Attribute Release Caching

By default, resolved attributes are cached to the length of the SSO session. If there are any attribute value changes since the commencement of SSO session, the changes are not reflected and returned back to the service upon release time.

Note: Remember that while the below policies are typically applied at release time on a per-service level, CAS automatically does create attribute release caching policies at a more global with configurable timeouts and durations.

The following settings and properties are available from the CAS configuration catalog:

• Required
• Optional
• Signing & Encryption
• Hibernate & JDBC
• Email Servers
• LDAP & Active Directory
• Authentication
• Password Encoding
• Principal Transformation
• Password Policy
• Notes

The following settings are shared by all principal attribute repositories:

Default

The default relationship between a CAS Principal and the underlying attribute repository source, such that principal attributes are kept as they are without any additional processes to evaluate and update them. This need not be configured explicitly.

Caching

The relationship between a CAS Principal and the underlying attribute repository source, that describes how and at what length the CAS Principal attributes should be cached. Upon attribute release time, this component is consulted to ensure that appropriate attribute values are released to the scoped service, per the cache expiration policy. If the expiration policy has passed, the underlying attribute repository source will be consulted to figure out the available set of attributes.

This component also has the ability to resolve conflicts between existing principal attributes and those that are retrieved from repository source via a mergingStrategy property. This is useful if you want to preserve the collection of attributes that are already available to the principal that were retrieved from a different place during the authentication event, etc.

Sample configuration follows:

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{
  "@class" : "org.apereo.cas.services.RegexRegisteredService",
  "serviceId" : "sample",
  "name" : "sample",
  "id" : 100,
  "attributeReleasePolicy" : {
    "@class" : "org.apereo.cas.services.ReturnAllowedAttributeReleasePolicy",
    "principalAttributesRepository" : {
      "@class" : "org.apereo.cas.authentication.principal.cache.CachingPrincipalAttributesRepository",
      "timeUnit" : "HOURS",
      "expiration" : 2,
      "mergingStrategy" : "NONE"
    }
  }
}

Merging Strategies

By default, no merging strategy takes place, which means the principal attributes are always ignored and attributes from the source are always returned. But any of the following merging strategies may be a suitable option:

Merge

Attributes with the same name are merged into multi-valued lists.

For example:

1. Principal has attributes {email=eric.dalquist@example.com, phone=123-456-7890}
2. Source has attributes {phone=[111-222-3333, 000-999-8888], office=3233}
3. The resulting merged would have attributes: {email=eric.dalquist@example.com, phone=[123-456-7890, 111-222-3333, 000-999-8888], office=3233}

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{
  "@class" : "org.apereo.cas.services.RegexRegisteredService",
  "serviceId" : "sample",
  "name" : "sample",
  "id" : 100,
  "attributeReleasePolicy" : {
    "@class" : "org.apereo.cas.services.ReturnAllowedAttributeReleasePolicy",
    "principalAttributesRepository" : {
      "@class" : "org.apereo.cas.authentication.principal.cache.CachingPrincipalAttributesRepository",
      "timeUnit" : "HOURS",
      "expiration" : 2,
      "mergingStrategy" : "MULTIVALUED"
    }
  }
}

Add

Attributes are merged such that attributes from the source that don’t already exist for the principal are produced.

For example:

1. Principal has attributes {email=eric.dalquist@example.com, phone=123-456-7890}
2. Source has attributes {phone=[111-222-3333, 000-999-8888], office=3233}
3. The resulting merged would have attributes: {email=eric.dalquist@example.com, phone=123-456-7890, office=3233}

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{
  "@class" : "org.apereo.cas.services.RegexRegisteredService",
  "serviceId" : "sample",
  "name" : "sample",
  "id" : 100,
  "attributeReleasePolicy" : {
    "@class" : "org.apereo.cas.services.ReturnAllowedAttributeReleasePolicy",
    "principalAttributesRepository" : {
      "@class" : "org.apereo.cas.authentication.principal.cache.CachingPrincipalAttributesRepository",
      "timeUnit" : "HOURS",
      "expiration" : 2,
      "mergingStrategy" : "ADD"
    }
  }
}

Replace

Attributes are merged such that attributes from the source always replace principal attributes.

For example:

1. Principal has attributes {email=eric.dalquist@example.com, phone=123-456-7890}
2. Source has attributes {phone=[111-222-3333, 000-999-8888], office=3233}
3. The resulting merged would have attributes: {email=eric.dalquist@example.com, phone=[111-222-3333, 000-999-8888], office=3233}

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{
  "@class" : "org.apereo.cas.services.RegexRegisteredService",
  "serviceId" : "sample",
  "name" : "sample",
  "id" : 100,
  "attributeReleasePolicy" : {
    "@class" : "org.apereo.cas.services.ReturnAllowedAttributeReleasePolicy",
    "principalAttributesRepository" : {
      "@class" : "org.apereo.cas.authentication.principal.cache.CachingPrincipalAttributesRepository",
      "timeUnit" : "HOURS",
      "expiration" : 2,
      "mergingStrategy" : "REPLACE"
    }
  }
}

Attribute Repository Filtering

Principal attribute repositories can consult attribute sources defined and controlled by Person Directory. Assuming a JSON attribute repository source is defined with the identifier MyJsonRepository, the following definition disregards all previously-resolved attributes and contacts MyJsonRepository again to fetch attributes and cache them for 30 minutes.

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{
  "@class" : "org.apereo.cas.services.RegexRegisteredService",
  "serviceId" : "^(https|imaps)://.*",
  "name" : "HTTPS and IMAPS",
  "id" : 1,
  "attributeReleasePolicy" : {
    "@class" : "org.apereo.cas.services.ReturnAllAttributeReleasePolicy",
    "principalAttributesRepository" : {
        "@class" : "org.apereo.cas.authentication.principal.cache.CachingPrincipalAttributesRepository",
        "timeUnit" : "MINUTES",
        "expiration" : 30,
        "ignoreResolvedAttributes": true,
        "attributeRepositoryIds": ["java.util.HashSet", [ "MyJsonRepository" ]],
        "mergingStrategy" : "MULTIVALUED"
    }
  }
}

Here is a similar example with caching turned off for the service where CAS attempts to combine previously-resolved attributes with the results from the attribute repository identified as MyJsonRepository. The expectation is that the attribute source MyJsonRepository is excluded from principal resolution during the authentication phase and should only be contacted at release time for this service:

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{
  "@class" : "org.apereo.cas.services.RegexRegisteredService",
  "serviceId" : "^(https|imaps)://.*",
  "name" : "HTTPS and IMAPS",
  "id" : 1,
  "attributeReleasePolicy" : {
    "@class" : "org.apereo.cas.services.ReturnAllAttributeReleasePolicy",
    "principalAttributesRepository" : {
        "@class" : "org.apereo.cas.authentication.principal.DefaultPrincipalAttributesRepository",
        "ignoreResolvedAttributes": false,
        "attributeRepositoryIds": ["java.util.HashSet", [ "MyJsonRepository" ]],
        "mergingStrategy" : "MULTIVALUED"
    }
  }
}