Re: [xmlblaster] how do i get erase notifications from xpath subscriptions now?

[Marcel Ruff <mr at marcelruff.info>]

Andrew.Yinger at Altarum.org wrote:
> In the latest change log it states:
>
> o Bugfix for sending ERASE events in UNREFERENCED topics with XPath
> subscription
>    Topics delivered by XPATH subscriptions don't send erase notifications
>    when they disappear as they match again if the[y] appear again
>
> So, how do I get erase notifications if I subscribe with XPath query now?

The XPath erase notfication had a bug in 0.91.
As it was not too simple to fix it, we decided to remove the
erase event for XPath:

1. If a topic is explicitely erase()d all EXACT subscription
   are lost. Therefore all EXACT subscribers have stale subscriptions
   and we considered a notification essential.
   This old behaviour is still functional in 0.91

2. XPath subscriptions automatically match again if a topic
   was erased and later was re-created. So the XPath subscriber
   has no harm.
   That was the reason we considered it not essential and did
   dare to remove it.

Other clients may be interested in topics how the come an go,
but such events are currently not fired (see the similar '__sys__Login'
and '__sys__Logout' events on which you can subscribe).

I have now reimplemented the 2. from above, if you update
xmlBlaster from cvs the XPath notifications are here again.

A subscriber can set <notify>true/false</notify> as in previous releases
so every subscription can control the events it gets (defaults to true).

Summary: xmlBlaster from current cvs behaves same again as it did before 0.91
(but the bug is fixed)

Regards

Marcel


> Thanks,
> Andrew


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