View Javadoc
1   /**
2    * This file Copyright (c) 2015-2018 Magnolia International
3    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
4    *
5    *
6    * This file is dual-licensed under both the Magnolia
7    * Network Agreement and the GNU General Public License.
8    * You may elect to use one or the other of these licenses.
9    *
10   * This file is distributed in the hope that it will be
11   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
12   * implied warranty of MERCHANTABILITY or FITNESS FOR A
13   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
14   * Redistribution, except as permitted by whichever of the GPL
15   * or MNA you select, is prohibited.
16   *
17   * 1. For the GPL license (GPL), you can redistribute and/or
18   * modify this file under the terms of the GNU General
19   * Public License, Version 3, as published by the Free Software
20   * Foundation.  You should have received a copy of the GNU
21   * General Public License, Version 3 along with this program;
22   * if not, write to the Free Software Foundation, Inc., 51
23   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
24   *
25   * 2. For the Magnolia Network Agreement (MNA), this file
26   * and the accompanying materials are made available under the
27   * terms of the MNA which accompanies this distribution, and
28   * is available at http://www.magnolia-cms.com/mna.html
29   *
30   * Any modifications to this file must keep this entire header
31   * intact.
32   *
33   */
34  package info.magnolia.module.ui;
35  
36  import info.magnolia.cms.util.ClasspathResourcesUtil;
37  
38  import java.io.IOException;
39  import java.io.InputStream;
40  
41  import javax.servlet.ServletOutputStream;
42  import javax.servlet.http.HttpServlet;
43  import javax.servlet.http.HttpServletRequest;
44  import javax.servlet.http.HttpServletResponse;
45  
46  import org.apache.commons.io.IOUtils;
47  import org.slf4j.Logger;
48  import org.slf4j.LoggerFactory;
49  
50  /**
51   * This is a _very_ primitive servlet that serves resources off of the classpath. It does absolutely no error checking
52   * or anything of the sort - it is expected we are in control of the install web resources and as such need no help.
53   * *Do not use this servlet in any other context than Magnolia's installation UI !*
54   */
55  public class InstallationResourcesServlet extends HttpServlet {
56      private final static Logger log = LoggerFactory.getLogger(InstallationResourcesServlet.class);
57      private final long constructionTimestamp;
58  
59      public InstallationResourcesServlet() {
60          constructionTimestamp = System.currentTimeMillis();
61      }
62  
63      @Override
64      protected long getLastModified(HttpServletRequest req) {
65          // All requests will have the same Last-Modified for the lifetime of the servlet.
66          // It's safe to assume a restart of the server could mean the resources have changed, but we don't need anything
67          // more specific than that, and we can thus rely on the default service() implementation.
68          return constructionTimestamp;
69      }
70  
71      @Override
72      public void doGet(HttpServletRequest req, HttpServletResponse res) throws IOException {
73          final String resourcePath = req.getPathInfo();
74          try (final InputStream in = ClasspathResourcesUtil.getStream(resourcePath);
75               final ServletOutputStream out = res.getOutputStream()) {
76              if (resourcePath.endsWith("svg")) {
77                  res.setContentType("image/svg+xml");
78              }
79              if (in == null) {
80                  throw new IllegalStateException("No resource found at " + resourcePath);
81              }
82              IOUtils.copy(in, out);
83              out.flush();
84          } catch (IOException e) {
85              // only log at debug level
86              // tomcat usually throws a ClientAbortException anytime the user stop loading the page
87              log.debug("Unable to spool resource due to {}", e, e);
88              if (!res.isCommitted()) {
89                  res.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
90              }
91          }
92      }
93  
94  }