= A long poll notification service =

We want web pages to update when the thing they are viewing changes. This offers a nicer feel and reduces the chance of in-flight collisions with very stale data.

'''Contact:''' Julian Edwards <<BR>>
'''On Launchpad:''' https://bugs.launchpad.net/launchpad-project/+bugs?field.tag=longpoll

'''As a ''' User<<BR>>
'''I want ''' Pages to show current information$FEATURE<<BR>>
'''so that ''' I'm not looking at stale information<<BR>>

== Rationale ==

We are bringing in rabbit to perform backend tasks more rapidly. In order to tell users that they have completed we need to signal the browser that things have changed.

== Stakeholders ==

Technical Architect

== Constraints and Requirements ==

=== Must ===

 * Meet the [[ArchitectureGuide/ServicesRequirements|new service requirements]].
 * Permit a page that a user is looking at to get notified of changes so that users can be shown them. E.g. new messages on a bug.

=== Nice to have ===

=== Must not ===

 * Must not involve a new domain.

=== Out of scope ===

== Subfeatures ==

== Success ==

=== How will we know when we are done? ===

When a page updates just-in-time when changes are made, without polling or requiring users to refresh.

''I'd argue that this isn't done-done until it's being used for two different pages.'' -- jml, 2011-06-24

=== How will we measure how well we have done? ===

== Thoughts? ==

 * Merge proposals (jobs more generically?) could be a good place to start -- jml, 2011-06-24