1 /*
2 * Copyright (C) 2015, Google Inc.
3 * and other copyright owners as documented in the project's IP log.
4 *
5 * This program and the accompanying materials are made available
6 * under the terms of the Eclipse Distribution License v1.0 which
7 * accompanies this distribution, is reproduced below, and is
8 * available at http://www.eclipse.org/org/documents/edl-v10.php
9 *
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or
13 * without modification, are permitted provided that the following
14 * conditions are met:
15 *
16 * - Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
23 *
24 * - Neither the name of the Eclipse Foundation, Inc. nor the
25 * names of its contributors may be used to endorse or promote
26 * products derived from this software without specific prior
27 * written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 */
43
44 package org.eclipse.jgit.transport;
45
46 import static org.eclipse.jgit.transport.GitProtocolConstants.OPTION_AGENT;
47
48 import java.util.Set;
49
50 import org.eclipse.jgit.util.StringUtils;
51
52 /**
53 * User agent to be reported by this JGit client and server on the network.
54 * <p>
55 * On HTTP transports this user agent string is always supplied by the JGit
56 * client in the {@code User-Agent} HTTP header.
57 * <p>
58 * On native transports this user agent string is always sent when JGit is a
59 * server. When JGit is a client the user agent string will be supplied to the
60 * remote server only if the remote server advertises its own agent identity.
61 *
62 * @since 4.0
63 */
64 public class UserAgent {
65 private static volatile String userAgent = computeUserAgent();
66
67 private static String computeUserAgent() {
68 return clean("JGit/" + computeVersion()); //$NON-NLS-1$
69 }
70
71 private static String computeVersion() {
72 Package pkg = UserAgent.class.getPackage();
73 if (pkg != null) {
74 String ver = pkg.getImplementationVersion();
75 if (!StringUtils.isEmptyOrNull(ver)) {
76 return ver;
77 }
78 }
79 return "unknown"; //$NON-NLS-1$
80 }
81
82 private static String clean(String s) {
83 s = s.trim();
84 StringBuilder b = new StringBuilder(s.length());
85 for (int i = 0; i < s.length(); i++) {
86 char c = s.charAt(i);
87 if (c <= 32 || c >= 127) {
88 if (b.length() > 0 && b.charAt(b.length() - 1) == '.')
89 continue;
90 c = '.';
91 }
92 b.append(c);
93 }
94 return b.length() > 0 ? b.toString() : null;
95 }
96
97 /**
98 * Get the user agent string advertised by JGit.
99 *
100 * @return a string similar to {@code "JGit/4.0"}; null if the agent has
101 * been cleared and should not be shared with a peer.
102 */
103 public static String get() {
104 return userAgent;
105 }
106
107 /**
108 * Change the user agent string advertised by JGit.
109 * <p>
110 * The new string should start with {@code "JGit/"} (for example
111 * {@code "JGit/4.0"}) to advertise the implementation as JGit based.
112 * <p>
113 * Spaces and other whitespace should be avoided as these will be
114 * automatically converted to {@code "."}.
115 * <p>
116 * User agent strings are restricted to printable ASCII.
117 *
118 * @param agent
119 * new user agent string for this running JGit library. Setting
120 * to null or empty string will avoid sending any identification
121 * to the peer.
122 */
123 public static void set(String agent) {
124 userAgent = StringUtils.isEmptyOrNull(agent) ? null : clean(agent);
125 }
126
127 static String getAgent(Set<String> options, String transportAgent) {
128 if (options == null || options.isEmpty()) {
129 return transportAgent;
130 }
131 for (String o : options) {
132 if (o.startsWith(OPTION_AGENT)
133 && o.length() > OPTION_AGENT.length()
134 && o.charAt(OPTION_AGENT.length()) == '=') {
135 return o.substring(OPTION_AGENT.length() + 1);
136 }
137 }
138 return transportAgent;
139 }
140
141 static boolean hasAgent(Set<String> options) {
142 return getAgent(options, null) != null;
143 }
144
145 private UserAgent() {
146 }
147 }