refresh the client list on demand

services/real-time/app/coffee/ConnectedUsersManager.coffee

@@ -10,6 +10,7 @@ ONE_DAY_IN_S = ONE_HOUR_IN_S * 24
 FOUR_DAYS_IN_S = ONE_DAY_IN_S * 4
 
 USER_TIMEOUT_IN_S = ONE_HOUR_IN_S / 4
+REFRESH_TIMEOUT_IN_S = 10  # only show clients which have responded to a refresh request in the last 10 seconds
 
 module.exports =
 	# Use the same method for when a user connects, and when a user sends a cursor
@@ -38,6 +39,16 @@ module.exports =
 				logger.err err:err, project_id:project_id, client_id:client_id, "problem marking user as connected"
 			callback(err)
 
+	refreshClient: (project_id, client_id, callback = (err) ->) ->
+		logger.log project_id:project_id, client_id:client_id, "refreshing connected client"
+		multi = rclient.multi()
+		multi.hset Keys.connectedUser({project_id, client_id}), "last_updated_at", Date.now()
+		multi.expire Keys.connectedUser({project_id, client_id}), USER_TIMEOUT_IN_S
+		multi.exec (err)->
+			if err?
+				logger.err err:err, project_id:project_id, client_id:client_id, "problem refreshing connected client"
+			callback(err)
+
 	markUserAsDisconnected: (project_id, client_id, callback)->
 		logger.log project_id:project_id, client_id:client_id, "marking user as disconnected"
 		multi = rclient.multi()
@@ -56,6 +67,7 @@ module.exports =
 			else
 				result.connected = true
 				result.client_id = client_id
+				result.client_age = (Date.now() - parseInt(result.last_updated_at,10)) / 1000
 				if result.cursorData?
 					try
 						result.cursorData = JSON.parse(result.cursorData)
@@ -74,6 +86,6 @@ module.exports =
 			async.series jobs, (err, users = [])->
 				return callback(err) if err?
 				users = users.filter (user) ->
-					user?.connected
+					user?.connected && user?.client_age < REFRESH_TIMEOUT_IN_S
 				callback null, users
 

services/real-time/app/coffee/WebsocketController.coffee

@@ -175,6 +175,7 @@ module.exports = WebsocketController =
 					}, callback)
 				WebsocketLoadBalancer.emitToRoom(project_id, "clientTracking.clientUpdated", cursorData)
 
+	CLIENT_REFRESH_DELAY: 1000
 	getConnectedUsers: (client, callback = (error, users) ->) ->
 		metrics.inc "editor.get-connected-users"
 		Utils.getClientAttributes client, ["project_id", "user_id"], (error, {project_id, user_id}) ->
@@ -183,11 +184,13 @@ module.exports = WebsocketController =
 			logger.log {user_id, project_id, client_id: client.id}, "getting connected users"
 			AuthorizationManager.assertClientCanViewProject client, (error) ->
 				return callback(error) if error?
-				ConnectedUsersManager.getConnectedUsers project_id, (error, users) ->
-					return callback(error) if error?
-					callback null, users
-					logger.log {user_id, project_id, client_id: client.id}, "got connected users"
-					
+				WebsocketLoadBalancer.emitToRoom project_id, 'clientTracking.refresh', project_id
+				setTimeout () ->
+					ConnectedUsersManager.getConnectedUsers project_id, (error, users) ->
+						return callback(error) if error?
+						callback null, users
+						logger.log {user_id, project_id, client_id: client.id}, "got connected users"
+				, WebsocketController.CLIENT_REFRESH_DELAY
 
 	applyOtUpdate: (client, doc_id, update, callback = (error) ->) ->
 		Utils.getClientAttributes client, ["user_id", "project_id"], (error, {user_id, project_id}) ->

services/real-time/app/coffee/WebsocketLoadBalancer.coffee

@@ -6,6 +6,7 @@ EventLogger = require "./EventLogger"
 HealthCheckManager = require "./HealthCheckManager"
 RoomManager = require "./RoomManager"
 ChannelManager = require "./ChannelManager"
+ConnectedUsersManager = require "./ConnectedUsersManager"
 
 module.exports = WebsocketLoadBalancer =
 	rclientPubList: RedisClientManager.createClientList(Settings.redis.pubsub)
@@ -54,6 +55,11 @@ module.exports = WebsocketLoadBalancer =
 				return
 			if message.room_id == "all"
 				io.sockets.emit(message.message, message.payload...)
+			else if message.message is 'clientTracking.refresh' && message.room_id?
+				clientList = io.sockets.clients(message.room_id)
+				logger.log {channel:channel, message: message.message, room_id: message.room_id, message_id: message._id, socketIoClients: (client.id for client in clientList)}, "refreshing client list"
+				for client in clientList 
+					ConnectedUsersManager.refreshClient(message.room_id, client.id)
 			else if message.room_id?
 				if message._id? && Settings.checkEventOrder
 					status = EventLogger.checkEventOrder("editor-events", message._id, message)