Milan
Hi, Alexis here from RabbitMQ.
One way to look at 'push messaging' technologies is to think about
four different parts:
- messages
- pubsub
- queues (and 'hubs')
- storage
PSHB defines a model for the first two but is somewhat silent on the
latter two. This will make it difficult to use PSHB for what you want
('queues') unless you write some custom code, thereby killing any
benefit you may get from 'simplicity'.
Let's take a closer look:
On Sat, Feb 6, 2010 at 9:37 AM, Ruka <[email protected]> wrote:
> Hi All,
> I'm interested in pshb to be used as a message queue system. Still I'm
> not sure if this use case is possible. Basically the system I need is
> a kind of command router - modules which are command servers subscribe
> to a message type (which is in pshb terminology topic or a feed).
PSHB has a routing model based on *subscriptions* to *topics*.
Currently topics are publisher-defined URLs for Atom feeds.
(*) Publication occurs by posting content (somewhere) and updating the
Atom feed. At some point, when content is added to a feed, the hub is
notified by the publisher that this has occurred.
> A
> module which initiates a command would be a publisher of a certain
> message type. As you can see, multiple modules can be publishers of
> the same message type/topic which is not exactly what pshb is made
> for?
Currently, only if all modules can do (*) above.
In effect, the feed would then be the queue. The hub would simply
cache copies of that queue for subscribers, who would 'share' this
queue and (potentially) consume all messages on it.
I don't think that is what your use case requires. Am I right?
I *think* what you want is a way for publishers to publish messages
directly to a shared queue (called 'topic') on a hub, from where the
messages can be round-robined to subscribers. Doing this with PSHB
would be quite a contortion right now.
> Also in this scenario subscriber comes first, not publisher - so
> it might be reversed used case to standard publish/subscribe?
>
> So my question is if Pubsubhubbub would be a good platform for this
> system? I know about Advanced Message Queuing Protocol which might be
> exactly what I need, but it's seems to heavy and I really like
> Pubsubhubbub simplicity and http/rest orientation.
I think AMQP gives you exactly what you need. If you want
Pubsubhubbub or HTTP/REST for a 'simpler' interface style, then look
at:
- RabbitHub
- RestMS
- or one of the RabbitMQ HTTP interfaces
Separately, you may find XMPP gives you the functionality you want.
alexis
