I'm trying to implement pubsub messaging with Google App Engine. I want to be able to store callbacks to other servers and then send them new data when it becomes available.
I've had a good look around but can't seem to come up with anything apart from implementing it myself. I've seen pubsubhubbub: https://code.google.com/p/pubsubhubbub/wiki/DeveloperGettingStartedGuide but I want to be able to store query parameters. Xmpp xep 60 for example includes capabilities to configure subscriptions with additional data (called options).
The XMPP service in App Engine doesn't seem to have the pubsub extension.
Is managing our own recipient list as: https://groups.google.com/forum/#!topic/google-appengine/CaBcX0EWO00 seems to suggest the only option?
App Engine seems to have implementations with devices in mind using: Channels for javascript: https://developers.google.com/appengine/docs/python/channel/
CloudBackendMessaging for devices: https://developers.google.com/cloud/samples/mbs/pubsub_messaging