AttributeDefinition multivalued to single value attribute?

[Baron Fujimoto]

Is there a recommended way to create an AttributeDefinition in the IdP's
attribute-resolver.xml that will map a multivalued source attribute to a
new single valued attribute?

For example, if I have the a multivalued source attribute, "someAttr" with
values as follows:

someAttr: foo
someAttr: bar
someAttr: baz

And I would like to define a new attribute, "hasFoo" which has value either
"true" or "false" depending on the value of someAttr.

If I do something like this

<resolver:AttributeDefinition xsi:type="ad:Mapped"
        id="hasFoo-enabled"
        sourceAttributeID="someAttr">

    [...]

    <!-- if someAttr is not "foo" return false -->
    <ad:DefaultValue>false</ad:DefaultValue>

    <!-- map "foo" to "true" -->
    <ad:ValueMap>
        <ad:ReturnValue>true</ad:ReturnValue>
        <ad:SourceValue ignoreCase="true">foo</ad:SourceValue>
    </ad:ValueMap>
</resolver:AttributeDefinition>

I wind up with a multivalued set of hasFoo like

hasFoo: true
hasFoo: false
hasFoo: false

But the result I really want is just a single hasFoo with value "true" if
there was a someAttr with value "foo", else hasFoo should be "false".

The broader context for this is that I would like to return the single
valued "hasFoo" in an AttributeFilterPolicy, and conditionally release
other attributes based on the value of hasFoo. Maybe there's a better
way to tackle this broader goal?

-- 
Baron Fujimoto <baron at hawaii.edu> :: UH Information Technology Services
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