Server pings clients periodically, clients error if lost connection

lobby.lua

@@ -38,9 +38,19 @@ function lobby_server_checkclients()
    oct_timer_register("lobby_server_checkclients", 3000, "lobby_server_checkclients", "")
 end
 
+function lobby_server_ping()
+   for k,v in pairs(oct_lobby_clientlist)
+   do
+	  local msg = json.encode({{ msg_type=OCT_LOBBY_MSG_PING, token=v["token"] }})
+	  oct_send(msg, v["addr"], v["port"])
+   end
+   oct_timer_register("lobby_server_ping", 3000, "lobby_server_ping", "")
+end
+
 function lobby_server(maxplayers)
    if lobby_server_first_call then
 	  oct_timer_register("lobby_server_checkclients", 3000, "lobby_server_checkclients", "")
+	  lobby_server_ping()
 	  lobby_server_first_call = false
    end
 
@@ -154,6 +164,21 @@ function lobby_clear_connect_form()
    unregister_textbox(lobby_name_textbox)
 end
 
+lobby_client_pinged = false
+
+function lobby_client_checkping()
+   if not lobby_client_pinged
+   then
+	  lobby_connect_message["x"] = 0
+	  lobby_connect_message["y"] = 20
+	  lobby_connect_message["shape"] = "Lost connection to server"
+	  lobby_connect_message["fg"] = TB_RED
+   else
+	  lobby_client_pinged = false
+	  oct_timer_register("lobby_client_checkping", 3000, "lobby_client_checkping", "")
+   end
+end
+
 -- every 1 second, ping the server to let it know we are still alive
 function lobby_client_ping()
    local msg = json.encode({
@@ -216,8 +241,9 @@ function lobby_client(key, ch, my_port)
    end
 
    msg,addr,port = oct_recv()
-   if (msg ~= "") then
+   if (msg and msg ~= "") then
-	  msg_obj = json.decode(msg)[1]
+	  local msg_obj = json.decode(msg)[1]
+	  OCT_LOG_DEBUG(msg_obj["msg_type"])
 	  
 	  -- State machine code here
 	  -- Registration was successful
@@ -230,6 +256,8 @@ function lobby_client(key, ch, my_port)
 		 client_connected = true
 		 client_wait_for_reg_response = false
 		 client_filling_in_connect_form = false
+		 lobby_client_pinged = true
+		 lobby_client_checkping()
 		 lobby_clear_connect_form()
 		 -- ping the server to let them know we are alive
 		 local ping_msg = json.encode({
@@ -261,6 +289,11 @@ function lobby_client(key, ch, my_port)
 		 do
 			client_clientlist_sprite["shape"] = client_clientlist_sprite["shape"] .. "\n" .. k
 		 end
+
+		 -- We received a ping from the server
+	  elseif (msg_obj["msg_type"] == OCT_LOBBY_MSG_PING and msg_obj["token"] == client_connect_token)
+	  then
+		 lobby_client_pinged = true
 	  end
    end
 end