techpack/sl_controller/server.lua

--[[

	sl_controller
	=============

	Copyright (C) 2018 Joachim Stolberg

	LGPLv2.1+
	See LICENSE.txt for more information

	server.lua:

]]--

local SERVER_CAPA = 5000
local DEFAULT_MEM = {
	size=0, 
	data={
		version = 1,
		info = "SaferLua key/value Server",
	}
}


local function on_time(pos, elasped)
	local meta = minetest.get_meta(pos)
	local number = meta:get_string("number")
	local mem = tubelib.get_data(number, "memory") or DEFAULT_MEM
	meta:set_string("infotext", "Server "..number..": ("..(mem.size or 0).."/"..SERVER_CAPA..")")
	return true
end

minetest.register_node("sl_controller:server", {
	description = "Central Server",
	tiles = {
		-- up, down, right, left, back, front
		"sl_controller_server_top.png",
		"sl_controller_server_top.png",
		"sl_controller_server_side.png",
		"sl_controller_server_side.png^[transformFX",
		"sl_controller_server_back.png",
		{
			image = "sl_controller_server_front.png",
			backface_culling = false,
			animation = {
				type = "vertical_frames",
				aspect_w = 32,
				aspect_h = 32,
				length = 1,
			},
		},
	},

	drawtype = "nodebox",
	node_box = {
		type = "fixed",
		fixed = {
			{ -3/16, -8/16, -7/16, 3/16, 6/16, 7/16},
		},
	},
	
	after_place_node = function(pos, placer)
		local meta = minetest.get_meta(pos)
		local number = tubelib.add_node(pos, "sl_controller:server")
		meta:set_string("owner", placer:get_player_name())
		meta:set_string("number", number)
		tubelib.set_data(number, "memory", DEFAULT_MEM)
		on_time(pos, 0)
		minetest.get_node_timer(pos):start(20)
	end,
	
	on_dig = function(pos, node, puncher, pointed_thing)
		if minetest.is_protected(pos, puncher:get_player_name()) then
			return
		end
		
		minetest.node_dig(pos, node, puncher, pointed_thing)
		tubelib.remove_node(pos)
	end,
		
	on_timer = on_time,
	
	paramtype = "light",
	sunlight_propagates = true,
	paramtype2 = "facedir",
	groups = {choppy=1, cracky=1, crumbly=1},
	drop = "",
	is_ground_content = false,
	sounds = default.node_sound_stone_defaults(),
})

minetest.register_craft({
	output = "sl_controller:server",
	recipe = {
		{"", "", ""},
		{"default:mese_crystal_fragment", "tubelib:wlanchip", "default:mese_crystal_fragment"},
		{"", "default:copper_ingot", ""},
	},
})

local function calc_size(v)
	if type(v) == "number" then
		return 1
	elseif v == nil then
		return 0
	elseif type(v) == "string" then
		return #v
	else
		return nil
	end
end

local function write_value(mem, key, value)
	if mem and mem.size < SERVER_CAPA then
		if value == nil then
			mem.size = mem.size - calc_size(mem.data[key])
		else
			mem.size = mem.size - calc_size(mem.data[key])
			mem.size = mem.size + calc_size(value)
		end
		mem.data[key] = value
	end
end	

tubelib.register_node("sl_controller:server", {}, {
	on_recv_message = function(pos, topic, payload)
		local meta = minetest.get_meta(pos)
		if meta then
			local number = meta:get_string("number")
			local mem = tubelib.get_data(number, "memory") or DEFAULT_MEM
			if topic == "read" then
				return mem.data[payload]
			elseif topic == "write" then
				write_value(mem, payload.key, payload.value)
				tubelib.set_data(number, "memory", mem)
			else
				return "unsupported"
			end
		end
	end,
})		


sl_controller.register_function("server_read", {
	cmnd = function(self, num, key) 
		if type(key) == "string" then
			return tubelib.send_request(num, "read", key)
		else
			self.error("Invalid server_read parameter")
		end
	end,
	help = " $server_read(num, key)\n"..
		" Read a value from the server.\n"..
		" 'key' must be a string.\n"..
		' example: state = $server_read("0123", "state")'
})

sl_controller.register_action("server_write", {
	cmnd = function(self, num, key, value)
		if type(key) == "string" and type(value) == "string" or type(value) == "number" then
			tubelib.send_message(num, self.meta.owner, nil, "write", {key=key, value=value})
		else
			self.error("Invalid server_write parameter")
		end
	end,
	help = " $server_write(num, key, value)\n"..
		" Store a value on the server under the key 'key'.\n"..
		" 'key' must be a string. 'value' can be\n"..
		" either a number or a string.\n"..
		' example: $server_write("0123", "state", state)'
})