Acceptable Usage Policy

Also known as Terms of Use or EULA, CAS presents the ability to allow the user to accept the usage policy before moving on to the application. Production-level deployments of this feature would require modifications to the flow such that the retrieval and/or acceptance of the policy would be handled via an external storage mechanism such as LDAP or JDBC.

Configuration

Support is enabled by including the following dependency in the WAR overlay:

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<dependency>
  <groupId>org.apereo.cas</groupId>
  <artifactId>cas-server-support-aup-webflow</artifactId>
  <version>${cas.version}</version>
</dependency>
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implementation "org.apereo.cas:cas-server-support-aup-webflow:${project.'cas.version'}"
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dependencyManagement {
  imports {
    mavenBom "org.apereo.cas:cas-server-support-bom:${project.'cas.version'}"
  }
}

dependencies {  
  implementation "org.apereo.cas:cas-server-support-aup-webflow"
}

Customize the policy by modifying the casAcceptableUsagePolicyView.html. See this guide to learn more about user interface customizations. Note that the view here should have full access to the resolved principal and attributes, if you wish to dynamically alter the page to present different text, etc.

Webflow Sequence

Remember that acceptable usage policy executes after a successful authentication event where CAS has already established the authentication principal, since the policy record is strongly tied to the identified user record. Implementing this feature before the authentication event would require rather heavy modifications to the CAS webflow as well as alternative means of storing and remembering decisions such as cookies or browser storage, etc.

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

The configuration settings listed below are tagged as Required in the CAS configuration metadata. This flag indicates that the presence of the setting may be needed to activate or affect the behavior of the CAS feature and generally should be reviewed, possibly owned and adjusted. If the setting is assigned a default value, you do not need to strictly put the setting in your copy of the configuration, but should review it nonetheless to make sure it matches your deployment expectations.

  • cas.acceptable-usage-policy.core.aup-attribute-name=aupAccepted
  • AUP attribute to choose in order to determine whether policy has been accepted or not. The attribute is expected to contain a boolean value where true indicates policy has been accepted and false indicates otherwise. The attribute is fetched for the principal from configured sources and compared for the right match to determine policy status. If the attribute is not found, the policy status is considered as denied.

    org.apereo.cas.configuration.model.support.aup.AcceptableUsagePolicyCoreProperties.

  • cas.acceptable-usage-policy.core.enabled=true
  • Allows AUP to be turned off on startup.

    org.apereo.cas.configuration.model.support.aup.AcceptableUsagePolicyCoreProperties.

    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.

  • cas.acceptable-usage-policy.core.aup-policy-terms-attribute-name=
  • AUP attribute to choose whose single value dictates how CAS should fetch the policy terms from the relevant message bundles.

    org.apereo.cas.configuration.model.support.aup.AcceptableUsagePolicyCoreProperties.

    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. When possible, properties should be stored in lower-case kebab format, such as cas.property-name=value.S ettings 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. The validation process is on by default and can be skipped on startup using a special system property SKIP_CONFIG_VALIDATION that should be set to true. 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.

    Per Service

    Acceptable usage policy can be disabled and skipped on a per-service basis:

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    {
      "@class": "org.apereo.cas.services.RegexRegisteredService",
      "serviceId": "https://app.example.org",
      "name": "Example",
      "id": 1,
      "acceptableUsagePolicy":
      {
        "@class": "org.apereo.cas.services.DefaultRegisteredServiceAcceptableUsagePolicy",
        "enabled": true,
        "messageCode": "example.code",
        "text": "example text"
      }
    }
    

    The policy assigned to each service includes the following features:

    Field Description
    enabled Control whether policy is active/inactive for this service. Default is true.
    messageCode The policy language code that is linked to the CAS language bundles which carries the actual policy text.
    text The policy text that should be displayed for this application.

    Storage Mechanism

    Usage policy user decisions are stored and remembered via the following ways.

    In almost all storage strategies, CAS allows the deployer to detect the current user’s policy choice via a CAS single-valued boolean attribute. The attribute must be resolved using the CAS attribute resolution strategy. If the attribute contains a value of false, CAS will attempt to ask for policy acceptance. Upon accepting the policy, the result will be stored back into storage.

    Storage Description
    Default See this guide.
    Groovy See this guide.
    LDAP See this guide.
    MongoDb See this guide.
    Redis See this guide.
    CouchDb See this guide.
    Couchbase See this guide.
    JDBC See this guide.
    REST See this guide.
    Custom See this guide.

    Policy Terms

    Storage options outlined above are also available to fetch the acceptable usage policy and pass it along to the appropriate views for display and acceptance under the attribute aupPolicy. The policy terms can reference to a particular message code found in CAS language bundles, or it can contain the default policy text that would be used for display verbatim.

    Unless the storage option overrides and specializes this ability, th default behavior to fetch policy terms is based on a single-valued attribute defined in CAS properties that typically might indicate user status or membership. The attribute value is appended to the language code screen.aup.policyterms to then allow CAS to look up the specific policy text from language bundles. If no such key is available in CAS languages bundles, a default policy text found under the same language key will be displayed.

    The defined attribute must of course be available for the resolved authenticated principal from the relevant sources.

    For example, if the policy terms attribute is defined as status with the value of developer, the expected language code to carry the policy text would be screen.aup.policyterms.developer=<p>Policy for developers</p>.