Source: by Mike Kazantsev
Upstream: http://code.google.com/p/pyicqt/issues/detail?id=5
Reason:
  Connect breaks frequently: "in a non-clean fashion"

  I didn't dig deep into code, just wrote a test-case (connection breaker)
 and compared the log of broken connection and a cleanly closed one, noticing
 that former gets connectionLost event before removing the session, while
 latter gets it as a result, and exploited this difference by introducing an
 "active_close" flag to session and a simple session re-creation sequence in
 removeMe method.

  Note that it's probably not the best way to do it, and it's only designed to
 be a cure for unexpectedly broken (for whatever reason) _TCP_ connections.

  Simple scapy-based script to hijack and break the tcp connection after any
 activity on it is attached to the tracker issue, which can be used as a simple
 real-world test-case (unless icq server bans you for too frequent reconnects)
 for further improvements.

diff --git a/src/legacy/icqt.py b/src/legacy/icqt.py
index d6fce48..923f33e 100644
--- a/src/legacy/icqt.py
+++ b/src/legacy/icqt.py
@@ -70,7 +70,7 @@ class B(oscar.BOSConnection):
 		oscar.BOSConnection.connectionLost(self, reason)
 
 		try:
-			self.session.removeMe()
+			self.session.connectionLost()
 		except:
 			pass
 
diff --git a/src/session.py b/src/session.py
index f2c3212..0f9a8fe 100644
--- a/src/session.py
+++ b/src/session.py
@@ -41,6 +41,7 @@ class Session(jabw.JabberConnection):
 		LogEvent(INFO, jabberID)
 		
 		self.pytrans = pytrans
+		self.active_close = None # Whether session was closed actively (by us) or not
 		self.alive = True
 		self.ready = False # Only ready when we're logged into the legacy service
 		self.jabberID = jabberID # the JabberID of the Session's user
@@ -61,7 +62,9 @@ class Session(jabw.JabberConnection):
 					# 4 = pep based avatar
 		self.lang = ulang
 
-		if rosterID.resource == "registered":
+		if isinstance(rosterID, bool):
+			self.registeredmunge = rosterID
+		elif rosterID.resource == "registered":
 			self.registeredmunge = True
 		else:
 			self.registeredmunge = False
@@ -97,6 +100,13 @@ class Session(jabw.JabberConnection):
 			self.pytrans.serviceplugins['Statistics'].stats["MaxConcurrentSessions"] = len(self.pytrans.sessions)+1
 		self.pytrans.serviceplugins['Statistics'].sessionUpdate(self.jabberID, "Connections", 1)
 	
+	def connectionLost(self):
+		"""Marks session as passively-closed ("in a non-clean fashion"), if nothing suggests otherwise.
+			Inteneded to be called from similar method in icq connection object.
+			Flag is used to determine whether it's necessary to re-create session."""
+		if self.active_close is None: self.active_close = False
+		self.removeMe()
+
 	def removeMe(self):
 		""" Safely removes the session object, including sending <presence type="unavailable"/> messages for each legacy related item on the user's contact list """
 		# Send offline presence to Jabber ID
@@ -105,6 +115,9 @@ class Session(jabw.JabberConnection):
 		
 		LogEvent(INFO, self.jabberID)
 		
+		# Mark session as closed by us, unless already set otherwise
+		if self.active_close is None: self.active_close = True
+
 		# Mark as dead
 		self.alive = False
 		self.ready = False
@@ -129,6 +142,17 @@ class Session(jabw.JabberConnection):
 		if self.pytrans:
 			# Remove us from the session list
 			del self.pytrans.sessions[self.jabberID]
+
+			if self.active_close is False:
+				# Schedule reconnect
+				from twisted.internet import reactor
+				def restore_session(pytrans=self.pytrans, jid=self.jabberID, ulang=self.lang, reg=self.registeredmunge):
+					s = makeSession(pytrans, jid, ulang, reg)
+					if s:
+						pytrans.sessions[jid] = s
+						LogEvent(INFO, msg="Re-created broken session")
+				reactor.callLater(5, restore_session)
+
 			# Clean up the no longer needed reference
 			self.pytrans = None