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+<?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 Auth_Yadis_ParseHTML()
+ {
+ $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));
+ }
+
+ /**
+ * Replace HTML entities (amp, lt, gt, and quot) as well as
+ * numeric entities (e.g. #x9f;) with their actual values and
+ * return the new string.
+ *
+ * @access private
+ * @param string $str The string in which to look for entities
+ * @return string $new_str The new string entities decoded
+ */
+ function replaceEntities($str)
+ {
+ foreach ($this->_entity_replacements as $old => $new) {
+ $str = preg_replace(sprintf("/&%s;/", $old), $new, $str);
+ }
+
+ // Replace numeric entities because html_entity_decode doesn't
+ // do it for us.
+ $str = preg_replace('~&#x([0-9a-f]+);~ei', 'chr(hexdec("\\1"))', $str);
+ $str = preg_replace('~&#([0-9]+);~e', 'chr(\\1)', $str);
+
+ return $str;
+ }
+
+ /**
+ * 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 = $this->replaceEntities(
+ $this->removeQuotes($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;
+ }
+}
+
+?> \ No newline at end of file