com.twelvemonkeys.servlet.cache.CacheResponseWrapper Maven / Gradle / Ivy
/*
* Copyright (c) 2008, Harald Kuhr
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name "TwelveMonkeys" nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.twelvemonkeys.servlet.cache;
import com.twelvemonkeys.lang.StringUtil;
import com.twelvemonkeys.net.NetUtil;
import com.twelvemonkeys.servlet.ServletResponseStreamDelegate;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponseWrapper;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
/**
* CacheResponseWrapper class description.
*
* Based on ideas and code found in the ONJava article
* Two
* Servlet Filters Every Web Application Should Have
* by Jayson Falkner.
*
* @author Jayson Falkner
* @author Harald Kuhr
* @author last modified by $Author: haku $
* @version $Id: //depot/branches/personal/haraldk/twelvemonkeys/release-2/twelvemonkeys-servlet/src/main/java/com/twelvemonkeys/servlet/cache/CacheResponseWrapper.java#3 $
*/
class CacheResponseWrapper extends HttpServletResponseWrapper {
private ServletResponseStreamDelegate mStreamDelegate;
private CacheResponse mResponse;
private CachedEntity mCached;
private WritableCachedResponse mCachedResponse;
private Boolean mCachable;
private int mStatus;
public CacheResponseWrapper(final ServletCacheResponse pResponse, final CachedEntity pCached) {
super(pResponse.getResponse());
mResponse = pResponse;
mCached = pCached;
init();
}
/*
NOTE: This class defers determining if a response is cachable until the
output stream is needed.
This it the reason for the somewhat complicated logic in the add/setHeader
methods below.
*/
private void init() {
mCachable = null;
mStatus = SC_OK;
mCachedResponse = mCached.createCachedResponse();
mStreamDelegate = new ServletResponseStreamDelegate(this) {
protected OutputStream createOutputStream() throws IOException {
// Test if this request is really cachable, otherwise,
// just write through to underlying response, and don't cache
if (isCachable()) {
return mCachedResponse.getOutputStream();
}
else {
mCachedResponse.setStatus(mStatus);
mCachedResponse.writeHeadersTo(CacheResponseWrapper.this.mResponse);
return super.getOutputStream();
}
}
};
}
CachedResponse getCachedResponse() {
return mCachedResponse.getCachedResponse();
}
public boolean isCachable() {
// NOTE: Intentionally not synchronized
if (mCachable == null) {
mCachable = isCachableImpl();
}
return mCachable;
}
private boolean isCachableImpl() {
if (mStatus != SC_OK) {
return false;
}
// Vary: *
String[] values = mCachedResponse.getHeaderValues(HTTPCache.HEADER_VARY);
if (values != null) {
for (String value : values) {
if ("*".equals(value)) {
return false;
}
}
}
// Cache-Control: no-cache, no-store, must-revalidate
values = mCachedResponse.getHeaderValues(HTTPCache.HEADER_CACHE_CONTROL);
if (values != null) {
for (String value : values) {
if (StringUtil.contains(value, "no-cache")
|| StringUtil.contains(value, "no-store")
|| StringUtil.contains(value, "must-revalidate")) {
return false;
}
}
}
// Pragma: no-cache
values = mCachedResponse.getHeaderValues(HTTPCache.HEADER_PRAGMA);
if (values != null) {
for (String value : values) {
if (StringUtil.contains(value, "no-cache")) {
return false;
}
}
}
return true;
}
public void flushBuffer() throws IOException {
mStreamDelegate.flushBuffer();
}
public void resetBuffer() {
// Servlet 2.3
mStreamDelegate.resetBuffer();
}
public void reset() {
if (Boolean.FALSE.equals(mCachable)) {
super.reset();
}
// No else, might be cachable after all..
init();
}
public ServletOutputStream getOutputStream() throws IOException {
return mStreamDelegate.getOutputStream();
}
public PrintWriter getWriter() throws IOException {
return mStreamDelegate.getWriter();
}
public boolean containsHeader(String name) {
return mCachedResponse.getHeaderValues(name) != null;
}
public void sendError(int pStatusCode, String msg) throws IOException {
// NOT cachable
mStatus = pStatusCode;
super.sendError(pStatusCode, msg);
}
public void sendError(int pStatusCode) throws IOException {
// NOT cachable
mStatus = pStatusCode;
super.sendError(pStatusCode);
}
public void setStatus(int pStatusCode, String sm) {
// NOTE: This method is deprecated
setStatus(pStatusCode);
}
public void setStatus(int pStatusCode) {
// NOT cachable unless pStatusCode == 200 (or a FEW others?)
if (pStatusCode != SC_OK) {
mStatus = pStatusCode;
super.setStatus(pStatusCode);
}
}
public void sendRedirect(String pLocation) throws IOException {
// NOT cachable
mStatus = SC_MOVED_TEMPORARILY;
super.sendRedirect(pLocation);
}
public void setDateHeader(String pName, long pValue) {
// If in write-trough-mode, set headers directly
if (Boolean.FALSE.equals(mCachable)) {
super.setDateHeader(pName, pValue);
}
mCachedResponse.setHeader(pName, NetUtil.formatHTTPDate(pValue));
}
public void addDateHeader(String pName, long pValue) {
// If in write-trough-mode, set headers directly
if (Boolean.FALSE.equals(mCachable)) {
super.addDateHeader(pName, pValue);
}
mCachedResponse.addHeader(pName, NetUtil.formatHTTPDate(pValue));
}
public void setHeader(String pName, String pValue) {
// If in write-trough-mode, set headers directly
if (Boolean.FALSE.equals(mCachable)) {
super.setHeader(pName, pValue);
}
mCachedResponse.setHeader(pName, pValue);
}
public void addHeader(String pName, String pValue) {
// If in write-trough-mode, set headers directly
if (Boolean.FALSE.equals(mCachable)) {
super.addHeader(pName, pValue);
}
mCachedResponse.addHeader(pName, pValue);
}
public void setIntHeader(String pName, int pValue) {
// If in write-trough-mode, set headers directly
if (Boolean.FALSE.equals(mCachable)) {
super.setIntHeader(pName, pValue);
}
mCachedResponse.setHeader(pName, String.valueOf(pValue));
}
public void addIntHeader(String pName, int pValue) {
// If in write-trough-mode, set headers directly
if (Boolean.FALSE.equals(mCachable)) {
super.addIntHeader(pName, pValue);
}
mCachedResponse.addHeader(pName, String.valueOf(pValue));
}
public final void setContentType(String type) {
setHeader(HTTPCache.HEADER_CONTENT_TYPE, type);
}
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