return Fault(webob.exc.HTTPBadRequest(),
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self._xmlns)
|
|
|
|
|
|
class Fault(webob.exc.HTTPException):
|
|
""" Generates an HTTP response from a webob HTTP exception"""
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|
|
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def __init__(self, exception, xmlns=None):
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|
"""Creates a Fault for the given webob.exc.exception."""
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|
self.wrapped_exc = exception
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|
self.status_int = self.wrapped_exc.status_int
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|
self._xmlns = xmlns
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|
|
|
@webob.dec.wsgify(RequestClass=Request)
|
|
def __call__(self, req):
|
|
"""Generate a WSGI response based on the exception passed to ctor."""
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|
# Replace the body with fault details.
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code = self.wrapped_exc.status_int
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fault_name = hasattr(self.wrapped_exc, 'title') and \
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self.wrapped_exc.title or "quantumServiceFault"
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fault_data = {
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fault_name: {
|
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'code': code,
|
|
'message': self.wrapped_exc.explanation,
|
|
'detail': str(self.wrapped_exc.detail)}}
|
|
# 'code' is an attribute on the fault tag itself
|
|
metadata = {'application/xml': {'attributes': {fault_name: 'code'}}}
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|
xml_serializer = XMLDictSerializer(metadata, self._xmlns)
|
|
content_type = req.best_match_content_type()
|
|
serializer = {
|
|
'application/xml': xml_serializer,
|
|
'application/json': JSONDictSerializer(),
|
|
}[content_type]
|
|
|
|
self.wrapped_exc.body = serializer.serialize(fault_data)
|
|
self.wrapped_exc.content_type = content_type
|
|
return self.wrapped_exc
|
|
|
|
|
|
# NOTE(salvatore-orlando): this class will go once the
|
|
# extension API framework is updated
|
|
class Controller(object):
|
|
"""WSGI app that dispatched to methods.
|
|
|
|
WSGI app that reads routing information supplied by RoutesMiddleware
|
|
and calls the requested action method upon itself. All action methods
|
|
must, in addition to their normal parameters, accept a 'req' argument
|
|
which is the incoming wsgi.Request. They raise a webob.exc exception,
|
|
or return a dict which will be serialized by requested content type.
|
|
|
|
"""
|
|
|
|
@webob.dec.wsgify(RequestClass=Request)
|
|
def __call__(self, req):
|
|
"""
|
|
Call the method specified in req.environ by RoutesMiddleware.
|
|
"""
|
|
arg_dict = req.environ['wsgiorg.routing_args'][1]
|
|
action = arg_dict['action']
|
|
method = getattr(self, action)
|
|
del arg_dict['controller']
|
|
del arg_dict['action']
|
|
if 'format' in arg_dict:
|
|
del arg_dict['format']
|
|
arg_dict['request'] = req
|
|
result = method(**arg_dict)
|
|
|
|
if isinstance(result, dict):
|
|
content_type = req.best_match_content_type()
|
|
default_xmlns = self.get_default_xmlns(req)
|
|
body = self._serialize(result, content_type, default_xmlns)
|
|
|
|
response = webob.Response()
|
|
response.headers['Content-Type'] = content_type
|
|
response.body = body
|
|
msg_dict = dict(url=req.url, status=response.status_int)
|
|
msg = _("%(url)s returned with HTTP %(status)d") % msg_dict
|
|
LOG.debug(msg)
|
|
return response
|
|
else:
|
|
return result
|
|
|
|
def _serialize(self, data, content_type, default_xmlns):
|
|
"""Serialize the given dict to the provided content_type.
|
|
|
|
Uses self._serialization_metadata if it exists, which is a dict mapping
|
|
MIME types to information needed to serialize to that type.
|
|
|
|
"""
|
|
_metadata = getattr(type(self), '_serialization_metadata', {})
|
|
|
|
serializer = Serializer(_metadata, default_xmlns)
|
|
try:
|
|
return serializer.serialize(data, content_type)
|
|
except exception.InvalidContentType:
|
|
raise webob.exc.HTTPNotAcceptable()
|
|
|
|
def _deserialize(self, data, content_type):
|
|
"""Deserialize the request body to the specefied content type.
|
|
|
|
Uses self._serialization_metadata if it exists, which is a dict mapping
|
|
MIME types to information needed to serialize to that type.
|
|
|
|
"""
|
|
_metadata = getattr(type(self), '_serialization_metadata', {})
|
|
serializer = Serializer(_metadata)
|
|
return serializer.deserialize(data, content_type)
|
|
|
|
def get_default_xmlns(self, req):
|
|
"""Provide the XML namespace to use if none is otherwise specified."""
|
|
return None
|
|
|
|
|
|
# NOTE(salvatore-orlando): this class will go once the
|
|
# extension API framework is updated
|
|
class Serializer(object):
|
|
"""Serializes and deserializes dictionaries to certain MIME types."""
|
|
|
|
def __init__(self, metadata=None, default_xmlns=None):
|
|
"""Create a serializer based on the given WSGI environment.
|
|
|
|
'metadata' is an optional dict mapping MIME types to information
|
|
needed to serialize a dictionary to that type.
|
|
|
|
"""
|
|
self.metadata = metadata or {}
|
|
self.default_xmlns = default_xmlns
|
|
|
|
def _get_serialize_handler(self, content_type):
|
|
handlers = {
|
|
'application/json': self._to_json,
|
|
'application/xml': self._to_xml,
|
|
}
|
|
|
|
try:
|
|
return handlers[content_type]
|
|
except Exception:
|
|
raise exception.InvalidContentType(content_type=content_type)
|
|
|
|
def serialize(self, data, content_type):
|
|
"""Serialize a dictionary into the specified content type."""
|
|
return self._get_serialize_handler(content_type)(data)
|
|
|
|
def deserialize(self, datastring, content_type):
|
|
"""Deserialize a string to a dictionary.
|
|
|
|
The string must be in the format of a supported MIME type.
|
|
|
|
"""
|
|
try:
|
|
return self.get_deserialize_handler(content_type)(datastring)
|
|
except Exception:
|
|
raise webob.exc.HTTPBadRequest("Could not deserialize data")
|
|
|
|
def get_deserialize_handler(self, content_type):
|
|
handlers = {
|
|
'application/json': self._from_json,
|
|
'application/xml': self._from_xml,
|
|
}
|
|
|
|
try:
|
|
return handlers[content_type]
|
|
except Exception:
|
|
raise exception.InvalidContentType(content_type=content_type)
|
|
|
|
def _from_json(self, datastring):
|
|
return utils.loads(datastring)
|
|
|
|
def _from_xml(self, datastring):
|
|
xmldata = self.metadata.get('application/xml', {})
|
|
plurals = set(xmldata.get('plurals', {}))
|
|
node = minidom.parseString(datastring).childNodes[0]
|
|
return {node.nodeName: self._from_xml_node(node, plurals)}
|
|
|
|
def _from_xml_node(self, node, listnames):
|
|
"""Convert a minidom node to a simple Python type.
|
|
|
|
listnames is a collection of names of XML nodes whose subnodes should
|
|
be considered list items.
|
|
|
|
"""
|
|
if len(node.childNodes) == 1 and node.childNodes[0].nodeType == 3:
|
|
return node.childNodes[0].nodeValue
|
|
elif node.nodeName in listnames:
|
|
return [self._from_xml_node(n, listnames)
|
|
for n in node.childNodes if n.nodeType != node.TEXT_NODE]
|
|
else:
|
|
result = dict()
|
|
for attr in node.attributes.keys():
|
|
result[attr] = node.attributes[attr].nodeValue
|
|
for child in node.childNodes:
|
|
if child.nodeType != node.TEXT_NODE:
|
|
result[child.nodeName] = self._from_xml_node(child,
|
|
listnames)
|
|
return result
|
|
|
|
def _to_json(self, data):
|
|
return utils.dumps(data)
|
|
|
|
def _to_xml(self, data):
|
|
metadata = self.metadata.get('application/xml', {})
|
|
# We expect data to contain a single key which is the XML root.
|
|
root_key = data.keys()[0]
|
|
doc = minidom.Document()
|
|
node = self._to_xml_node(doc, metadata, root_key, data[root_key])
|
|
|
|
xmlns = node.getAttribute('xmlns')
|
|
if not xmlns and self.default_xmlns:
|
|
node.setAttribute('xmlns', self.default_xmlns)
|
|
|
|
return node.toprettyxml(indent='', newl='')
|
|
|
|
def _to_xml_node(self, doc, metadata, nodename, data):
|
|
"""Recursive method to convert data members to XML nodes."""
|
|
result = doc.createElement(nodename)
|
|
|
|
# Set the xml namespace if one is specified
|
|
# TODO(justinsb): We could also use prefixes on the keys
|
|
xmlns = metadata.get('xmlns', None)
|
|
if xmlns:
|
|
result.setAttribute('xmlns', xmlns)
|
|
if isinstance(data, list):
|
|
collections = metadata.get('list_collections', {})
|
|
if nodename in collections:
|
|
metadata = collections[nodename]
|
|
for item in data:
|
|
node = doc.createElement(metadata['item_name'])
|
|
node.setAttribute(metadata['item_key'], str(item))
|
|
result.appendChild(node)
|
|
return result
|
|
singular = metadata.get('plurals', {}).get(nodename, None)
|
|
if singular is None:
|
|
if nodename.endswith('s'):
|
|
singular = nodename[:-1]
|
|
else:
|
|
singular = 'item'
|
|
for item in data:
|
|
node = self._to_xml_node(doc, metadata, singular, item)
|
|
result.appendChild(node)
|
|
elif isinstance(data, dict):
|
|
collections = metadata.get('dict_collections', {})
|
|
if nodename in collections:
|
|
metadata = collections[nodename]
|
|
for k, v in data.items():
|
|
node = doc.createElement(metadata['item_name'])
|
|
node.setAttribute(metadata['item_key'], str(k))
|
|
text = doc.createTextNode(str(v))
|
|
node.appendChild(text)
|
|
result.appendChild(node)
|
|
return result
|
|
attrs = metadata.get('attributes', {}).get(nodename, {})
|
|
for k, v in data.items():
|
|
if k in attrs:
|
|
result.setAttribute(k, str(v))
|
|
else:
|
|
node = self._to_xml_node(doc, metadata, k, v)
|
|
result.appendChild(node)
|
|
else:
|
|
# Type is atom.
|
|
node = doc.createTextNode(str(data))
|
|
result.appendChild(node)
|
|
return result
|