Quiero omitir el formulario de inicio de sesión para una aplicación Spring webflow (Spring 2.0.5) en ciertos escenarios (por lo que el formulario de inicio de sesión se presenta para usuarios normales pero cuando la URL es comohttp://server.com/myspringapp/fakelogin?username=FakeUser&password=FakePassword entonces al usuario no se le debe presentar el formulario de inicio de sesión, sino solo autenticarlo internamente según los parámetros de solicitud y luego llevarlo a la página segura).

Así que no quiero Preauthenticastion, más bien una autenticación transparente en ocasiones especiales (cuando la URL es como se mencionó anteriormente). Vi hilos comohttp://forum.springsource.org/showthread.php?t=59108 pero no donde se menciona una solución. Intenté implementar AuthenticationProcessingFilter pero no estoy muy seguro de cómo implementar el método requireAuthentication ().

El siguiente es mi XML de seguridad actual:

<?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"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
                        http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-2.0.xsd">

    <bean id="customAuthenticationProvider" class="com.myco.jsf.spring.security.MyAuthenticationProvider">
        <security:custom-authentication-provider/>
        <constructor-arg>
            <ref bean="webSessionFactory"/>
        </constructor-arg>
        <constructor-arg>
            <ref bean="authenticationBridge"/>
        </constructor-arg>
    </bean>

    <bean id="myEntryPoint" class="com.myco.web.filter.CustomAuthenticationEntryPoint">
        <property name="loginFormUrl" value="/spring/login" />
    </bean>

    <bean id="myProcessingFilter" class="com.myco.web.filter.CustomAuthenticationProcessingFilter">
        <security:custom-filter position="AUTHENTICATION_PROCESSING_FILTER" />
        <property name="defaultTargetUrl" value="/spring/secure" /> 
        <property name="authenticationFailureUrl" value="/spring/login" />
        <property name="alwaysUseDefaultTargetUrl" value="false" />
        <property name="filterProcessesUrl" value="/spring/j_spring_security_check" />    
        <property name="authenticationManager" ref="authenticationManager" />            
        <!--             
        <property name="allowSessionCreation" value="true" />                
         -->
    </bean>    

    <security:authentication-manager alias="authenticationManager"/>

        <security:http auto-config="false" access-denied-page="/spring/notpermitted" entry-point-ref="myEntryPoint">       
        <security:anonymous/>
        <!--     
        <security:form-login login-page="/spring/login" login-processing-url="/spring/j_spring_security_check" default-target-url="/spring/secure" 
            always-use-default-target="false" authentication-failure-url="/spring/login" />
         -->
        <security:logout logout-url="/spring/j_spring_security_logout" logout-success-url="/spring/pages/logout" />
        </security:http>

</beans> 

La siguiente es mi clase de filtro:

public class CustomAuthenticationProcessingFilter extends
        AuthenticationProcessingFilter {

    @Override
    protected void successfulAuthentication(HttpServletRequest request,
            HttpServletResponse response, Authentication authResult)
            throws IOException, ServletException {
        super.successfulAuthentication(request, response, authResult);

        System.out.println("==successful login==");
    }

    @Override
    protected void unsuccessfulAuthentication(HttpServletRequest request,
            HttpServletResponse response, AuthenticationException failed)
            throws IOException, ServletException {
        super.unsuccessfulAuthentication(request, response, failed);

        System.out.println("==failed login==");
    }

    @Override
    protected boolean requiresAuthentication(HttpServletRequest request,
            HttpServletResponse response) {
        boolean retVal = false;
        String username = request.getParameter("j_username");
        String password = request.getParameter("j_password");

        if (username != null && password != null) {
            Authentication authResult = null;
            try {
                authResult = attemptAuthentication(request);                
                if (authResult == null) {
                    retVal = false;
                }

            } catch (AuthenticationException failed) {
                try {
                    unsuccessfulAuthentication(request, response, failed);
                } catch (Exception e) {
                    retVal = false;
                }
                retVal = false;
            }

            try {
                successfulAuthentication(request, response, authResult);
            } catch (Exception e) {
                retVal = false;
            }

            return false;
        } else {
            retVal = super.requiresAuthentication(request, response);
        }
        return retVal;
    }

}

Puedo autenticarme utilizando los parámetros de solicitud suministrados y el objeto de autenticación se crea correctamente. Una vez que el filtro avanza, obtengo la excepción:

15:29:08,734 INFO  [STDOUT] 53453 ERROR [http-127.0.0.1-8080-2]     org.ajax4jsf.webapp.BaseXMLFilter     - Exception in the filter chain
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.IllegalStateException
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:659)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:552)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:206)
    at org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290)
    at org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:388)
    at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:515)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at com.myco.jsf.filter.CharsetFilter.doFilter(CharsetFilter.java:38)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
    at org.springframework.security.intercept.web.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:109)
    at org.springframework.security.intercept.web.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
    at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
    at org.springframework.security.ui.SessionFixationProtectionFilter.doFilterHttp(SessionFixationProtectionFilter.java:67)
    at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
    at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
    at org.springframework.security.ui.ExceptionTranslationFilter.doFilterHttp(ExceptionTranslationFilter.java:101)
    at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
    at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
    at org.springframework.security.providers.anonymous.AnonymousProcessingFilter.doFilterHttp(AnonymousProcessingFilter.java:105)
    at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
    at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
    at org.springframework.security.wrapper.SecurityContextHolderAwareRequestFilter.doFilterHttp(SecurityContextHolderAwareRequestFilter.java:91)
    at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
    at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
    at org.springframework.security.ui.AbstractProcessingFilter.doFilterHttp(AbstractProcessingFilter.java:278)
    at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
    at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
    at org.springframework.security.ui.logout.LogoutFilter.doFilterHttp(LogoutFilter.java:89)
    at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
    at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
    at org.springframework.security.context.HttpSessionContextIntegrationFilter.doFilterHttp(HttpSessionContextIntegrationFilter.java:235)
    at org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
    at org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
    at org.springframework.security.util.FilterChainProxy.doFilter(FilterChainProxy.java:175)
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:237)
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:173)
    at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:182)
    at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:84)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
    at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:157)
    at org.apache.catalina.authenticator.SingleSignOn.invoke(SingleSignOn.java:393)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:241)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
    at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.IllegalStateException
    at org.apache.catalina.connector.ResponseFacade.sendError(ResponseFacade.java:407)
    at javax.servlet.http.HttpServletResponseWrapper.sendError(HttpServletResponseWrapper.java:108)
    at org.springframework.security.context.HttpSessionContextIntegrationFilter$OnRedirectUpdateSessionResponseWrapper.sendError(HttpSessionContextIntegrationFilter.java:498)
    at javax.servlet.http.HttpServletResponseWrapper.sendError(HttpServletResponseWrapper.java:108)
    at org.ajax4jsf.webapp.FilterServletResponseWrapper.sendError(FilterServletResponseWrapper.java:655)
    at com.sun.facelets.FaceletViewHandler.handleFaceletNotFound(FaceletViewHandler.java:711)
    at com.sun.facelets.FaceletViewHandler.renderView(FaceletViewHandler.java:658)
    at org.ajax4jsf.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:100)
    at org.ajax4jsf.application.AjaxViewHandler.renderView(AjaxViewHandler.java:176)
    at org.springframework.faces.mvc.JsfView.renderMergedOutputModel(JsfView.java:83)
    at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:250)
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1060)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:798)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:716)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:647)
    ... 61 more

¿Me pueden ayudar con por qué recibo este error? ¿Estoy usando el tipo correcto de filtro personalizado? Aprecio tu ayuda.