/*
 * 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.HBaseInterfaceAudience;
import org.apache.yetus.audience.InterfaceAudience;

@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.CONFIG)
public class GzipFilter implements Filter {
  private Set<String> mimeTypes = new HashSet<>();

  @Override
  public void init(FilterConfig filterConfig) {
    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).contains("gzip"))) {
      request = new GZIPRequestWrapper(request);
    }
    if (
      ((acceptEncoding != null) && (acceptEncoding.toLowerCase(Locale.ROOT).contains("gzip")))
        || ((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();
      }
    }
  }
}
