/*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you 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.apache.shiro.web.filter.mgt;

 import org.apache.shiro.util.AntPathMatcher;

 import org.apache.shiro.util.PatternMatcher;

 import org.apache.shiro.web.util.WebUtils;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 import javax.servlet.FilterChain;

 import javax.servlet.FilterConfig;

 import javax.servlet.ServletRequest;

 import javax.servlet.ServletResponse;

 /**

  * A {@code FilterChainResolver} that resolves {@link FilterChain}s based on url path

  * matching, as determined by a configurable {@link #setPathMatcher(org.apache.shiro.util.PatternMatcher) PathMatcher}.

  * <p/>

  * This implementation functions by consulting a {@link org.apache.shiro.web.filter.mgt.FilterChainManager} for all configured filter chains (keyed

  * by configured path pattern).  If an incoming Request path matches one of the configured path patterns (via

  * the {@code PathMatcher}, the corresponding configured {@code FilterChain} is returned.

  *

  * @since 1.0

  */

 public class PathMatchingFilterChainResolver implements FilterChainResolver {

     private static transient final Logger log = LoggerFactory.getLogger(PathMatchingFilterChainResolver.class);

     private FilterChainManager filterChainManager;

     private PatternMatcher pathMatcher;

     public PathMatchingFilterChainResolver() {

         this.pathMatcher = new AntPathMatcher();

         this.filterChainManager = new DefaultFilterChainManager();

     }

     public PathMatchingFilterChainResolver(FilterConfig filterConfig) {

         this.pathMatcher = new AntPathMatcher();

         this.filterChainManager = new DefaultFilterChainManager(filterConfig);

     }

     /**

      * Returns the {@code PatternMatcher} used when determining if an incoming request's path

      * matches a configured filter chain.  Unless overridden, the

      * default implementation is an {@link org.apache.shiro.util.AntPathMatcher AntPathMatcher}.

      *

      * @return the {@code PatternMatcher} used when determining if an incoming request's path

      *         matches a configured filter chain.

      */

     public PatternMatcher getPathMatcher() {

         return pathMatcher;

     }

     /**

      * Sets the {@code PatternMatcher} used when determining if an incoming request's path

      * matches a configured filter chain.  Unless overridden, the

      * default implementation is an {@link org.apache.shiro.util.AntPathMatcher AntPathMatcher}.

      *

      * @param pathMatcher the {@code PatternMatcher} used when determining if an incoming request's path

      *                    matches a configured filter chain.

      */

     public void setPathMatcher(PatternMatcher pathMatcher) {

         this.pathMatcher = pathMatcher;

     }

     public FilterChainManager getFilterChainManager() {

         return filterChainManager;

     }

     @SuppressWarnings({"UnusedDeclaration"})

     public void setFilterChainManager(FilterChainManager filterChainManager) {

         this.filterChainManager = filterChainManager;

     }

     public FilterChain getChain(ServletRequest request, ServletResponse response, FilterChain originalChain) {

         FilterChainManager filterChainManager = getFilterChainManager();

         if (!filterChainManager.hasChains()) {

             return null;

         }

         String requestURI = getPathWithinApplication(request);

         //the 'chain names' in this implementation are actually path patterns defined by the user.  We just use them

         //as the chain name for the FilterChainManager's requirements

         for (String pathPattern : filterChainManager.getChainNames()) {

             // If the path does match, then pass on to the subclass implementation for specific checks:

             if (pathMatches(pathPattern, requestURI)) {

                 if (log.isTraceEnabled()) {

                     log.trace("Matched path pattern [" + pathPattern + "] for requestURI [" + requestURI + "].  " +

                             "Utilizing corresponding filter chain...");

                 }

                 return filterChainManager.proxy(originalChain, pathPattern);

             }

         }

         return null;

     }

     /**

      * Returns {@code true} if an incoming request path (the {@code path} argument)

      * matches a configured filter chain path (the {@code pattern} argument), {@code false} otherwise.

      * <p/>

      * Simply delegates to

      * <b><code>{@link #getPathMatcher() getPathMatcher()}.{@link org.apache.shiro.util.PatternMatcher#matches(String, String) matches(pattern,path)}</code></b>.

      * Subclass implementors should think carefully before overriding this method, as typically a custom

      * {@code PathMatcher} should be configured for custom path matching behavior instead.  Favor OO composition

      * rather than inheritance to limit your exposure to Shiro implementation details which may change over time.

      *

      * @param pattern the pattern to match against

      * @param path    the value to match with the specified {@code pattern}

      * @return {@code true} if the request {@code path} matches the specified filter chain url {@code pattern},

      *         {@code false} otherwise.

      */

     protected boolean pathMatches(String pattern, String path) {

         PatternMatcher pathMatcher = getPathMatcher();

         return pathMatcher.matches(pattern, path);

     }

     /**

      * Merely returns

      * <code>WebUtils.{@link org.apache.shiro.web.util.WebUtils#getPathWithinApplication(javax.servlet.http.HttpServletRequest) getPathWithinApplication(request)}</code>

      * and can be overridden by subclasses for custom request-to-application-path resolution behavior.

      *

      * @param request the incoming {@code ServletRequest}

      * @return the request's path within the appliation.

      */

     protected String getPathWithinApplication(ServletRequest request) {

         return WebUtils.getPathWithinApplication(WebUtils.toHttp(request));

     }

 }