rc.lua

-- #######################################
-- Simple remote control through REST API
-- Endpoints:
-- /     -> return last status
-- /up   -> trigger up button
-- /down -> trigger down button
-- #######################################

-- Global vars
ssid = "cyanidewifi"
pass = "laboulette!4321"
hostname = "node-rc"
pin_up = 1
pin_down = 2
last_status = "UNKNOWN"

-- =======================================

function triggerPin(pin, duration)
  if pin == pin_up then
    last_status = "UP"
  elseif pin == pin_down then
    last_status = "DOWN"
  end
  gpio.mode(pin, gpio.OUTPUT)
  gpio.write(pin, gpio.LOW)
  tmr.alarm(0, duration, tmr.ALARM_SINGLE, function()
    gpio.write(pin, gpio.HIGH)
  end)
end

function split(str, sep)
  -- copy string, as gmatch consumes it
  local s = str .. ""
  local r = {}
  local i = 1
  for val in s:gmatch(sep) do
    r[i] = val
    i = i + 1
  end
  if r[1] == nil or r[1] == "" then
    r[1] = str
  end
  return r
end

function parseHttpRequest(payload)
  local request = {}
  local data = split(payload, "^\r\n\r\n")
  if (data[2] ~= nil and data[2] ~= "") then
    request.data = json.decode(data[1])
  end
  local header = split(data[1], "%S+")
  request.method = header[1]
  request.path = header[2]
  -- ignore headers...
  return request
end

-- Response format: { status: 200, json: false, data: "Hello" }
-- If json == false, content is assumed to be HTML
function sendHttpResponse(sck, response)
  if response == nil then
    response = {}
  end
  if response.status == nil then
   response.status = 200
  end
  local res = {"HTTP/1.1 " .. response.status .. " OK\r\n"}
  if response.data ~= nil then
    local type = "text/html"
    local content = response.data
    if response.json ~= nil and response.json then
      type = "application/json"
      content = json.encode(response.data)
    end
    if response.encoding ~= nil then
      res[1] = res[1] .. "Content-Encoding:" .. response.encoding .. "\r\n"
    end
    res[1] = res[1] .. "Content-Type:" .. type .. "\r\n\r\n"
    while content ~= nil do
      local len = content:len()
      res[#res + 1] = content:sub(1, math.min(len, 1024))
      if len > 1024 then
        content = content:sub(1025)
      else
        content = nil
      end
    end
  else
    res[1] = res[1] .. "\r\n"
  end
  local function send(s)
    if #res > 0
    then s:send(table.remove(res, 1))
    else
      s:close()
      res = nil
    end
  end
  sck:on("sent", send)
  send(sck)
end

-- =======================================

-- Setup wifi
wifi.setmode(wifi.STATION)
wifi.sta.config(ssid, pass)

-- Setup mDNS discovery
wifi.eventmon.register(wifi.eventmon.STA_GOT_IP, function()
  mdns.register(hostname)
  wifi.eventmon.unregister(wifi.eventmon.STA_GOT_IP)
end)

-- Blink led
led_on = 0
gpio.mode(4, gpio.OUTPUT)
gpio.write(4, gpio.LOW)
tmr.alarm(0, 50, tmr.ALARM_AUTO, function()
  if led_on == 0 then
    led_on = 1
    gpio.write(4, gpio.HIGH)
  else
    led_on = 0
    gpio.write(4, gpio.LOW)
  end
end)
tmr.alarm(1, 1000, tmr.ALARM_SINGLE, function()
  gpio.write(4, gpio.HIGH)
  tmr.unregister(0)
end)

-- Init pins
gpio.write(pin_up, gpio.HIGH)
gpio.write(pin_down, gpio.HIGH)

-- Load web.html file
if file.open("web.html.gz") then
  local chunk = file.read()
  html = ""
  while chunk ~= nil do
    html = html .. chunk
    chunk = file.read()
  end
  file.close()
end

-- Init server
srv = net.createServer(net.TCP)

function receive(sck, data)
  local request = parseHttpRequest(data)
  if request.path == "/up" then
    triggerPin(pin_up, 200)
    sendHttpResponse(sck)
  elseif request.path == "/down" then
    triggerPin(pin_down, 200)
    sendHttpResponse(sck)
  elseif request.path == "/status" then
    sendHttpResponse(sck, { data = last_status })
  elseif request.path == "/" then
    sendHttpResponse(sck, { data = html, encoding = "gzip" })
  else
    sendHttpResponse(sck, { status = 404 })
  end
  collectgarbage()
end

srv:listen(80, function(conn)
  conn:on("receive", receive)
end)