Subject: [core] #258: Be explicit about the "observe key"

From: "core issue tracker" <[email-masked]>
Date: Tue, 06 Nov 2012 11:48:47 -0000

#258: Be explicit about the "observe key"

 Matthias Kovatsch notes (msg03748b):

 Section 5

 Because a client (or an intermediary in the client role) can only be once
 in the list of observers of a resource at a server (or an intermediary in
 the server role) -- it is useless to observe the same resource multiple
 times -- an intermediary MUST observe a resource only once, even if there
 are multiple clients for which it observes the resource.

 What about different content-types/accept options? An intermediary must be
 able to serve them if they are supported by the origin server. But if they
 cannot be converted, the intermediary can only use observing for one
 content-type.

 Maybe the observe list entry should also be dependent on the content-type?

 Proposal:

 1) Explicitly define which options go into the key that separates one
 observation relationship from another; include the URI and Accept.  (What
 else?)

 2) It will be hard to "merge" observation relationships on the server that
 lead to the same content-format (e.g., overlapping Accept options); this
 will require some client (proxy) action upon receiving the first response.
 (We do promise that the Content-Format will not change.)  Add this as an
 implementation note.

-- 
-----------------------------+---------------------------------------
 Reporter:  cabo@…           |      Owner:  draft-ietf-core-observe@…
     Type:  other technical  |     Status:  new
 Priority:  minor            |  Milestone:  post-WGLC-1
Component:  observe          |    Version:  observe-07
 Severity:  In WG Last Call  |   Keywords:
-----------------------------+---------------------------------------

Ticket URL: <http://trac.tools.ietf.org/wg/core/trac/ticket/258>
core <http://tools.ietf.org/core/>