/*
    *
    * 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.hadoop.hbase.rest.filter;
  
  import java.io.IOException;
  import java.io.OutputStream;
  import java.util.HashSet;
  import java.util.Locale;
  import java.util.Set;
  import java.util.StringTokenizer;
  
  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;
  import javax.servlet.http.HttpServletResponse;
  
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.HBaseInterfaceAudience;
  
  @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.CONFIG)
  public class GzipFilter implements Filter {
    private Set<String> mimeTypes = new HashSet<String>();
  
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
      String s = filterConfig.getInitParameter("mimeTypes");
      if (s != null) {
        StringTokenizer tok = new StringTokenizer(s, ",", false);
        while (tok.hasMoreTokens()) {
          mimeTypes.add(tok.nextToken());
        }
      }
    }
  
    @Override
    public void destroy() {
    }
  
    @Override
    public void doFilter(ServletRequest req, ServletResponse rsp,
        FilterChain chain) throws IOException, ServletException {
      HttpServletRequest request = (HttpServletRequest)req;
      HttpServletResponse response = (HttpServletResponse)rsp;
      String contentEncoding = request.getHeader("content-encoding");
      String acceptEncoding = request.getHeader("accept-encoding");
      String contentType = request.getHeader("content-type");
      if ((contentEncoding != null) &&
          (contentEncoding.toLowerCase(Locale.ROOT).indexOf("gzip") > -1)) {
        request = new GZIPRequestWrapper(request);
      }
      if (((acceptEncoding != null) &&
            (acceptEncoding.toLowerCase(Locale.ROOT).indexOf("gzip") > -1)) ||
          ((contentType != null) && mimeTypes.contains(contentType))) {
        response = new GZIPResponseWrapper(response);
      }
      chain.doFilter(request, response);
      if (response instanceof GZIPResponseWrapper) {
        OutputStream os = response.getOutputStream();
        if (os instanceof GZIPResponseStream) {
          ((GZIPResponseStream)os).finish();
        }
      }
    }
  
  }