cosmopolite

See https://www.cosmopolite.org/ for tutorial, reference, etc.

Client/server publish/subscribe and key/value storage for AppEngine.

Components:

• A server API built on the AppEngine Python framework.
• A browser client library written in JavaScript.

Feature overview:

• Near-realtime notification to subscribers of messages published to a "subject"
• Server-side storage of past messages for replay later to clients
• Support for associating a key with a message and for lookup of the most recent message for a given key
• Client identification persistence via localStorage tokens or in combination with Google account signin
• Complex messages supported via transparent JSON serialization
• Server-side strict ordering of messages
• Client-side message queueing in localStorage and resumption on restart
• Message duplication detection and elimination
• Promise support for notification of client -> server operation completion