The CasAuthenticationProvider distinguishes between stateful and stateless clients. A stateful client is considered any that submits to the filterProcessUrl of the CasAuthenticationFilter. A stateless client is any that presents an authentication request to CasAuthenticationFilter on a URL other than the filterProcessUrl.

Because remoting protocols have no way of presenting themselves within the context of an HttpSession, it isn’t possible to rely on the default practice of storing the security context in the session between requests. Furthermore, because the CAS server invalidates a ticket after it has been validated by the TicketValidator, presenting the same proxy ticket on subsequent requests will not work.

One obvious option is to not use CAS at all for remoting protocol clients. However, this would eliminate many of the desirable features of CAS. As a middle-ground, the CasAuthenticationProvider uses a StatelessTicketCache. This is used solely for stateless clients which use a principal equal to CasAuthenticationFilter.CAS_STATELESS_IDENTIFIER. What happens is the CasAuthenticationProvider will store the resulting CasAuthenticationToken in the StatelessTicketCache, keyed on the proxy ticket. Accordingly, remoting protocol clients can present the same proxy ticket and the CasAuthenticationProvider will not need to contact the CAS server for validation (aside from the first request). Once authenticated, the proxy ticket could be used for URLs other than the original target service.

This section builds upon the previous sections to accommodate proxy ticket authentication. The first step is to specify to authenticate all artifacts as shown below.

<bean id="serviceProperties"
	class="org.springframework.security.cas.ServiceProperties">
<property name="authenticateAllArtifacts" value="true"/>
</bean>

The next step is to specify serviceProperties and the authenticationDetailsSource for the CasAuthenticationFilter. The serviceProperties property instructs the CasAuthenticationFilter to attempt to authenticate all artifacts instead of only ones present on the filterProcessUrl. The ServiceAuthenticationDetailsSource creates a ServiceAuthenticationDetails that ensures the current URL, based upon the HttpServletRequest, is used as the service URL when validating the ticket. The method for generating the service URL can be customized by injecting a custom AuthenticationDetailsSource that returns a custom ServiceAuthenticationDetails.

<bean id="casFilter"
	class="org.springframework.security.cas.web.CasAuthenticationFilter">
<property name="serviceProperties" ref="serviceProperties"/>
<property name="authenticationDetailsSource">
	<bean class=
	"org.springframework.security.cas.web.authentication.ServiceAuthenticationDetailsSource">
	<constructor-arg ref="serviceProperties"/>
	</bean>
</property>
</bean>

You will also need to update the CasAuthenticationProvider to handle proxy tickets. To do this replace the Cas20ServiceTicketValidator with a Cas20ProxyTicketValidator. You will need to configure the statelessTicketCache and which proxies you want to accept. You can find an example of the updates required to accept all proxies below.

<bean id="casAuthenticationProvider"
	class="org.springframework.security.cas.authentication.CasAuthenticationProvider">
<property name="ticketValidator">
	<bean class="org.jasig.cas.client.validation.Cas20ProxyTicketValidator">
	<constructor-arg value="https://localhost:9443/cas"/>
	<property name="acceptAnyProxy" value="true"/>
	</bean>
</property>
<property name="statelessTicketCache">
	<bean class="org.springframework.security.cas.authentication.EhCacheBasedTicketCache">
	<property name="cache">
		<bean class="net.sf.ehcache.Cache"
			init-method="initialise" destroy-method="dispose">
		<constructor-arg value="casTickets"/>
		<constructor-arg value="50"/>
		<constructor-arg value="true"/>
		<constructor-arg value="false"/>
		<constructor-arg value="3600"/>
		<constructor-arg value="900"/>
		</bean>
	</property>
	</bean>