prevent sending invalid XML chars in pm and in muc. Fixes #4354

src/groupchat_control.py

@@ -129,6 +129,11 @@ class PrivateChatControl(ChatControl):
 
 	def send_message(self, message):
 		'''call this function to send our message'''
+		if not message:
+			return
+
+		message = helpers.remove_invalid_xml_chars(message)
+
 		if not message:
 			return
 
@@ -1604,6 +1609,11 @@ class GroupchatControl(ChatControlBase):
 
 	def send_message(self, message):
 		'''call this function to send our message'''
+		if not message:
+			return
+
+		message = helpers.remove_invalid_xml_chars(message)
+
 		if not message:
 			return