Spring Security整合CAS的示例代码

这里使用的是spring-security和原生的jasig cas包来进行整合，为什么没有直接使用spring提供的spring-security-cas，后面会进行解释。

配置

web.xml

<filter>
<filter-name>casFilterChain</filter-name>
<filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
</filter>
<filter-mapping>
<filter-name>casFilterChain</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

<listener>
<listener-class>org.jasig.cas.client.session.SingleSignOutHttpSessionListener</listener-class>
</listener>

applicationContext-security.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xmlns:security="http://www.springframework.org/schema/security"
 xmlns:util="http://www.springframework.org/schema/util"
 xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
 http://www.springframework.org/schema/security
 http://www.springframework.org/schema/security/spring-security-3.2.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd">

<bean id="casFilterChain" class="org.springframework.security.web.FilterChainProxy">
 <constructor-arg>
  <util:list>
   <security:filter-chain pattern="/**" filters="singleSignOutFilter, cas20ProxyReceivingTicketValidationFilter, authenticationFilter, httpServletRequestWrapperFilter, assertionThreadLocalFilter"/>
  </util:list>
 </constructor-arg>
</bean>

<bean id="singleSignOutFilter" class="org.jasig.cas.client.session.SingleSignOutFilter"/>

<bean id="cas20ProxyReceivingTicketValidationFilter"
  class="org.jasig.cas.client.validation.Cas20ProxyReceivingTicketValidationFilter">
 <property name="serverName" value="${client.url}"/>
 <property name="ticketValidator" ref="cas20ServiceTicketValidator"/>
</bean>

<bean id="cas20ServiceTicketValidator" class="org.jasig.cas.client.validation.Cas20ServiceTicketValidator">
 <constructor-arg value="${cas.url}"/>
 <property name="renew" value="false"/>
</bean>

<bean id="authenticationFilter" class="org.jasig.cas.client.authentication.AuthenticationFilter">
 <property name="renew" value="false"/>
 <property name="casServerLoginUrl" value="${cas.url}"/>
 <property name="serverName" value="${client.url}"/>
</bean>

<bean id="httpServletRequestWrapperFilter" class="org.jasig.cas.client.util.HttpServletRequestWrapperFilter"/>

<bean id="assertionThreadLocalFilter" class="org.jasig.cas.client.util.AssertionThreadLocalFilter"/>

</beans>

properties

#CAS服务地址
cas.url=https://cas.example.com:8443
#CAS客户端地址，就是本应用的地址
client.url=http://localhost:8080

分析

在applicationContext-security.xml中的security filter chain中，我们使用了5个filter，分别是：singleSignOutFilter、cas20ProxyReceivingTicketValidationFilter、authenticationFilter、httpServletRequestWrapperFilter、assertionThreadLocalFilter。

为什么不用spring-security-cas

spring-security-cas

在spring-security-cas中负责ticket validator filter使用的是org.springframework.security.cas.authentication.CasAuthenticationProvider。

private CasAuthenticationToken authenticateNow(final Authentication authentication) throws AuthenticationException {
try {
 final Assertion assertion = this.ticketValidator.validate(authentication.getCredentials().toString(), getServiceUrl(authentication));
 ...

在构建validator的validator方法的第二个参数时

private String getServiceUrl(Authentication authentication) {
String serviceUrl;
if(authentication.getDetails() instanceof ServiceAuthenticationDetails) {
 serviceUrl = ((ServiceAuthenticationDetails)authentication.getDetails()).getServiceUrl();
}else if(serviceProperties == null){
 throw new IllegalStateException("serviceProperties cannot be null unless Authentication.getDetails() implements ServiceAuthenticationDetails.");
}else if(serviceProperties.getService() == null){
 throw new IllegalStateException("serviceProperties.getService() cannot be null unless Authentication.getDetails() implements ServiceAuthenticationDetails.");
}else {
 serviceUrl = serviceProperties.getService();
}
if(logger.isDebugEnabled()) {
 logger.debug("serviceUrl = "+serviceUrl);
}
return serviceUrl;
}

来源：http://atbug.com/spring-security-integrated-with-cas/