Re: [xmlblaster] Quick question

[Marcel Ruff <ruff at swand.lake.de>]

Maurice Finbarr O'Brien wrote:
> Hi,
> When subscribing to an XML message of which some
> matching messages have been published prior to this,
> is there any way i can inhibit XMLBlaster from
> updateing me with the old messages eg some qos tag, or
> should i just filter these out using their timestamps?
> Regards,
> Finbarr

Currently there is no such QoS, adding a QoS to supress
an update of an existing message on subscribe would be
easy.

But i believe you want to supress the update only
in this case where you have received the message already.
If you subscribe and the current message was never delivered
to the client, than i guess you want to have it.

This scenario is a bit more complex since the server
would need to remember what has been delivered
some decades ago to some arbitrary client.
The coming durable subscription will address and resolve
this issue.

Filtering with the timestamp is possible as the
timestamp is a unique identifier of each message instance,
there will NEVER be the same timestamp in one xmlBlaster
server instance.
Even when using xmlBlaster clusters the timestamp is unique
if you define exactly one master node.

What is exactly your need?

regards,

Marcel


PS: How have you solved your PtP callback channel question?


--
Marcel Ruff
mailto:ruff at swand.lake.de
http://www.lake.de/home/lake/swand/
http://www.xmlBlaster.org