conditions references in rules: xml to the rescue?

["Simon Godik" <simon.godik@overxeer.com>]

How to reuse complicated conditions in rules?

 

There is a simple way to do it with parsed general entities, both internal and external.

As such, parsed general entities allow to reuse any part of the rule or policy as long as entity is

well formed xml.

 

In this case, policy model is not broken and we get syntactic shorcut without schema modifications.

 

Here is an example with external parsed general entity (internal parsed gen entity is also possible)

 

Suppose we have parsed general entity in cond.xml:

<?xml version="1.0" encoding="..."?>

<Condition>

    <Apply FunctionId="...">

    </Apply>

</Condition>

 

Then in policy.xml:

 

<?xml version="1.0" encoding="..."/>

<!DOCTYPE Policy [

    <!ENTITY cond SYSTEM "cond.xml"

]>

<Policy xmlns:xacml="...">

<Rule ...>

    &cond; <-- entity reference
</Rule>

</Policy>

 

Simon