On 10/24/2016 01:12 PM, tim Rowledge wrote:
> Happily my use case is about as simple as I could imagine; several
> devices - probably one Pi and a bunch of ESP8266 nodes - publishing
> some small amounts of data every 15 minutes or so, and one recipient
> wanting to get that data to make pretty graphs and stuff. AIUI that
> means having a broker in the middle.

Can your devices make HTTP requests?

I'd POST the data to something in the middle, and GET it from the
rendering bit. (Or use the filesystem directly, if the rendering bit is
conveniently located at the same place as the POST-receiving server.)

You might find the recently-published W3C PubSub draft of interest:
https://www.w3.org/TR/pubsub/

Regards,
  Tony