First working version

README.md

 # Luanti LED Tree
-
-You have to add the mod to the trusted mods in minetest.conf:
-
-secure.http_mods = ledtree

init.lua

@@ -2,40 +2,79 @@
 --
 -- SPDX-License-Identifier: GPL-3.0-or-later
 
-local HTTPApiTable = core.request_http_api()
+local modname = core.get_current_modname()
+local modpath = core.get_modpath(modname)
 
 local data = {
-    url = "https://mqtt.felix-zauberer.de:443",
+    url = "mqtt.felix-zauberer.de",
     clientId = "ledtree_luanti",
     username = "kalle1",
-    token = "eZcKn1zBE6KtbeFnZ33lV1EKnr9Bcn8B",
+    password = "eZcKn1zBE6KtbeFnZ33lV1EKnr9Bcn8B",
 }
 
-change_color = function(led_id)
-    local request = {
-        url = data.url,
-        method = 'POST',
-        timeout = 15,
-        username = data.username,
-        clientId = data.clientId,
-        extra_headers = {
-            "Authorization: Bearer "..data.token,
-        }
-    }
-    HTTPApiTable.fetch(request, function(response)
-        print(dump(request))
-        if response.code ~= 200 then
-            return false
-        else
-            return true
-        end
-    end)
+local mqttBaseTopic = core.settings:get("ledtree_base_topic") or "ledtree"
+
+local client = mqtt.connect(data.url, data.clientId, data.username, data.password)
+
+local change_color = function(player, led_id)
+    local formspec = "size[3,3]" ..
+                     "image_button[0,0;1,1;red.png;red;red;false;false;]" ..
+                     "image_button[1,0;1,1;green.png;gren;green;false;false;]" ..
+                     "image_button[2,0;1,1;blue.png;blue;blue;false;false;]" ..
+                     "image_button[0,1;1,1;yellow.png;yellow;yellow;false;false;]" ..
+                     "image_button[1,1;1,1;cyan.png;cyan;cyan;false;false;]" ..
+                     "image_button[2,1;1,1;magenta.png;magenta;magenta;false;false;]" ..
+                     "image_button[0,2;1,1;white.png;white;white;false;false;]" ..
+                     "image_button[1,2;1,1;black.png;black;black;false;false;]" ..
+                     "image_button[2,2;1,1;gray.png;gray;gray;false;false;]"
+
+    core.show_formspec(player:get_player_name(), "ledtree:colorpicker", formspec)
+end
+
+local function send_mqtt(id, rgb)
+    mqtt.publish(client, mqttBaseTopic.."/led/"..id, "["..rgb.."]")
 end
 
 for id=1, 10, 1 do
     core.register_node("ledtree:led"..id, {
         description = "LED"..id,
         --tiles = "",
-        on_rightclick = change_color(id),
+        on_rightclick = function(pos, node, player, itemstack, pointed_thing)
+            change_color(player, id)
+        end,
     })
 end
+
+core.register_on_player_receive_fields(function(player, formname, fields)
+    if formname == "ledtree:colorpicker" then
+        for color, _ in pairs(fields) do
+            if color then
+                local rgb = ""
+                if color == "red" then
+                    rgb = "255,0,0"
+                elseif color == "green" then
+                    rgb = "0,255,0"
+                elseif color == "blue" then
+                    rgb = "0,0,255"
+                elseif color == "yellow" then
+                    rgb = "255,255,0"
+                elseif color == "cyan" then
+                    rgb = "0,255,255"
+                elseif color == "magenta" then
+                    rgb = "255,0,255"
+                elseif color == "white" then
+                    rgb = "255,255,255"
+                elseif color == "black" then
+                    rgb = "0,0,0"
+                elseif color == "gray" then
+                    rgb = "128,128,128"
+                end
+
+                if rgb ~= "" then
+                    core.chat_send_player(player:get_player_name(), "RGB: " .. rgb)
+                    send_mqtt(1, rgb)
+                end
+            end
+        end
+    end
+end)

mod.conf

 name = ledtree
 title = Teckids LED-Weihnachtsbaum
 description = Teckids LED-Weihnachtsbaum
+depends = mqtt
 author = Tuxilio <mail@tuxil.io>

settingtypes.txt

+ledtree_base_topic (Base topic (e.g. /[base_topic]/led/1)) string ledtree