text: # Copyright (C) 2014 SDN Hub
  #
  # Licensed under the GNU GENERAL PUBLIC LICENSE, Version 3.
  # You may not use this file except in compliance with this License.
  # You may obtain a copy of the License at
  #
  #    http://www.gnu.org/licenses/gpl-3.0.txt
  #
  # 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.
  
  # REST API
  #
  ############# Host tracker ##############
  #
  # get all hosts
  # GET /hosts
  #
  # get all hosts associated with a switch
  # GET /hosts/{dpid}
  #
  #
  
  import logging
  import json
  from webob import Response
  import time
  
  from ryu.base import app_manager
  from ryu.controller import ofp_event
  from ryu.controller.handler import MAIN_DISPATCHER
  from ryu.controller.handler import set_ev_cls
  from ryu.controller import dpset
  from ryu.app.wsgi import ControllerBase, WSGIApplication, route
  
  from ryu.lib.packet import packet
  from ryu.lib.packet import ethernet
  from ryu.lib.packet import ipv4
  from ryu.ofproto import ether
  from ryu.ofproto import ofproto_v1_0, ofproto_v1_3
  from ryu.app.sdnhub_apps import host_tracker
  from ryu.lib import dpid as dpid_lib
  
  
  class HostTrackerController(ControllerBase):
  
      def __init__(self, req, link, data, **config):
          super(HostTrackerController, self).__init__(req, link, data, **config)
          self.host_tracker = data['host_tracker']
          self.dpset = data['dpset']
  
      @route('hosts', '/v1.0/hosts', methods=['GET'])
      def get_all_hosts(self, req, **kwargs):
          return Response(status=200, content_type='application/json',
                          body=json.dumps(self.host_tracker.hosts))
  
      @route('hosts', '/v1.0/hosts/{dpid}', methods=['GET'])
              # requirements={'dpid': dpid_lib.DPID_PATTERN})
      def get_hosts(self, req, dpid, **_kwargs):
          dp = self.dpset.get(int(dpid))
          if dp is None:
              return Response(status=404)
  
          switch_hosts = {}
          for key, val in self.host_tracker.hosts.iteritems():
              if val['dpid'] == dpid_lib.dpid_to_str(dp.id):
                  switch_hosts[key] = val
  
          return Response(status=200, content_type='application/json',
                          body=json.dumps(switch_hosts))
  
  
  class HostTrackerRestApi(app_manager.RyuApp):
      OFP_VERSIONS = [ofproto_v1_0.OFP_VERSION,
                      ofproto_v1_3.OFP_VERSION]
  
      _CONTEXTS = {
          'dpset': dpset.DPSet,
          'wsgi': WSGIApplication,
          'host_tracker': host_tracker.HostTracker
      }
  
      def __init__(self, *args, **kwargs):
          super(HostTrackerRestApi, self).__init__(*args, **kwargs)
          dpset = kwargs['dpset']
          wsgi = kwargs['wsgi']
          host_tracker = kwargs['host_tracker']
  
          self.data = {}
          self.data['dpset'] = dpset
          self.data['waiters'] = {}
          self.data['host_tracker'] = host_tracker
  
          wsgi.register(HostTrackerController, self.data)
          #mapper = wsgi.mapper
  
          # mapper.connect('hosts', '/v1.0/hosts', controller=HostTrackerController, action='get_all_hosts',
          #        conditions=dict(method=['GET']))
          # mapper.connect('hosts', '/v1.0/hosts/{dpid}', controller=HostTrackerController, action='get_hosts',
          #        conditions=dict(method=['GET']), requirements={'dpid': dpid_lib.DPID_PATTERN})
  