Attribute filter

[Rod Widdowson]

> I think that was because it's problematic to know what the name in
> metadata is when all you have is the internal ID, but I probably was just
> being lazy.

Oh yes, I understand.
 
> As long as we have a reasonable way to figure out the SAML attribute name
> to look for.

As *currently* configured the EntityAttributeInMetadata assumes a mapping
configuration derived from the attribute resolver (just the same as the
RequestedAttribute), and that works surprisingly well:

    <resolver:DataConnector id="staticAttributes" xsi:type="dc:Static">
        <dc:Attribute id="ea_1">
 
<dc:Value>http://id.incommon.org/category/research-and-scholarship</dc:Value
>
        </dc:Attribute>
   </resolver:DataConnector>
    <resolver:AttributeDefinition xsi:type="ad:Simple" id="IdPEA1"
sourceAttributeID="ea_1">
        <resolver:Dependency ref="staticAttributes" />
        <resolver:AttributeEncoder xsi:type="enc:SAML2String" 
            name="http://macedir.org/entity-category"
            nameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri"
friendlyName="eaOne" />
    </resolver:AttributeDefinition>

Although it might become confusing.  You and I have discussed providing a
different mapping configuration for EntityAttributes.  This is all a bit
open-ended in my mind since I don't have a  good feel for the sorts of
deployments that would need this level of control.  

That's one reason why I want this to remain undocumented - to give us room
play around with this to see what the most natural approach is.

Rod