summaryrefslogtreecommitdiff
path: root/plugins/OStatus/lib/discovery.php
blob: 7187c1f3e95ca122f704d52b4d92f6712e23dead (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
<?php
/**
 * StatusNet - the distributed open-source microblogging tool
 * Copyright (C) 2010, StatusNet, Inc.
 *
 * A sample module to show best practices for StatusNet plugins
 *
 * PHP version 5
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @package   StatusNet
 * @author    James Walker <james@status.net>
 * @copyright 2010 StatusNet, Inc.
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
 * @link      http://status.net/
 */

/**
 * This class implements LRDD-based service discovery based on the "Hammer Draft"
 * (including webfinger)
 *
 * @see http://groups.google.com/group/webfinger/browse_thread/thread/9f3d93a479e91bbf
 */
class Discovery
{

    const LRDD_REL = 'lrdd';
    const PROFILEPAGE = 'http://webfinger.net/rel/profile-page';
    const UPDATESFROM = 'http://schemas.google.com/g/2010#updates-from';
    const HCARD = 'http://microformats.org/profile/hcard';

    public $methods = array();

    public function __construct()
    {
        $this->registerMethod('Discovery_LRDD_Host_Meta');
        $this->registerMethod('Discovery_LRDD_Link_Header');
        $this->registerMethod('Discovery_LRDD_Link_HTML');
    }

    public function registerMethod($class)
    {
        $this->methods[] = $class;
    }

    /**
     * Given a "user id" make sure it's normalized to either a webfinger
     * acct: uri or a profile HTTP URL.
     */
    public static function normalize($user_id)
    {
        if (substr($user_id, 0, 5) == 'http:' ||
            substr($user_id, 0, 6) == 'https:' ||
            substr($user_id, 0, 5) == 'acct:') {
            return $user_id;
        }

        if (strpos($user_id, '@') !== FALSE) {
            return 'acct:' . $user_id;
        }

        return 'http://' . $user_id;
    }

    public static function isWebfinger($user_id)
    {
        $uri = Discovery::normalize($user_id);

        return (substr($uri, 0, 5) == 'acct:');
    }

    /**
     * This implements the actual lookup procedure
     */
    public function lookup($id)
    {
        // Normalize the incoming $id to make sure we have a uri
        $uri = $this->normalize($id);

        foreach ($this->methods as $class) {
            $links = call_user_func(array($class, 'discover'), $uri);
            if ($link = Discovery::getService($links, Discovery::LRDD_REL)) {
                // Load the LRDD XRD
                if (!empty($link['template'])) {
                    $xrd_uri = Discovery::applyTemplate($link['template'], $uri);
                } else {
                    $xrd_uri = $link['href'];
                }

                $xrd = $this->fetchXrd($xrd_uri);
                if ($xrd) {
                    return $xrd;
                }
            }
        }

        throw new Exception('Unable to find services for '. $id);
    }

    public static function getService($links, $service) {
        if (!is_array($links)) {
            return false;
        }

        foreach ($links as $link) {
            if ($link['rel'] == $service) {
                return $link;
            }
        }
    }

    public static function applyTemplate($template, $id)
    {
        $template = str_replace('{uri}', urlencode($id), $template);

        return $template;
    }

    public static function fetchXrd($url)
    {
        try {
            $client = new HTTPClient();
            $response = $client->get($url);
        } catch (HTTP_Request2_Exception $e) {
            return false;
        }

        if ($response->getStatus() != 200) {
            return false;
        }

        return XRD::parse($response->getBody());
    }
}

interface Discovery_LRDD
{
    public function discover($uri);
}

class Discovery_LRDD_Host_Meta implements Discovery_LRDD
{
    public function discover($uri)
    {
        if (Discovery::isWebfinger($uri)) {
            // We have a webfinger acct: - start with host-meta
            list($name, $domain) = explode('@', $uri);
        } else {
            $domain = parse_url($uri, PHP_URL_HOST);
        }
        
        $url = 'http://'. $domain .'/.well-known/host-meta';

        $xrd = Discovery::fetchXrd($url);

        if ($xrd) {
            if ($xrd->host != $domain) {
                return false;
            }

            return $xrd->links;
        }
    }
}

class Discovery_LRDD_Link_Header implements Discovery_LRDD
{
    public function discover($uri)
    {
        try {
            $client = new HTTPClient();
            $response = $client->get($uri);
        } catch (HTTP_Request2_Exception $e) {
            return false;
        }

        if ($response->getStatus() != 200) {
            return false;
        }

        $link_header = $response->getHeader('Link');
        if (!$link_header) {
            //            return false;
        }

        return array(Discovery_LRDD_Link_Header::parseHeader($link_header));
    }

    protected static function parseHeader($header)
    {
        $lh = new LinkHeader($header);

        return array('href' => $lh->href,
                     'rel'  => $lh->rel,
                     'type' => $lh->type);
    }
}

class Discovery_LRDD_Link_HTML implements Discovery_LRDD
{
    public function discover($uri)
    {
        try {
            $client = new HTTPClient();
            $response = $client->get($uri);
        } catch (HTTP_Request2_Exception $e) {
            return false;
        }

        if ($response->getStatus() != 200) {
            return false;
        }

        return Discovery_LRDD_Link_HTML::parse($response->getBody());
    }

    public function parse($html)
    {
        $links = array();

        preg_match('/<head(\s[^>]*)?>(.*?)<\/head>/is', $html, $head_matches);
        $head_html = $head_matches[2];

        preg_match_all('/<link\s[^>]*>/i', $head_html, $link_matches);

        foreach ($link_matches[0] as $link_html) {
            $link_url = null;
            $link_rel = null;
            $link_type = null;

            preg_match('/\srel=(("|\')([^\\2]*?)\\2|[^"\'\s]+)/i', $link_html, $rel_matches);
            if ( isset($rel_matches[3]) ) {
                $link_rel = $rel_matches[3];
            } else if ( isset($rel_matches[1]) ) {
                $link_rel = $rel_matches[1];
            }

            preg_match('/\shref=(("|\')([^\\2]*?)\\2|[^"\'\s]+)/i', $link_html, $href_matches);
            if ( isset($href_matches[3]) ) {
                $link_uri = $href_matches[3];
            } else if ( isset($href_matches[1]) ) {
                $link_uri = $href_matches[1];
            }

            preg_match('/\stype=(("|\')([^\\2]*?)\\2|[^"\'\s]+)/i', $link_html, $type_matches);
            if ( isset($type_matches[3]) ) {
                $link_type = $type_matches[3];
            } else if ( isset($type_matches[1]) ) {
                $link_type = $type_matches[1];
            }

            $links[] = array(
                'href' => $link_url,
                'rel' => $link_rel,
                'type' => $link_type,
            );
        }

        return $links;
    }
}