summaryrefslogtreecommitdiff
blob: e0e9043c4546c23a9d7fbf8e09f15c8d2d95b382 (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
<?php

/**
 * This is the HTML pseudo-parser for the Yadis library.
 *
 * PHP versions 4 and 5
 *
 * LICENSE: See the COPYING file included in this distribution.
 *
 * @package OpenID
 * @author JanRain, Inc. <openid@janrain.com>
 * @copyright 2005-2008 Janrain, Inc.
 * @license http://www.apache.org/licenses/LICENSE-2.0 Apache
 */

/**
 * This class is responsible for scanning an HTML string to find META
 * tags and their attributes.  This is used by the Yadis discovery
 * process.  This class must be instantiated to be used.
 *
 * @package OpenID
 */
class Auth_Yadis_ParseHTML {

    /**
     * @access private
     */
    var $_re_flags = "si";

    /**
     * @access private
     */
    var $_removed_re =
           "<!--.*?-->|<!\[CDATA\[.*?\]\]>|<script\b(?!:)[^>]*>.*?<\/script>";

    /**
     * @access private
     */
    var $_tag_expr = "<%s%s(?:\s.*?)?%s>";

    /**
     * @access private
     */
    var $_attr_find = '\b([-\w]+)=(".*?"|\'.*?\'|.+?)[\/\s>]';

    function __construct()
    {
        $this->_attr_find = sprintf("/%s/%s",
                                    $this->_attr_find,
                                    $this->_re_flags);

        $this->_removed_re = sprintf("/%s/%s",
                                     $this->_removed_re,
                                     $this->_re_flags);

        $this->_entity_replacements = array(
                                            'amp' => '&',
                                            'lt' => '<',
                                            'gt' => '>',
                                            'quot' => '"'
                                            );

        $this->_ent_replace =
            sprintf("&(%s);", implode("|",
                                      $this->_entity_replacements));
    }

    /**
     * Strip single and double quotes off of a string, if they are
     * present.
     *
     * @access private
     * @param string $str The original string
     * @return string $new_str The new string with leading and
     * trailing quotes removed
     */
    function removeQuotes($str)
    {
        $matches = array();
        $double = '/^"(.*)"$/';
        $single = "/^\'(.*)\'$/";

        if (preg_match($double, $str, $matches)) {
            return $matches[1];
        } else if (preg_match($single, $str, $matches)) {
            return $matches[1];
        } else {
            return $str;
        }
    }

    /**
     * Create a regular expression that will match an opening 
     * or closing tag from a set of names.
     *
     * @access private
     * @param mixed $tag_names Tag names to match
     * @param mixed $close false/0 = no, true/1 = yes, other = maybe
     * @param mixed $self_close false/0 = no, true/1 = yes, other = maybe
     * @return string $regex A regular expression string to be used
     * in, say, preg_match.
     */
    function tagPattern($tag_names, $close, $self_close)
    {
        if (is_array($tag_names)) {
            $tag_names = '(?:'.implode('|',$tag_names).')';
        }
        if ($close) {
            $close = '\/' . (($close == 1)? '' : '?');
        } else {
            $close = '';
        }
        if ($self_close) {
            $self_close = '(?:\/\s*)' . (($self_close == 1)? '' : '?');
        } else {
            $self_close = '';
        }
        $expr = sprintf($this->_tag_expr, $close, $tag_names, $self_close);

        return sprintf("/%s/%s", $expr, $this->_re_flags);
    }

    /**
     * Given an HTML document string, this finds all the META tags in
     * the document, provided they are found in the
     * <HTML><HEAD>...</HEAD> section of the document.  The <HTML> tag
     * may be missing.
     *
     * @access private
     * @param string $html_string An HTMl document string
     * @return array $tag_list Array of tags; each tag is an array of
     * attribute -> value.
     */
    function getMetaTags($html_string)
    {
        $html_string = preg_replace($this->_removed_re,
                                    "",
                                    $html_string);

        $key_tags = array($this->tagPattern('html', false, false),
                          $this->tagPattern('head', false, false),
                          $this->tagPattern('head', true, false),
                          $this->tagPattern('html', true, false),
                          $this->tagPattern(array(
                          'body', 'frameset', 'frame', 'p', 'div',
                          'table','span','a'), 'maybe', 'maybe'));
        $key_tags_pos = array();
        foreach ($key_tags as $pat) {
            $matches = array();
            preg_match($pat, $html_string, $matches, PREG_OFFSET_CAPTURE);
            if($matches) {
                $key_tags_pos[] = $matches[0][1];
            } else {
                $key_tags_pos[] = null;
            }
        }
        // no opening head tag
        if (is_null($key_tags_pos[1])) {
            return array();
        }
        // the effective </head> is the min of the following
        if (is_null($key_tags_pos[2])) {
            $key_tags_pos[2] = strlen($html_string);
        }
        foreach (array($key_tags_pos[3], $key_tags_pos[4]) as $pos) {
            if (!is_null($pos) && $pos < $key_tags_pos[2]) {
                $key_tags_pos[2] = $pos;
            }
        }
        // closing head tag comes before opening head tag
        if ($key_tags_pos[1] > $key_tags_pos[2]) {
            return array();
        }
        // if there is an opening html tag, make sure the opening head tag
        // comes after it
        if (!is_null($key_tags_pos[0]) && $key_tags_pos[1] < $key_tags_pos[0]) {
            return array();
        }
        $html_string = substr($html_string, $key_tags_pos[1],
                              ($key_tags_pos[2]-$key_tags_pos[1]));

        $link_data = array();
        $link_matches = array();
        
        if (!preg_match_all($this->tagPattern('meta', false, 'maybe'),
                            $html_string, $link_matches)) {
            return array();
        }

        foreach ($link_matches[0] as $link) {
            $attr_matches = array();
            preg_match_all($this->_attr_find, $link, $attr_matches);
            $link_attrs = array();
            foreach ($attr_matches[0] as $index => $full_match) {
                $name = $attr_matches[1][$index];
                $value = html_entity_decode(
                              $this->removeQuotes($attr_matches[2][$index]));

                $link_attrs[strtolower($name)] = $value;
            }
            $link_data[] = $link_attrs;
        }

        return $link_data;
    }

    /**
     * Looks for a META tag with an "http-equiv" attribute whose value
     * is one of ("x-xrds-location", "x-yadis-location"), ignoring
     * case.  If such a META tag is found, its "content" attribute
     * value is returned.
     *
     * @param string $html_string An HTML document in string format
     * @return mixed $content The "content" attribute value of the
     * META tag, if found, or null if no such tag was found.
     */
    function getHTTPEquiv($html_string)
    {
        $meta_tags = $this->getMetaTags($html_string);

        if ($meta_tags) {
            foreach ($meta_tags as $tag) {
                if (array_key_exists('http-equiv', $tag) &&
                    (in_array(strtolower($tag['http-equiv']),
                              array('x-xrds-location', 'x-yadis-location'))) &&
                    array_key_exists('content', $tag)) {
                    return $tag['content'];
                }
            }
        }

        return null;
    }
}