/* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited

  *

  * Licensed under the Apache License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  *

  *     http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.acegisecurity.ui.cas;

 import org.acegisecurity.Authentication;

 import org.acegisecurity.AuthenticationException;

 import org.acegisecurity.providers.UsernamePasswordAuthenticationToken;

 import org.acegisecurity.ui.AbstractProcessingFilter;

 import javax.servlet.FilterConfig;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServletRequest;

 /**

  * Processes a CAS service ticket.<p>A service ticket consists of an opaque ticket string. It arrives at this

  * filter by the user's browser successfully authenticating using CAS, and then receiving a HTTP redirect to a

  * <code>service</code>. The opaque ticket string is presented in the <code>ticket</code> request parameter. This

  * filter monitors the <code>service</code> URL so it can receive the service ticket and process it. The CAS server

  * knows which <code>service</code> URL to use via the {@link ServiceProperties#getService()} method.</p>

  *  <p>Processing the service ticket involves creating a <code>UsernamePasswordAuthenticationToken</code> which

  * uses {@link #CAS_STATEFUL_IDENTIFIER} for the <code>principal</code> and the opaque ticket string as the

  * <code>credentials</code>.</p>

  *  <p>The configured <code>AuthenticationManager</code> is expected to provide a provider that can recognise

  * <code>UsernamePasswordAuthenticationToken</code>s containing this special <code>principal</code> name, and process

  * them accordingly by validation with the CAS server.</p>

  *  <p><b>Do not use this class directly.</b> Instead configure <code>web.xml</code> to use the {@link

  * org.acegisecurity.util.FilterToBeanProxy}.</p>

  *

  * @author Ben Alex

  * @version $Id: CasProcessingFilter.java 1496 2006-05-23 13:38:33Z benalex $

  */

 public class CasProcessingFilter extends AbstractProcessingFilter {

     //~ Static fields/initializers =====================================================================================

     /** Used to identify a CAS request for a stateful user agent, such as a web browser. */

     public static final String CAS_STATEFUL_IDENTIFIER = "_cas_stateful_";

     /**

      * Used to identify a CAS request for a stateless user agent, such as a remoting protocol client (eg

      * Hessian, Burlap, SOAP etc). Results in a more aggressive caching strategy being used, as the absence of a

      * <code>HttpSession</code> will result in a new authentication attempt on every request.

      */

     public static final String CAS_STATELESS_IDENTIFIER = "_cas_stateless_";

     //~ Methods ========================================================================================================

     public Authentication attemptAuthentication(HttpServletRequest request)

         throws AuthenticationException {

         String username = CAS_STATEFUL_IDENTIFIER;

         String password = request.getParameter("ticket");

         if (password == null) {

             password = "";

         }

         UsernamePasswordAuthenticationToken authRequest = new UsernamePasswordAuthenticationToken(username, password);

         authRequest.setDetails(authenticationDetailsSource.buildDetails((HttpServletRequest) request));

         return this.getAuthenticationManager().authenticate(authRequest);

     }

     /**

      * This filter by default responds to <code>/j_acegi_cas_security_check</code>.

      *

      * @return the default

      */

     public String getDefaultFilterProcessesUrl() {

         return "/j_acegi_cas_security_check";

     }

     public void init(FilterConfig filterConfig) throws ServletException {}

 }