Thingsboard GPIO MQTT for Wemos D1 Mini

gpio_mqtt.lua

--MQTT params
local mqtt_settings = {
  module = "ESP8266_"..node.chipid(),
  ip = "<brokerip>",
  port = 1883,
  token = "tokendevice"
}
-- local pins data
local gpio_pins = {
  {pin = 0, value = "false"},
  {pin = 1, value = "false"},
  {pin = 2, value = "false"},
  {pin = 3, value = "false"},
  {pin = 4, value = "false"},
  {pin = 5, value = "false"},
  {pin = 6, value = "false"},
  {pin = 7, value = "false"},
  {pin = 8, value = "false"}
}
-- put pin value to table
local function pValue(idx, value)
    gpio_pins[idx].value = value
end
-- read from cache
-- cache.txt is a file containing the pin values: 0,1,0,0,0,0,1,0,0
if file.open("cache.txt") then
    last = file.read()
    file.close()
    t = {}
    for v in string.gmatch(last, "[^,]") do table.insert(t,v) end
    for i = 1, 9 do if t[i] == "0" then pValue(i,"false") else pValue(i,"true") end end
end
-- set gpio to OUTPUT
for i = 1, 8 do
    gpio.mode(gpio_pins[i].pin, gpio.OUTPUT)
end
-- mount string to cache last value
local function cache_last_value()
    str = ""
    for i = 1, 9 do if gpio_pins[i].value == "true" then str = str .. "1," else str = str .. "0," end end
    str = string.sub(str, 0, -2)
    if file.open("cache.txt", "w") then
        file.write(str)
        file.close()
    end
end
-- mount string json GPIO data response
local function get_gpio_string()
    str = "{"
    for i = 1, 9 do
        str = str .. "\"" ..gpio_pins[i].pin .. "\": " ..gpio_pins[i].value.. ", " 
    end
    str = string.sub(str, 0, -3)
    str = str .. "}"
    return str
end
-- set GPIO value from MQTT request
local function set_gpio_value(data)
    if data.enabled == true then
       gpio.write(data.pin, gpio.HIGH)
    else
       gpio.write(data.pin, gpio.LOW)
    end
    gpio_pins[data.pin+1].value = tostring(data.enabled)
    -- save cache
    cache_last_value()
end
-- handler payload data
local function handler_payload(topic, data)
    print(data)
    resTopic = topic:gsub("request", "response")
    payload = sjson.decode(data)
    print(resTopic)
    if payload.method == "getGpioStatus" then
       m:publish(resTopic, get_gpio_string(), 0, 0, function(client) print("Response sent :: getGpioStatus") end)
    elseif payload.method == "setGpioStatus" then
       -- set gpio
       set_gpio_value(payload.params)
       m:publish(resTopic, get_gpio_string(), 0, 0, function(client) print("Response sent :: setGpioStatus") end)
       m:publish("v1/devices/me/attributes", get_gpio_string(), 0, 0, function(client) print("Attributes sent") end) 
    else
       print("No payload method")
    end    
end
-- create mqtt client
m = mqtt.Client(mqtt_settings.module, 41, mqtt_settings.token, "password")
m:on("message", function(client, topic, data)
  print(topic ..":")
  if data ~= nil then
    handler_payload(topic, data)
  end
end)
-- handler error 
function handler_mqtt_error(client, reason)
  print(reason)
  tmr.create():alarm(10 * 1000, tmr.ALARM_SINGLE, do_mqtt_connect)
end
-- handler mqtt success connected
function handler_mqtt_connect(client)
    print("Connected")
    client:subscribe("v1/devices/me/rpc/request/+", 0, function(client) print("subscribe success") end)
    client:publish("v1/devices/me/attributes", get_gpio_string(), 0, 0, function(client) print("Data sent") end)        
end
-- performs connect mqtt
function do_mqtt_connect()
  print("Connecting "..node.chipid().." to MQTT broker...")
  m:connect(mqtt_settings.ip, mqtt_settings.port, handler_mqtt_connect, handler_mqtt_error)
end
-- connect
do_mqtt_connect()

:25 cache.txt is a file containing the pin values: 0,1,0,0,0,0,1,0,0