[ckan-discuss] CKAN notification service

[Rufus Pollock]

On 24 May 2010 19:08, David Read <david.read at okfn.org> wrote:
> I've sketched out a system for clients to register interest in CKAN
> data, so that they get callbacks when it changes. Do check it out
> here:
> http://knowledgeforge.net/ckan/trac/ticket/325
> (which also references sub-tickets)

Great stuff!

> Amongst other things, this can alert an external search module (such
> as SOLR) to index packages as soon as they are updated, rather than
> having to poll the API.

I can also think of other nice use cases:

  1. (On package resource update) Test whether resource exists (no 404)
  2. (Ditto) Do some processing on resource (e.g. extract sample data
for display)
  3. Webhooks: (this is obviously more than just the notification --
need to allow for registration of interest etc, but webhook
notification at least should be done out of band using worker
listening to event notifications)

> The design is based on the open message queue format AMQP (using
> RabbitMQ). The objects that will give notifications are: Package, Tag,
> Group and Rating (not User, Authz, Relationships or License) and the
> message payload will be the object in JSON format (just as for the
> REST interface).

What about package resource or is this merged into package. I think it
might be useful to have package resource a first order entity here
(see examples above). I also think we may want to allow for User to
also generate notifications (e.g. user registration -- for example
this could be useful for sending out welcome emails etc)

Regards,

Rufus