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Diffstat (limited to 'Services/Yadis/ParseHTML.php')
| -rw-r--r-- | Services/Yadis/ParseHTML.php | 270 |
1 files changed, 270 insertions, 0 deletions
diff --git a/Services/Yadis/ParseHTML.php b/Services/Yadis/ParseHTML.php new file mode 100644 index 0000000..fc0df17 --- /dev/null +++ b/Services/Yadis/ParseHTML.php @@ -0,0 +1,270 @@ +<?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 Yadis + * @author JanRain, Inc. <openid@janrain.com> + * @copyright 2005 Janrain, Inc. + * @license http://www.gnu.org/copyleft/lesser.html LGPL + */ + +/** + * 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 Yadis + */ +class Services_Yadis_ParseHTML { + + /** + * @access private + */ + var $_re_flags = "si"; + + /** + * @access private + */ + var $_tag_expr = "<%s\b(?!:)([^>]*?)(?:\/>|>(.*?)(?:<\/?%s\s*>|\Z))"; + + /** + * @access private + */ + var $_close_tag_expr = "<\/?%s\s*>"; + + /** + * @access private + */ + var $_removed_re = + "<!--.*?-->|<!\[CDATA\[.*?\]\]>|<script\b(?!:)[^>]*>.*?<\/script>"; + + /** + * @access private + */ + var $_attr_find = '\b([-\w]+)=("[^"]*"|\'[^\']*\'|[^\'"\s\/<>]+)'; + + function Services_Yadis_ParseHTML() + { + $this->_meta_find = sprintf("/<meta\b(?!:)([^>]*)(?!<)>/%s", + $this->_re_flags); + + $this->_removed_re = sprintf("/%s/%s", + $this->_removed_re, + $this->_re_flags); + + $this->_attr_find = sprintf("/%s/%s", + $this->_attr_find, + $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 (and + * optional) closing tag of a given name. + * + * @access private + * @param string $tag_name The tag name to match + * @param array $close_tags An array of tag names which also + * constitute closing of the original tag + * @return string $regex A regular expression string to be used + * in, say, preg_match. + */ + function tagMatcher($tag_name, $close_tags = null) + { + if ($close_tags) { + $options = implode("|", array_merge(array($tag_name), $close_tags)); + $closer = sprintf("(?:%s)", $options); + } else { + $closer = $tag_name; + } + + $expr = sprintf($this->_tag_expr, $tag_name, $closer); + return sprintf("/%s/%s", $expr, $this->_re_flags); + } + + /** + * @access private + */ + function htmlFind($str) + { + return $this->tagMatcher('html', array('body')); + } + + /** + * @access private + */ + function headFind() + { + return $this->tagMatcher('head', array('body')); + } + + /** + * 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) + { + $stripped = preg_replace($this->_removed_re, + "", + $html_string); + + // Look for the closing body tag. + $body_closer = sprintf($this->_close_tag_expr, 'body'); + $body_matches = array(); + preg_match($body_closer, $html_string, $body_matches, + PREG_OFFSET_CAPTURE); + if ($body_matches) { + $html_string = substr($html_string, 0, $body_matches[0][1]); + } + + // Look for the opening body tag, and discard everything after + // that tag. + $body_re = $this->tagMatcher('body'); + $body_matches = array(); + preg_match($body_re, $html_string, $body_matches, PREG_OFFSET_CAPTURE); + if ($body_matches) { + $html_string = substr($html_string, 0, $body_matches[0][1]); + } + + // If an HTML tag is found at all, it must be in the right + // order; else, it may be missing (which is a case we allow + // for). + $html_re = $this->tagMatcher('html', array('body')); + preg_match($html_re, $html_string, $html_matches); + if ($html_matches) { + $html = $html_matches[0]; + } else { + $html = $html_string; + } + + // Try to find the <HEAD> tag. + $head_re = $this->headFind(); + $head_matches = array(); + if (!preg_match($head_re, $html, $head_matches)) { + return array(); + } + + $link_data = array(); + $link_matches = array(); + + if (!preg_match_all($this->_meta_find, $head_matches[0], + $link_matches)) { + return array(); + } + + foreach ($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; + } +} + +?>
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