Has someone already integrated LG ThinQ

[admin]

Try this for the signature calculation. You might need to swap message and secret arguments if it does not work.

Code:

function oauth2_signature(message, secret)
  local encdec = require('encdec')
  local hashed = encdec.hmacsha1(secret, message, true)
  return encdec.base64enc(hashed)
end

Use log() instead of self:debug. There are no callbacks for HTTP requests anyway, just the return values. Search the forums, there are many similar HTTP request examples available.