Pubsub with Google App Engine

[Christopher Winstanley]

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/DeveloperGettingStartedGuidebut 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

[Jay]

Prospective search might be what you are looking for. However, it is in "Experimental" 

https://developers.google.com/appengine/docs/python/prospectivesearch/

Rolling your own turns out to be quite doable. I have used this approach. It really amounts to some event which kicks off some form of fanout which can be accomplished with cascading tasks using taskqueue. You just want to use task naming or some other means to ensure that you don't get a 'fork bomb'.