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;
031
032/**
033 * A filter to change parameter names to lower cases
034 * so that parameter names are considered as case insensitive.
035 */
036public 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}