/*
* Copyright 2010 Xemantic
*
* Licensed 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 com.xemantic.tadedon.servlet;
import java.io.IOException;
import java.util.Date;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet applying "never cache" HTTP headers.
* <p>
* See:
* <ul>
* <li><a href="http://code.google.com/p/doctype/wiki/ArticleHttpCaching">ArticleHttpCaching</a></li>
* <li><a href="http://seewah.blogspot.com/2009/02/gwt-tips-2-nocachejs-getting-cached-in.html">GWT Tips 2 - nocache.js getting cached in browser</a></li>
* </ul>
* <p>
* Created on Aug 6, 2010
*
* @author hshsce
*/
public class CacheDisablingFilter extends SimpleFilter {
private static final long ONE_DAY_IN_MILISECONDS = (1000L * 60L * 60L * 24L);
/** {@inheritDoc} */
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
if (response instanceof HttpServletResponse) {
HttpServletResponse httpResponse = (HttpServletResponse) response;
Date now = new Date();
httpResponse.setDateHeader("Date", now.getTime());
httpResponse.setDateHeader("Expires", now.getTime() + ONE_DAY_IN_MILISECONDS);
httpResponse.setHeader("Pragma", "no-cache");
httpResponse.setHeader("Cache-control", "no-cache, no-store, must-revalidate");
}
chain.doFilter(request, response);
}
}