<?php
/**
* Content Extractor
*
* Uses patterns specified in site config files and auto detection (hNews/PHP Readability)
* to extract content from HTML files.
*
* @version 0.8
* @date 2012-02-21
* @author Keyvan Minoukadeh
* @copyright 2011 Keyvan Minoukadeh
* @license http://www.gnu.org/licenses/agpl-3.0.html AGPL v3
*/
class ContentExtractor
{
protected static $tidy_config = array(
'clean' => true,
'output-xhtml' => true,
'logical-emphasis' => true,
'show-body-only' => false,
'new-blocklevel-tags' => 'article, aside, footer, header, hgroup, menu, nav, section, details, datagrid',
'new-inline-tags' => 'mark, time, meter, progress, data',
'wrap' => 0,
'drop-empty-paras' => true,
'drop-proprietary-attributes' => false,
'enclose-text' => true,
'enclose-block-text' => true,
'merge-divs' => true,
'merge-spans' => true,
'char-encoding' => 'utf8',
'hide-comments' => true
);
protected $html;
protected $config;
protected $title;
protected $author = array();
protected $language;
protected $date;
protected $body;
protected $success = false;
public $fingerprints = array();
public $readability;
public $debug = false;
function __construct($path, $fallback=null) {
SiteConfig::set_config_path($path, $fallback);
}
protected function debug($msg) {
if ($this->debug) {
$mem = round(memory_get_usage()/1024, 2);
$memPeak = round(memory_get_peak_usage()/1024, 2);
echo '* ',$msg;
echo ' - mem used: ',$mem," (peak: $memPeak)\n";
ob_flush();
flush();
}
}
public function reset() {
$this->html = null;
$this->readability = null;
$this->config = null;
$this->title = null;
$this->body = null;
$this->author = array();
$this->language = null;
$this->date = null;
$this->success = false;
}
public function findHostUsingFingerprints($html) {
$this->debug('Checking fingerprints...');
$head = substr($html, 0, 8000);
foreach ($this->fingerprints as $_fp => $_fphost) {
$lookin = 'html';
if (is_array($_fphost)) {
if (isset($_fphost['head']) && $_fphost['head']) {
$lookin = 'head';
}
$_fphost = $_fphost['hostname'];
}
if (strpos($$lookin, $_fp) !== false) {
$this->debug("Found match: $_fphost");
return $_fphost;
}
}
return false;
}
// returns true on success, false on failure
// $smart_tidy indicates that if tidy is used and no results are produced, we will
// try again without it. Tidy helps us deal with PHP's patchy HTML parsing most of the time
// but it has problems of its own which we try to avoid with this option.
public function process($html, $url, $smart_tidy=true) {
$this->reset();
// extract host name
$host = @parse_url($url, PHP_URL_HOST);
if (!($this->config = SiteConfig::build($host))) {
// no match, check HTML for fingerprints
if (!empty($this->fingerprints) && ($_fphost = $this->findHostUsingFingerprints($html))) {
$this->config = SiteConfig::build($_fphost);
}
unset($_fphost);
if (!$this->config) {
// no match, so use defaults
$this->config = new SiteConfig();
}
}
// store copy of config in our static cache array in case we need to process another URL
SiteConfig::add_to_cache($host, $this->config);
// do string replacements
foreach ($this->config->replace_string as $_repl) {
$html = str_replace($_repl[0], $_repl[1], $html);
}
unset($_repl);
// use tidy (if it exists)?
// This fixes problems with some sites which would otherwise
// trouble DOMDocument's HTML parsing. (Although sometimes it
// makes matters worse, which is why you can override it in site config files.)
$tidied = false;
if ($this->config->tidy && function_exists('tidy_parse_string') && $smart_tidy) {
$this->debug('Using Tidy');
$tidy = tidy_parse_string($html, self::$tidy_config, 'UTF8');
if (tidy_clean_repair($tidy)) {
$original_html = $html;
$tidied = true;
// $html = $tidy->value;
}
$body = $tidy->body();
if (preg_replace('/\s+/', '', $body->value) !== "<body></body>") {
$html = $tidy->value;
}
unset($tidy);
}
// load and parse html
$this->readability = new PocheReadability($html, $url);
// we use xpath to find elements in the given HTML document
// see http://en.wikipedia.org/wiki/XPath_1.0
$xpath = new DOMXPath($this->readability->dom);
// try to get title
foreach ($this->config->title as $pattern) {
$elems = @$xpath->evaluate($pattern, $this->readability->dom);
if (is_string($elems)) {
$this->debug('Title expression evaluated as string');
$this->title = trim($elems);
break;
} elseif ($elems instanceof DOMNodeList && $elems->length > 0) {
$this->debug('Title matched');
$this->title = $elems->item(0)->textContent;
// remove title from document
try {
$elems->item(0)->parentNode->removeChild($elems->item(0));
} catch (DOMException $e) {
// do nothing
}
break;
}
}
// try to get author (if it hasn't already been set)
if (empty($this->author)) {
foreach ($this->config->author as $pattern) {
$elems = @$xpath->evaluate($pattern, $this->readability->dom);
if (is_string($elems)) {
$this->debug('Author expression evaluated as string');
if (trim($elems) != '') {
$this->author[] = trim($elems);
break;
}
} elseif ($elems instanceof DOMNodeList && $elems->length > 0) {
foreach ($elems as $elem) {
if (!isset($elem->parentNode)) continue;
$this->author[] = trim($elem->textContent);
}
if (!empty($this->author)) break;
}
}
}
// try to get language
$_lang_xpath = array('//html[@lang]/@lang', '//meta[@name="DC.language"]/@content');
foreach ($_lang_xpath as $pattern) {
$elems = @$xpath->evaluate($pattern, $this->readability->dom);
if (is_string($elems)) {
if (trim($elems) != '') {
$this->language = trim($elems);
break;
}
} elseif ($elems instanceof DOMNodeList && $elems->length > 0) {
foreach ($elems as $elem) {
if (!isset($elem->parentNode)) continue;
$this->language = trim($elem->textContent);
}
if ($this->language) break;
}
}
// try to get date
foreach ($this->config->date as $pattern) {
$elems = @$xpath->evaluate($pattern, $this->readability->dom);
if (is_string($elems)) {
$this->debug('Date expression evaluated as string');
$this->date = strtotime(trim($elems, "; \t\n\r\0\x0B"));
} elseif ($elems instanceof DOMNodeList && $elems->length > 0) {
$this->debug('Date matched');
$this->date = $elems->item(0)->textContent;
$this->date = strtotime(trim($this->date, "; \t\n\r\0\x0B"));
// remove date from document
// $elems->item(0)->parentNode->removeChild($elems->item(0));
}
if (!$this->date) {
$this->date = null;
} else {
break;
}
}
// strip elements (using xpath expressions)
foreach ($this->config->strip as $pattern) {
$elems = @$xpath->query($pattern, $this->readability->dom);
// check for matches
if ($elems && $elems->length > 0) {
$this->debug('Stripping '.$elems->length.' elements (strip)');
for ($i=$elems->length-1; $i >= 0; $i--) {
$elems->item($i)->parentNode->removeChild($elems->item($i));
}
}
}
// strip elements (using id and class attribute values)
foreach ($this->config->strip_id_or_class as $string) {
$string = strtr($string, array("'"=>'', '"'=>''));
$elems = @$xpath->query("//*[contains(@class, '$string') or contains(@id, '$string')]", $this->readability->dom);
// check for matches
if ($elems && $elems->length > 0) {
$this->debug('Stripping '.$elems->length.' elements (strip_id_or_class)');
for ($i=$elems->length-1; $i >= 0; $i--) {
$elems->item($i)->parentNode->removeChild($elems->item($i));
}
}
}
// strip images (using src attribute values)
foreach ($this->config->strip_image_src as $string) {
$string = strtr($string, array("'"=>'', '"'=>''));
$elems = @$xpath->query("//img[contains(@src, '$string')]", $this->readability->dom);
// check for matches
if ($elems && $elems->length > 0) {
$this->debug('Stripping '.$elems->length.' image elements');
for ($i=$elems->length-1; $i >= 0; $i--) {
$elems->item($i)->parentNode->removeChild($elems->item($i));
}
}
}
// strip elements using Readability.com and Instapaper.com ignore class names
// .entry-unrelated and .instapaper_ignore
// See https://www.readability.com/publishers/guidelines/#view-plainGuidelines
// and http://blog.instapaper.com/post/730281947
$elems = @$xpath->query("//*[contains(concat(' ',normalize-space(@class),' '),' entry-unrelated ') or contains(concat(' ',normalize-space(@class),' '),' instapaper_ignore ')]", $this->readability->dom);
// check for matches
if ($elems && $elems->length > 0) {
$this->debug('Stripping '.$elems->length.' .entry-unrelated,.instapaper_ignore elements');
for ($i=$elems->length-1; $i >= 0; $i--) {
$elems->item($i)->parentNode->removeChild($elems->item($i));
}
}
// strip elements that contain style="display: none;"
$elems = @$xpath->query("//*[contains(@style,'display:none')]", $this->readability->dom);
// check for matches
if ($elems && $elems->length > 0) {
$this->debug('Stripping '.$elems->length.' elements with inline display:none style');
for ($i=$elems->length-1; $i >= 0; $i--) {
$elems->item($i)->parentNode->removeChild($elems->item($i));
}
}
// try to get body
foreach ($this->config->body as $pattern) {
$elems = @$xpath->query($pattern, $this->readability->dom);
// check for matches
if ($elems && $elems->length > 0) {
$this->debug('Body matched');
if ($elems->length == 1) {
$this->body = $elems->item(0);
// prune (clean up elements that may not be content)
if ($this->config->prune) {
$this->debug('Pruning content');
$this->readability->prepArticle($this->body);
}
break;
} else {
$this->body = $this->readability->dom->createElement('div');
$this->debug($elems->length.' body elems found');
foreach ($elems as $elem) {
if (!isset($elem->parentNode)) continue;
$isDescendant = false;
foreach ($this->body->childNodes as $parent) {
if ($this->isDescendant($parent, $elem)) {
$isDescendant = true;
break;
}
}
if ($isDescendant) {
$this->debug('Element is child of another body element, skipping.');
} else {
// prune (clean up elements that may not be content)
if ($this->config->prune) {
$this->debug('Pruning content');
$this->readability->prepArticle($elem);
}
$this->debug('Element added to body');
$this->body->appendChild($elem);
}
}
}
}
}
// auto detect?
$detect_title = $detect_body = $detect_author = $detect_date = false;
// detect title?
if (!isset($this->title)) {
if (empty($this->config->title) || $this->config->autodetect_on_failure) {
$detect_title = true;
}
}
// detect body?
if (!isset($this->body)) {
if (empty($this->config->body) || $this->config->autodetect_on_failure) {
$detect_body = true;
}
}
// detect author?
if (empty($this->author)) {
if (empty($this->config->author) || $this->config->autodetect_on_failure) {
$detect_author = true;
}
}
// detect date?
if (!isset($this->date)) {
if (empty($this->config->date) || $this->config->autodetect_on_failure) {
$detect_date = true;
}
}
// check for hNews
if ($detect_title || $detect_body) {
// check for hentry
$elems = @$xpath->query("//*[contains(concat(' ',normalize-space(@class),' '),' hentry ')]", $this->readability->dom);
if ($elems && $elems->length > 0) {
$this->debug('hNews: found hentry');
$hentry = $elems->item(0);
if ($detect_title) {
// check for entry-title
$elems = @$xpath->query(".//*[contains(concat(' ',normalize-space(@class),' '),' entry-title ')]", $hentry);
if ($elems && $elems->length > 0) {
$this->debug('hNews: found entry-title');
$this->title = $elems->item(0)->textContent;
// remove title from document
$elems->item(0)->parentNode->removeChild($elems->item(0));
$detect_title = false;
}
}
if ($detect_date) {
// check for time element with pubdate attribute
$elems = @$xpath->query(".//time[@pubdate] | .//abbr[contains(concat(' ',normalize-space(@class),' '),' published ')]", $hentry);
if ($elems && $elems->length > 0) {
$this->debug('hNews: found publication date');
$this->date = strtotime(trim($elems->item(0)->textContent));
// remove date from document
//$elems->item(0)->parentNode->removeChild($elems->item(0));
if ($this->date) {
$detect_date = false;
} else {
$this->date = null;
}
}
}
if ($detect_author) {
// check for time element with pubdate attribute
$elems = @$xpath->query(".//*[contains(concat(' ',normalize-space(@class),' '),' vcard ') and (contains(concat(' ',normalize-space(@class),' '),' author ') or contains(concat(' ',normalize-space(@class),' '),' byline '))]", $hentry);
if ($elems && $elems->length > 0) {
$this->debug('hNews: found author');
$author = $elems->item(0);
$fn = @$xpath->query(".//*[contains(concat(' ',normalize-space(@class),' '),' fn ')]", $author);
if ($fn && $fn->length > 0) {
foreach ($fn as $_fn) {
if (trim($_fn->textContent) != '') {
$this->author[] = trim($_fn->textContent);
}
}
} else {
if (trim($author->textContent) != '') {
$this->author[] = trim($author->textContent);
}
}
$detect_author = empty($this->author);
}
}
// check for entry-content.
// according to hAtom spec, if there are multiple elements marked entry-content,
// we include all of these in the order they appear - see http://microformats.org/wiki/hatom#Entry_Content
if ($detect_body) {
$elems = @$xpath->query(".//*[contains(concat(' ',normalize-space(@class),' '),' entry-content ')]", $hentry);
if ($elems && $elems->length > 0) {
$this->debug('hNews: found entry-content');
if ($elems->length == 1) {
// what if it's empty? (some sites misuse hNews - place their content outside an empty entry-content element)
$e = $elems->item(0);
if (($e->tagName == 'img') || (trim($e->textContent) != '')) {
$this->body = $elems->item(0);
// prune (clean up elements that may not be content)
if ($this->config->prune) {
$this->debug('Pruning content');
$this->readability->prepArticle($this->body);
}
$detect_body = false;
} else {
$this->debug('hNews: skipping entry-content - appears not to contain content');
}
unset($e);
} else {
$this->body = $this->readability->dom->createElement('div');
$this->debug($elems->length.' entry-content elems found');
foreach ($elems as $elem) {
if (!isset($elem->parentNode)) continue;
$isDescendant = false;
foreach ($this->body->childNodes as $parent) {
if ($this->isDescendant($parent, $elem)) {
$isDescendant = true;
break;
}
}
if ($isDescendant) {
$this->debug('Element is child of another body element, skipping.');
} else {
// prune (clean up elements that may not be content)
if ($this->config->prune) {
$this->debug('Pruning content');
$this->readability->prepArticle($elem);
}
$this->debug('Element added to body');
$this->body->appendChild($elem);
}
}
$detect_body = false;
}
}
}
}
}
// check for elements marked with instapaper_title
if ($detect_title) {
// check for instapaper_title
$elems = @$xpath->query("//*[contains(concat(' ',normalize-space(@class),' '),' instapaper_title ')]", $this->readability->dom);
if ($elems && $elems->length > 0) {
$this->debug('title found (.instapaper_title)');
$this->title = $elems->item(0)->textContent;
// remove title from document
$elems->item(0)->parentNode->removeChild($elems->item(0));
$detect_title = false;
}
}
// check for elements marked with instapaper_body
if ($detect_body) {
$elems = @$xpath->query("//*[contains(concat(' ',normalize-space(@class),' '),' instapaper_body ')]", $this->readability->dom);
if ($elems && $elems->length > 0) {
$this->debug('body found (.instapaper_body)');
$this->body = $elems->item(0);
// prune (clean up elements that may not be content)
if ($this->config->prune) {
$this->debug('Pruning content');
$this->readability->prepArticle($this->body);
}
$detect_body = false;
}
}
// Find author in rel="author" marked element
// We only use this if there's exactly one.
// If there's more than one, it could indicate more than
// one author, but it could also indicate that we're processing
// a page listing different articles with different authors.
if ($detect_author) {
$elems = @$xpath->query("//a[contains(concat(' ',normalize-space(@rel),' '),' author ')]", $this->readability->dom);
if ($elems && $elems->length == 1) {
$this->debug('Author found (rel="author")');
$author = trim($elems->item(0)->textContent);
if ($author != '') {
$this->author[] = $author;
$detect_author = false;
}
}
}
// Find date in pubdate marked time element
// For the same reason given above, we only use this
// if there's exactly one element.
if ($detect_date) {
$elems = @$xpath->query("//time[@pubdate]", $this->readability->dom);
if ($elems && $elems->length == 1) {
$this->debug('Date found (pubdate marked time element)');
$this->date = strtotime(trim($elems->item(0)->textContent));
// remove date from document
//$elems->item(0)->parentNode->removeChild($elems->item(0));
if ($this->date) {
$detect_date = false;
} else {
$this->date = null;
}
}
}
// still missing title or body, so we detect using Readability
if ($detect_title || $detect_body) {
$this->debug('Using Readability');
// clone body if we're only using Readability for title (otherwise it may interfere with body element)
if (isset($this->body)) $this->body = $this->body->cloneNode(true);
$success = $this->readability->init();
}
if ($detect_title) {
$this->debug('Detecting title');
$this->title = $this->readability->getTitle()->textContent;
}
if ($detect_body && $success) {
$this->debug('Detecting body');
$this->body = $this->readability->getContent();
if ($this->body->childNodes->length == 1 && $this->body->firstChild->nodeType === XML_ELEMENT_NODE) {
$this->body = $this->body->firstChild;
}
// prune (clean up elements that may not be content)
if ($this->config->prune) {
$this->debug('Pruning content');
$this->readability->prepArticle($this->body);
}
}
if (isset($this->body)) {
// remove scripts
$this->readability->removeScripts($this->body);
// remove any h1-h6 elements that appear as first thing in the body
// and which match our title
if (isset($this->title) && ($this->title != '')) {
$firstChild = $this->body->firstChild;
while ($firstChild->nodeType && ($firstChild->nodeType !== XML_ELEMENT_NODE)) {
$firstChild = $firstChild->nextSibling;
}
if (($firstChild->nodeType === XML_ELEMENT_NODE)
&& in_array(strtolower($firstChild->tagName), array('h1', 'h2', 'h3', 'h4', 'h5', 'h6'))
&& (strtolower(trim($firstChild->textContent)) == strtolower(trim($this->title)))) {
$this->body->removeChild($firstChild);
}
}
$this->success = true;
}
// if we've had no success and we've used tidy, there's a chance
// that tidy has messed up. So let's try again without tidy...
if (!$this->success && $tidied && $smart_tidy) {
$this->debug('Trying again without tidy');
$this->process($original_html, $url, false);
}
return $this->success;
}
private function isDescendant(DOMElement $parent, DOMElement $child) {
$node = $child->parentNode;
while ($node != null) {
if ($node->isSameNode($parent)) return true;
$node = $node->parentNode;
}
return false;
}
public function getContent() {
return $this->body;
}
public function getTitle() {
return $this->title;
}
public function getAuthors() {
return $this->author;
}
public function getLanguage() {
return $this->language;
}
public function getDate() {
return $this->date;
}
public function getSiteConfig() {
return $this->config;
}
}
?>
