454 lines
15 KiB
PHP
454 lines
15 KiB
PHP
<?php
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/**
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* Content Extractor
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*
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* Uses patterns specified in site config files and auto detection (hNews/PHP Readability)
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* to extract content from HTML files.
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*
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* @version 0.5
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* @date 2011-03-07
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* @author Keyvan Minoukadeh
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* @copyright 2011 Keyvan Minoukadeh
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* @license http://www.gnu.org/licenses/agpl-3.0.html AGPL v3
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*/
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class ContentExtractor
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{
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const HOSTNAME_REGEX = '/^(([a-zA-Z0-9-]*[a-zA-Z0-9])\.)*([A-Za-z0-9-]*[A-Za-z0-9])$/';
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protected static $config_cache = array();
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protected static $tidy_config = array(
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'clean' => true,
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'output-xhtml' => true,
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'logical-emphasis' => true,
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'show-body-only' => false,
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'wrap' => 0,
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'drop-empty-paras' => true,
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'drop-proprietary-attributes' => false,
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'enclose-text' => true,
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'enclose-block-text' => true,
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'merge-divs' => true,
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'merge-spans' => true,
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'char-encoding' => 'utf8',
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'hide-comments' => true
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);
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protected $config_path;
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protected $html;
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protected $config;
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protected $title;
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protected $body;
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protected $success = false;
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protected $fallback;
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public $readability;
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public $debug = false;
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function __construct($config_path=null, ContentExtractor $config_fallback=null) {
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$this->config_path = $config_path;
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$this->fallback = $config_fallback;
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}
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protected function debug($msg) {
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if ($this->debug) {
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$mem = round(memory_get_usage()/1024, 2);
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$memPeak = round(memory_get_peak_usage()/1024, 2);
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echo '* ',$msg;
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echo ' - mem used: ',$mem," (peak: $memPeak)\n";
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ob_flush();
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flush();
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}
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}
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public function reset() {
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$this->html = null;
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$this->readability = null;
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$this->config = null;
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$this->title = null;
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$this->body = null;
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$this->success = false;
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}
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// returns SiteConfig instance if an appropriate one is found, false otherwise
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public function get_site_config($host) {
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$host = strtolower($host);
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if (substr($host, 0, 4) == 'www.') $host = substr($host, 4);
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if (!$host || (strlen($host) > 200) || !preg_match(self::HOSTNAME_REGEX, $host)) return false;
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// check for site configuration
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$try = array($host);
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$split = explode('.', $host);
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if (count($split) > 1) {
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array_shift($split);
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$try[] = '.'.implode('.', $split);
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}
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foreach ($try as $h) {
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if (array_key_exists($h, self::$config_cache)) {
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$this->debug("... cached ($h)");
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return self::$config_cache[$h];
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} elseif (file_exists($this->config_path."/$h.txt")) {
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$this->debug("... from file ($h)");
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$file = $this->config_path."/$h.txt";
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break;
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}
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}
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if (!isset($file)) {
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if (isset($this->fallback)) {
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$this->debug("... trying fallback ($host)");
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return $this->fallback->get_site_config($host);
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} else {
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$this->debug("... no match ($host)");
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return false;
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}
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}
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$config_file = file($file, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
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if (!$config_file || !is_array($config_file)) return false;
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$config = new SiteConfig();
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foreach ($config_file as $line) {
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$line = trim($line);
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// skip comments, empty lines
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if ($line == '' || $line[0] == '#') continue;
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// get command
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$command = explode(':', $line, 2);
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// if there's no colon ':', skip this line
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if (count($command) != 2) continue;
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$val = trim($command[1]);
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$command = trim($command[0]);
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if ($command == '' || $val == '') continue;
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// check for commands where we accept multiple statements
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if (in_array($command, array('title', 'body', 'strip', 'strip_id_or_class', 'strip_image_src'))) {
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array_push($config->$command, $val);
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// check for single statement commands that evaluate to true or false
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} elseif (in_array($command, array('tidy', 'prune', 'autodetect_on_failure'))) {
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$config->$command = ($val == 'yes');
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// check for single statement commands stored as strings
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} elseif (in_array($command, array('test_url'))) {
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$config->$command = $val;
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}
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}
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// store copy of config in our static cache array in case we need to process another URL
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self::$config_cache[$h] = $config;
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return $config;
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}
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// returns true on success, false on failure
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// $smart_tidy indicates that if tidy is used and no results are produced, we will
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// try again without it. Tidy helps us deal with PHP's patchy HTML parsing most of the time
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// but it has problems of its own which we try to avoid with this option.
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public function process($html, $url, $smart_tidy=true) {
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$this->reset();
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// extract host name
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$host = @parse_url($url, PHP_URL_HOST);
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if (!($this->config = $this->get_site_config($host))) {
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// no match, so use defaults
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$this->config = new SiteConfig();
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self::$config_cache[$host] = $this->config;
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}
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// use tidy (if it exists)?
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// This fixes problems with some sites which would otherwise
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// trouble DOMDocument's HTML parsing. (Although sometimes it
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// makes matters worse, which is why you can override it in site config files.)
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$tidied = false;
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if ($this->config->tidy && function_exists('tidy_parse_string') && $smart_tidy) {
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$this->debug('Using Tidy');
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$tidy = tidy_parse_string($html, self::$tidy_config, 'UTF8');
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if (tidy_clean_repair($tidy)) {
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$original_html = $html;
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$tidied = true;
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$html = $tidy->value;
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}
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unset($tidy);
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}
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// load and parse html
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$this->readability = new Readability($html, $url);
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// we use xpath to find elements in the given HTML document
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// see http://en.wikipedia.org/wiki/XPath_1.0
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$xpath = new DOMXPath($this->readability->dom);
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// strip elements (using xpath expressions)
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foreach ($this->config->strip as $pattern) {
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$elems = @$xpath->query($pattern, $this->readability->dom);
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// check for matches
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if ($elems && $elems->length > 0) {
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$this->debug('Stripping '.$elems->length.' elements (strip)');
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for ($i=$elems->length-1; $i >= 0; $i--) {
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$elems->item($i)->parentNode->removeChild($elems->item($i));
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}
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}
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}
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// strip elements (using id and class attribute values)
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foreach ($this->config->strip_id_or_class as $string) {
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$string = strtr($string, array("'"=>'', '"'=>''));
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$elems = @$xpath->query("//*[contains(@class, '$string') or contains(@id, '$string')]", $this->readability->dom);
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// check for matches
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if ($elems && $elems->length > 0) {
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$this->debug('Stripping '.$elems->length.' elements (strip_id_or_class)');
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for ($i=$elems->length-1; $i >= 0; $i--) {
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$elems->item($i)->parentNode->removeChild($elems->item($i));
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}
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}
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}
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// strip images (using src attribute values)
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foreach ($this->config->strip_image_src as $string) {
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$string = strtr($string, array("'"=>'', '"'=>''));
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$elems = @$xpath->query("//img[contains(@src, '$string')]", $this->readability->dom);
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// check for matches
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if ($elems && $elems->length > 0) {
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$this->debug('Stripping '.$elems->length.' image elements');
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for ($i=$elems->length-1; $i >= 0; $i--) {
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$elems->item($i)->parentNode->removeChild($elems->item($i));
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}
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}
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}
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// strip elements using Readability.com and Instapaper.com ignore class names
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// .entry-unrelated and .instapaper_ignore
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// See https://www.readability.com/publishers/guidelines/#view-plainGuidelines
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// and http://blog.instapaper.com/post/730281947
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$elems = @$xpath->query("//*[contains(concat(' ',normalize-space(@class),' '),' entry-unrelated ') or contains(concat(' ',normalize-space(@class),' '),' instapaper_ignore ')]", $this->readability->dom);
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// check for matches
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if ($elems && $elems->length > 0) {
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$this->debug('Stripping '.$elems->length.' .entry-unrelated,.instapaper_ignore elements');
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for ($i=$elems->length-1; $i >= 0; $i--) {
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$elems->item($i)->parentNode->removeChild($elems->item($i));
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}
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}
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// strip elements that contain style="display: none;"
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$elems = @$xpath->query("//*[contains(@style,'display:none')]", $this->readability->dom);
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// check for matches
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if ($elems && $elems->length > 0) {
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$this->debug('Stripping '.$elems->length.' elements with inline display:none style');
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for ($i=$elems->length-1; $i >= 0; $i--) {
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$elems->item($i)->parentNode->removeChild($elems->item($i));
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}
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}
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// try to get title
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foreach ($this->config->title as $pattern) {
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$elems = @$xpath->evaluate($pattern, $this->readability->dom);
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if (is_string($elems)) {
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$this->debug('Title expression evaluated as string');
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$this->title = trim($elems);
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break;
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} elseif ($elems instanceof DOMNodeList && $elems->length > 0) {
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$this->debug('Title matched');
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$this->title = $elems->item(0)->textContent;
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break;
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}
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}
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// try to get body
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foreach ($this->config->body as $pattern) {
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$elems = @$xpath->query($pattern, $this->readability->dom);
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// check for matches
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if ($elems && $elems->length > 0) {
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$this->debug('Body matched');
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if ($elems->length == 1) {
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$this->body = $elems->item(0);
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// prune (clean up elements that may not be content)
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if ($this->config->prune) {
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$this->debug('Pruning content');
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$this->readability->prepArticle($this->body);
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}
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break;
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} else {
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$this->body = $this->readability->dom->createElement('div');
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$this->debug($elems->length.' body elems found');
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foreach ($elems as $elem) {
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$isDescendant = false;
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foreach ($this->body->childNodes as $parent) {
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if ($this->isDescendant($parent, $elem)) {
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$isDescendant = true;
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break;
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}
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}
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if ($isDescendant) {
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$this->debug('Element is child of another body element, skipping.');
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} else {
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// prune (clean up elements that may not be content)
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if ($this->config->prune) {
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$this->debug('Pruning content');
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$this->readability->prepArticle($elem);
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}
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$this->debug('Element added to body');
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$this->body->appendChild($elem);
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}
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}
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}
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}
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}
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// auto detect?
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$detect_title = $detect_body = false;
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// detect title?
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if (!isset($this->title)) {
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if (empty($this->config->title) || (!empty($this->config->title) && $this->config->autodetect_on_failure)) {
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$detect_title = true;
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}
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}
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// detect body?
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if (!isset($this->body)) {
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if (empty($this->config->body) || (!empty($this->config->body) && $this->config->autodetect_on_failure)) {
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$detect_body = true;
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}
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}
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// check for hNews
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if ($detect_title || $detect_body) {
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// check for hentry
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$elems = @$xpath->query("//*[contains(concat(' ',normalize-space(@class),' '),' hentry ')]", $this->readability->dom);
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if ($elems && $elems->length > 0) {
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$this->debug('hNews: found hentry');
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$hentry = $elems->item(0);
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if ($detect_title) {
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// check for entry-title
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$elems = @$xpath->query(".//*[contains(concat(' ',normalize-space(@class),' '),' entry-title ')]", $hentry);
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if ($elems && $elems->length > 0) {
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$this->debug('hNews: found entry-title');
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$this->title = $elems->item(0)->textContent;
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$detect_title = false;
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}
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}
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// check for entry-content.
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// according to hAtom spec, if there are multiple elements marked entry-content,
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// we include all of these in the order they appear - see http://microformats.org/wiki/hatom#Entry_Content
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if ($detect_body) {
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$elems = @$xpath->query(".//*[contains(concat(' ',normalize-space(@class),' '),' entry-content ')]", $hentry);
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if ($elems && $elems->length > 0) {
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$this->debug('hNews: found entry-content');
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if ($elems->length == 1) {
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// what if it's empty? (some sites misuse hNews - place their content outside an empty entry-content element)
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$e = $elems->item(0);
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if (($e->tagName == 'img') || (trim($e->textContent) != '')) {
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$this->body = $elems->item(0);
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// prune (clean up elements that may not be content)
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if ($this->config->prune) {
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$this->debug('Pruning content');
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$this->readability->prepArticle($this->body);
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}
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$detect_body = false;
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} else {
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$this->debug('hNews: skipping entry-content - appears not to contain content');
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}
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unset($e);
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} else {
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$this->body = $this->readability->dom->createElement('div');
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$this->debug($elems->length.' entry-content elems found');
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foreach ($elems as $elem) {
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$isDescendant = false;
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foreach ($this->body->childNodes as $parent) {
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if ($this->isDescendant($parent, $elem)) {
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$isDescendant = true;
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break;
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}
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}
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if ($isDescendant) {
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$this->debug('Element is child of another body element, skipping.');
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} else {
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// prune (clean up elements that may not be content)
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if ($this->config->prune) {
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$this->debug('Pruning content');
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$this->readability->prepArticle($elem);
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}
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$this->debug('Element added to body');
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$this->body->appendChild($elem);
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}
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}
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$detect_body = false;
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}
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}
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}
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}
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}
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// check for elements marked with instapaper_title
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if ($detect_title) {
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// check for instapaper_title
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$elems = @$xpath->query("//*[contains(concat(' ',normalize-space(@class),' '),' instapaper_title ')]", $this->readability->dom);
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if ($elems && $elems->length > 0) {
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$this->debug('title found (.instapaper_title)');
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$this->title = $elems->item(0)->textContent;
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$detect_title = false;
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}
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}
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// check for elements marked with instapaper_body
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if ($detect_body) {
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$elems = @$xpath->query("//*[contains(concat(' ',normalize-space(@class),' '),' instapaper_body ')]", $this->readability->dom);
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if ($elems && $elems->length > 0) {
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$this->debug('body found (.instapaper_body)');
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$this->body = $elems->item(0);
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// prune (clean up elements that may not be content)
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if ($this->config->prune) {
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$this->debug('Pruning content');
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$this->readability->prepArticle($this->body);
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}
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$detect_body = false;
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}
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}
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// still missing title or body, so we detect using Readability
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if ($detect_title || $detect_body) {
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$this->debug('Using Readability');
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// clone body if we're only using Readability for title (otherwise it may interfere with body element)
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if (isset($this->body)) $this->body = $this->body->cloneNode(true);
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$success = $this->readability->init();
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}
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if ($detect_title) {
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$this->debug('Detecting title');
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$this->title = $this->readability->getTitle()->textContent;
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}
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if ($detect_body && $success) {
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$this->debug('Detecting body');
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$this->body = $this->readability->getContent();
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if ($this->body->childNodes->length == 1 && $this->body->firstChild->nodeType === XML_ELEMENT_NODE) {
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$this->body = $this->body->firstChild;
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}
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// prune (clean up elements that may not be content)
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if ($this->config->prune) {
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$this->debug('Pruning content');
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$this->readability->prepArticle($this->body);
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}
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}
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if (isset($this->body)) {
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// remove scripts
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$this->readability->removeScripts($this->body);
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$this->success = true;
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}
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// if we've had no success and we've used tidy, there's a chance
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// that tidy has messed up. So let's try again without tidy...
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if (!$this->success && $tidied && $smart_tidy) {
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$this->debug('Trying again without tidy');
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$this->process($original_html, $url, false);
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}
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return $this->success;
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}
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private function isDescendant(DOMElement $parent, DOMElement $child) {
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$node = $child->parentNode;
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while ($node != null) {
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if ($node->isSameNode($parent)) return true;
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$node = $node->parentNode;
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}
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return false;
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}
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public function getContent() {
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return $this->body;
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}
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public function getTitle() {
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return $this->title;
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}
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public function getSiteConfig() {
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return $this->config;
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}
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}
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?>
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