使用nodemcu玩轉物聯網系列（七）：notemcu通過mqtt協議“訂閱功能”實現onenet設備的“開關”

一、實現訂閱功能：
mqtt:subscribe(topic, qos[, function(client)])
二、實現觸發功能：
mqtt:on(event, function(client[, topic[, message]]))
參數：
event 可以是“ connect”，“ suback”，“ unsuback”，“ puback”，“ message”，“ overflow”或“ offline”
function(client[, topic[, message]])回調函數。第一個參數是客戶端。如果event爲“ message”，則接收第二個和第三個參數主題和消息（字符串）。

gpio.mode(2,gpio.OUTPUT)
wifi.setmode(wifi.STATION)
cfg = {}
cfg.ssid = "kyn"
cfg.pwd = "20160118"
wifi.sta.config(cfg)
wifi.sta.connect()

DeviceId = "587667371"
ProductId = "325428"
AuthoInfo = "test"
host = "183.230.40.39"
port = 6002

url = 'http://api.heclouds.com/devices/'..DeviceId..'/datapoints?type=3'
headers = 'api-key:BO6XuBiKw07JRXakBNvn4JKX7MI=\r\n'

dht_pin = 5
--led燈連接在三腳
led_pin = 3
gpio.mode(dht_pin,gpio.INPUT)
gpio.mode(led_pin,gpio.OUTPUT)

timer = tmr.create()
function con()
    if wifi.sta.getip() == nil then
        print("coneting........")
    else
        timer:stop()
        print("success!~")
        gpio.write(2,gpio.HIGH)
        print(wifi.sta.getip())


        client_hum = mqtt.Client(DeviceId,120,ProductId,AuthoInfo)
        client_hum:connect(host,port,0,function(client)
        print("connect success!")
        end)


        function h()
        status,temp,humi,temp_dec, humi_dec = dht.read11(dht_pin)
        print("DHT Temperature:"..temp..";".."Humidity:"..humi)
        
		--主要代碼如下：
        client_hum:subscribe("$dp",0, function(client)
            print("subscribe success")
        end)
        --提前在onenet“應用管理”中新建on/off按鈕
        client_hum:on("message", function(client,topic,message)
            print(message)
            if(message == "1") then
                gpio.write(led_pin,gpio.HIGH)
            else
                gpio.write(led_pin,gpio.LOW)
            end
        end)





--        http.post(url, headers, '{"DHT Temperature":'..temp..',"Humidity":'..humi..'}', function(code,date) 
--            if(code < 0) then
--                print("HTTP request failed")
--               else
--                print(code,date)
--            end
--            end)

        weather = {}
        weather.Temperature = temp
        weather.Humidity = humi
        state,weather_message = pcall(sjson.encode,weather)
        --mqtt:publish(topic, payload, qos, retain[, function(client)])
        payload = string.char(3,0,string.len(weather_message))..weather_message
        client_hum:publish("$dp", payload, 0, 0, function(client)
            print("upload success!~")
        end)


            
        end
        
        tmr.create():alarm(1500,tmr.ALARM_AUTO,h)

    end
end

timer:alarm(1000,tmr.ALARM_AUTO,con)