/* 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.providers.anonymous;

 import org.acegisecurity.Authentication;

 import org.acegisecurity.context.SecurityContextHolder;

 import org.acegisecurity.ui.AuthenticationDetailsSource;

 import org.acegisecurity.ui.AuthenticationDetailsSourceImpl;

 import org.acegisecurity.userdetails.memory.UserAttribute;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.springframework.beans.factory.InitializingBean;

 import org.springframework.util.Assert;

 import java.io.IOException;

 import javax.servlet.Filter;

 import javax.servlet.FilterChain;

 import javax.servlet.FilterConfig;

 import javax.servlet.ServletException;

 import javax.servlet.ServletRequest;

 import javax.servlet.ServletResponse;

 import javax.servlet.http.HttpServletRequest;

 /**

  * Detects if there is no <code>Authentication</code> object in the <code>SecurityContextHolder</code>,  and

  * populates it with one if needed.<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: AnonymousProcessingFilter.java 1496 2006-05-23 13:38:33Z benalex $

  */

 public class AnonymousProcessingFilter implements Filter, InitializingBean {

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

     private static final Log logger = LogFactory.getLog(AnonymousProcessingFilter.class);

     //~ Instance fields ================================================================================================

     private AuthenticationDetailsSource authenticationDetailsSource = new AuthenticationDetailsSourceImpl();

     private String key;

     private UserAttribute userAttribute;

     private boolean removeAfterRequest = true;

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

     public void afterPropertiesSet() throws Exception {

         Assert.notNull(userAttribute);

         Assert.hasLength(key);

     }

     /**

      * Enables subclasses to determine whether or not an anonymous authentication token should be setup for

      * this request. This is useful if anonymous authentication should be allowed only for specific IP subnet ranges

      * etc.

      *

      * @param request to assist the method determine request details

      *

      * @return <code>true</code> if the anonymous token should be setup for this request (provided that the request

      *         doesn't already have some other <code>Authentication</code> inside it), or <code>false</code> if no

      *         anonymous token should be setup for this request

      */

     protected boolean applyAnonymousForThisRequest(ServletRequest request) {

         return true;

     }

     protected Authentication createAuthentication(ServletRequest request) {

         Assert.isInstanceOf(HttpServletRequest.class, request,

             "ServletRequest must be an instance of HttpServletRequest");

         AnonymousAuthenticationToken auth = new AnonymousAuthenticationToken(key, userAttribute.getPassword(),

                 userAttribute.getAuthorities());

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

         return auth;

     }

     /**

      * Does nothing - we reply on IoC lifecycle services instead.

      */

     public void destroy() {}

     public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)

         throws IOException, ServletException {

         boolean addedToken = false;

         if (applyAnonymousForThisRequest(request)) {

             if (SecurityContextHolder.getContext().getAuthentication() == null) {

                 SecurityContextHolder.getContext().setAuthentication(createAuthentication(request));

                 addedToken = true;

                 if (logger.isDebugEnabled()) {

                     logger.debug("Populated SecurityContextHolder with anonymous token: '"

                         + SecurityContextHolder.getContext().getAuthentication() + "'");

                 }

             } else {

                 if (logger.isDebugEnabled()) {

                     logger.debug("SecurityContextHolder not populated with anonymous token, as it already contained: '"

                         + SecurityContextHolder.getContext().getAuthentication() + "'");

                 }

             }

         }

         try {

             chain.doFilter(request, response);

         } finally {

             if (addedToken && removeAfterRequest

                 && createAuthentication(request).equals(SecurityContextHolder.getContext().getAuthentication())) {

                 SecurityContextHolder.getContext().setAuthentication(null);

             }

         }

     }

     public String getKey() {

         return key;

     }

     public UserAttribute getUserAttribute() {

         return userAttribute;

     }

     /**

      * Does nothing - we reply on IoC lifecycle services instead.

      *

      * @param ignored not used

      *

      * @throws ServletException DOCUMENT ME!

      */

     public void init(FilterConfig ignored) throws ServletException {}

     public boolean isRemoveAfterRequest() {

         return removeAfterRequest;

     }

     public void setAuthenticationDetailsSource(AuthenticationDetailsSource authenticationDetailsSource) {

         Assert.notNull(authenticationDetailsSource, "AuthenticationDetailsSource required");

         this.authenticationDetailsSource = authenticationDetailsSource;

     }

     public void setKey(String key) {

         this.key = key;

     }

     /**

      * Controls whether the filter will remove the Anonymous token after the request is complete. Generally

      * this is desired to avoid the expense of a session being created by {@link

      * org.acegisecurity.context.HttpSessionContextIntegrationFilter HttpSessionContextIntegrationFilter} simply to

      * store the Anonymous authentication token.<p>Defaults to <code>true</code>, being the most optimal and

      * appropriate option (ie <code>AnonymousProcessingFilter</code> will clear the token at the end of each request,

      * thus avoiding the session creation overhead in a typical configuration.</p>

      *

      * @param removeAfterRequest DOCUMENT ME!

      */

     public void setRemoveAfterRequest(boolean removeAfterRequest) {

         this.removeAfterRequest = removeAfterRequest;

     }

     public void setUserAttribute(UserAttribute userAttributeDefinition) {

         this.userAttribute = userAttributeDefinition;

     }

 }