OpenID

OpenID is an open, decentralized, free framework for user-centric digital identity. Users represent themselves using URIs. For more information see the http://www.openid.net. As of CAS 3.1, CAS supports the "dumb" mode of the OpenID protocol. Dumb mode acts in a similar fashion to the existing CAS protocol.

Giving your users URIs

Configuring your users to have URIs.

You'll need to set up a local mechanism for generating URIs for your users based on their username (i.e. http://openid.rutgers.edu/battags).

The endpoint pages look something like this:

<html>
	<head>
		<link rel="openid.server" href="https://localhost/cas/login" />
	</head>
</html>

Enabling OpenID in CAS

Note: We're assuming you are using the Default AuthenticationManager.

Modifying the deployerConfigContext.xml

Open your deployerConfigContext.xml and add the following entries:

Add a new AuthenticationHandler to your AuthenticationManager

<bean class="org.jasig.cas.support.openid.authentication.handler.support.OpenIdCredentialsAuthenticationHandler"
   p:ticketRegistry-ref="ticketRegistry" />

Add a new CredentialsToPrincipalResolver to your AuthenticationManager

<bean class="org.jasig.cas.support.openid.authentication.principal.OpenIdCredentialsAuthenticationHandler" />

Modifying the cas-servlet.xml

Add the Url Mapping Handler

Add the following entry to your cas-servlet.xml (it can go anywhere):

<bean id="handlerMappingA" class="org.jasig.cas.support.openid.web.support.OpenIdPostUrlHandlerMapping">
	<property
		name="mappings">
		<props>
			<prop
				key="/login">openIdValidateController</prop>
		</props>
	</property>
</bean>

This will direct validation requests to the correct controller.

OpenId Validation Controller

Add the following to enable validation of an OpenID request:

	<bean id="openIdValidateController" class="org.jasig.cas.web.ServiceValidateController"
		p:validationSpecificationClass="org.jasig.cas.validation.Cas20WithoutProxyingValidationSpecification"
		p:centralAuthenticationService-ref="centralAuthenticationService"
		p:proxyHandler-ref="proxy20Handler"
		p:argumentExtractor-ref="openIdArgumentExtractor"
		p:successView="casOpenIdServiceSuccessView"
		p:failureView="casOpenIdServiceFailureView" />

ArgumentExtractor

Next, we need to add the ArgumentExtractor that can actually detect the OpenID request:

<bean
	id="openIdArgumentExtractor"
	class="org.jasig.cas.support.openid.web.support.OpenIdArgumentExtractor" />

Then, locate the <util:list> entry in the cas-servlet.xml and add a:

<ref bean="openIdArgumentExtractor" />

It should look something like this (it will vary depending on what is enabled):

<util:list id="argumentExtractors">
	<ref bean="casArgumentExtractor" />
	<ref bean="samlArgumentExtractor" />
	<ref bean="openIdArgumentExtractor" />
</util:list>

Add the Action for the Web Flow

Finally, in the cas-servlet.xml you'll need to add the action that we will reference in the login flow xml file:

    <bean id="openIdSingleSignOnAction" class="org.jasig.cas.support.openid.web.flow.OpenIdSingleSignOnAction"
    	p:centralAuthenticationService-ref="centralAuthenticationService" />

Be Careful

The OpenIdSingleSignOnAction has an additional parameter not configured here. Its the "extractor" property which accepts a "org.jasig.cas.support.openid.web.support.OpenIdUserNameExtractor". The default one merely accepts the value after the last "/". A more robust implementation should check the entire URL. Note, that means the default one SHOULD NOT be used in production.