This wiki has undergone a migration to Confluence found Here
<meta name="googlebot" content="noindex">

FHIR Subscription Working Page

From HL7Wiki
Revision as of 15:07, 8 October 2015 by Josh mandel (talk | contribs)
Jump to navigation Jump to search

Notes from Thurs Q0 Atlanta 2015

  • when content is sent as a response to a notification, it should be a bundle - this is for rest-hook, websockets, and messaging
    • Rationale: provide the same payload semantics across all channels
  • payload is mandatory, since a bundle will always be sent
  • the subscription id should be one of the links in the bundle (rel to be determined — e.g. "triggered-by-subscription")
  • unless otherwise specified, the bundle will be empty
  • specify a list of GET operations using the template syntax in the URLS as defined by cds-hook (find somewhere common to specify that)
  • server puts a bundle entry in the bundle for each GET operation
  • same approach to be used in cds-hook


Question:

  • when you have a web socket subscription, should it queue up notifications while not connected?
  • should a websocket subscription auto-expire?

Answer:

  • If you register a subscription on the REST interface, it doesn't expire, and it queues transactions
  • if you create a subscription when you connect on the web socket, then it expirse as soon as the websocket is closed

Corollary:

  • when you connect you can either subst :id or subst {} or subst <> to just define the subst for the socket

(**What does "subst" mean?**)

Web socket protocol: rather than bare keywords like "ping", we should define JSON messages, which are objects with a "type" property. This will let us build a richer protocol later. E.g.

   {"action": "subscribeWhileThisSocketStaysOpen", "subscription": {Subscription Resource>}
   {"action": "listenOnAnExistingSubscription", "subscriptionId": <id>}