ap_mode.lua

print("Lua WIFI Manager ")
print("https://github.com/gfnord/lua_wifimanager")

-- put module in AP mode
wifi.setmode(wifi.SOFTAP)
print("ESP8266 mode is: " .. wifi.getmode())

-- Set the SSID of the module in AP mode and access password
cfg={}
cfg.ssid="ESP_" .. node.chipid()
cfg.pwd="passw0rd"
print("Chip ID: " .. node.chipid())
print("ESP8266 SSID is: " .. cfg.ssid .. " and PASSWORD is: " .. cfg.pwd)

-- Now you should see an SSID wireless router named ESP_STATION when you scan 
--   for available WIFI networks
-- Lets connect to the module from a computer of mobile device. So, 
--   find the SSID and connect using the password selected
wifi.ap.config(cfg)
ap_mac = wifi.ap.getmac()
print("AP MAC: " .. ap_mac)

-- create a server on port 80 and wait for a connection, when a connection 
--   is coming in function c will be executed
sv = net.createServer(net.TCP, 30) -- 30s timeout

-- Latch: once a credential pair has been accepted, every later request is
-- ignored. sv:close() only closes the listener, so sockets that were already
-- accepted can still deliver data, and without this latch a second request
-- would overwrite the credentials the pending timer is about to save.
-- (docs/KNOWN-ISSUES.md #21)
local provisioning = false

-- Percent- and plus-decode a query-string value. Form input arrives
-- URL-encoded and must be decoded before it can name a real network.
-- (docs/KNOWN-ISSUES.md #1)
local function urldecode(s)
  s = string.gsub(s, "+", " ")
  return (string.gsub(s, "%%(%x%x)", function(h) return string.char(tonumber(h, 16)) end))
end

-- Accept only what the radio can actually join, so bad input is rejected at
-- the form instead of stranding the device mid-provisioning: SSID 1-32 bytes,
-- passphrase empty (open network) or 8-64 bytes, and no control characters
-- (they are never legitimate in input taken from a query string and cannot
-- be stored in the line-based credentials file).
local function valid_credentials(ssid, password)
  local function clean(s)
    return type(s) == "string" and #s > 0 and not string.find(s, "%c")
  end
  return clean(ssid) and #ssid <= 32
    and type(password) == "string" and #password <= 64
    and (#password == 0 or (#password >= 8 and not string.find(password, "%c")))
end

function receiver(sck, data)
  -- parse the SSID and the password out of the request line:
  --   GET /?SSID=<ssid>&PASSWORD=<password> HTTP/1.1
  -- Delimiters are searched for literally, so an '&' inside the SSID no
  -- longer desynchronises the split.
  print(string.match(data,"GET"))
  local ssid, password
  local s = string.find(data, "SSID=", 1, true)
  if s then
    local p = string.find(data, "&PASSWORD=", s + 5, true)
    if p then
      local h = string.find(data, " HTTP/1.1", p + 10, true)
      if h then
        ssid = urldecode(string.sub(data, s + 5, p - 1))
        password = urldecode(string.sub(data, p + 10, h - 1))
      end
    end
  end

  if ssid and password and valid_credentials(ssid, password) and not provisioning then
    provisioning = true
    print("ESP8266 connecting to SSID: " .. ssid .. " with PASSWORD: " .. password)
    -- close the server and set the module to STATION mode
    sv:close()
    wifi.setmode(wifi.STATION)
    print("ESP8266 mode now is: " .. wifi.getmode())
    -- configure the module so it can connect to the network using the received SSID and password
    local config_wifi={}
    config_wifi.ssid=ssid
    config_wifi.pwd=password
    wifi.sta.config(config_wifi)
    wifi.sta.connect()
    print("Setting up ESP8266 for station mode... Please wait.")
    -- Poll for a connection; give up after 12 tries (~60 s) and fall back to
    -- AP mode instead of retrying forever. ssid and password are locals of
    -- receiver captured here, so no later request can change what is saved.
    -- (docs/KNOWN-ISSUES.md #3, #21)
    local tries = 0
    tmr.alarm(2,5000,tmr.ALARM_AUTO,function()
      -- Connect wifi
      if wifi.sta.getip() == nil then
        tries = tries + 1
        print('IP unavaiable, waiting...')
        if tries >= 12 then
          tmr.stop(2)
          print('Giving up after '..(tries*5)..'s, returning to AP mode')
          file.remove("credentials.lua")
          node.restart()
        end
      else
        tmr.stop(2)
        -- Save the credentials as plain data lines, one per line. Never as
        -- Lua source: this file is read back with file.readline(), so its
        -- contents can never execute. (docs/KNOWN-ISSUES.md #2)
        file.open("credentials.lua","w+")
        file.writeline(ssid)
        file.writeline(password)
        file.close()

        print('The module MAC address is: ' .. wifi.ap.getmac())
        print('Config done, IP is '..wifi.sta.getip())
      end
    end)

  end

  -- this is the webpage form presented to be configured
  local title = "AQS Sensor"
  local subtitle = "Configure AQS Sensor Wifi</h2><p>Use the following form to connect this AQS Sensor on your Wifi network"

  local response = {"HTTP/1.0 200 OK\r\nServer: NodeMCU on ESP8266\r\nContent-Type: text/html\r\n\r\n"}
  response[#response + 1] = "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\"><html xmlns=\"http://www.w3.org/1999/xhtml\"><head>" 
  response[#response + 1] = "<meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF-8\"><title>" .. title .. "</title></head><body><div><h1><a>" .. title .. "</a></h1>" 
  response[#response + 1] = "<form method=\"get\" action=\"/?SSID=\"><div>"
  response[#response + 1] = "<h2>" .. subtitle .. "</p></div>"
  response[#response + 1] = "<ul ><li><label> SSID </label><div><input name=\"SSID\" type=\"text\" maxlength=\"255\" value=\"\"/>" 
  response[#response + 1] = "</div> </li><li><label> Password </label><div><input name=\"PASSWORD\" type=\"text\" maxlength=\"255\" value=\"\"/> </div> </li><input type=\"submit\" value=\"Save\" /></ul></form>"
  response[#response + 1] = "<div>Powered by <a href=\"https://www.levare.io\">Levare Research Inc @ 2018</a></div></div></body></html>"
  response[#response + 1] =  "The module MAC address is: " .. ap_mac


  -- sends and removes the first element from the 'response' table
  local function send(localSocket)
    if #response > 0 then
      localSocket:send(table.remove(response, 1))
    else
      localSocket:close()
      response = nil
    end
  end

  -- triggers the send() function again once the first chunk of data was sent
  sck:on("sent", send)
  send(sck)
end

if sv then
  print("Server Created.")
  sv:listen(80, function(conn) -- listen on port 80
    print("Receiving connection on port 80.")
    conn:on("receive", receiver)
  end)
else
  print("ERR: Server was not created.")
end