1 /*
2 * Copyright (C) 2013 4th Line GmbH, Switzerland
3 *
4 * The contents of this file are subject to the terms of either the GNU
5 * Lesser General Public License Version 2 or later ("LGPL") or the
6 * Common Development and Distribution License Version 1 or later
7 * ("CDDL") (collectively, the "License"). You may not use this file
8 * except in compliance with the License. See LICENSE.txt for more
9 * information.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
14 */
15
16 package org.fourthline.cling.transport.impl;
17
18 import org.fourthline.cling.model.UnsupportedDataException;
19 import org.fourthline.cling.model.XMLUtil;
20 import org.fourthline.cling.model.message.gena.IncomingEventRequestMessage;
21 import org.fourthline.cling.transport.spi.GENAEventProcessor;
22 import org.seamless.xml.XmlPullParserUtils;
23
24 import javax.enterprise.inject.Alternative;
25 import java.util.logging.Logger;
26 import java.util.regex.Matcher;
27 import java.util.regex.Pattern;
28
29
30 /**
31 * Implementation based on the <em>Xml Pull Parser</em> XML processing API.
32 * <p>
33 * This processor extends {@link PullGENAEventProcessorImpl}, it will always
34 * first try to read messages regularly with the superclass' methods before
35 * trying to recover from a failure.
36 * </p>
37 * <p>
38 * When the superclass can't read the message, this processor will try to
39 * recover from broken XML by for example, detecting wrongly encoded XML entities,
40 * and working around other vendor-specific bugs caused by incompatible UPnP
41 * stacks in the wild.
42 * </p>
43 * <p>
44 * This processor will also return partial results, if at least a single
45 * state variable value could be recovered from the (broken) event XML.
46 * </p>
47 *
48 * @author Michael Pujos
49 */
50 @Alternative
51 public class RecoveringGENAEventProcessorImpl extends PullGENAEventProcessorImpl {
52
53 private static Logger log = Logger.getLogger(GENAEventProcessor.class.getName());
54
55 public void readBody(IncomingEventRequestMessage requestMessage) throws UnsupportedDataException {
56 try {
57 super.readBody(requestMessage);
58 } catch (UnsupportedDataException ex) {
59
60 // Can't recover from this
61 if (!requestMessage.isBodyNonEmptyString())
62 throw ex;
63
64 log.warning("Trying to recover from invalid GENA XML event: " + ex);
65
66 // Some properties may have been read at this point, so reset the list
67 requestMessage.getStateVariableValues().clear();
68
69 String body = getMessageBody(requestMessage);
70
71 String fixedBody = fixXMLEncodedLastChange(
72 XmlPullParserUtils.fixXMLEntities(body)
73 );
74
75 try {
76 // Try again, if this fails, we are done...
77 requestMessage.setBody(fixedBody);
78 super.readBody(requestMessage);
79 } catch (UnsupportedDataException ex2) {
80 // Check if some properties were read
81 if (requestMessage.getStateVariableValues().isEmpty()) {
82 // Throw the initial exception containing unmodified XML
83 throw ex;
84 }
85 log.warning("Partial read of GENA event properties (probably due to truncated XML)");
86 }
87 }
88 }
89
90 protected String fixXMLEncodedLastChange(String xml) {
91 Pattern pattern = Pattern.compile("<LastChange>(.*)</LastChange>", Pattern.DOTALL);
92 Matcher matcher = pattern.matcher(xml);
93
94 if (matcher.find() && matcher.groupCount() == 1) {
95
96 String lastChange = matcher.group(1);
97
98 if (XmlPullParserUtils.isNullOrEmpty(lastChange))
99 return xml;
100
101 lastChange = lastChange.trim();
102
103 String fixedLastChange = lastChange;
104
105 if (lastChange.charAt(0) == '<') {
106 // TODO: UPNP VIOLATION: Orange Liveradio does not encode LastChange XML properly
107 fixedLastChange = XMLUtil.encodeText(fixedLastChange);
108 } else {
109 /* Doesn't work for Philips NP2900, there is complete garbage after the HTML
110 // TODO: UPNP VIOLATION: Philips NP2900 inserts garbage HTML, try to fix it
111 fixedLastChange = fixedLastChange.replaceAll("<", "");
112 fixedLastChange = fixedLastChange.replaceAll(">", "");
113 */
114 }
115
116 if (fixedLastChange.equals(lastChange)) {
117 return xml;
118 }
119
120 return "<?xml version=\"1.0\" encoding=\"utf-8\"?>" +
121 "<e:propertyset xmlns:e=\"urn:schemas-upnp-org:event-1-0\">" +
122 "<e:property>" +
123 "<LastChange>" +
124 fixedLastChange +
125 "</LastChange>" +
126 "</e:property>" +
127 "</e:propertyset>";
128 }
129 return xml;
130 }
131 }