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//
// ========================================================================
// Copyright (c) 1995-2015 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package org.eclipse.jetty.servlets;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.eclipse.jetty.util.URIUtil;
/**
* <p>This servlet may be used to concatenate multiple resources into
* a single response.</p>
* <p>It is intended to be used to load multiple
* javascript or css files, but may be used for any content of the
* same mime type that can be meaningfully concatenated.</p>
* <p>The servlet uses {@link RequestDispatcher#include(javax.servlet.ServletRequest, javax.servlet.ServletResponse)}
* to combine the requested content, so dynamically generated content
* may be combined (Eg engine.js for DWR).</p>
* <p>The servlet uses parameter names of the query string as resource names
* relative to the context root. So these script tags:</p>
* <pre>
* <script type="text/javascript" src="../js/behaviour.js"></script>
* <script type="text/javascript" src="../js/ajax.js"></script>
* <script type="text/javascript" src="../chat/chat.js"></script>
* </pre>
* <p>can be replaced with the single tag (with the {@code ConcatServlet}
* mapped to {@code /concat}):</p>
* <pre>
* <script type="text/javascript" src="../concat?/js/behaviour.js&/js/ajax.js&/chat/chat.js"></script>
* </pre>
* <p>The {@link ServletContext#getMimeType(String)} method is used to determine the
* mime type of each resource. If the types of all resources do not match, then a 415
* UNSUPPORTED_MEDIA_TYPE error is returned.</p>
* <p>If the init parameter {@code development} is set to {@code true} then the servlet
* will run in development mode and the content will be concatenated on every request.</p>
* <p>Otherwise the init time of the servlet is used as the lastModifiedTime of the combined content
* and If-Modified-Since requests are handled with 304 NOT Modified responses if
* appropriate. This means that when not in development mode, the servlet must be
* restarted before changed content will be served.</p>
*/
public class ConcatServlet extends HttpServlet
{
private boolean _development;
private long _lastModified;
@Override
public void init() throws ServletException
{
_lastModified = System.currentTimeMillis();
_development = Boolean.parseBoolean(getInitParameter("development"));
}
/*
* @return The start time of the servlet unless in development mode, in which case -1 is returned.
*/
@Override
protected long getLastModified(HttpServletRequest req)
{
return _development ? -1 : _lastModified;
}
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
String query = request.getQueryString();
if (query == null)
{
response.sendError(HttpServletResponse.SC_NO_CONTENT);
return;
}
List<RequestDispatcher> dispatchers = new ArrayList<>();
String[] parts = query.split("\\&");
String type = null;
for (String part : parts)
{
String path = URIUtil.canonicalPath(URIUtil.decodePath(part));
if (path == null)
{
response.sendError(HttpServletResponse.SC_NOT_FOUND);
return;
}
// Verify that the path is not protected.
if (startsWith(path, "/WEB-INF/") || startsWith(path, "/META-INF/"))
{
response.sendError(HttpServletResponse.SC_NOT_FOUND);
return;
}
String t = getServletContext().getMimeType(path);
if (t != null)
{
if (type == null)
{
type = t;
}
else if (!type.equals(t))
{
response.sendError(HttpServletResponse.SC_UNSUPPORTED_MEDIA_TYPE);
return;
}
}
RequestDispatcher dispatcher = getServletContext().getRequestDispatcher(path);
if (dispatcher != null)
dispatchers.add(dispatcher);
}
if (type != null)
response.setContentType(type);
for (RequestDispatcher dispatcher : dispatchers)
dispatcher.include(request, response);
}
private boolean startsWith(String path, String prefix)
{
// Case insensitive match.
return prefix.regionMatches(true, 0, path, 0, prefix.length());
}
}
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