001//========================================================================
002//Copyright 2006 Mort Bay Consulting Pty. Ltd.
003//------------------------------------------------------------------------
004//Licensed under the Apache License, Version 2.0 (the "License");
005//you may not use this file except in compliance with the License.
006//You may obtain a copy of the License at
007//http://www.apache.org/licenses/LICENSE-2.0
008//Unless required by applicable law or agreed to in writing, software
009//distributed under the License is distributed on an "AS IS" BASIS,
010//WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
011//See the License for the specific language governing permissions and
012//limitations under the License.
013//========================================================================
014
015package org.apache.activemq.web;
016
017import java.io.ByteArrayOutputStream;
018import java.io.IOException;
019import java.io.InputStream;
020import java.net.URL;
021import java.util.HashMap;
022import java.util.Map;
023
024import javax.servlet.ServletException;
025import javax.servlet.http.HttpServletRequest;
026import javax.servlet.http.HttpServletResponse;
027
028/* ------------------------------------------------------------ */
029/**
030 * AjaxServlet. The AjaxServlet extends the {@link MessageListenerServlet} with
031 * the capability to server the <code>amq.js</code> script and associated
032 * scripts from resources within the activemq-web jar. The amq.js script is the
033 * client side companion to the MessageListenerServlet and supports sending
034 * messages and long polling for receiving messages (Also called Comet style
035 * Ajax).
036 */
037public class AjaxServlet extends MessageListenerServlet {
038
039    private static final long serialVersionUID = -3875280764356406114L;
040    private Map<String, byte[]> jsCache = new HashMap<String, byte[]>();
041    private long jsLastModified = 1000 * (System.currentTimeMillis() / 1000);
042
043    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
044        if (request.getPathInfo() != null && request.getPathInfo().endsWith(".js")) {
045            doJavaScript(request, response);
046        } else {
047            super.doGet(request, response);
048        }
049    }
050
051    protected void doJavaScript(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
052
053        // Look for a local resource first.
054        String js = request.getServletPath() + request.getPathInfo();
055        URL url = getServletContext().getResource(js);
056        if (url != null) {
057            getServletContext().getNamedDispatcher("default").forward(request, response);
058            return;
059        }
060
061        // Serve from the classpath resources
062        String resource = "org/apache/activemq/web" + request.getPathInfo();
063        synchronized (jsCache) {
064
065            byte[] data = jsCache.get(resource);
066            if (data == null) {
067                try(InputStream in = Thread.currentThread().getContextClassLoader().getResourceAsStream(resource)) {
068                    if (in != null) {
069                        try(ByteArrayOutputStream out = new ByteArrayOutputStream()) {
070                            byte[] buf = new byte[4096];
071                            int len = in.read(buf);
072                            while (len >= 0) {
073                                out.write(buf, 0, len);
074                                len = in.read(buf);
075                            }
076                            data = out.toByteArray();
077                            jsCache.put(resource, data);
078                        }
079                    }
080                }
081            }
082
083            if (data != null) {
084
085                long ifModified = request.getDateHeader("If-Modified-Since");
086
087                if (ifModified == jsLastModified) {
088                    response.sendError(HttpServletResponse.SC_NOT_MODIFIED);
089                } else {
090                    response.setContentType("application/x-javascript");
091                    response.setContentLength(data.length);
092                    response.setDateHeader("Last-Modified", jsLastModified);
093                    response.getOutputStream().write(data);
094                }
095            } else {
096                response.sendError(HttpServletResponse.SC_NOT_FOUND);
097            }
098        }
099    }
100}