001    /**
002     * Copyright (c) 2000-2013 Liferay, Inc. All rights reserved.
003     *
004     * This library is free software; you can redistribute it and/or modify it under
005     * the terms of the GNU Lesser General Public License as published by the Free
006     * Software Foundation; either version 2.1 of the License, or (at your option)
007     * any later version.
008     *
009     * This library is distributed in the hope that it will be useful, but WITHOUT
010     * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
011     * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
012     * details.
013     */
014    
015    package com.liferay.portal.servlet.filters.etag;
016    
017    import com.liferay.portal.kernel.servlet.RestrictedByteBufferCacheServletResponse;
018    import com.liferay.portal.kernel.util.ParamUtil;
019    import com.liferay.portal.servlet.filters.BasePortalFilter;
020    import com.liferay.portal.util.PropsValues;
021    
022    import java.nio.ByteBuffer;
023    
024    import javax.servlet.FilterChain;
025    import javax.servlet.http.HttpServletRequest;
026    import javax.servlet.http.HttpServletResponse;
027    
028    /**
029     * @author Eduardo Lundgren
030     * @author Brian Wing Shun Chan
031     * @author Raymond Aug??
032     * @author Shuyang Zhou
033     */
034    public class ETagFilter extends BasePortalFilter {
035    
036            public static final String SKIP_FILTER =
037                    ETagFilter.class.getName() + "SKIP_FILTER";
038    
039            @Override
040            public boolean isFilterEnabled(
041                    HttpServletRequest request, HttpServletResponse response) {
042    
043                    if (ParamUtil.getBoolean(request, _ETAG, true) &&
044                            !isAlreadyFiltered(request)) {
045    
046                            return true;
047                    }
048                    else {
049                            return false;
050                    }
051            }
052    
053            protected boolean isAlreadyFiltered(HttpServletRequest request) {
054                    if (request.getAttribute(SKIP_FILTER) != null) {
055                            return true;
056                    }
057                    else {
058                            return false;
059                    }
060            }
061    
062            protected boolean isEligibleForETag(int status) {
063                    if ((status >= HttpServletResponse.SC_OK) &&
064                            (status < HttpServletResponse.SC_MULTIPLE_CHOICES)) {
065    
066                            return true;
067                    }
068                    else {
069                            return false;
070                    }
071            }
072    
073            @Override
074            protected void processFilter(
075                            HttpServletRequest request, HttpServletResponse response,
076                            FilterChain filterChain)
077                    throws Exception {
078    
079                    request.setAttribute(SKIP_FILTER, Boolean.TRUE);
080    
081                    RestrictedByteBufferCacheServletResponse
082                            restrictedByteBufferCacheServletResponse =
083                                    new RestrictedByteBufferCacheServletResponse(
084                                            response, PropsValues.ETAG_RESPONSE_SIZE_MAX);
085    
086                    processFilter(
087                            ETagFilter.class, request, restrictedByteBufferCacheServletResponse,
088                            filterChain);
089    
090                    if (!restrictedByteBufferCacheServletResponse.isOverflowed()) {
091                            ByteBuffer byteBuffer =
092                                    restrictedByteBufferCacheServletResponse.getByteBuffer();
093    
094                            if (!isEligibleForETag(
095                                            restrictedByteBufferCacheServletResponse.getStatus()) ||
096                                    !ETagUtil.processETag(request, response, byteBuffer)) {
097    
098                                    restrictedByteBufferCacheServletResponse.finishResponse(false);
099    
100                                    restrictedByteBufferCacheServletResponse.flushCache();
101                            }
102                    }
103            }
104    
105            private static final String _ETAG = "etag";
106    
107    }