text: # Copyright (c) 2013 OpenStack Foundation.
  #
  # 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.
  
  from swift.common.swob import Request, Response
  from swift.common.utils import register_swift_info
  
  
  class CrossDomainMiddleware(object):
  
      """
      Cross domain middleware used to respond to requests for cross domain
      policy information.
  
      If the path is /crossdomain.xml it will respond with an xml cross domain
      policy document. This allows web pages hosted elsewhere to use client
      side technologies such as Flash, Java and Silverlight to interact
      with the Swift API.
  
      To enable this middleware, add it to the pipeline in your proxy-server.conf
      file. It should be added before any authentication (e.g., tempauth or
      keystone) middleware. In this example ellipsis (...) indicate other
      middleware you may have chosen to use::
  
          [pipeline:main]
          pipeline =  ... crossdomain ... authtoken ... proxy-server
  
      And add a filter section, such as::
  
          [filter:crossdomain]
          use = egg:swift#crossdomain
          cross_domain_policy = <allow-access-from domain="*.example.com" />
              <allow-access-from domain="www.example.com" secure="false" />
  
      For continuation lines, put some whitespace before the continuation
      text. Ensure you put a completely blank line to terminate the
      cross_domain_policy value.
  
      The cross_domain_policy name/value is optional. If omitted, the policy
      defaults as if you had specified::
  
          cross_domain_policy = <allow-access-from domain="*" secure="false" />
  
  
      """
  
      def __init__(self, app, conf, *args, **kwargs):
          self.app = app
          self.conf = conf
          default_domain_policy = '<allow-access-from domain="*"' \
                                  ' secure="false" />'
          self.cross_domain_policy = self.conf.get('cross_domain_policy',
                                                   default_domain_policy)
  
      def GET(self, req):
          """Returns a 200 response with cross domain policy information """
          body = '<?xml version="1.0"?>\n' \
                 '<!DOCTYPE cross-domain-policy SYSTEM ' \
                 '"http://www.adobe.com/xml/dtds/cross-domain-policy.dtd" >\n' \
                 '<cross-domain-policy>\n' \
                 '%s\n' \
                 '</cross-domain-policy>' % self.cross_domain_policy
          return Response(request=req, body=body,
                          content_type="application/xml")
  
      def __call__(self, env, start_response):
          req = Request(env)
          if req.path == '/crossdomain.xml' and req.method == 'GET':
              return self.GET(req)(env, start_response)
          else:
              return self.app(env, start_response)
  
  
  def filter_factory(global_conf, **local_conf):
      conf = global_conf.copy()
      conf.update(local_conf)
      register_swift_info('crossdomain')
  
      def crossdomain_filter(app):
          return CrossDomainMiddleware(app, conf)
      return crossdomain_filter
  