class MulticastEventListener:
""" Represents a multicast event listener. Contains some control
functions for starting and stopping the listener.
"""
msg_already_started = 'tried to start() MulticastEventListener when already started'
msg_already_stopped = 'tried to stop() MulticastEventListener when already stopped'
def __init__(self, control_point, start=True):
""" Constructor for the MulticastEventListener class.
@param ssdp: ssdp server instance that will receive new device events
and subscriptions
@param start: if True starts the search when constructed
@param ssdp_addr: ssdp address for listening (UDP)
@param ssdp_port: ssdp port for listening (UDP)
@type ssdp: SSDPServer
@type start: boolean
@type ssdp_addr: string
@type ssdp_port integer
"""
self.udp_transport = UDPTransport()
self.listen_udp = UDPListener(UPnPDefaults.MULTICAST_EVENT_ADDR,
UPnPDefaults.MULTICAST_EVENT_PORT,
data_callback=self._datagram_received,
shared_socket=self.udp_transport.socket)
self.control_point = control_point
if start:
self.start()
def _datagram_received(self, data, address):
""" Callback for the UDPListener when messages arrive.
@param data: raw data received
@param host: host where data came from
@param port: port where data came from
@type data: string
@type host: string
@type port: integer
"""
(host, port) = address
try:
cmd, headers = parse_http_response(data)
body = data[data.find("<"):data.rfind(">")+1]
except Exception as err:
log.error('Error while receiving datagram packet: %s', str(err))
return
# Render notify message
if not (cmd[0] == 'NOTIFY' and cmd[1] == '*' and cmd[2] == 'HTTP/1.0' and \
'content-type' in headers and \
headers['content-type'] == 'text/xml; charset="utf-8"' and \
'nt' in headers and headers['nt'] == 'upnp:event' and \
'nts' in headers and headers['nts'] == 'upnp:propchange' and \
'host' in headers and 'usn' in headers and \
'svcid' in headers and 'seq' in headers and \
'lvl' in headers and 'bootid.upnp.org' in headers and \
'content-length' in headers):
log.warning('Invalid message')
return
addr = headers['host'].split(':')[0]
port = int(headers['host'].split(':')[1])
udn = headers['usn'].split('::')[0]
service_type = headers['usn'].split('::')[1]
svcid = headers['svcid']
seq = int(headers['seq'])
lvl = headers['lvl']
content_length = int(headers['content-length'])
bootid = int(headers['bootid.upnp.org'])
if addr != UPnPDefaults.MULTICAST_EVENT_ADDR or \
port != UPnPDefaults.MULTICAST_EVENT_PORT:
log.warning('Invalid address %s:%d' % (addr, port))
return
changed_vars = read_notify_message_body(body)
self.control_point._on_event('', changed_vars)
for id, dev in list(self.control_point._known_devices.items()):
service = self._find_service(dev, udn, service_type, svcid)
if service != None:
service._on_event(changed_vars)
log.debug('Multicast event. Event changed vars: %s', changed_vars)
def is_running(self):
""" Returns True if the listener is running.
@rtype: boolean
"""
return self.listen_udp.is_running()
def start(self):
""" Starts the listener.
"""
if not self.is_running():
self.listen_udp.start()
log.debug('Multicast event listener started')
else:
log.warning(self.msg_already_started)
def stop(self):
""" Stops the search.
"""
if self.is_running():
log.debug('Multicast event listener stopped')
self.listen_udp.stop()
else:
log.warning(self.msg_already_stopped)
def destroy(self):
""" Destroys and quits MSearch.
"""
if self.is_running():
self.stop()
self.listen_udp.destroy()
self._cleanup()
def _find_service(self, device, udn, service_type, svcid):
""" Method to find a service.
@param device: instance of a device
@param udn: device id
@param service_type: service type
@param svcid: service id
@type device: RootDevice or Device
@type udn: string
@type service_type: string
@type svcid: string
@return: if found, the service
@rtype: Service or None
"""
if device.udn != udn:
for child_dev in list(device.devices.values()):
service = self._find_service(child_dev, udn, service_type, svcid)
if service:
return service
else:
for k, service in list(device.services.items()):
if service.service_type == service_type and \
str(service.id) == svcid:
return service
return None
def _cleanup(self):
""" Clean up references.
"""
self.ssdp = None
self.listen_udp = None
self.control_point = None
