Server Reactor Implementation

Notes to help design and implementation of a reactor-type core for INDX.

Architecture

server handler types
- box (box ops, e.g. update, get/set acl, get, query, diff, file ops)
- auth (login/logout, openid callback, get token)
- admin (global [non-box] actions, e.g. list/create/del boxes, list/create/del users, list apps)
- services (start/stop, get/set configs, is_running/poll status)
- subscribe/unsubscribe (listen/unlisten to specific callbacks about actions occurring)
interfaces (translate between handlers and websocket/http calls)
- websocket server
- websocket client (outgoing from server)
- http server
- http client (outgoing from server)
callbacks (e.g. to websocket)
- box operations (only to websocket authed to that box)
- admin (to all)
- auth (to superuser ? at all ?)
- services (only to websocket authed to services, or to box also?)

URL mappings (map from a call to a handler)
Session manager
- Allow multiple sessions per websocket, e.g. "request a new session", then auth to it, then request another, auth to it as someone else, etc.
Handler registration/dereg
Subscriber registration/dereg
Event handling
- callbacks from handlers
- callbacks to subscribers
- callbacks from database
Outgoing connection manager
- initial connections on launch
- exponential back off upon connection failure
- reconnection upon disconnection
Incoming connection manager
- Map HTTP to handlers, return results
- Websockets incoming, map to handlers
- Outgoing websockets, incoming requests, map to handlers/sessions