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.hbase.http;
019
020import java.io.IOException;
021import javax.servlet.Filter;
022import javax.servlet.FilterChain;
023import javax.servlet.FilterConfig;
024import javax.servlet.ServletException;
025import javax.servlet.ServletRequest;
026import javax.servlet.ServletResponse;
027import javax.servlet.http.HttpServletResponse;
028import org.apache.hadoop.hbase.HBaseInterfaceAudience;
029import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
030import org.apache.yetus.audience.InterfaceAudience;
031
032@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.CONFIG)
033public class NoCacheFilter implements Filter {
034
035  /**
036   * Constant for the configuration property that indicates no-store cache control is enabled.
037   */
038  public static final String NO_STORE = "no-store.enable";
039
040  private boolean noStoreEnabled = false;
041
042  @Override
043  public void init(FilterConfig filterConfig) throws ServletException {
044    this.noStoreEnabled = Boolean.valueOf(filterConfig.getInitParameter(NO_STORE));
045  }
046
047  @Override
048  public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
049    throws IOException, ServletException {
050    HttpServletResponse httpRes = (HttpServletResponse) res;
051    StringBuilder header = new StringBuilder("no-cache");
052    if (noStoreEnabled) {
053      header.append(", no-store, max-age=0");
054    }
055    httpRes.setHeader("Cache-Control", header.toString());
056    long now = EnvironmentEdgeManager.currentTime();
057    httpRes.addDateHeader("Expires", now);
058    httpRes.addDateHeader("Date", now);
059    httpRes.addHeader("Pragma", "no-cache");
060    chain.doFilter(req, res);
061  }
062
063  @Override
064  public void destroy() {
065  }
066}