Java Apereo CAS Client

Intro

This is the official home of the Java Apereo CAS client. The client consists of a collection of Servlet filters that are suitable for most Java-based web applications. It also serves as an API platform to interact with the CAS server programmatically to make authentication requests, validate tickets and consume principal attributes.

All client artifacts are published to Maven central. Depending on functionality, applications will need include one or more of the listed dependencies in their configuration.

Build

git clone git@github.com:apereo/java-cas-client.git
cd java-cas-client
mvn clean package

Components

• Core functionality, which includes CAS authentication/validation filters.

<dependency>
    <groupId>org.apereo.cas.client</groupId>
    <artifactId>cas-client-core</artifactId>
    <version>${java.cas.client.version}</version>
</dependency>

• Support for SAML functionality is provided by this dependency:

<dependency>
   <groupId>org.apereo.cas.client</groupId>
   <artifactId>cas-client-support-saml</artifactId>
   <version>${java.cas.client.version}</version>
</dependency>

• Distributed proxy ticket caching with Ehcache is provided by this dependency:

<dependency>
   <groupId>org.apereo.cas.client</groupId>
   <artifactId>cas-client-support-distributed-ehcache</artifactId>
   <version>${java.cas.client.version}</version>
</dependency>

• Distributed proxy ticket caching with Memcached is provided by this dependency:

<dependency>
   <groupId>org.apereo.cas.client</groupId>
   <artifactId>cas-client-support-distributed-memcached</artifactId>
   <version>${java.cas.client.version}</version>
</dependency>

• Spring Boot AutoConfiguration is provided by this dependency:

<dependency>
   <groupId>org.apereo.cas.client</groupId>
   <artifactId>cas-client-support-springboot</artifactId>
   <version>${java.cas.client.version}</version>
</dependency>

Configuration

Strategies

The client provides multiple strategies for the deployer to provide client settings. The following strategies are supported:

• JNDI (JNDI)
• Properties File (PROPERTY_FILE). The configuration is provided via an external properties file. The path may be specified in the web context as such:

<context-param>
    <param-name>configFileLocation</param-name>
    <param-value>/etc/cas/file.properties</param-value>
</context-param>

If no location is specified, by default /etc/java-cas-client.properties will be used.

• System Properties (SYSTEM_PROPERTIES)
• Web Context (WEB_XML)
• Default (DEFAULT)

In order to instruct the client to pick a strategy, strategy name must be specified in the web application's context:

<context-param>
    <param-name>configurationStrategy</param-name>
    <param-value>DEFAULT</param-value>
</context-param>

If no configurationStrategy is defined, DEFAULT is used which is a combination of WEB_XML and JNDI.

Client Configuration Using web.xml

The client can be configured in web.xml via a series of context-params and filter init-params. Each filter for the client has a required (and optional) set of properties. The filters are designed to look for these properties in the following way:

• Check the filter's local init-params for a parameter matching the required property name.
• Check the context-params for a parameter matching the required property name.
• If two properties are found with the same name in the init-params and the context-params, the init-param takes precedence.

Note: If you're using the serverName property, you should note well that the fragment-URI (the stuff after the #) is not sent to the server by all browsers, thus the CAS client can't capture it as part of the URL.

An example application that is protected by the client is available here.

org.apereo.cas.client.authentication.AuthenticationFilter

The AuthenticationFilter is what detects whether a user needs to be authenticated or not. If a user needs to be authenticated, it will redirect the user to the CAS server.

<filter>
  <filter-name>CAS Authentication Filter</filter-name>
  <filter-class>org.apereo.cas.client.authentication.AuthenticationFilter</filter-class>
  <init-param>
    <param-name>casServerUrlPrefix</param-name>
    <param-value>https://battags.ad.ess.rutgers.edu:8443/cas</param-value>
  </init-param>
  <init-param>
    <param-name>serverName</param-name>
    <param-value>http://www.acme-client.com</param-value>
  </init-param>
</filter>
<filter-mapping>
    <filter-name>CAS Authentication Filter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

Property	Description	Required
casServerUrlPrefix	The start of the CAS server URL, i.e. https://localhost:8443/cas	Yes (unless casServerLoginUrl is set)
casServerLoginUrl	Defines the location of the CAS server login URL, i.e. https://localhost:8443/cas/login. This overrides casServerUrlPrefix, if set.	Yes (unless casServerUrlPrefix is set)
serverName	The name of the server this application is hosted on. Service URL will be dynamically constructed using this, i.e. https://localhost:8443 (you must include the protocol, but port is optional if it's a standard port).	Yes
service	The service URL to send to the CAS server, i.e. https://localhost:8443/yourwebapp/index.html	No
renew	specifies whether renew=true should be sent to the CAS server. Valid values are either true/false (or no value at all). Note that renew cannot be specified as local init-param setting.	No
gateway	specifies whether gateway=true should be sent to the CAS server. Valid values are either true/false (or no value at all)	No
artifactParameterName	specifies the name of the request parameter on where to find the artifact (i.e. ticket).	No
serviceParameterName	specifies the name of the request parameter on where to find the service (i.e. service)	No
encodeServiceUrl	Whether the client should auto encode the service url. Defaults to true	No
ignorePattern	Defines the url pattern to ignore, when intercepting authentication requests.	No
ignoreUrlPatternType	Defines the type of the pattern specified. Defaults to REGEX. Other types are CONTAINS, EXACT, FULL_REGEX. Can also accept a fully-qualified class name that implements UrlPatternMatcherStrategy.	No
gatewayStorageClass	The storage class used to record gateway requests	No
authenticationRedirectStrategyClass	The class name of the component to decide how to handle authn redirects to CAS	No
method	The method used by the CAS server to send the user back to the application. Defaults to null	No

Ignore Patterns

The following types are supported:

Type	Description
REGEX	Matches the URL the ignorePattern using Matcher#find(). It matches the next occurrence within the substring that matches the regex.
CONTAINS	Uses the String#contains() operation to determine if the url contains the specified pattern. Behavior is case-sensitive.
EXACT	Uses the String#equals() operation to determine if the url exactly equals the specified pattern. Behavior is case-sensitive.
FULL_REGEX	Matches the URL the ignorePattern using Matcher#matches(). It matches the expression against the entire string as it implicitly add a ^ at the start and $ at the end of the pattern, so it will not match substring or part of the string. ^ and $ are meta characters that represents start of the string and end of the string respectively.

org.apereo.cas.client.authentication.Saml11AuthenticationFilter

The SAML 1.1 AuthenticationFilter is what detects whether a user needs to be authenticated or not. If a user needs to be authenticated, it will redirect the user to the CAS server.

<filter>
  <filter-name>CAS Authentication Filter</filter-name>
  <filter-class>org.apereo.cas.client.authentication.Saml11AuthenticationFilter</filter-class>
  <init-param>
    <param-name>casServerLoginUrl</param-name>
    <param-value>https://somewhere.cas.edu:8443/cas/login</param-value>
  </init-param>
  <init-param>
    <param-name>serverName</param-name>
    <param-value>http://www.the-client.com</param-value>
  </init-param>
</filter>
<filter-mapping>
    <filter-name>CAS Authentication Filter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

Property	Description	Required
casServerUrlPrefix	The start of the CAS server URL, i.e. https://localhost:8443/cas	Yes (unless casServerLoginUrl is set)
casServerLoginUrl	Defines the location of the CAS server login URL, i.e. https://localhost:8443/cas/login. This overrides casServerUrlPrefix, if set.	Yes (unless casServerUrlPrefix is set)
serverName	The name of the server this application is hosted on. Service URL will be dynamically constructed using this, i.e. https://localhost:8443 (you must include the protocol, but port is optional if it's a standard port).	Yes
service	The service URL to send to the CAS server, i.e. https://localhost:8443/yourwebapp/index.html	No
renew	specifies whether renew=true should be sent to the CAS server. Valid values are either true/false (or no value at all). Note that renew cannot be specified as local init-param setting.	No
gateway	specifies whether gateway=true should be sent to the CAS server. Valid values are either true/false (or no value at all)	No
artifactParameterName	specifies the name of the request parameter on where to find the artifact (i.e. SAMLart).	No
serviceParameterName	specifies the name of the request parameter on where to find the service (i.e. TARGET)	No
encodeServiceUrl	Whether the client should auto encode the service url. Defaults to true	No
method	The method used by the CAS server to send the user back to the application. Defaults to null	No

org.apereo.cas.client.validation.Cas10TicketValidationFilter

Validates tickets using the CAS 1.0 Protocol.

<filter>
  <filter-name>CAS Validation Filter</filter-name>
  <filter-class>org.apereo.cas.client.validation.Cas10TicketValidationFilter</filter-class>
  <init-param>
    <param-name>casServerUrlPrefix</param-name>
    <param-value>https://somewhere.cas.edu:8443/cas</param-value>
  </init-param>
  <init-param>
    <param-name>serverName</param-name>
    <param-value>http://www.the-client.com</param-value>
  </init-param>    
</filter>
<filter-mapping>
    <filter-name>CAS Validation Filter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

Property	Description	Required
casServerUrlPrefix	The start of the CAS server URL, i.e. https://localhost:8443/cas	Yes
serverName	The name of the server this application is hosted on. Service URL will be dynamically constructed using this, i.e. https://localhost:8443 (you must include the protocol, but port is optional if it's a standard port).	Yes
renew	Specifies whether renew=true should be sent to the CAS server. Valid values are either true/false (or no value at all). Note that renew cannot be specified as local init-param setting.	No
redirectAfterValidation	Whether to redirect to the same URL after ticket validation, but without the ticket in the parameter. Defaults to true.	No
useSession	Whether to store the Assertion in session or not. If sessions are not used, tickets will be required for each request. Defaults to true.	No
exceptionOnValidationFailure	Whether to throw an exception or not on ticket validation failure. Defaults to true.	No
sslConfigFile	A reference to a properties file that includes SSL settings for client-side SSL config, used during back-channel calls. The configuration includes keys for protocol which defaults to SSL, keyStoreType, keyStorePath, keyStorePass, keyManagerType which defaults to SunX509 and certificatePassword.	No.
encoding	Specifies the encoding charset the client should use	No
hostnameVerifier	Hostname verifier class name, used when making back-channel calls	No

org.apereo.cas.client.validation.Saml11TicketValidationFilter

Validates tickets using the SAML 1.1 protocol.

<filter>
  <filter-name>CAS Validation Filter</filter-name>
  <filter-class>org.apereo.cas.client.validation.Saml11TicketValidationFilter</filter-class>
  <init-param>
    <param-name>casServerUrlPrefix</param-name>
    <param-value>https://battags.ad.ess.rutgers.edu:8443/cas</param-value>
  </init-param>
  <init-param>
    <param-name>serverName</param-name>
    <param-value>http://www.acme-client.com</param-value>
  </init-param>
</filter>
<filter-mapping>
    <filter-name>CAS Validation Filter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

Property	Description	Required
casServerUrlPrefix	The start of the CAS server URL, i.e. https://localhost:8443/cas	Yes
serverName	The name of the server this application is hosted on. Service URL will be dynamically constructed using this, i.e. https://localhost:8443 (you must include the protocol, but port is optional if it's a standard port).	Yes
renew	Specifies whether renew=true should be sent to the CAS server. Valid values are either true/false (or no value at all). Note that renew cannot be specified as local init-param setting.	No
redirectAfterValidation	Whether to redirect to the same URL after ticket validation, but without the ticket in the parameter. Defaults to true.	No
useSession	Whether to store the Assertion in session or not. If sessions are not used, tickets will be required for each request. Defaults to true.	No
exceptionOnValidationFailure	whether to throw an exception or not on ticket validation failure. Defaults to true	No
tolerance	The tolerance for drifting clocks when validating SAML tickets. Note that 10 seconds should be more than enough for most environments that have NTP time synchronization. Defaults to 1000 msec	No
sslConfigFile	A reference to a properties file that includes SSL settings for client-side SSL config, used during back-channel calls. The configuration includes keys for protocol which defaults to SSL, keyStoreType, keyStorePath, keyStorePass, keyManagerType which defaults to SunX509 and certificatePassword.	No.
encoding	Specifies the encoding charset the client should use	No
hostnameVerifier	Hostname verifier class name, used when making back-channel calls	No

org.apereo.cas.client.validation.Cas20ProxyReceivingTicketValidationFilter

Validates the tickets using the CAS 2.0 protocol. If you provide either the acceptAnyProxy or the allowedProxyChains parameters, a Cas20ProxyTicketValidator will be constructed. Otherwise a general Cas20ServiceTicketValidator will be constructed that does not accept proxy tickets.

Note: If you are using proxy validation, you should place the filter-mapping of the validation filter before the authentication filter.

<filter>
  <filter-name>CAS Validation Filter</filter-name>
  <filter-class>org.apereo.cas.client.validation.Cas20ProxyReceivingTicketValidationFilter</filter-class>
  <init-param>
    <param-name>casServerUrlPrefix</param-name>
    <param-value>https://battags.ad.ess.rutgers.edu:8443/cas</param-value>
  </init-param>
  <init-param>
    <param-name>serverName</param-name>
    <param-value>http://www.acme-client.com</param-value>
  </init-param>
</filter>
<filter-mapping>
    <filter-name>CAS Validation Filter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

Property	Description	Required
casServerUrlPrefix	The start of the CAS server URL, i.e. https://localhost:8443/cas	Yes
serverName	The name of the server this application is hosted on. Service URL will be dynamically constructed using this, i.e. https://localhost:8443 (you must include the protocol, but port is optional if it's a standard port).	Yes
renew	Specifies whether renew=true should be sent to the CAS server. Valid values are either true/false (or no value at all). Note that renew cannot be specified as local init-param setting.	No
redirectAfterValidation	Whether to redirect to the same URL after ticket validation, but without the ticket in the parameter. Defaults to true.	No
useSession	Whether to store the Assertion in session or not. If sessions are not used, tickets will be required for each request. Defaults to true.	No
exceptionOnValidationFailure	whether to throw an exception or not on ticket validation failure. Defaults to true	No
proxyReceptorUrl	The URL to watch for PGTIOU/PGT responses from the CAS server. Should be defined from the root of the context. For example, if your application is deployed in /cas-client-app and you want the proxy receptor URL to be /cas-client-app/my/receptor you need to configure proxyReceptorUrl to be /my/receptor.	No
acceptAnyProxy	Specifies whether any proxy is OK. Defaults to false.	No
allowedProxyChains	Specifies the proxy chain. Each acceptable proxy chain should include a space-separated list of URLs (for exact match) or regular expressions of URLs (starting by the ^ character). Each acceptable proxy chain should appear on its own line.	No
proxyCallbackUrl	The callback URL to provide the CAS server to accept Proxy Granting Tickets.	No
proxyGrantingTicketStorageClass	Specify an implementation of the ProxyGrantingTicketStorage class that has a no-arg constructor.	No
sslConfigFile	A reference to a properties file that includes SSL settings for client-side SSL config, used during back-channel calls. The configuration includes keys for protocol which defaults to SSL, keyStoreType, keyStorePath, keyStorePass, keyManagerType which defaults to SunX509 and certificatePassword.	No.
encoding	Specifies the encoding charset the client should use	No
secretKey	The secret key used by the proxyGrantingTicketStorageClass if it supports encryption.	No
cipherAlgorithm	The algorithm used by the proxyGrantingTicketStorageClass if it supports encryption. Defaults to DESede	No
millisBetweenCleanUps	Startup delay for the cleanup task to remove expired tickets from the storage. Defaults to 60000 msec	No
ticketValidatorClass	Ticket validator class to use/create	No
hostnameVerifier	Hostname verifier class name, used when making back-channel calls	No
privateKeyPath	The path to a private key to decrypt PGTs directly sent encrypted as an attribute	No
privateKeyAlgorithm	The algorithm of the private key. Defaults to RSA	No

org.apereo.cas.client.validation.Cas30ProxyReceivingTicketValidationFilter

Validates the tickets using the CAS 3.0 protocol. If you provide either the acceptAnyProxy or the allowedProxyChains parameters, a Cas30ProxyTicketValidator will be constructed. Otherwise a general Cas30ServiceTicketValidator will be constructed that does not accept proxy tickets. Supports all configurations that are available for Cas20ProxyReceivingTicketValidationFilter.

org.apereo.cas.client.validation.Cas30JsonProxyReceivingTicketValidationFilter

Identical to Cas30ProxyReceivingTicketValidationFilter, yet the filter is able to accept validation responses from CAS that are formatted as JSON per guidelines laid out by the CAS protocol. See the protocol documentation for more info.

org.apereo.cas.client.validation.CasJWTTicketValidationFilter

Validates service tickets that issued by the CAS server as JWTs.

Supported JWTs are:

• The JWT must be signed and encrypted, in that order, or...
• The JWT must be encrypted and signed, in that order, or...
• The JWT must be encrypted.

<filter>
  <filter-name>CAS Validation Filter</filter-name>
  <filter-class>org.apereo.cas.client.validation.CasJWTTicketValidationFilter</filter-class>
  <init-param>
    <param-name>signingKey</param-name>
    <param-value>...</param-value>
  </init-param>
  <init-param>
    <param-name>encryptionKey</param-name>
    <param-value>...</param-value>
  </init-param>
</filter>
<filter-mapping>
    <filter-name>CAS Validation Filter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

Property	Description	Required
signingKey	The signing key. Only AES secret keys are supported.	Yes
encryptionKey	The encryption key. Only AES secret keys are supported.	Yes
expectedIssuer	iss claim value that is required to match what is in the JWT.	Yes
expectedAudience	aud claim value that is required to match what is in the JWT.	Yes
encryptionKeyAlgorithm	Default is AES.	No
encryptionKeyAlgorithm	Default is AES.	No
requiredClaims	Default is sub,aud,iat,jti,exp,iss.	No
base64EncryptionKey	If encryption key should be base64-decoded first. Default is true.	No
base64SigningKey	If encryption key should be base64-decoded first. Default is false.	No
maxClockSkew	Maximum acceptable clock skew when validating expiration dates. Default is 60 seconds.	No

Proxy Authentication vs. Distributed Caching

The client has support for clustering and distributing the TGT state among application nodes that are behind a load balancer. In order to do so, the parameter needs to be defined as such for the filter.

Ehcache

Configure the client:

<init-param>
  <param-name>proxyGrantingTicketStorageClass</param-name>
  <param-value>org.apereo.cas.client.EhcacheBackedProxyGrantingTicketStorageImpl</param-value>
</init-param>

The setting provides an implementation for proxy storage using EhCache to take advantage of its replication features so that the PGT is successfully replicated and shared among nodes, regardless which node is selected as the result of the load balancer rerouting.

Configuration of this parameter is not enough. The EhCache configuration needs to enable the replication mechanism through once of its suggested ways. A sample of that configuration based on RMI replication can be found here. Please note that while the sample is done for a distributed ticket registry implementation, the basic idea and configuration should easily be transferable.

When loading from the web.xml, the Apereo CAS Client relies on a series of default values, one of which being that the cache must be configured in the default location (i.e. classpath:ehcache.xml).

<cacheManagerPeerProviderFactory class="net.sf.ehcache.distribution.RMICacheManagerPeerProviderFactory"
   properties="peerDiscovery=automatic,
   multicastGroupAddress=230.0.0.1, multicastGroupPort=4446"/>
 
<cacheManagerPeerListenerFactory class="net.sf.ehcache.distribution.RMICacheManagerPeerListenerFactory"/>
 
<cache
   name="org.apereo.cas.client.EhcacheBackedProxyGrantingTicketStorageImpl.cache"
   maxElementsInMemory="100"
   eternal="false"
   timeToIdleSeconds="100"
   timeToLiveSeconds="100"
   overflowToDisk="false">
   <cacheEventListenerFactory class="net.sf.ehcache.distribution.RMICacheReplicatorFactory"/>
</cache>

Memcached

A similar implementation based on Memcached is also available.

Configure the client:

<init-param>
  <param-name>proxyGrantingTicketStorageClass</param-name>
  <param-value>org.apereo.cas.client.proxy.MemcachedBackedProxyGrantingTicketStorageImpl</param-value>
</init-param>

When loading from the web.xml, the Client relies on a series of default values, one of which being that the list of memcached servers must be defined in /cas/casclient_memcached_hosts.txt on the classpath). The file is a simple list of <hostname>:<ports> on separate lines. BE SURE NOT TO HAVE EXTRA LINE BREAKS.

org.apereo.cas.client.HttpServletRequestWrapperFilter

Wraps an HttpServletRequest so that the getRemoteUser and getPrincipal return the CAS related entries.

<filter>
  <filter-name>CAS HttpServletRequest Wrapper Filter</filter-name>
  <filter-class>org.apereo.cas.client.HttpServletRequestWrapperFilter</filter-class>
</filter>
<filter-mapping>
  <filter-name>CAS HttpServletRequest Wrapper Filter</filter-name>
  <url-pattern>/*</url-pattern>
</filter-mapping>

Property	Description	Required
roleAttribute	Used to determine the principal role.	No
ignoreCase	Whether role checking should ignore case. Defaults to false	No

org.apereo.cas.client.AssertionThreadLocalFilter

Places the Assertion in a ThreadLocal for portions of the application that need access to it. This is useful when the Web application that this filter "fronts" needs to get the Principal name, but it has no access to the HttpServletRequest, hence making getRemoteUser() call impossible.

<filter>
  <filter-name>CAS Assertion Thread Local Filter</filter-name>
  <filter-class>org.apereo.cas.client.AssertionThreadLocalFilter</filter-class>
</filter>
<filter-mapping>
  <filter-name>CAS Assertion Thread Local Filter</filter-name>
  <url-pattern>/*</url-pattern>
</filter-mapping>

org.apereo.cas.client.ErrorRedirectFilter

Filters that redirects to the supplied url based on an exception. Exceptions and the urls are configured via init filter name/param values.

Property	Description	Required
defaultErrorRedirectPage	Default url to redirect to, in case no error matches are found.	Yes
java.lang.Exception	Fully qualified exception name. Its value must be redirection url	No

<filter>
  <filter-name>CAS Error Redirect Filter</filter-name>
  <filter-class>org.apereo.cas.client.ErrorRedirectFilter</filter-class>
  <init-param>
    <param-name>java.lang.Exception</param-name>
    <param-value>/error.jsp</param-value>
  </init-param>
  <init-param>
    <param-name>defaultErrorRedirectPage</param-name>
    <param-value>/defaulterror.jsp</param-value>
  </init-param>
</filter>
<filter-mapping>
  <filter-name>CAS Error Redirect Filter</filter-name>
  <url-pattern>/*</url-pattern>
</filter-mapping>

Client Configuration Using Spring

Configuration via Spring IoC will depend heavily on DelegatingFilterProxy class. For each filter that will be configured for CAS via Spring, a corresponding DelegatingFilterProxy is needed in the web.xml.

As the HttpServletRequestWrapperFilter and AssertionThreadLocalFilter have no configuration options, we recommend you just configure them in the web.xml

<filter>
    <filter-name>CAS Authentication Filter</filter-name>
    <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
    <init-param>
        <param-name>targetBeanName</param-name>
        <param-value>authenticationFilter</param-value>
    </init-param>
  </filter>
<filter-mapping>
    <filter-name>CAS Authentication Filter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

Bean Configuration

AuthenticationFilter

<bean
    name="authenticationFilter"
    class="org.apereo.cas.client.authentication.AuthenticationFilter"
    p:casServerLoginUrl="https://localhost:8443/cas/login"
    p:renew="false"
    p:gateway="false"
    p:service="https://my.local.service.com/cas-client" />

Cas10TicketValidationFilter

<bean
    name="ticketValidationFilter"
    class="org.apereo.cas.client.validation.Cas10TicketValidationFilter"
    p:service="https://my.local.service.com/cas-client">
    <property name="ticketValidator">
        <bean class="org.apereo.cas.client.validation.Cas10TicketValidator">
            <constructor-arg index="0" value="https://localhost:8443/cas" />
        </bean>
    </property>
</bean>

Saml11TicketValidationFilter

<bean
    name="ticketValidationFilter"
    class="org.apereo.cas.client.validation.Saml11TicketValidationFilter"
    p:service="https://my.local.service.com/cas-client">
    <property name="ticketValidator">
        <bean class="org.apereo.cas.client.validation.Saml11TicketValidator">
            <constructor-arg index="0" value="https://localhost:8443/cas" />
        </bean>
    </property>
</bean>

Cas20ProxyReceivingTicketValidationFilter

Configuration to validate tickets:

<bean
    name="ticketValidationFilter"
    class="org.apereo.cas.client.validation.Cas20ProxyReceivingTicketValidationFilter"
    p:service="https://my.local.service.com/cas-client">
    <property name="ticketValidator">
        <bean class="org.apereo.cas.client.validation.Cas20ServiceTicketValidator">
            <constructor-arg index="0" value="https://localhost:8443/cas" />
        </bean>
    </property>
</bean>

Configuration to accept a Proxy Granting Ticket:

<bean
    name="ticketValidationFilter"
    class="org.apereo.cas.client.validation.Cas20ProxyReceivingTicketValidationFilter"
    p:service="https://my.local.service.com/cas-client"
    p:proxyReceptorUrl="/proxy/receptor">
    <property name="ticketValidator">
        <bean
            class="org.apereo.cas.client.validation.Cas20ServiceTicketValidator"
            p:proxyCallbackUrl="/proxy/receptor">
            <constructor-arg index="0" value="https://localhost:8443/cas" />
        </bean>
    </property>
</bean>

Configuration to accept any Proxy Ticket (and Proxy Granting Tickets):

<bean
    name="ticketValidationFilter"
    class="org.apereo.cas.client.validation.Cas20ProxyReceivingTicketValidationFilter"
    p:service="https://my.local.service.com/cas-client"
    p:proxyReceptorUrl="/proxy/receptor">
    <property name="ticketValidator">
        <bean class="org.apereo.cas.client.validation.Cas20ProxyTicketValidator"
            p:acceptAnyProxy="true"
            p:proxyCallbackUrl="/proxy/receptor">
            <constructor-arg index="0" value="https://localhost:8443/cas" />
        </bean>
    </property>
</bean>

Configuration to accept Proxy Ticket from a chain (and Proxy Granting Tickets):

<bean
    name="ticketValidationFilter"
    class="org.apereo.cas.client.validation.Cas20ProxyReceivingTicketValidationFilter"
    p:service="https://my.local.service.com/cas-client"
    p:proxyReceptorUrl="/proxy/receptor">
    <property name="ticketValidator">
        <bean class="org.apereo.cas.client.validation.Cas20ProxyTicketValidator"
            p:proxyCallbackUrl="/proxy/receptor">
            <constructor-arg index="0" value="https://localhost:8443/cas" />
            <property name="allowedProxyChains">
                <list>
                    <value>http://proxy1 http://proxy2</value>
                </list>
            </property>
        </bean>
    </property>
</bean>

The specific filters can be configured in the following ways. Please see the JavaDocs included in the distribution for specific required and optional properties:

Spring Boot AutoConfiguration

Usage

• Define a dependency:

Maven:

<dependency>
   <groupId>org.apereo.cas.client</groupId>
   <artifactId>cas-client-support-springboot</artifactId>
   <version>${java.cas.client.version}</version>
</dependency>

Gradle:

dependencies {
    ...
    implementation 'org.apereo.cas.client:cas-client-support-springboot:${java.cas.client.version}'
    ...
}

• Add the following required properties in Spring Boot's application.properties or application.yml:

cas.server-url-prefix=https://cashost.com/cas
cas.server-login-url=https://cashost.com/cas/login
cas.client-host-url=https://casclient.com

• Annotate Spring Boot application (or any @Configuration class) with @EnableCasClient annotation

@SpringBootApplication
@Controller
@EnableCasClient
public class MyApplication { .. }

For CAS3 protocol (authentication and validation filters) - which is default if nothing is specified

cas.validation-type=CAS3

For CAS2 protocol (authentication and validation filters)

cas.validation-type=CAS

For SAML protocol (authentication and validation filters)

cas.validation-type=SAML

Available optional properties

• cas.single-logout.enabled
• cas.authentication-url-patterns
• cas.validation-url-patterns
• cas.request-wrapper-url-patterns
• cas.assertion-thread-local-url-patterns
• cas.gateway
• cas.use-session
• cas.attribute-authorities
• cas.redirect-after-validation
• cas.allowed-proxy-chains
• cas.proxy-callback-url
• cas.proxy-receptor-url
• cas.accept-any-proxy
• server.context-parameters.renew

Spring Security Integration

An application that is handling security concerns via Spring Security can take advantage of this module to automatically populate the Spring Security authentication context with roles and authorities that are fetched as attributes from the CAS assertion.

To do so, the attributes names (i.e. membership) from the CAS assertion that should be translated to Spring Security authorities must be specified in the configuration:

cas.attribute-authorities=membership

The application may then enforce role-based security via:

@SpringBootApplication
@EnableCasClient
public class MyConfiguration extends WebSecurityConfigurerAdapter {
    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.authorizeRequests()
            .antMatchers("/").permitAll()
            .antMatchers("/protected-endpoint").hasAuthority("ADMIN")
            .anyRequest().authenticated();
    }
}

The translation between CAS attributes and Spring Security authorities and/or roles can be customized using the following bean definition:

@Bean
public AuthenticationUserDetailsService<CasAssertionAuthenticationToken> springSecurityCasUserDetailsService() {
    return null;
}

Advanced configuration

This module does not expose ALL the CAS client configuration options via standard Spring property sources, but only most commonly used ones. If there is a need however, to set any number of not exposed, 'exotic' properties, you can implement the CasClientConfigurer class in your @EnableCasClient annotated class and override appropriate configuration method(s) for CAS client filter(s) in question. For example:

@SpringBootApplication
@EnableCasClient
class CasProtectedApplication implements CasClientConfigurer {    
    @Override
    void configureValidationFilter(FilterRegistrationBean validationFilter) {           
        validationFilter.getInitParameters().put("millisBetweenCleanUps", "120000");
    }        
    @Override
    void configureAuthenticationFilter(FilterRegistrationBean authenticationFilter) {
        authenticationFilter.getInitParameters().put("artifactParameterName", "casTicket");
        authenticationFilter.getInitParameters().put("serviceParameterName", "targetService");
    }                                
}

Configuring Single Sign Out

The Single Sign Out support in CAS consists of configuring one SingleSignOutFilter and one ContextListener. Please note that if you have configured the CAS Client for Java as Web filters, this filter must come before the other filters as described.

The SingleSignOutFilter can affect character encoding. This becomes most obvious when used in conjunction with applications such as Atlassian Confluence. It's recommended you explicitly configure either the VT Character Encoding Filter or the Spring Character Encoding Filter with explicit encodings.

Configuration

Property	Description	Required
artifactParameterName	The ticket artifact parameter name. Defaults to ticket	No
logoutParameterName	Defaults to logoutRequest	No
relayStateParameterName	Defaults to RelayState	No
eagerlyCreateSessions	Defaults to true	No
artifactParameterOverPost	Defaults to false	No
logoutCallbackPath	The path which is expected to receive logout callback requests from the CAS server. This is necessary if your app needs access to the raw input stream when handling form posts. If not configured, the default behavior will check every form post for a logout parameter.	No

CAS Protocol

<filter>
   <filter-name>CAS Single Sign Out Filter</filter-name>
   <filter-class>org.apereo.cas.client.session.SingleSignOutFilter</filter-class>
</filter>
...
<filter-mapping>
   <filter-name>CAS Single Sign Out Filter</filter-name>
   <url-pattern>/*</url-pattern>
</filter-mapping>
...
<listener>
    <listener-class>org.apereo.cas.client.session.SingleSignOutHttpSessionListener</listener-class>
</listener>

SAML Protocol

<filter>
   <filter-name>CAS Single Sign Out Filter</filter-name>
   <filter-class>org.apereo.cas.client.session.SingleSignOutFilter</filter-class>
   <init-param>
      <param-name>artifactParameterName</param-name>
      <param-value>SAMLart</param-value>
   </init-param>
</filter>
...
<filter-mapping>
   <filter-name>CAS Single Sign Out Filter</filter-name>
   <url-pattern>/*</url-pattern>
</filter-mapping>
...
<listener>
    <listener-class>org.apereo.cas.client.session.SingleSignOutHttpSessionListener</listener-class>
</listener>

Recommend Logout Procedure

The client has no code to help you handle log out. The client merely places objects in session. Therefore, we recommend you do a session.invalidate() call when you log a user out. However, that's entirely your application's responsibility. We recommend that text similar to the following appear when the application's session is ended.

You have been logged out of [APPLICATION NAME GOES HERE].
To log out of all applications, click here. (provide link to CAS server's logout)

JAAS

The client supports the Java Authentication and Authorization Service (JAAS) framework, which provides authn facilities to CAS-enabled JEE applications.

A general JAAS authentication module, CasLoginModule, is available with the specific purpose of providing authentication and authorization services to CAS-enabled JEE applications. The design of the module is simple: given a service URL and a service ticket in a NameCallback and PasswordCallback, respectively, the module contacts the CAS server and attempts to validate the ticket. In keeping with CAS integration for Java applications, a JEE container-specific servlet filter is needed to protect JEE Web applications. The JAAS support should be extensible to any JEE container.

Configure CasLoginModule

It is expected that for JEE applications both authentication and authorization services will be required for CAS integration. The following JAAS module configuration file excerpt demonstrates how to leverage SAML 1.1 attribute release in CAS to provide authorization data in addition to authentication:

cas {
  jaas.org.apereo.cas.client.CasLoginModule required
    ticketValidatorClass="org.apereo.cas.client.validation.Saml11TicketValidator"
    casServerUrlPrefix="https://cas.example.com/cas"
    tolerance="20000"
    service="https://webapp.example.com/webapp"
    defaultRoles="admin,operator"
    roleAttributeNames="memberOf,eduPersonAffiliation"
    principalGroupName="CallerPrincipal"
    roleGroupName="Roles"
    cacheAssertions="true"
    cacheTimeout="480";
}

Property	Description	Required
ticketValidatorClass	Fully-qualified class name of CAS ticket validator class.	Yes
casServerUrlPrefix	URL to root of CAS Web application context.	Yes
service	CAS service parameter that may be overridden by callback handler. Note: service must be specified by at least one component such that it is available at service ticket validation time.	No
defaultRoles	Comma-delimited list of static roles applied to all authenticated principals.	No
roleAttributeNames	Comma-delimited list of attribute names that describe role data delivered to CAS in the service-ticket validation response that should be applied to the current authenticated principal.	No
principalGroupName	The name of a group principal containing the primary principal name of the current JAAS subject. The default value is CallerPrincipal.	No
roleGroupName	The name of a group principal containing all role data. The default value is Roles.	No
cacheAssertions	Flag to enable assertion caching. This may be required for JAAS providers that attempt to periodically reauthenticate to renew principal. Since CAS tickets are one-time-use, a cached assertion must be provided on reauthentication.	No
cacheTimeout	Assertion cache timeout in minutes.	No
tolerance	The tolerance for drifting clocks when validating SAML tickets.	No

Programmatic JAAS login using the Servlet 3

A jaas.org.apereo.cas.client.Servlet3AuthenticationFilter servlet filter that performs a programmatic JAAS login using the Servlet 3.0 HttpServletRequest#login() facility. This component should be compatible with any servlet container that supports the Servlet 3.0/JEE6 specification.

The filter executes when it receives a CAS ticket and expects the CasLoginModule JAAS module to perform the CAS ticket validation in order to produce an AssertionPrincipal from which the CAS assertion is obtained and inserted into the session to enable SSO.

If a service init-param is specified for this filter, it supersedes the service defined for the CasLoginModule.