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.

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

The configuration settings listed below are tagged as Optional in the CAS configuration metadata. This flag indicates that the presence of the setting is not immediately necessary in the end-user CAS configuration, because a default value is assigned or the activation of the feature is not conditionally controlled by the setting value. In other words, you should only include this field in your configuration if you need to modify the default value or if you need to turn on the feature controlled by the setting.

Configuration Metadata

The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.

Be Selective

This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.

YAGNI

Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.

Naming Convention

Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those that might be presented to the system via an external library or framework such as Spring Boot, etc.

:information_source: Note

When possible, properties should be stored in lower-case kebab format, such as cas.property-name=value. The only possible exception to this rule is when naming actuator endpoints; The name of the actuator endpoints (i.e. ssoSessions) MUST remain in camelCase mode.

Settings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the way you intend.

Validation

Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be recognized or validated by the configuration schema. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.

Indexed Settings

CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be incremented by the adopter to allow for distinct multiple configuration blocks.

Principal Attribute Repositories

The following settings are shared by all principal attribute repositories:

Name Value
mergingStrategy Indicate the merging strategy when combining attributes from multiple sources. Accepted values are MULTIVALUED, ADD, NONE, MULTIVALUED
attributeRepositoryIds A Set of attribute repository identifiers to consult for attribute resolution at release time.
ignoreResolvedAttributes Ignore the collection of attributes that may have been resolved during the principal resolution phase, typically via attribute repositories.

The following caching strategies are offered by CAS:

  • 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.

  • 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.

    :information_source: Caching Upon Release

    Note that the policy is only consulted at release time, upon a service ticket validation event. If there are any custom webflows and such that wish to rely on the resolved Principal AND also wish to receive an updated set of attributes, those components must consult the underlying source directory without relying on the Principal.

    Sample configuration follows:

    

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    {
  "@class" : "org.apereo.cas.services.CasRegisteredService",
  "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:

  • 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.CasRegisteredService",
  "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"
    }
  }
}

  • 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.CasRegisteredService",
  "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"
    }
  }
}

  • 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.CasRegisteredService",
  "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"
    }
  }
}