Make cannon 'fire' response optional, defaulting to off.

digiline.lua

@@ -31,7 +31,7 @@ spacecannon.digiline_handler_get = function(pos, node, channel)
 	digilines.receptor_send(pos, spacecannon.digiline_rules, channel, resp)
 end
 
-spacecannon.digiline_handler_fire = function(pos, node, channel)
+spacecannon.digiline_handler_fire = function(pos, node, channel, msg)
 	local meta = minetest.get_meta(pos)
 
 	-- TODO: Add ability to set "target node" in the msg, and if its within
@@ -60,8 +60,15 @@ spacecannon.digiline_handler_fire = function(pos, node, channel)
 		pos = pos
 	}
 
+	-- Only send response if the fire request specifically asked for it.
+	-- Consider a large (N) bank of cannons on the same digiline.  Firing all N
+	-- at the same time would generate N responses, which would be seen by the LUAC
+	-- and the (N-1) other cannons, resulting in N^2 message processing.  If N>20,
+	-- the LUAC will get fried.
+	if msg.verbose then
 		digilines.receptor_send(pos, spacecannon.digiline_rules, channel, resp)
 	end
+end
 
 spacecannon.digiline_effector = function(pos, node, channel, msg)
 	if type(msg) ~= "table" then

readme.md

@@ -36,7 +36,7 @@ An "on" signal triggers a fire-action.
 Fire a cannon:
 ```lua
 if event.type == "program" then
- digiline_send("cannon", { command="fire" })
+ digiline_send("cannon", { command="fire", verbose=false })
 end
 ```
 
@@ -66,7 +66,14 @@ Example response from a "get" request:
 }
 ```
 
-Example response from a "fire" request:
+The "fire" request can specify an optional "verbose" flag.  If this flag
+evaluates to true, then the following example response will be sent back.
+Note that if you have a large number of cannons that you will likely want
+to disable responses.  N cannons firing and generating responses will
+cause N^2 messages to be processed, as each cannon receives the fire response
+from all of its peers.  If N>20, your LUAC will overheat.  N>900, and your
+server admin will want to have a chat with you.
+
 ```lua
 {
         type = "digiline",