CAS 浅析 - 服务端登录流程简介(一) - 相关的配置文件

声明：这只是个人见解，不代表官方。
登录流程的主要在以下几个位置有配置：
1. web.xml里Servlet里的配置:

<servlet-mapping>
	<servlet-name>cas</servlet-name>
	<url-pattern>/login</url-pattern>
</servlet-mapping>

2. cas-servlet.xml 这个是webflow的配置.这个配置里面还有一些login-webflow用到的bean 的注入.

<webflow:flow-registry id="flowRegistry" flow-builder-services="builder">
        <webflow:flow-location path="/WEB-INF/login-webflow.xml" id="login" />
    </webflow:flow-registry>

3. login-webflow.xml 这是webflow的详细配置.

<?xml version="1.0" encoding="UTF-8"?>
<flow xmlns="http://www.springframework.org/schema/webflow"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://www.springframework.org/schema/webflow
      http://www.springframework.org/schema/webflow/spring-webflow-2.0.xsd">

    <var name="credentials" class="org.jasig.cas.authentication.principal.UsernamePasswordCredentials" />
    <on-start>
        <evaluate expression="initialFlowSetupAction" />
    </on-start>

	<decision-state id="ticketGrantingTicketExistsCheck">
		<if test="flowScope.ticketGrantingTicketId neq null" then="hasServiceCheck" else="gatewayRequestCheck" />
	</decision-state>
    
	<decision-state id="gatewayRequestCheck">
		<if test="externalContext.requestParameterMap['gateway'] neq '' &amp;&amp; externalContext.requestParameterMap['gateway'] neq null &amp;&amp; flowScope.service neq null" then="gatewayServicesManagementCheck" else="generateLoginTicket" />
	</decision-state>
	
	<decision-state id="hasServiceCheck">
		<if test="flowScope.service != null" then="renewRequestCheck" else="viewGenericLoginSuccess" />
	</decision-state>
	
	<decision-state id="renewRequestCheck">
		<if test="externalContext.requestParameterMap['renew'] neq '' &amp;&amp; externalContext.requestParameterMap['renew'] neq null" then="generateLoginTicket" else="generateServiceTicket" />
	</decision-state>
	
	<!-- 
		The "warn" action makes the determination of whether to redirect directly to the requested
		service or display the "confirmation" page to go back to the server.
	-->
	<decision-state id="warn">
		<if test="flowScope.warnCookieValue" then="showWarningView" else="redirect" />
	</decision-state>
	
	<!-- 
	<action-state id="startAuthenticate">
		<action bean="x509Check" />
		<transition on="success" to="sendTicketGrantingTicket" />
		<transition on="warn" to="warn" />
		<transition on="error" to="generateLoginTicket" />
	</action-state>
	 -->
   
	<action-state id="generateLoginTicket">
        <evaluate expression="generateLoginTicketAction.generate(flowRequestContext)" />
		<transition on="generated" to="viewLoginForm" />
	</action-state>
    
	<view-state id="viewLoginForm" view="casLoginView" model="credentials">
        <binder>
            <binding property="username" />
            <binding property="password" />
        </binder>
        <on-entry>
            <set name="viewScope.commandName" value="'credentials'" />
        </on-entry>
		<transition on="submit" bind="true" validate="true" to="realSubmit">
            <evaluate expression="authenticationViaFormAction.doBind(flowRequestContext, flowScope.credentials)" />
        </transition>
        	
	</view-state>
	

	<action-state id="realSubmit">
        <evaluate expression="authenticationViaFormAction.submit(flowRequestContext, flowScope.credentials, messageContext)" />
		<transition on="warn" to="warn" />
		<transition on="success" to="sendTicketGrantingTicket" />
		<transition on="error" to="generateLoginTicket" />
	</action-state>
	
	<action-state id="sendTicketGrantingTicket">
        <evaluate expression="sendTicketGrantingTicketAction" />
		<transition to="serviceCheck" />
	</action-state>

	<decision-state id="serviceCheck">
		<if test="flowScope.service neq null" then="generateServiceTicket" else="viewGenericLoginSuccess" />
	</decision-state>
	
	<action-state id="generateServiceTicket">
        <evaluate expression="generateServiceTicketAction" />
		<transition on="success" to ="warn" />
		<transition on="error" to="generateLoginTicket" />
		<transition on="gateway" to="gatewayServicesManagementCheck" />
	</action-state>

    <action-state id="gatewayServicesManagementCheck">
        <evaluate expression="gatewayServicesManagementCheck" />
        <transition on="success" to="redirect" />
    </action-state>

    <action-state id="redirect">
        <evaluate expression="flowScope.service.getResponse(requestScope.serviceTicketId)" result-type="org.jasig.cas.authentication.principal.Response" result="requestScope.response" />
        <transition to="postRedirectDecision" />
    </action-state>

    <decision-state id="postRedirectDecision">
        <if test="requestScope.response.responseType.name() eq 'POST'" then="postView" else="redirectView" />
    </decision-state>

	<!-- 
		the "viewGenericLogin" is the end state for when a user attempts to login without coming directly from a service.
		They have only initialized their single-sign on session.
	-->
	<end-state id="viewGenericLoginSuccess" view="casLoginGenericSuccessView" />

	<!-- 
		The "showWarningView" end state is the end state for when the user has requested privacy settings (to be "warned") to be turned on.  It delegates to a 
		view defines in default_views.properties that display the "Please click here to go to the service." message.
	-->
	<end-state id="showWarningView" view="casLoginConfirmView" />

    <end-state id="postView" view="postResponseView">
        <on-entry>
            <set name="requestScope.parameters" value="requestScope.response.attributes" />
            <set name="requestScope.originalUrl" value="flowScope.service.id" />
        </on-entry>
    </end-state>

	<!-- 
		The "redirect" end state allows CAS to properly end the workflow while still redirecting
		the user back to the service required.
	-->
	<end-state id="redirectView" view="externalRedirect:${requestScope.response.url}" />
	
	<end-state id="viewServiceErrorView" view="viewServiceErrorView" />
    
    <end-state id="viewServiceSsoErrorView" view="viewServiceSsoErrorView" />

	<global-transitions>
		<transition to="viewServiceErrorView" on-exception="org.springframework.webflow.execution.repository.NoSuchFlowExecutionException" />
        <transition to="viewServiceSsoErrorView" on-exception="org.jasig.cas.services.UnauthorizedSsoServiceException" />
		<transition to="viewServiceErrorView" on-exception="org.jasig.cas.services.UnauthorizedServiceException" />
	</global-transitions>
</flow>

其实了解webflow的人，根据上面的配置大概能看懂50%的流程了。
CAS 浅析 - 服务端登录流程简介(二) - login-webflow.xml简介http://feng-henry.iteye.com/blog/1545764