Switch from Groups to grouping services based on activity UID

sugar/presence/Group.py

@@ -1,61 +0,0 @@
-import Service
-
-import sugar.util
-
-def is_group_service_type(stype):
-	"""Return True if the service type matches a group
-	service type, or False if it does not."""
-	if stype.endswith("_group_olpc._tcp") or stype.endswith("_group_olpc._udp"):
-		return True
-	return False
-
-__GROUP_NAME_TAG = "Name"
-__GROUP_RESOURCE_TAG = "Resource"
-
-def new_group_service(group_name, resource):
-	"""Create a new service suitable for defining a new group."""
-	if type(group_name) != type("") or not len(group_name):
-		raise ValueError("group name must be a valid string.")
-	if type(resource) != type("") or not len(resource):
-		raise ValueError("group resource must be a valid string.")
-
-	# Create a randomized service type
-	data = "%s%s" % (group_name, resource)
-	stype = "_%s_group_olpc._udp" % sugar.util.unique_id(data)
-
-	properties = {__GROUP_NAME_TAG: group_name, __GROUP_RESOURCE_TAG: resource }
-	owner_nick = ""
-	port = random.randint(5000, 65000)
-	# Use random currently unassigned multicast address
-	address = "232.%d.%d.%d" % (random.randint(0, 254), random.randint(1, 254),
-			random.randint(1, 254))
-	service = Service.Service(owner_nick, stype, "local", address=address,
-			port=port, properties=properties)
-	return service
-
-
-class Group(object):
-	"""Represents a collection of buddies all interested in the same resource."""
-	def __init__(self, service):
-		if not isinstance(service, Service.Service):
-			raise ValueError("service argument was not a Service object.")
-		if not service.is_group_service():
-			raise ValueError("provided serivce was not a group service.")
-		name = service.get_one_property(__GROUP_NAME_TAG)
-		if name == None:
-			raise ValueError("provided service did not provide a group name.")
-		self._name = name
-		resource = service.get_one_property(__GROUP_RESOURCE_TAG)
-		if resource == None:
-			raise ValueError("provided service did not provide a group resource.")
-		self._resource = resource
-		self._service = service
-
-	def get_name(self):
-		return self._name
-
-	def get_service(self):
-		return self._service
-
-	def get_resource(self):
-		return self._resource

sugar/presence/PresenceService.py

@@ -2,9 +2,9 @@ import threading
 import avahi, dbus, dbus.glib, dbus.dbus_bindings, gobject
 import Buddy
 import Service
-import Group
 import os
-
+import string
+from sugar import util
 
 def _get_local_ip_address(ifname):
 	"""Call Linux specific bits to retrieve our own IP address."""
@@ -97,8 +97,8 @@ class PresenceService(gobject.GObject):
 		# Our owner object
 		self._owner = None
 
-		# group UID -> Group: groups we've found
+		# activity UID -> Service: services grouped by activity UID
-		self._groups = {}
+		self._activity_services = {}
 
 		# All the mdns service types we care about
 		self._allowed_service_types = []
@@ -110,7 +110,7 @@ class PresenceService(gobject.GObject):
 		# Resolved service list
 		self._service_advs = []
 
-		# Main activity UID to filter on
+		# Main activity UID to filter services on
 		self._activity_uid = None
 
 		self._bus = dbus.SystemBus()
@@ -126,8 +126,8 @@ class PresenceService(gobject.GObject):
 		self._started = True
 		self._lock.release()
 
-		if activity_uid and (not type(activity_uid) == type("") or not len(activity_uid)):
+		if activity_uid and not util.validate_activity_uid(activity_uid):
-			raise ValueError("activity uid must be a string.")
+			raise ValueError("activity uid must be a valid UID string.")
 		self._activity_uid = activity_uid
 
 		# Always browse .local
@@ -177,8 +177,6 @@ class PresenceService(gobject.GObject):
 		type, and False if it's not."""
 		if stype == Buddy.PRESENCE_SERVICE_TYPE:
 			return True
-		if Group.is_group_service_type(stype):
-			return True
 		return False
 
 	def _handle_new_service_for_buddy(self, service):
@@ -204,12 +202,24 @@ class PresenceService(gobject.GObject):
 			self.emit("buddy-appeared", buddy)
 		return buddy
 
-	def _handle_new_service_for_group(self, service, buddy):
+	def _handle_new_service_for_activity(self, service, buddy):
 		# If the serivce is a group service, merge it into our groups list
-		group = None
+		uid = service.get_activity_uid()
-		if not self._groups.has_key(service.get_type()):
+		if not uid:
-			group = Group.Group(service)
+			uid = "*"
-			self._groups[service.get_type()] = group
+		if not self._activity_services.has_key(uid):
+			self._activity_services[uid] = []
+		self._activity_services[uid].append((buddy, service))
+
+	def _handle_remove_service_for_activity(self, service, buddy):
+		uid = service.get_activity_uid()
+		if not uid:
+			uid = "*"
+		if self._activity_services.has_key(uid):
+			try:
+				self._activity_services.remove((buddy, service))
+			except:
+				pass
 
 	def _resolve_service_reply_cb(self, interface, protocol, name, stype, domain, host, aprotocol, address, port, txt, flags):
 		"""When the service discovery finally gets here, we've got enough information about the
@@ -226,13 +236,14 @@ class PresenceService(gobject.GObject):
 		adv.set_resolved(True)
 
 		# Update the service now that it's been resolved
-		service = Service.Service(name, stype, domain, address, port, txt)
+		service = Service.Service(name=name, stype=stype, domain=domain,
+				address=address, port=port, properties=txt)
 		adv.set_service(service)
 
 		# Merge the service into our buddy and group lists, if needed
 		buddy = self._handle_new_service_for_buddy(service)
-		if buddy and service.is_group_service():
+		if buddy and service.get_activity_uid():
-			self._handle_new_service_for_group(service, buddy)
+			self._handle_new_service_for_activity(service, buddy)
 
 		return False
 
@@ -268,8 +279,19 @@ class PresenceService(gobject.GObject):
 				if addr:
 					self._local_addrs[interface] = addr
 
+		# Decompose service type if we can
+		(uid, stype) = Service._decompose_service_type(stype)
+
 		# If we care about the service right now, resolve it
-		if stype in self._allowed_service_types or self._is_special_service_type(stype):
+		resolve = False
+		if self._activity_uid and self._activity_uid == uid:
+			if stype in self._allowed_service_types:
+				resolve = True
+		elif not self._activity_uid:
+			resolve = True
+		if self._is_special_service_type(stype):
+			resolve = True
+		if resolve:
 			gobject.idle_add(self._resolve_service, interface, protocol, name, stype, domain, flags)
 		return False
 
@@ -284,20 +306,23 @@ class PresenceService(gobject.GObject):
 		if not adv_list:
 			return False
 
-		# Unresolved services by definition aren't assigned to a buddy
+		# Get the service object; if none, we have nothing left to do
+		adv = adv_list[0]
+		service = adv.service()
+		if not service:
+			return False
+
+		# Remove the service from the buddy
 		try:
-			# Remove the service from the buddy
 			buddy = self._buddies[name]
-			# FIXME: need to be more careful about how we remove services
+		except KeyError:
-			# from buddies; this could be spoofed
+			pass
-			adv = adv_list[0]
+		else:
-			service = adv.get_service()
 			buddy.remove_service(service)
 			if not buddy.is_valid():
 				self.emit("buddy-disappeared", buddy)
 				del self._buddies[name]
-		except KeyError:
+			self._handle_remove_service_for_activity(service, buddy)
-			pass
 
 		return False
 

sugar/presence/Service.py

@@ -1,5 +1,28 @@
 import avahi
-import Group
+from sugar import util
+import string
+
+def new_group_service(group_name, resource):
+	"""Create a new service suitable for defining a new group."""
+	if type(group_name) != type("") or not len(group_name):
+		raise ValueError("group name must be a valid string.")
+	if type(resource) != type("") or not len(resource):
+		raise ValueError("group resource must be a valid string.")
+
+	# Create a randomized service type
+	data = "%s%s" % (group_name, resource)
+	stype = "_%s_group_olpc._udp" % sugar.util.unique_id(data)
+
+	properties = {__GROUP_NAME_TAG: group_name, __GROUP_RESOURCE_TAG: resource }
+	owner_nick = ""
+	port = random.randint(5000, 65000)
+	# Use random currently unassigned multicast address
+	address = "232.%d.%d.%d" % (random.randint(0, 254), random.randint(1, 254),
+			random.randint(1, 254))
+	service = Service.Service(owner_nick, stype, "local", address=address,
+			port=port, properties=properties)
+	return service
+
 
 def _txt_to_dict(txt):
 	"""Convert an avahi-returned TXT record formatted
@@ -18,6 +41,21 @@ def _txt_to_dict(txt):
 		prop_dict[key] = value
 	return prop_dict
 
+def _decompose_service_type(stype):
+	"""Break a service type into the UID and real service type, if we can."""
+	if len(stype) < util.ACTIVITY_UID_LEN + 5:
+		return (None, stype)
+	if stype[0] != "_":
+		return (None, stype)
+	start = 1
+	end = start + util.ACTIVITY_UID_LEN
+	if stype[end] != "_":
+		return (None, stype)
+	uid = stype[start:end]
+	if not util.validate_activity_uid(uid):
+		return (None, stype)
+	return (uid, stype[end:])
+
 def is_multicast_address(address):
 	"""Simple numerical check for whether an IP4 address
 	is in the range for multicast addresses or not."""
@@ -31,12 +69,10 @@ def is_multicast_address(address):
 	return False
 
 
-__GROUP_UID_TAG = "GroupUID"
-
 class Service(object):
 	"""Encapsulates information about a specific ZeroConf/mDNS
 	service as advertised on the network."""
-	def __init__(self, name, stype, domain, address=None, port=-1, properties=None, group=None):
+	def __init__(self, name, stype, domain, address=None, port=-1, properties=None):
 		# Validate immutable options
 		if not name or (type(name) != type("") and type(name) != type(u"")) or not len(name):
 			raise ValueError("must specify a valid service name.")
@@ -51,15 +87,13 @@ class Service(object):
 		if len(domain) and domain != "local" and domain != u"local":
 			raise ValueError("must use the 'local' domain (for now).")
 
-		# Group services must have multicast addresses
+		(uid, real_stype) = _decompose_service_type(stype)
-		if Group.is_group_service_type(stype) and address and not is_multicast_address(address):
+		if uid and not util.validate_activity_uid(activity_uid):
-			raise ValueError("group service type specified, but address was not multicast.")
+			raise ValueError("activity_uid not a valid activity UID.")
-
-		if group and not isinstance(group, Group.Group):
-			raise ValueError("group was not a valid group object.")
 		
 		self._name = name
 		self._stype = stype
+		self._real_stype = real_stype
 		self._domain = domain
 		self._address = None
 		self.set_address(address)
@@ -67,9 +101,7 @@ class Service(object):
 		self.set_port(port)
 		self._properties = {}
 		self.set_properties(properties)
-		self._group = group
+		self._activity_uid = uid
-		if group:
-			self._properties[__GROUP_UID_TAG] = group.get_uid()
 
 	def get_name(self):
 		"""Return the service's name, usually that of the
@@ -81,11 +113,6 @@ class Service(object):
 		False if it is not."""
 		return is_multicast_address(self._address)
 
-	def is_group_service(self):
-		"""Return True if the service represents a Group,
-		False if it does not."""
-		return Group.is_group_service_type(self._stype)
-
 	def get_one_property(self, key):
 		"""Return one property of the service, or None
 		if the property was not found.  Cannot distinguish
@@ -131,17 +158,15 @@ class Service(object):
 				raise ValueError("must specify a valid address.")
 			if not len(address):
 				raise ValueError("must specify a valid address.")
-			if Group.is_group_service_type(self._stype) and not is_multicast_address(address):
-				raise ValueError("group service type specified, but address was not multicast.")
 		self._address = address
 
 	def get_domain(self):
 		"""Return the ZeroConf/mDNS domain the service was found in."""
 		return self._domain
 
-	def get_group(self):
+	def get_activity_uid(self):
-		"""Return the group this service is associated with, if any."""
+		"""Return the activity UID this service is associated with, if any."""
-		return self._group
+		return self._activity_uid
 
 
 #################################################################

sugar/util.py

@@ -19,3 +19,20 @@ def _sha_data(data):
 def unique_id(data = ''):
 	data_string = "%s%s%s" % (time.time(), random.randint(10000, 100000), data)
 	return _stringify_sha(_sha_data(data_string))
+
+
+ACTIVITY_UID_LEN = 40
+
+def is_hex(s):
+	return s.strip(string.hexdigits) == ''	
+
+def validate_activity_uid(uid):
+	"""Validate an activity UID."""
+	if type(uid) != type(""):
+		return False
+	if len(uid) != ACTIVITY_UID_LEN:
+		return False
+	if not is_hex(uid):
+		return False
+	return True
+