001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    package org.apache.hadoop.hdfs.web;
019    
020    import java.net.URI;
021    import java.util.List;
022    import java.util.Map;
023    
024    import javax.ws.rs.core.MultivaluedMap;
025    import javax.ws.rs.core.UriBuilder;
026    
027    import com.sun.jersey.spi.container.ContainerRequest;
028    import com.sun.jersey.spi.container.ContainerRequestFilter;
029    import com.sun.jersey.spi.container.ContainerResponseFilter;
030    import com.sun.jersey.spi.container.ResourceFilter;
031    
032    /**
033     * A filter to change parameter names to lower cases
034     * so that parameter names are considered as case insensitive.
035     */
036    public class ParamFilter implements ResourceFilter {
037      private static final ContainerRequestFilter LOWER_CASE
038          = new ContainerRequestFilter() {
039        @Override
040        public ContainerRequest filter(final ContainerRequest request) {
041          final MultivaluedMap<String, String> parameters = request.getQueryParameters();
042          if (containsUpperCase(parameters.keySet())) {
043            //rebuild URI
044            final URI lower = rebuildQuery(request.getRequestUri(), parameters);
045            request.setUris(request.getBaseUri(), lower);
046          }
047          return request;
048        }
049      };
050    
051      @Override
052      public ContainerRequestFilter getRequestFilter() {
053        return LOWER_CASE;
054      }
055    
056      @Override
057      public ContainerResponseFilter getResponseFilter() {
058        return null;
059      }
060    
061      /** Do the strings contain upper case letters? */
062      static boolean containsUpperCase(final Iterable<String> strings) {
063        for(String s : strings) {
064          for(int i = 0; i < s.length(); i++) {
065            if (Character.isUpperCase(s.charAt(i))) {
066              return true;
067            }
068          }
069        }
070        return false;
071      }
072    
073      /** Rebuild the URI query with lower case parameter names. */
074      private static URI rebuildQuery(final URI uri,
075          final MultivaluedMap<String, String> parameters) {
076        UriBuilder b = UriBuilder.fromUri(uri).replaceQuery("");
077        for(Map.Entry<String, List<String>> e : parameters.entrySet()) {
078          final String key = e.getKey().toLowerCase();
079          for(String v : e.getValue()) {
080            b = b.queryParam(key, v);
081          }
082        }
083        return b.build();
084      }
085    }