NodeMCU 從網上取得時間

基於 : http://softbugbug.blogspot.com/2015/10/python.html

要有全域變數 HH, MM, SS
timer 要數時間
此段程式碼功能為 連上網路更新 HH, MM, SS 的數值

-- ['gettime.lua'] 
-- get time from web
-- update NodeMCU time base on get from web  
url = "http://time.artjoey.com/js/basetime.php"
site = "time.artjoey.com"
loc = "/js/basetime.php"

data = "GET "
  ..loc.." HTTP/1.1\r\nHost: "
  ..site.."\r\nConnection: keep-alive\r\nAccept: */*\r\n\r\n"

sk=net.createConnection(net.TCP, 0)

sk:on("receive", function(sck, c) 
  print("receive") 
  print(c)

  get={string.find(c,"baseTime=")}
  --If GET value exist,
  if get[2] ~= nil then 
    print("P:")
    print(get[2] )   -- print the start location of serch string 
    basetime = string.sub(c, get[2]+1, -7)   -- last char are 000;CrLf.  get basetime
-- example basetime = 1443789637
--  NodeMCU max value 2147483647 
    print(basetime)
    print("before:"..HH..":"..MM..":"..SS)
    esp_update() 
    print("after:"..HH..":"..MM..":"..SS)
  end

end )
sk:on("disconnection", function(sck, c) 
  print("disconnection")
  print(c)
end )
sk:on("connection", function(sck, c) 
  print("connection") 
  print(c)
end )

sk:connect(80,ip)
sk:send(data)

function esp_update() 
  twsec = basetime + 28800  -- 60 * 60 * 8  add 8Hr (tw: GMT + 8)
  daysec = twsec % 86400    -- 60 * 60 * 24
  HH = daysec / 3600        -- 60 * 60
  MM = (daysec / 60) % 60    
  SS = daysec % 60
--  webs()                  -- run http_server after update time
end

題外話：
NodeMCU 的字串連接式為 ..
ex: 
 str1 = "Hellow"
 str2 = str1..123     -- 數值型態的資料在此會自動轉為字串
 print(str2)
 Hellow123