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 */
018package org.apache.hadoop.hdfs.web;
019
020import java.net.URI;
021import java.util.List;
022import java.util.Map;
023
024import javax.ws.rs.core.MultivaluedMap;
025import javax.ws.rs.core.UriBuilder;
026
027import com.sun.jersey.spi.container.ContainerRequest;
028import com.sun.jersey.spi.container.ContainerRequestFilter;
029import com.sun.jersey.spi.container.ContainerResponseFilter;
030import com.sun.jersey.spi.container.ResourceFilter;
031import org.apache.hadoop.util.StringUtils;
032
033/**
034 * A filter to change parameter names to lower cases
035 * so that parameter names are considered as case insensitive.
036 */
037public class ParamFilter implements ResourceFilter {
038  private static final ContainerRequestFilter LOWER_CASE
039      = new ContainerRequestFilter() {
040    @Override
041    public ContainerRequest filter(final ContainerRequest request) {
042      final MultivaluedMap<String, String> parameters = request.getQueryParameters();
043      if (containsUpperCase(parameters.keySet())) {
044        //rebuild URI
045        final URI lower = rebuildQuery(request.getRequestUri(), parameters);
046        request.setUris(request.getBaseUri(), lower);
047      }
048      return request;
049    }
050  };
051
052  @Override
053  public ContainerRequestFilter getRequestFilter() {
054    return LOWER_CASE;
055  }
056
057  @Override
058  public ContainerResponseFilter getResponseFilter() {
059    return null;
060  }
061
062  /** Do the strings contain upper case letters? */
063  static boolean containsUpperCase(final Iterable<String> strings) {
064    for(String s : strings) {
065      for(int i = 0; i < s.length(); i++) {
066        if (Character.isUpperCase(s.charAt(i))) {
067          return true;
068        }
069      }
070    }
071    return false;
072  }
073
074  /** Rebuild the URI query with lower case parameter names. */
075  private static URI rebuildQuery(final URI uri,
076      final MultivaluedMap<String, String> parameters) {
077    UriBuilder b = UriBuilder.fromUri(uri).replaceQuery("");
078    for(Map.Entry<String, List<String>> e : parameters.entrySet()) {
079      final String key = StringUtils.toLowerCase(e.getKey());
080      for(String v : e.getValue()) {
081        b = b.queryParam(key, v);
082      }
083    }
084    return b.build();
085  }
086}