Mod to list cumulative online players periodically.

szutil_nowonline/README

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+------------------------------------------------------------------------
+
+When players log in or log out, reannounce the cumulative list of online
+players.  This is particularly useful for szutil_chatsocket connections
+to external chat bridges, where no command is provided for getting the
+list of online players.
+
+Player lists are only sent if either a certain amount of time has
+passed, or a certain number of public chat lines, since the last
+announcement (configurable) to prevent a ton of noise on busy servers.
+
+The maximum number of names listed is configurable; beyond that limit,
+a random sample of players will be shown, and "(# more)" displayed at
+the end of the list.
+
+------------------------------------------------------------------------

szutil_nowonline/init.lua

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+-- LUALOCALS < ---------------------------------------------------------
+local math, minetest, pairs, table, tonumber, tostring
+    = math, minetest, pairs, table, tonumber, tostring
+local math_random, table_concat, table_remove, table_sort
+    = math.random, table.concat, table.remove, table.sort
+-- LUALOCALS > ---------------------------------------------------------
+
+local modname = minetest.get_current_modname()
+
+local timedelay = tonumber(minetest.settings:get(modname .. "_time")) or 300
+local linedelay = tonumber(minetest.settings:get(modname .. "_lines")) or 25
+local maxnames = tonumber(minetest.settings:get(modname .. "_names")) or 50
+
+local lines = 0
+local exp = 0
+
+local function delaymsg(msg)
+	return minetest.after(0, function()
+			return minetest.chat_send_all(msg)
+		end)
+end
+
+local function sendall(isann)
+	lines = lines + 1
+	if not isann then return end
+
+	local now = minetest.get_us_time() / 1000000
+	if (lines < linedelay) or (now < exp) then return end
+
+	exp = now + timedelay
+	lines = 0
+	local names = {}
+	for _, player in pairs(minetest.get_connected_players()) do
+		names[#names + 1] = player:get_player_name()
+	end
+	table_sort(names)
+
+	local more = 0
+	while #names > maxnames do
+		table_remove(names, math_random(1, #names))
+		more = more + 1
+	end
+	if more > 0 then
+		names[#names + 1] = "(" .. more .. " more)"
+	end
+
+	if #names > 0 then
+		delaymsg("*** Online: " .. table_concat(names, ", "))
+	else
+		delaymsg("*** Server is empty.")
+	end
+end
+
+do
+	local old_sendall = minetest.chat_send_all
+	function minetest.chat_send_all(text, ...)
+		sendall(tostring(text):match("^%s*%*%*%*%s"))
+		return old_sendall(text, ...)
+	end
+end
+
+minetest.register_on_chat_message(function(pname, text)
+		if text:sub(1, 1) ~= "/"
+		and minetest.check_player_privs(pname, "shout") then
+			sendall()
+		end
+	end)