Add most bits of new presence service code

4 files changed, 993 insertions, 0 deletions

diff --git a/shell/PresenceService/Activity.py b/shell/PresenceService/Activity.py
new file mode 100644
index 0000000..5fbe8a5
--- /dev/null
+++ b/shell/PresenceService/Activity.py
@@ -0,0 +1,29 @@
+import dbus
+
+
+class ActivityDBusHelper(dbus.service.Object):
+	def __init__(self, parent, bus_name, object_path):
+		self._parent = parent
+		self._bus_name = bus_name
+		self._object_path = object_path
+		dbus.service.Object.__init__(self, bus_name, self._object_path)
+
+
+class Activity(object):
+	def __init__(self, bus_name, object_id, activity_id):
+		self._activity_id = activity_id
+
+		self._buddies = []
+		self._services = {}	# service type -> Service
+
+		self._object_id = object_id
+		self._object_path = "/org/laptop/Presence/Activities/%d" % self._object_id
+		self._dbus_helper = ActivityDBusHelper(self, bus_name, self._object_path)
+
+	def get_id(self):
+		return self._activity_id
+
+	def get_service_of_type(self, stype):
+		if self._services.has_key(stype):
+			return self._services[stype]
+		return None
diff --git a/shell/PresenceService/Buddy.py b/shell/PresenceService/Buddy.py
new file mode 100644
index 0000000..c3d17e1
--- /dev/null
+++ b/shell/PresenceService/Buddy.py
@@ -0,0 +1,253 @@
+import base64
+import logging
+
+import gtk
+import gobject
+
+from sugar.p2p import Stream
+from sugar.p2p import network
+from sugar.presence import Service
+
+PRESENCE_SERVICE_TYPE = "_presence_olpc._tcp"
+BUDDY_DBUS_INTERFACE = "org.laptop.Presence.Buddy"
+
+class NotFoundError(Exception):
+	pass
+
+class BuddyDBusHelper(dbus.service.Object):
+	def __init__(self, parent, bus_name, object_path):
+		self._parent = parent
+		self._bus_name = bus_name
+		self._object_path = object_path
+		dbus.service.Object.__init__(self, bus_name, self._object_path)
+
+	@dbus.service.signal(BUDDY_DBUS_INTERFACE)
+	def ServiceAppeared(self, object_path):
+		pass
+
+	@dbus.service.signal(BUDDY_DBUS_INTERFACE)
+	def ServiceDisappeared(self, object_path):
+		pass
+
+	@dbus.service.signal(BUDDY_DBUS_INTERFACE)
+	def IconChanged(self):
+		pass
+
+	@dbus.service.signal(BUDDY_DBUS_INTERFACE)
+	def JoinedActivity(self, object_path):
+		pass
+
+	@dbus.service.signal(BUDDY_DBUS_INTERFACE)
+	def LeftActivity(self, object_path):
+		pass
+
+	@dbus.service.method(BUDDY_DBUS_INTERFACE,
+						in_signature="", out_signature="ay")
+	def getIcon(self):
+		icon = self._parent.get_icon()
+		if not icon:
+			return ""
+		return icon
+
+	@dbus.service.method(BUDDY_DBUS_INTERFACE,
+						in_signature="", out_signature="o")
+	def getServiceOfType(self, stype):
+		service = self._parent.get_service_of_type(stype)
+		if not service:
+			raise NotFoundError("Not found")
+		return service
+
+	@dbus.service.method(BUDDY_DBUS_INTERFACE,
+						in_signature="", out_signature="ao")
+	def getJoinedActivities(self):
+		acts = []
+		return acts
+
+	@dbus.service.method(BUDDY_DBUS_INTERFACE,
+						in_signature="", out_signature="a{sv}")
+	def getProperties(self):
+		props = {}
+		props['name'] = self._parent.get_nick_name()
+		props['ip4_address'] = self._parent.get_address()
+		props['owner'] = self._parent.is_owner()
+		return props
+
+
+class Buddy(object):
+	"""Represents another person on the network and keeps track of the
+	activities and resources they make available for sharing."""
+
+	def __init__(self, bus_name, object_id, service):
+		if not bus_name:
+			raise ValueError("DBus bus name must be valid")
+		if not object_id or type(object_id) != type(1):
+			raise ValueError("object id must be a valid number")
+
+		self._services = {}
+		self._activities = {}
+
+		self._nick_name = service.get_name()
+		self._address = service.get_publisher_address()
+		self._valid = False
+		self._icon = None
+		self._icon_tries = 0
+		self._owner = False
+		self.add_service(service)
+
+		self._object_id = object_id
+		self._object_path = "/org/laptop/Presence/Buddies/%d" % self._object_id
+		self._dbus_helper = BuddyDBusHelper(self, bus_name, self._object_path)
+
+	def object_path(self):
+		return self._object_path
+
+	def _request_buddy_icon_cb(self, result_status, response, user_data):
+		"""Callback when icon request has completed."""
+		icon = response
+		service = user_data
+		if result_status == network.RESULT_SUCCESS:
+			if icon and len(icon):
+				icon = base64.b64decode(icon)
+				print "Buddy icon for '%s' is size %d" % (self._nick_name, len(icon))
+				self._set_icon(icon)
+
+		if (result_status == network.RESULT_FAILED or not icon) and self._icon_tries < 3:
+			self._icon_tries = self._icon_tries + 1
+			print "Failed to retrieve buddy icon for '%s' on try %d of %d" % (self._nick_name, \
+					self._icon_tries, 3)
+			gobject.timeout_add(1000, self._request_buddy_icon, service)
+		return False
+
+	def _request_buddy_icon(self, service):
+		"""Contact the buddy to retrieve the buddy icon."""
+		buddy_stream = Stream.Stream.new_from_service(service, start_reader=False)
+		writer = buddy_stream.new_writer(service)
+		success = writer.custom_request("get_buddy_icon", self._request_buddy_icon_cb, service)
+		if not success:
+			del writer, buddy_stream
+			gobject.timeout_add(1000, self._request_buddy_icon, service)
+		return False
+
+	def add_service(self, service):
+		"""Adds a new service to this buddy's service list, returning
+		True if the service was successfully added, and False if it was not."""
+		if service.get_name() != self._nick_name:
+			return False
+		publisher_addr = service.get_publisher_address()
+		if publisher_addr != self._address:
+			logging.error('Service publisher and buddy address doesnt match: %s %s' % (publisher_addr, self._address))
+			return False
+		stype = service.get_type()
+		if stype in self._services.keys():
+			return False
+		self._services[stype] = service
+		if self._valid:
+			self._dbus_helper.ServiceAppeared(dbus.ObjectPath(service.object_path()))
+
+		# If this is the first service we've seen that's owned  by
+		# a particular activity, send out the 'joined-activity' signal
+		actid = service.get_activity_id()
+		if actid is not None:
+			found = False
+			for serv in self._services.values():
+				if serv.get_activity_id() == actid and serv.get_type() != stype:
+					found = True
+					break
+			if not found:
+				print "Buddy (%s) joined activity %s." % (self._nick_name, actid)
+				self._dbus_helper.JoinedActivity(dbus.ObjectPath(activity.object_path()))
+
+		if stype == PRESENCE_SERVICE_TYPE:
+			# A buddy isn't valid until its official presence
+			# service has been found and resolved
+			self._valid = True
+			print 'Requesting buddy icon %s' % self._nick_name
+			self._request_buddy_icon(service)
+		return True
+
+	def remove_service(self, service):
+		"""Remove a service from a buddy; ie, the activity was closed
+		or the buddy went away."""
+		if service.get_publisher_address() != self._address:
+			return
+		if service.get_name() != self._nick_name:
+			return
+		stype = service.get_type()
+		if self._services.has_key(stype):
+			if self._valid:
+				self._dbus_helper.ServiceDisappeared(dbus.ObjectPath(service.object_path()))
+			del self._services[stype]
+
+		# If this is the lase service owned  by a particular activity,
+		# and it's just been removed, send out the 'left-actvity' signal
+		actid = service.get_activity_id()
+		if actid is not None:
+			found = False
+			for serv in self._services.values():
+				if serv.get_activity_id() == actid:
+					found = True
+					break
+			if not found:
+				print "Buddy (%s) left activity %s." % (self._nick_name, actid)
+				self._dbus_helper.LeftActivity(dbus.ObjectPath(activity.object_path()))
+
+		if stype == PRESENCE_SERVICE_TYPE:
+			self._valid = False
+
+	def get_service_of_type(self, stype=None, activity=None):
+		"""Return a service of a certain type, or None if the buddy
+		doesn't provide that service."""
+		if not stype:
+			raise RuntimeError("Need to specify a service type.")
+
+		if activity:
+			actid = activity.get_id()
+			for service in self._services.values():
+				if service.get_type() == stype and service.get_activity_id() == actid:
+					return service
+		if self._services.has_key(stype):
+			return self._services[stype]
+		return None
+
+	def is_valid(self):
+		"""Return whether the buddy is valid or not.  A buddy is
+		not valid until its official presence service has been found
+		and successfully resolved."""
+		return self._valid
+
+	def get_icon_pixbuf(self):
+		if self._icon:
+			pbl = gtk.gdk.PixbufLoader()
+			pbl.write(self._icon)
+			pbl.close()
+			return pbl.get_pixbuf()
+		else:
+			return None
+
+	def get_icon(self):
+		"""Return the buddies icon, if any."""
+		return self._icon
+		
+	def get_address(self):
+		return self._address
+
+	def get_nick_name(self):
+		return self._nick_name
+
+	def _set_icon(self, icon):
+		"""Can only set icon for other buddies.  The Owner
+		takes care of setting it's own icon."""
+		if icon != self._icon:
+			self._icon = icon
+			self._dbus_helper.IconChanged()
+
+	def is_owner(self):
+		return self._owner
+
+
+class Owner(Buddy):
+	"""Class representing the owner of the machine.  This is the client
+	portion of the Owner, paired with the server portion in Owner.py."""
+	def __init__(self, service):
+		Buddy.__init__(self, service)
+		self._owner = True
diff --git a/shell/PresenceService/PresenceService.py b/shell/PresenceService/PresenceService.py
new file mode 100644
index 0000000..cd5bd7f
--- /dev/null
+++ b/shell/PresenceService/PresenceService.py
@@ -0,0 +1,259 @@
+import avahi, dbus, dbus.glib, dbus.dbus_bindings, gobject
+import Buddy
+import Service
+import random
+import logging
+from sugar import env
+
+
+def _get_local_ip_address(ifname):
+	"""Call Linux specific bits to retrieve our own IP address."""
+	import socket
+	import sys
+	import fcntl
+
+	addr = None
+	SIOCGIFADDR = 0x8915
+	sockfd = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+	try:
+		ifreq = (ifname + '\0'*32)[:32]
+		result = fcntl.ioctl(sockfd.fileno(), SIOCGIFADDR, ifreq)
+		addr = socket.inet_ntoa(result[20:24])
+	except IOError, exc:
+		print "Error getting IP address: %s" % exc
+	sockfd.close()
+	return addr
+
+
+class ServiceAdv(object):
+	"""Wrapper class to track services from Avahi."""
+	def __init__(self, interface, protocol, name, stype, domain):
+		self._interface = interface
+		self._protocol = protocol
+		if type(name) != type(u""):
+			raise ValueError("service advertisement name must be unicode.")
+		self._name = name
+		if type(stype) != type(u""):
+			raise ValueError("service advertisement type must be unicode.")
+		self._stype = stype
+		if type(domain) != type(u""):
+			raise ValueError("service advertisement domain must be unicode.")
+		self._domain = domain
+		self._service = None
+		self._resolved = False
+
+	def interface(self):
+		return self._interface
+	def protocol(self):
+		return self._protocol
+	def name(self):
+		return self._name
+	def stype(self):
+		return self._stype
+	def domain(self):
+		return self._domain
+	def service(self):
+		return self._service
+	def set_service(self, service):
+		if not isinstance(service, Service.Service):
+			raise ValueError("must be a valid service.")
+		self._service = service
+	def resolved(self):
+		return self._resolved
+	def set_resolved(self, resolved):
+		self._resolved = resolved
+
+
+_PRESENCE_INTERFACE = "org.laptop.Presence"
+
+class PresenceService(dbus.service.Object):
+	def __init__(self):
+		# interface -> IP address: interfaces we've gotten events on so far
+		self._local_addrs = {}
+
+		# Our owner object
+		self._owner = None
+
+		self._buddies = {} 		# nick -> Buddy
+		self._services = {}		# (name, type) -> Service
+		self._activities = {}	# activity id -> Activity
+
+		# Keep track of stuff we're already browsing with ZC
+		self._service_type_browsers = {}
+		self._service_browsers = {}
+		self._resolve_queue = [] # Track resolve requests
+
+		# Resolved service list
+		self._service_advs = []
+
+		# Set up the dbus service we provide
+		session_bus = dbus.SessionBus()
+		bus_name = dbus.service.BusName('org.laptop.Presence', bus=session_bus)		
+		dbus.service.Object.__init__(self, bus_name, '/org/laptop/Presence')
+
+		# Connect to Avahi for mDNS stuff
+		self._system_bus = dbus.SystemBus()
+		self._mdns_service = dbus.Interface(self._bus.get_object(avahi.DBUS_NAME,
+				avahi.DBUS_PATH_SERVER), avahi.DBUS_INTERFACE_SERVER)
+		# Start browsing the local mDNS domain
+		self._start()
+
+	def _start(self):
+		# Always browse .local
+		self._new_domain_cb(avahi.IF_UNSPEC, avahi.PROTO_UNSPEC, "local")
+
+		# Connect to Avahi and start looking for stuff
+		domain_browser = self._mdns_service.DomainBrowserNew(avahi.IF_UNSPEC, avahi.PROTO_UNSPEC,
+						"", avahi.DOMAIN_BROWSER_BROWSE, dbus.UInt32(0))
+		db = dbus.Interface(self._system_bus.get_object(avahi.DBUS_NAME, domain_browser), avahi.DBUS_INTERFACE_DOMAIN_BROWSER)
+		db.connect_to_signal('ItemNew', self._new_domain_cb_glue)
+
+	def _find_service_adv(self, interface=None, protocol=None, name=None, stype=None, domain=None):
+		"""Search a list of service advertisements for ones matching certain criteria."""
+		adv_list = []
+		for adv in self._service_advs:
+			if interface and adv.interface() != interface:
+				continue
+			if protocol and adv.protocol() != protocol:
+				continue
+			if name and adv.name() != name:
+				continue
+			if stype and adv.stype() != stype:
+				continue
+			if domain and adv.domain() != domain:
+				continue
+			adv_list.append(adv)
+		return adv_list
+
+	def _service_appeared_cb(self, interface, protocol, full_name, stype, domain, flags):
+		logging.debug("found service '%s' (%d) of type '%s' in domain '%s' on %i.%i." % (full_name, flags, stype, domain, interface, protocol))
+
+		# Add the service to our unresolved services list
+		adv_list = self._find_service_adv(interface=interface, protocol=protocol,
+				name=full_name, stype=stype, domain=domain)
+		adv = None
+		if not adv_list:
+			adv = ServiceAdv(interface=interface, protocol=protocol, name=full_name,
+					stype=stype, domain=domain)
+			self._service_advs.append(adv)
+		else:
+			adv = adv_list[0]
+
+		# Find out the IP address of this interface, if we haven't already
+		if interface not in self._local_addrs.keys():
+			ifname = self._server.GetNetworkInterfaceNameByIndex(interface)
+			if ifname:
+				addr = _get_local_ip_address(ifname)
+				if addr:
+					self._local_addrs[interface] = addr
+
+		# Decompose service name if we can
+		(actid, buddy_name) = Service._decompose_service_name(full_name)
+
+		# FIXME: find a better way of letting the StartPage get everything
+		self.emit('new-service-adv', actid, stype)
+
+		# If we care about the service right now, resolve it
+		resolve = False
+		if actid is not None or stype in self._allowed_service_types:
+			resolve = True
+		if self._is_special_service_type(stype):
+			resolve = True
+		if resolve and not adv in self._resolve_queue:
+			self._resolve_queue.append(adv)
+			gobject.idle_add(self._resolve_service, adv)
+		else:
+			logging.debug("Do not resolve service '%s' of type '%s', we don't care about it." % (full_name, stype))
+			
+		return False
+
+	def _service_appeared_cb_glue(self, interface, protocol, name, stype, domain, flags):
+		gobject.idle_add(self._service_appeared_cb, interface, protocol, name, stype, domain, flags)
+
+	def _service_disappeared_cb(self, interface, protocol, full_name, stype, domain, flags):
+		logging.debug("service '%s' of type '%s' in domain '%s' on %i.%i disappeared." % (full_name, stype, domain, interface, protocol))
+
+		# If it's an unresolved service, remove it from our unresolved list
+		adv_list = self._find_service_adv(interface=interface, protocol=protocol,
+				name=full_name, stype=stype, domain=domain)
+		if not adv_list:
+			return False
+
+		# Get the service object; if none, we have nothing left to do
+		adv = adv_list[0]
+		if adv in self._resolve_queue:
+			self._resolve_queue.remove(adv)
+		service = adv.service()
+		if not service:
+			return False
+
+		# Decompose service name if we can
+		(actid, buddy_name) = Service._decompose_service_name(full_name)
+
+		# Remove the service from the buddy
+		try:
+			buddy = self._buddies[buddy_name]
+		except KeyError:
+			pass
+		else:
+			buddy.remove_service(service)
+			self.emit('service-disappeared', buddy, service)
+			if not buddy.is_valid():
+				self.emit("buddy-disappeared", buddy)
+				del self._buddies[buddy_name]
+			self._handle_remove_service_for_activity(service, buddy)
+
+		return False
+
+	def _service_disappeared_cb_glue(self, interface, protocol, name, stype, domain, flags):
+		gobject.idle_add(self._service_disappeared_cb, interface, protocol, name, stype, domain, flags)
+
+	def _new_service_type_cb(self, interface, protocol, stype, domain, flags):
+		# Are we already browsing this domain for this type? 
+		if self._service_browsers.has_key((interface, protocol, stype, domain)):
+			return
+
+		# Start browsing for all services of this type in this domain
+		s_browser = self._mdns_service.ServiceBrowserNew(interface, protocol, stype, domain, dbus.UInt32(0))
+		browser_obj = dbus.Interface(self._system_bus.get_object(avahi.DBUS_NAME, s_browser),
+						avahi.DBUS_INTERFACE_SERVICE_BROWSER)
+		logging.debug("now browsing for services of type '%s' in domain '%s' on %i.%i ..." % (stype, domain, interface, protocol))
+		browser_obj.connect_to_signal('ItemNew', self._service_appeared_cb_glue)
+		browser_obj.connect_to_signal('ItemRemove', self._service_disappeared_cb_glue)
+
+		self._service_browsers[(interface, protocol, stype, domain)] = browser_obj
+		return False
+
+	def _new_service_type_cb_glue(self, interface, protocol, stype, domain, flags):
+		gobject.idle_add(self._new_service_type_cb, interface, protocol, stype, domain, flags)
+
+	def _new_domain_cb(self, interface, protocol, domain, flags=0):
+		"""Callback from Avahi when a new domain has been found.  Start
+		browsing the new domain."""
+		# Only use .local for now...
+		if domain != "local":
+			return
+
+		# Are we already browsing this domain?
+		if self._service_type_browsers.has_key((interface, protocol, domain)):
+			return
+
+		# Start browsing this domain for the services its members offer
+		try:
+			st_browser = self._mdns_service.ServiceTypeBrowserNew(interface, protocol, domain, dbus.UInt32(0))
+			browser_obj = dbus.Interface(self._system_bus.get_object(avahi.DBUS_NAME, st_browser),
+							avahi.DBUS_INTERFACE_SERVICE_TYPE_BROWSER)
+		except dbus.DBusException, exc:
+			logging.error("got exception %s while attempting to browse domain %s on %i.%i" % (domain, interface, protocol))
+			str_exc = str(exc)
+			if str_exc.find("The name org.freedesktop.Avahi was not provided by any .service files") >= 0:
+				raise Exception("Avahi does not appear to be running.  '%s'" % str_exc)
+			else:
+				raise exc
+		logging.debug("now browsing domain '%s' on %i.%i ..." % (domain, interface, protocol))
+		browser_obj.connect_to_signal('ItemNew', self._new_service_type_cb_glue)
+		self._service_type_browsers[(interface, protocol, domain)] = browser_obj
+		return False
+
+	def _new_domain_cb_glue(self, interface, protocol, domain, flags=0):
+		gobject.idle_add(self._new_domain_cb, interface, protocol, domain, flags)
diff --git a/shell/PresenceService/Service.py b/shell/PresenceService/Service.py
new file mode 100644
index 0000000..6475567
--- /dev/null
+++ b/shell/PresenceService/Service.py
@@ -0,0 +1,452 @@
+import avahi
+import sys, os
+sys.path.insert(0, os.path.abspath("../../"))
+from sugar import util
+import dbus, dbus.service
+
+def _txt_to_dict(txt):
+	"""Convert an avahi-returned TXT record formatted
+	as nested arrays of integers (from dbus) into a dict
+	of key/value string pairs."""
+	prop_dict = {}
+	props = avahi.txt_array_to_string_array(txt)
+	for item in props:
+		key = value = None
+		if '=' not in item:
+			# No = means a boolean value of true
+			key = item
+			value = True
+		else:
+			(key, value) = item.split('=')
+		prop_dict[key] = value
+	return prop_dict
+
+def compose_service_name(name, activity_id):
+	if not name:
+		raise ValueError("name must be a valid string.")
+	if not activity_id:
+		return name
+	if type(name) != type(u""):
+		raise ValueError("name must be in unicode.")
+	composed = "%s [%s]" % (name, activity_id)
+	return composed.encode()
+
+def _decompose_service_name(name):
+	"""Break a service name into the name and activity ID, if we can."""
+	if type(name) != type(u""):
+		raise ValueError("name must be a valid unicode string.")
+	name_len = len(name)
+	if name_len < util.ACTIVITY_ID_LEN + 5:
+		return (None, name)
+	# check for activity id end marker
+	if name[name_len - 1] != "]":
+		return (None, name)
+	start = name_len - 1 - util.ACTIVITY_ID_LEN
+	end = name_len - 1
+	# check for activity id start marker
+	if name[start - 1] != "[" or name[start - 2] != " ":
+		return (None, name)
+	activity_id = name[start:end]
+	if not util.validate_activity_id(activity_id):
+		return (None, name)
+	return (activity_id, name[:start - 2])
+
+def is_multicast_address(address):
+	"""Simple numerical check for whether an IP4 address
+	is in the range for multicast addresses or not."""
+	if not address:
+		return False
+	if address[3] != '.':
+		return False
+	first = int(address[:3])
+	if first >= 224 and first <= 239:
+		return True
+	return False
+
+def deserialize(sdict):
+	try:
+		name = sdict['name']
+		if type(name) != type(u""):
+			raise ValueError("name must be unicode.")
+		stype = sdict['stype']
+		if type(stype) != type(u""):
+			raise ValueError("type must be unicode.")
+		domain = sdict['domain']
+		if type(domain) != type(u""):
+			raise ValueError("domain must be unicode.")
+		port = sdict['port']
+		properties = sdict['properties']
+	except KeyError, exc:
+		raise ValueError("Serialized service object was not valid.")
+
+	address = None
+	try:
+		address = sdict['address']
+		if type(address) != type(u""):
+			raise ValueError("address must be unicode.")
+	except KeyError:
+		pass
+	
+	activity_id = None
+	try:
+		activity_id = sdict['activity_id']
+		if type(activity_id) != type(u""):
+			raise ValueError("activity id must be unicode.")
+	except KeyError:
+		pass
+
+	if activity_id is not None:
+		name = compose_service_name(name, activity_id)
+
+	return Service(name, stype, domain, address=address,
+		port=port, properties=properties)
+
+
+_ACTIVITY_ID_TAG = "ActivityID"
+SERVICE_DBUS_INTERFACE = "org.laptop.Presence.Service"
+
+class ServiceDBusHelper(dbus.service.Object):
+	"""Handle dbus requests and signals for Service objects"""
+	def __init__(self, parent, bus_name, object_path):
+		self._parent = parent
+		self._bus_name = bus_name
+		self._object_path = object_path
+		dbus.service.Object.__init__(self, bus_name, self._object_path)
+
+	@dbus.service.method(SERVICE_DBUS_INTERFACE,
+						in_signature="", out_signature="a{sv}")
+	def getProperties(self):
+		"""Return service properties."""
+		pary = {}
+		pary['name'] = self._parent.get_name()
+		pary['type'] = self._parent.get_type()
+		pary['domain'] = self._parent.get_domain()
+		pary['activityId'] = self._parent.get_activity_id()
+		port = self._parent.get_port()
+		if port:
+			pary['port'] = self._parent.get_port()
+		addr = self._parent.get_address()
+		if addr:
+			pary['address'] = addr
+		source_addr = self._parent.get_publisher_address()
+		if source_addr:
+			pary['sourceAddress'] = source_addr
+		return pary
+
+	@dbus.service.method(SERVICE_DBUS_INTERFACE,
+						in_signature="s", out_signature="s")
+	def getPublishedValue(self, key):
+		"""Return the value belonging to the requested key from the
+		service's TXT records."""
+		value = self._parent.get_one_property(key)
+		if type(value) == type(True):
+			value = str(value)
+		return value
+
+class Service(object):
+	"""Encapsulates information about a specific ZeroConf/mDNS
+	service as advertised on the network."""
+	def __init__(self, bus_name, object_id, name, stype, domain, address=None, port=-1, properties=None):
+		if not bus_name:
+			raise ValueError("DBus bus name must be valid")
+		if not object_id or type(object_id) != type(1):
+			raise ValueError("object id must be a valid number")
+
+		# Validate immutable options
+		if name and type(name) != type(u""):
+			raise ValueError("name must be unicode.")
+		if not name or not len(name):
+			raise ValueError("must specify a valid service name.")
+
+		if stype and type(stype) != type(u""):
+			raise ValueError("service type must be in unicode.")
+		if not stype or not len(stype):
+			raise ValueError("must specify a valid service type.")
+		if not stype.endswith("._tcp") and not stype.endswith("._udp"):
+			raise ValueError("must specify a TCP or UDP service type.")
+
+		if domain and type(domain) != type(u""):
+			raise ValueError("domain must be in unicode.")
+		if len(domain) and domain != "local":
+			raise ValueError("must use the 'local' domain (for now).")
+
+		(actid, real_name) = _decompose_service_name(name)
+		self._name = real_name
+		self._stype = stype
+		self._domain = domain
+		self._port = -1
+		self.set_port(port)
+		self._properties = {}
+		self.set_properties(properties)
+		# Publisher address is the unicast source IP
+		self._publisher_address = address
+		# Address is the published address, could be multicast or unicast
+		self._address = None
+		if self._properties.has_key('address'):
+			self.set_address(self._properties['address'])
+		else:
+			self.set_address(address)
+
+		# Ensure that an ActivityID tag, if given, matches
+		# what we expect from the service type
+		if self._properties.has_key(_ACTIVITY_ID_TAG):
+			prop_actid = self._properties[_ACTIVITY_ID_TAG]
+			if (prop_actid and not actid) or (prop_actid != actid):
+				raise ValueError("ActivityID property specified, but the service names's activity ID didn't match it: %s, %s" % (prop_actid, actid))
+		self._activity_id = actid
+		if actid and not self._properties.has_key(_ACTIVITY_ID_TAG):
+			self._properties[_ACTIVITY_ID_TAG] = actid
+
+		# register ourselves with dbus
+		self._object_id = object_id
+		self._object_path = "/org/laptop/Presence/Services/%d" % self._object_id
+		self._dbus_helper = ServiceDBusHelper(self, bus_name, self._object_path)
+
+	def object_path(self):
+		return self._object_path
+
+	def serialize(self, owner=None):
+		sdict = {}
+		if owner is not None:
+			sdict['name'] = dbus.Variant(owner.get_nick_name())
+		else:
+			sdict['name'] = dbus.Variant(self._name)
+		sdict['stype'] = dbus.Variant(self._stype)
+		if self._activity_id:
+			sdict['activity_id'] = dbus.Variant(self._activity_id)
+		sdict['domain'] = dbus.Variant(self._domain)
+		if self._address:
+			sdict['address'] = dbus.Variant(self._address)
+		sdict['port'] = dbus.Variant(self._port)
+		sdict['properties'] = dbus.Variant(self._properties)
+		return sdict
+
+	def get_name(self):
+		"""Return the service's name, usually that of the
+		buddy who provides it."""
+		return self._name
+
+	def is_multicast_service(self):
+		"""Return True if the service's address is a multicast address,
+		False if it is not."""
+		return is_multicast_address(self._address)
+
+	def get_one_property(self, key):
+		"""Return one property of the service, or None
+		if the property was not found.  Cannot distinguish
+		between lack of a property, and a property value that
+		actually is None."""
+		if key in self._properties.keys():
+			return self._properties[key]
+		return None
+
+	def get_properties(self):
+		"""Return a python dictionary of all the service's
+		properties."""
+		return self._properties
+
+	def set_properties(self, properties):
+		"""Set the service's properties from either an Avahi
+		TXT record (a list of lists of integers), or a
+		python dictionary."""
+		self._properties = {}
+		props = {}
+		if type(properties) == type([]):
+			props = _txt_to_dict(properties)
+		elif type(properties) == type({}):
+			props = properties
+
+		# Set key/value pairs on internal property list, 
+		# also convert everything to local encoding (for now)
+		# to ensure consistency
+		for key, value in props.items():
+			tmp_key = key
+			tmp_val = value
+			if type(tmp_key) == type(u""):
+				tmp_key = tmp_key.encode()
+			if type(tmp_val) == type(u""):
+				tmp_val = tmp_val.encode()
+			self._properties[tmp_key] = tmp_val
+
+	def get_type(self):
+		"""Return the service's service type."""
+		return self._stype
+
+	def get_activity_id(self):
+		"""Return the activity ID this service is associated with, if any."""
+		return self._activity_id
+
+	def get_port(self):
+		return self._port
+
+	def set_port(self, port):
+		if type(port) != type(1) or (port <= 1024 and port > 65536):
+			raise ValueError("must specify a valid port number between 1024 and 65536.")
+		self._port = port
+
+	def get_publisher_address(self):
+		return self._publisher_address
+
+	def get_address(self):
+		return self._address
+
+	def set_address(self, address):
+		if address is not None:
+			if type(address) != type(u""):
+				raise ValueError("address must be unicode")
+		self._address = address
+
+	def get_domain(self):
+		"""Return the ZeroConf/mDNS domain the service was found in."""
+		return self._domain
+
+
+#################################################################
+# Tests
+#################################################################
+
+import unittest
+
+class ServiceTestCase(unittest.TestCase):
+	_DEF_NAME = u"foobar"
+	_DEF_STYPE = u"_foo._bar._tcp"
+	_DEF_DOMAIN = u"local"
+	_DEF_ADDRESS = u"1.1.1.1"
+	_DEF_PORT = 1234
+	_DEF_PROPS = {'foobar': 'baz'}
+	
+	_STR_TEST_ARGS = [None, 0, [], {}]
+
+	def _test_init_fail(self, name, stype, domain, address, port, properties, fail_msg):
+		"""Test something we expect to fail."""
+		try:
+			service = Service(name, stype, domain, address, port, properties)
+		except ValueError, exc:
+			pass
+		else:
+			self.fail("expected a ValueError for %s." % fail_msg)
+
+	def testName(self):
+		for item in self._STR_TEST_ARGS:
+			self._test_init_fail(item, self._DEF_STYPE, self._DEF_DOMAIN, self._DEF_ADDRESS,
+					self._DEF_PORT, self._DEF_PROPS, "invalid name")
+
+	def testType(self):
+		for item in self._STR_TEST_ARGS:
+			self._test_init_fail(self._DEF_NAME, item, self._DEF_DOMAIN, self._DEF_ADDRESS,
+					self._DEF_PORT, self._DEF_PROPS, "invalid service type")
+		self._test_init_fail(self._DEF_NAME, "_bork._foobar", self._DEF_DOMAIN, self._DEF_ADDRESS,
+				self._DEF_PORT, self._DEF_PROPS, "invalid service type")
+
+	def testDomain(self):
+		for item in self._STR_TEST_ARGS:
+			self._test_init_fail(self._DEF_NAME, self._DEF_STYPE, item, self._DEF_ADDRESS,
+					self._DEF_PORT, self._DEF_PROPS, "invalid domain")
+		# Only accept local for now
+		self._test_init_fail(self._DEF_NAME, self._DEF_STYPE, "foobar", self._DEF_ADDRESS,
+				self._DEF_PORT, self._DEF_PROPS, "invalid domain")
+		# Make sure "" works
+		session_bus = dbus.SessionBus()
+		bus_name = dbus.service.BusName('org.laptop.Presence', bus=session_bus)		
+		service = Service(bus_name, 1, self._DEF_NAME, self._DEF_STYPE, "", self._DEF_ADDRESS,
+				self._DEF_PORT, self._DEF_PROPS)
+		del bus_name, session_bus
+		assert service, "Empty domain was not accepted!"
+
+	def testAddress(self):
+		self._test_init_fail(self._DEF_NAME, self._DEF_STYPE, self._DEF_DOMAIN, [],
+				self._DEF_PORT, self._DEF_PROPS, "invalid address")
+		self._test_init_fail(self._DEF_NAME, self._DEF_STYPE, self._DEF_DOMAIN, {},
+				self._DEF_PORT, self._DEF_PROPS, "invalid address")
+		self._test_init_fail(self._DEF_NAME, self._DEF_STYPE, self._DEF_DOMAIN, 1234,
+				self._DEF_PORT, self._DEF_PROPS, "invalid address")
+
+	def testPort(self):
+		self._test_init_fail(self._DEF_NAME, self._DEF_STYPE, self._DEF_DOMAIN, self._DEF_ADDRESS,
+				[], self._DEF_PROPS, "invalid port")
+		self._test_init_fail(self._DEF_NAME, self._DEF_STYPE, self._DEF_DOMAIN, self._DEF_ADDRESS,
+				{}, self._DEF_PROPS, "invalid port")
+		self._test_init_fail(self._DEF_NAME, self._DEF_STYPE, self._DEF_DOMAIN, self._DEF_ADDRESS,
+				"adf", self._DEF_PROPS, "invalid port")
+
+	def testGoodInit(self):
+		session_bus = dbus.SessionBus()
+		bus_name = dbus.service.BusName('org.laptop.Presence', bus=session_bus)		
+		service = Service(bus_name, 1, self._DEF_NAME, self._DEF_STYPE, self._DEF_DOMAIN, self._DEF_ADDRESS,
+				self._DEF_PORT, self._DEF_PROPS)
+		del bus_name, session_bus
+		assert service.get_name() == self._DEF_NAME, "service name wasn't correct after init."
+		assert service.get_type() == self._DEF_STYPE, "service type wasn't correct after init."
+		assert service.get_domain() == "local", "service domain wasn't correct after init."
+		assert service.get_address() == self._DEF_ADDRESS, "service address wasn't correct after init."
+		assert service.get_port() == self._DEF_PORT, "service port wasn't correct after init."
+		value = service.get_one_property('foobar')
+		assert value and value == 'baz', "service property wasn't correct after init."
+
+	def testAvahiProperties(self):
+		props = [[111, 114, 103, 46, 102, 114, 101, 101, 100, 101, 115, 107, 116, 111, 112, 46, 65, 118, 97, 104, 105, 46, 99, 111, 111, 107, 105, 101, 61, 50, 54, 48, 49, 53, 52, 51, 57, 53, 50]]
+		key = "org.freedesktop.Avahi.cookie"
+		expected_value = "2601543952"
+		session_bus = dbus.SessionBus()
+		bus_name = dbus.service.BusName('org.laptop.Presence', bus=session_bus)		
+		service = Service(bus_name, 1, self._DEF_NAME, self._DEF_STYPE, self._DEF_DOMAIN, self._DEF_ADDRESS,
+				self._DEF_PORT, props)
+		del bus_name, session_bus
+		value = service.get_one_property(key)
+		assert value and value == expected_value, "service properties weren't correct after init."
+		value = service.get_one_property('bork')
+		assert not value, "service properties weren't correct after init."
+
+	def testBoolProperty(self):
+		props = [[111, 114, 103, 46, 102, 114, 101, 101, 100, 101, 115, 107, 116, 111, 112, 46, 65, 118, 97, 104, 105, 46, 99, 111, 111, 107, 105, 101]]
+		key = "org.freedesktop.Avahi.cookie"
+		expected_value = True
+		session_bus = dbus.SessionBus()
+		bus_name = dbus.service.BusName('org.laptop.Presence', bus=session_bus)		
+		service = Service(bus_name, 1, self._DEF_NAME, self._DEF_STYPE, self._DEF_DOMAIN, self._DEF_ADDRESS,
+				self._DEF_PORT, props)
+		value = service.get_one_property(key)
+		del bus_name, session_bus
+		assert value is not None and value == expected_value, "service properties weren't correct after init."
+
+	def testGroupService(self):
+		# Valid group service type, non-multicast address
+		group_stype = u"_af5e5a7c998e89b9a_group_olpc._udp"
+		self._test_init_fail(self._DEF_NAME, group_stype, self._DEF_DOMAIN, self._DEF_ADDRESS,
+				self._DEF_PORT, self._DEF_PROPS, "group service type, but non-multicast address")
+
+		# Valid group service type, None address
+		session_bus = dbus.SessionBus()
+		bus_name = dbus.service.BusName('org.laptop.Presence', bus=session_bus)		
+		service = Service(bus_name, 1, self._DEF_NAME, group_stype, self._DEF_DOMAIN, None,
+				self._DEF_PORT, self._DEF_PROPS)
+		assert service.get_address() == None, "address was not None as expected!"
+
+		# Valid group service type and multicast address, ensure it works
+		mc_addr = u"224.0.0.34"
+		service = Service(bus_name, 1, self._DEF_NAME, group_stype, self._DEF_DOMAIN, mc_addr,
+				self._DEF_PORT, self._DEF_PROPS)
+		del bus_name, session_bus
+		assert service.get_address() == mc_addr, "address was not expected address!"
+
+	def addToSuite(suite):
+		suite.addTest(ServiceTestCase("testName"))
+		suite.addTest(ServiceTestCase("testType"))
+		suite.addTest(ServiceTestCase("testDomain"))
+		suite.addTest(ServiceTestCase("testAddress"))
+		suite.addTest(ServiceTestCase("testPort"))
+		suite.addTest(ServiceTestCase("testGoodInit"))
+		suite.addTest(ServiceTestCase("testAvahiProperties"))
+		suite.addTest(ServiceTestCase("testBoolProperty"))
+		suite.addTest(ServiceTestCase("testGroupService"))
+	addToSuite = staticmethod(addToSuite)
+
+
+def main():
+	suite = unittest.TestSuite()
+	ServiceTestCase.addToSuite(suite)
+	runner = unittest.TextTestRunner()
+	runner.run(suite)
+
+if __name__ == "__main__":
+	main()