Hi, I am not sure if this Succeeded to write a device handler parsing my arduino humidity and temperature webpage will help you but this is how I made a devicehandler that grabs data from a website I host on my NAS. The idea is that this device handler, instead of querying directly my Arduino board who performs the measurement, goes to a webpage where it access a MySQL database where my Arduino pushes the measurement.
Maybe you can find similarities with your use-case.