Rajnish,
I think there should be provision for specifying "On failure Actions" for
every
rule author( publisher/consumer). And it should be certainly for end user(
consumer).
By doing so we're very likely to run into scalability problems as
mentioned by Hilarie (i.e. too many user-specific rules in the rules
engine). So, rather than specifying individual failure actions for
each user, a system can pre-define possible failure actions (e.g.
block or do not block unscanned downloads) and users are assigned to
the corresponding set based on their preference (e.g. users that want
unscanned downloads blocked, and users that don't want them blocked).
Few days back, I had put up these issues in mailing list. I had also
proposed changes in rule file by addition of one attribute "MANDATORY" to
"ACTION" element.
A "mandatory" element only allows to specify that an error has to be
sent in the failure case. It does not allow to specify other actions
in case of a failure. It would be more flexible to allow specification
of certain actions (or default behavior) in case of a failure (which I
believe is very much like the "alternative" action you proposed). In
this case, the "mandatory" element might not even be necessary -
either specify a "send error message" on failure, or we could assume
that lack of a failure action implicates sending of an error message.
-Markus