tangent.lua

hs.console.clearConsole()

local hubMessage = {
    ["INITIATE_COMMS"]                          = 0x01,
    ["PARAMETER_CHANGE"]                        = 0x02,
    ["PARAMETER_RESET"]                         = 0x03,
    ["PARAMETER_VALUE_REQUEST"]                 = 0x04,
    ["MENU_CHANGE"]                             = 0x05,
    ["MENU_RESET"]                              = 0x06,
    ["MENU_STRING_REQUEST"]                     = 0x07,
    ["ACTION_ON"]                               = 0x08,
    ["MODE_CHANGE"]                             = 0x09,
    ["TRANSPORT"]                               = 0x0A,
    ["ACTION_OFF"]                              = 0x0B,
    ["UNMANAGED_PANEL_CAPABILITIES"]            = 0x30,
    ["UNMANAGED_BUTTON_DOWN"]                   = 0x31,
    ["UNMANAGED_BUTTON_UP"]                     = 0x32,
    ["UNMANAGED_ENCODER_CHANGE"]                = 0x33,
    ["UNMANAGED_DISPLAY_REFRESH"]               = 0x34,
    ["PANEL_CONNECTION_STATE"]                  = 0x35,
}

local appMessage = {
    ["APPLICATION_DEFINITION"]                  = 0x81,
    ["PARAMETER_VALUE"]                         = 0x82,
    ["MENU_STRING"]                             = 0x83,
    ["ALL_CHANGE"]                              = 0x84,
    ["MODE_VALUE"]                              = 0x85,
    ["DISPLAY_TEXT"]                            = 0x86,
    ["UNMANAGED_PANEL_CAPABILITIES_REQUEST"]    = 0xA0,
    ["UNMANAGED_DISPLAY_WRITE"]                 = 0xA1,
    ["RENAME_CONTROL"]                          = 0xA2,
    ["HIGHLIGHT_CONTROL"]                       = 0xA3,
    ["INDICATE_CONTROL"]                        = 0xA4,
    ["REQUEST_PANEL_CONNECTION_STATES"]         = 0xA5,
}

local panelType = {
    ["CP200-BK"]                                = 0x03,
    ["CP200-K"]                                    = 0x04,
    ["CP200-TS"]                                = 0x05,
    ["CP200-S"]                                    = 0x09,
    ["Wave"]                                    = 0x0A,
    ["Element-Tk"]                                = 0x0C,
    ["Element-Mf"]                                = 0x0D,
    ["Element-Kb"]                                = 0x0E,
    ["Element-Bt"]                                = 0x0F,
    ["Ripple"]                                    = 0x11,
}

local logger    = require("hs.logger")
logger.defaultLogLevel = 'debug'
local log         = logger.new("tangent")
local socket     = require("hs.socket")
local utf8         = require("hs.utf8")

messageBuffer = {}
messageLength = 0
messageCount = 0
readBytesRemaining = 0

function getPanelType(id)
    for i,v in pairs(panelType) do
        if id == v then
            return i
        end
    end
end

function byteStringToNumber(str, offset, num_bytes)
  assert(num_bytes >= 1 and num_bytes <= 4)
  local x = 0
  for i = 1, num_bytes do
    x = x * 0x0100
    x = x + math.fmod(string.byte(str, i + offset - 1) or 0, 0x0100)
  end
  return x
end

function numberToByteString(n)
    local t = {}
    local char = string.char
    t[1] = char(n >> 24 & 0xFF)
    t[2] = char(n >> 16 & 0xFF)
    t[3] = char(n >> 08 & 0xFF)
    t[4] = char(n >> 00 & 0xFF)
    return table.concat(t)
end

function buildMessage(msgType, msgParts)
    local byteString = numberToByteString(msgType)

    for _,partValue in pairs(msgParts) do
        byteString = byteString .. numberToByteString(#partValue)
        byteString = byteString .. partValue
    end

    log.df("buildMessage constructed: "..utf8.hexDump(byteString))
    return byteString
end

function processHubCommand(data)
    local id = byteStringToNumber(data, 1, 4)
    if id == hubMessage["INITIATE_COMMS"] then
        -- 0x01, <protocolRev>, <numPanels>, (<panelType>, <panelID>)...
        log.df("InitiateComms (0x01) Triggered:")

        local protocolRev = byteStringToNumber(data, 5, 4)
        local numberOfPanels = byteStringToNumber(data, 9, 4)

        log.df("    protocolRev: %s", protocolRev)
        log.df("    numberOfPanels: %s", numberOfPanels)

        local startNumber = 13
        for i=1, numberOfPanels do
            local currentPanelType = byteStringToNumber(data, startNumber, 4)
            startNumber = startNumber + 4
            local currentPanelID = byteStringToNumber(data, startNumber, 4)
            startNumber = startNumber + 4
            log.df("    panelType: %s        panelID: %s", getPanelType(currentPanelType), currentPanelID)
        end

        -- Respond with ApplicationDefinition (0x81):
        log.df("Responding with ApplicationDefinition (0x81)")
        local byteString = buildMessage(appMessage["APPLICATION_DEFINITION"], {"CommandPost", "/Users/cmsj", ""})
        tangentSocket:send(byteStringToNumber(#byteString)..byteString)

    else
        log.df("Unknown Reply: %s", hs.inspect(data))
    end
end

log.df("CONNECTING TO TANGENT HUB...")
tangentSocket = socket.new()
    :setCallback(function(data, tag)
        local hexDump = utf8.hexDump(data)
        log.df("Received data: "..hexDump)

        if readBytesRemaining == 0 then
            -- Each message starts with an integer value indicating the number of bytes to follow
            -- We don't have any bytes left to read of a previous message, so this must be the first 4 bytes
            readBytesRemaining = byteStringToNumber(data, 1, 4)
            log.df("New command received from hub, of length: "..readBytesRemaining)
            hs.timer.doAfter(0.5, function() tangentSocket:read(readBytesRemaining) end)
        else
            -- We've read the rest of a command
            readBytesRemaining = 0
            processHubCommand(data)

            -- Get set up for the next command
            hs.timer.doAfter(0.5, function() tangentSocket:read(4) end)
        end
    end)
    :connect("127.0.0.1", 64246, function()
        log.df("CONNECTION TO TANGENT HUB ESTABLISHED.")
    end)
tangentSocket:read(4) -- Read the first 4 bytes, which will trigger the callback.

FYI: Line 126 should be:

tangentSocket:send(numberToByteString(#byteString)..byteString)

Apart from that works BRILLIANTLY! THANK YOU!!