Improvements in handling attribute definitions and requested attributes in MetadataRequestedAttributesAttributeReleasePolicy

[Marcin Roman]

Hi, I created pull request https://github.com/apereo/cas/pull/5124

I would like to break it to 2 separate patches and submit it to master branch.

Could you comment on these proposed changes?

1. Add support for getRequestedDefinitions to MetadataRequestedAttributesAttributeReleasePolicy.

This change is a continuation of https://github.com/apereo/cas/pull/5051, which creates attributes when requested based on attribute definitions.

2. Change of getAttributesForSamlRegisteredService in MetadataRequestedAttributesAttributeReleasePolicy.

Instead of selecting attributes for release using RequestedAttributes Name or FriendlyName provided in SP metadata:

- try to search for SamlIdPAttributeDefinition in AttributeDefinitionStore using urn provided Name attribute of RequestedAttribute ,
- if such SamlIdPAttributeDefinition exists, then use the key provided in this attribute definition to search and release user attribute,
- if above fails, then try to search for user attribute using RequestedAttribute FriendlyName.

Sample RequestedAttribute definition in SP metadata looks like this: 

       <md:RequestedAttribute FriendlyName="schacPersonalUniqueCode" Name="urn:oid:1.3.6.1.4.1.25178.1.2.14" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri" isRequired="true"/>

Without this change it is necessary to define attribute twice to handle resolution by both urn and friendly name, ex.:

    "schacPersonalUniqueCode" : {
     "@class" : "org.apereo.cas.support.saml.web.idp.profile.builders.attr.SamlIdPAttributeDefinition",
     "key" : "schacPersonalUniqueCode",
     "name" : "schacPersonalUniqueCode",
     "urn" : "urn:oid:1.3.6.1.4.1.25178.1.2.14",
     "friendlyName" : "schacPersonalUniqueCode"
   },

    "urn:oid:1.3.6.1.4.1.25178.1.2.14" : {
     "@class" : "org.apereo.cas.support.saml.web.idp.profile.builders.attr.SamlIdPAttributeDefinition",
     "key" : "urn:oid:1.3.6.1.4.1.25178.1.2.14",
     "name" : "schacPersonalUniqueCode",

     "urn" : "urn:oid:1.3.6.1.4.1.25178.1.2.14",
     "friendlyName" : "schacPersonalUniqueCode",

     "attribute" : "schacPersonalUniqueCode",  
    },

Besides, selecting attributes using urn provided in attribute definition is more robust then using friendly names, because friendly names are inconsistently used in SP metadata.