inc/3rdparty/Readability.php

   1 <?php
   2 /**
   3 * Arc90's Readability ported to PHP for FiveFilters.org
   4 * Based on readability.js version 1.7.1 (without multi-page support)
   5 * Updated to allow HTML5 parsing with html5lib
   6 * Updated with lightClean mode to preserve more images and youtube/vimeo/viddler embeds
   7 * ------------------------------------------------------
   8 * Original URL: http://lab.arc90.com/experiments/readability/js/readability.js
   9 * Arc90's project URL: http://lab.arc90.com/experiments/readability/
  10 * JS Source: http://code.google.com/p/arc90labs-readability
  11 * Ported by: Keyvan Minoukadeh, http://www.keyvan.net
  12 * More information: http://fivefilters.org/content-only/
  13 * License: Apache License, Version 2.0
  14 * Requires: PHP5
  15 * Date: 2012-09-19
  16 *
  17 * Differences between the PHP port and the original
  18 * ------------------------------------------------------
  19 * Arc90's Readability is designed to run in the browser. It works on the DOM
  20 * tree (the parsed HTML) after the page's CSS styles have been applied and
  21 * Javascript code executed. This PHP port does not run inside a browser.
  22 * We use PHP's ability to parse HTML to build our DOM tree, but we cannot
  23 * rely on CSS or Javascript support. As such, the results will not always
  24 * match Arc90's Readability. (For example, if a web page contains CSS style
  25 * rules or Javascript code which hide certain HTML elements from display,
  26 * Arc90's Readability will dismiss those from consideration but our PHP port,
  27 * unable to understand CSS or Javascript, will not know any better.)
  28 *
  29 * Another significant difference is that the aim of Arc90's Readability is
  30 * to re-present the main content block of a given web page so users can
  31 * read it more easily in their browsers. Correct identification, clean up,
  32 * and separation of the content block is only a part of this process.
  33 * This PHP port is only concerned with this part, it does not include code
  34 * that relates to presentation in the browser - Arc90 already do
  35 * that extremely well, and for PDF output there's FiveFilters.org's
  36 * PDF Newspaper: http://fivefilters.org/pdf-newspaper/.
  37 *
  38 * Finally, this class contains methods that might be useful for developers
  39 * working on HTML document fragments. So without deviating too much from
  40 * the original code (which I don't want to do because it makes debugging
  41 * and updating more difficult), I've tried to make it a little more
  42 * developer friendly. You should be able to use the methods here on
  43 * existing DOMElement objects without passing an entire HTML document to
  44 * be parsed.
  45 */
  46
  47 // This class allows us to do JavaScript like assignements to innerHTML
  48 require_once(dirname(__FILE__).'/JSLikeHTMLElement.php');
  49
  50 // Alternative usage (for testing only!)
  51 // uncomment the lines below and call Readability.php in your browser
  52 // passing it the URL of the page you'd like content from, e.g.:
  53 // Readability.php?url=http://medialens.org/alerts/09/090615_the_guardian_climate.php
  54
  55 /*
  56 if (!isset($_GET['url']) || $_GET['url'] == '') {
  57     die('Please pass a URL to the script. E.g. Readability.php?url=bla.com/story.html');
  58 }
  59 $url = $_GET['url'];
  60 if (!preg_match('!^https?://!i', $url)) $url = 'http://'.$url;
  61 $html = file_get_contents($url);
  62 $r = new Readability($html, $url);
  63 $r->init();
  64 echo $r->articleContent->innerHTML;
  65 */
  66
  67 class Readability
  68 {
  69     public $version = '1.7.1-without-multi-page';
  70     public $convertLinksToFootnotes = false;
  71     public $revertForcedParagraphElements = true;
  72     public $articleTitle;
  73     public $articleContent;
  74     public $dom;
  75     public $url = null; // optional - URL where HTML was retrieved
  76     public $debug = false;
  77     public $lightClean = true; // preserves more content (experimental) added 2012-09-19
  78     protected $body = null; //
  79     protected $bodyCache = null; // Cache the body HTML in case we need to re-use it later
  80     protected $flags = 7; // 1 | 2 | 4;   // Start with all flags set.
  81     protected $success = false; // indicates whether we were able to extract or not
  82
  83     /**
  84     * All of the regular expressions in use within readability.
  85     * Defined up here so we don't instantiate them repeatedly in loops.
  86     **/
  87     public $regexps = array(
  88         'unlikelyCandidates' => '/combx|comment|community|disqus|extra|foot|header|menu|remark|rss|shoutbox|sidebar|sponsor|ad-break|agegate|pagination|pager|popup/i',
  89         'okMaybeItsACandidate' => '/and|article|body|column|main|shadow/i',
  90         'positive' => '/article|body|content|entry|hentry|main|page|attachment|pagination|post|text|blog|story/i',
  91         'negative' => '/combx|comment|com-|contact|foot|footer|_nav|footnote|masthead|media|meta|outbrain|promo|related|scroll|shoutbox|sidebar|sponsor|shopping|tags|tool|widget/i',
  92         'divToPElements' => '/<(a|blockquote|dl|div|img|ol|p|pre|table|ul)/i',
  93         'replaceBrs' => '/(<br[^>]*>[ \n\r\t]*){2,}/i',
  94         'replaceFonts' => '/<(\/?)font[^>]*>/i',
  95         // 'trimRe' => '/^\s+|\s+$/g', // PHP has trim()
  96         'normalize' => '/\s{2,}/',
  97         'killBreaks' => '/(<br\s*\/?>(\s|&nbsp;?)*){1,}/',
  98         'video' => '!//(player\.|www\.)?(youtube|vimeo|viddler)\.com!i',
  99         'skipFootnoteLink' => '/^\s*(\[?[a-z0-9]{1,2}\]?|^|edit|citation needed)\s*$/i'
 100     );
 101
 102     /* constants */
 103     const FLAG_STRIP_UNLIKELYS = 1;
 104     const FLAG_WEIGHT_CLASSES = 2;
 105     const FLAG_CLEAN_CONDITIONALLY = 4;
 106
 107     /**
 108     * Create instance of Readability
 109     * @param string UTF-8 encoded string
 110     * @param string (optional) URL associated with HTML (used for footnotes)
 111     * @param string which parser to use for turning raw HTML into a DOMDocument (either 'libxml' or 'html5lib')
 112     */
 113     function __construct($html, $url=null, $parser='libxml')
 114     {
 115         $this->url = $url;
 116         /* Turn all double br's into p's */
 117         $html = preg_replace($this->regexps['replaceBrs'], '</p><p>', $html);
 118         $html = preg_replace($this->regexps['replaceFonts'], '<$1span>', $html);
 119         $html = mb_convert_encoding($html, 'HTML-ENTITIES', "UTF-8");
 120         if (trim($html) == '') $html = '<html></html>';
 121         if ($parser=='html5lib' && ($this->dom = HTML5_Parser::parse($html))) {
 122             // all good
 123         } else {
 124             $this->dom = new DOMDocument();
 125             $this->dom->preserveWhiteSpace = false;
 126             @$this->dom->loadHTML($html);
 127         }
 128         $this->dom->registerNodeClass('DOMElement', 'JSLikeHTMLElement');
 129     }
 130
 131     /**
 132     * Get article title element
 133     * @return DOMElement
 134     */
 135     public function getTitle() {
 136         return $this->articleTitle;
 137     }
 138
 139     /**
 140     * Get article content element
 141     * @return DOMElement
 142     */
 143     public function getContent() {
 144         return $this->articleContent;
 145     }
 146
 147     /**
 148     * Runs readability.
 149     *
 150     * Workflow:
 151     *  1. Prep the document by removing script tags, css, etc.
 152     *  2. Build readability's DOM tree.
 153     *  3. Grab the article content from the current dom tree.
 154     *  4. Replace the current DOM tree with the new one.
 155     *  5. Read peacefully.
 156     *
 157     * @return boolean true if we found content, false otherwise
 158     **/
 159     public function init()
 160     {
 161         if (!isset($this->dom->documentElement)) return false;
 162         $this->removeScripts($this->dom);
 163         //die($this->getInnerHTML($this->dom->documentElement));
 164
 165         // Assume successful outcome
 166         $this->success = true;
 167
 168         $bodyElems = $this->dom->getElementsByTagName('body');
 169         if ($bodyElems->length > 0) {
 170             if ($this->bodyCache == null) {
 171                 $this->bodyCache = $bodyElems->item(0)->innerHTML;
 172             }
 173             if ($this->body == null) {
 174                 $this->body = $bodyElems->item(0);
 175             }
 176         }
 177
 178         $this->prepDocument();
 179
 180         //die($this->dom->documentElement->parentNode->nodeType);
 181         //$this->setInnerHTML($this->dom->documentElement, $this->getInnerHTML($this->dom->documentElement));
 182         //die($this->getInnerHTML($this->dom->documentElement));
 183
 184         /* Build readability's DOM tree */
 185         $overlay        = $this->dom->createElement('div');
 186         $innerDiv       = $this->dom->createElement('div');
 187         $articleTitle   = $this->getArticleTitle();
 188         $articleContent = $this->grabArticle();
 189
 190         if (!$articleContent) {
 191             $this->success = false;
 192             $articleContent = $this->dom->createElement('div');
 193             $articleContent->setAttribute('id', 'readability-content');
 194             $articleContent->innerHTML = '<p>Sorry, Readability was unable to parse this page for content.</p>';
 195         }
 196
 197         $overlay->setAttribute('id', 'readOverlay');
 198         $innerDiv->setAttribute('id', 'readInner');
 199
 200         /* Glue the structure of our document together. */
 201         $innerDiv->appendChild($articleTitle);
 202         $innerDiv->appendChild($articleContent);
 203         $overlay->appendChild($innerDiv);
 204
 205         /* Clear the old HTML, insert the new content. */
 206         $this->body->innerHTML = '';
 207         $this->body->appendChild($overlay);
 208         //document.body.insertBefore(overlay, document.body.firstChild);
 209         $this->body->removeAttribute('style');
 210
 211         $this->postProcessContent($articleContent);
 212
 213         // Set title and content instance variables
 214         $this->articleTitle = $articleTitle;
 215         $this->articleContent = $articleContent;
 216
 217         return $this->success;
 218     }
 219
 220     /**
 221     * Debug
 222     */
 223     protected function dbg($msg) {
 224         if ($this->debug) echo '* ',$msg, "\n";
 225     }
 226
 227     /**
 228     * Run any post-process modifications to article content as necessary.
 229     *
 230     * @param DOMElement
 231     * @return void
 232     */
 233     public function postProcessContent($articleContent) {
 234         if ($this->convertLinksToFootnotes && !preg_match('/wikipedia\.org/', @$this->url)) {
 235             $this->addFootnotes($articleContent);
 236         }
 237     }
 238
 239     /**
 240     * Get the article title as an H1.
 241     *
 242     * @return DOMElement
 243     */
 244     protected function getArticleTitle() {
 245         $curTitle = '';
 246         $origTitle = '';
 247
 248         try {
 249             $curTitle = $origTitle = $this->getInnerText($this->dom->getElementsByTagName('title')->item(0));
 250         } catch(Exception $e) {}
 251
 252         if (preg_match('/ [\|\-] /', $curTitle))
 253         {
 254             $curTitle = preg_replace('/(.*)[\|\-] .*/i', '$1', $origTitle);
 255
 256             if (count(explode(' ', $curTitle)) < 3) {
 257                 $curTitle = preg_replace('/[^\|\-]*[\|\-](.*)/i', '$1', $origTitle);
 258             }
 259         }
 260         else if (strpos($curTitle, ': ') !== false)
 261         {
 262             $curTitle = preg_replace('/.*:(.*)/i', '$1', $origTitle);
 263
 264             if (count(explode(' ', $curTitle)) < 3) {
 265                 $curTitle = preg_replace('/[^:]*[:](.*)/i','$1', $origTitle);
 266             }
 267         }
 268         else if(strlen($curTitle) > 150 || strlen($curTitle) < 15)
 269         {
 270             $hOnes = $this->dom->getElementsByTagName('h1');
 271             if($hOnes->length == 1)
 272             {
 273                 $curTitle = $this->getInnerText($hOnes->item(0));
 274             }
 275         }
 276
 277         $curTitle = trim($curTitle);
 278
 279         if (count(explode(' ', $curTitle)) <= 4) {
 280             $curTitle = $origTitle;
 281         }
 282
 283         $articleTitle = $this->dom->createElement('h1');
 284         $articleTitle->innerHTML = $curTitle;
 285
 286         return $articleTitle;
 287     }
 288
 289     /**
 290     * Prepare the HTML document for readability to scrape it.
 291     * This includes things like stripping javascript, CSS, and handling terrible markup.
 292     *
 293     * @return void
 294     **/
 295     protected function prepDocument() {
 296         /**
 297         * In some cases a body element can't be found (if the HTML is totally hosed for example)
 298         * so we create a new body node and append it to the document.
 299         */
 300         if ($this->body == null)
 301         {
 302             $this->body = $this->dom->createElement('body');
 303             $this->dom->documentElement->appendChild($this->body);
 304         }
 305         $this->body->setAttribute('id', 'readabilityBody');
 306
 307         /* Remove all style tags in head */
 308         $styleTags = $this->dom->getElementsByTagName('style');
 309         for ($i = $styleTags->length-1; $i >= 0; $i--)
 310         {
 311             $styleTags->item($i)->parentNode->removeChild($styleTags->item($i));
 312         }
 313
 314         /* Turn all double br's into p's */
 315         /* Note, this is pretty costly as far as processing goes. Maybe optimize later. */
 316         //document.body.innerHTML = document.body.innerHTML.replace(readability.regexps.replaceBrs, '</p><p>').replace(readability.regexps.replaceFonts, '<$1span>');
 317         // We do this in the constructor for PHP as that's when we have raw HTML - before parsing it into a DOM tree.
 318         // Manipulating innerHTML as it's done in JS is not possible in PHP.
 319     }
 320
 321     /**
 322     * For easier reading, convert this document to have footnotes at the bottom rather than inline links.
 323     * @see http://www.roughtype.com/archives/2010/05/experiments_in.php
 324     *
 325     * @return void
 326     **/
 327     public function addFootnotes($articleContent) {
 328         $footnotesWrapper = $this->dom->createElement('div');
 329         $footnotesWrapper->setAttribute('id', 'readability-footnotes');
 330         $footnotesWrapper->innerHTML = '<h3>References</h3>';
 331
 332         $articleFootnotes = $this->dom->createElement('ol');
 333         $articleFootnotes->setAttribute('id', 'readability-footnotes-list');
 334         $footnotesWrapper->appendChild($articleFootnotes);
 335
 336         $articleLinks = $articleContent->getElementsByTagName('a');
 337
 338         $linkCount = 0;
 339         for ($i = 0; $i < $articleLinks->length; $i++)
 340         {
 341             $articleLink  = $articleLinks->item($i);
 342             $footnoteLink = $articleLink->cloneNode(true);
 343             $refLink      = $this->dom->createElement('a');
 344             $footnote     = $this->dom->createElement('li');
 345             $linkDomain   = @parse_url($footnoteLink->getAttribute('href'), PHP_URL_HOST);
 346             if (!$linkDomain && isset($this->url)) $linkDomain = @parse_url($this->url, PHP_URL_HOST);
 347             //linkDomain   = footnoteLink.host ? footnoteLink.host : document.location.host,
 348             $linkText     = $this->getInnerText($articleLink);
 349
 350             if ((strpos($articleLink->getAttribute('class'), 'readability-DoNotFootnote') !== false) || preg_match($this->regexps['skipFootnoteLink'], $linkText)) {
 351                 continue;
 352             }
 353
 354             $linkCount++;
 355
 356             /** Add a superscript reference after the article link */
 357             $refLink->setAttribute('href', '#readabilityFootnoteLink-' . $linkCount);
 358             $refLink->innerHTML = '<small><sup>[' . $linkCount . ']</sup></small>';
 359             $refLink->setAttribute('class', 'readability-DoNotFootnote');
 360             $refLink->setAttribute('style', 'color: inherit;');
 361
 362             //TODO: does this work or should we use DOMNode.isSameNode()?
 363             if ($articleLink->parentNode->lastChild == $articleLink) {
 364                 $articleLink->parentNode->appendChild($refLink);
 365             } else {
 366                 $articleLink->parentNode->insertBefore($refLink, $articleLink->nextSibling);
 367             }
 368
 369             $articleLink->setAttribute('style', 'color: inherit; text-decoration: none;');
 370             $articleLink->setAttribute('name', 'readabilityLink-' . $linkCount);
 371
 372             $footnote->innerHTML = '<small><sup><a href="#readabilityLink-' . $linkCount . '" title="Jump to Link in Article">^</a></sup></small> ';
 373
 374             $footnoteLink->innerHTML = ($footnoteLink->getAttribute('title') != '' ? $footnoteLink->getAttribute('title') : $linkText);
 375             $footnoteLink->setAttribute('name', 'readabilityFootnoteLink-' . $linkCount);
 376
 377             $footnote->appendChild($footnoteLink);
 378             if ($linkDomain) $footnote->innerHTML = $footnote->innerHTML . '<small> (' . $linkDomain . ')</small>';
 379
 380             $articleFootnotes->appendChild($footnote);
 381         }
 382
 383         if ($linkCount > 0) {
 384             $articleContent->appendChild($footnotesWrapper);
 385         }
 386     }
 387
 388     /**
 389     * Reverts P elements with class 'readability-styled'
 390     * to text nodes - which is what they were before.
 391     *
 392     * @param DOMElement
 393     * @return void
 394     */
 395     function revertReadabilityStyledElements($articleContent) {
 396         $xpath = new DOMXPath($articleContent->ownerDocument);
 397         $elems = $xpath->query('.//p[@class="readability-styled"]', $articleContent);
 398         //$elems = $articleContent->getElementsByTagName('p');
 399         for ($i = $elems->length-1; $i >= 0; $i--) {
 400             $e = $elems->item($i);
 401             $e->parentNode->replaceChild($articleContent->ownerDocument->createTextNode($e->textContent), $e);
 402             //if ($e->hasAttribute('class') && $e->getAttribute('class') == 'readability-styled') {
 403             //  $e->parentNode->replaceChild($this->dom->createTextNode($e->textContent), $e);
 404             //}
 405         }
 406     }
 407
 408     /**
 409     * Prepare the article node for display. Clean out any inline styles,
 410     * iframes, forms, strip extraneous <p> tags, etc.
 411     *
 412     * @param DOMElement
 413     * @return void
 414     */
 415     function prepArticle($articleContent) {
 416         $this->cleanStyles($articleContent);
 417         $this->killBreaks($articleContent);
 418         if ($this->revertForcedParagraphElements) {
 419             $this->revertReadabilityStyledElements($articleContent);
 420         }
 421
 422         /* Clean out junk from the article content */
 423         $this->cleanConditionally($articleContent, 'form');
 424         $this->clean($articleContent, 'object');
 425         $this->clean($articleContent, 'h1');
 426
 427         /**
 428         * If there is only one h2, they are probably using it
 429         * as a header and not a subheader, so remove it since we already have a header.
 430         ***/
 431         if (!$this->lightClean && ($articleContent->getElementsByTagName('h2')->length == 1)) {
 432             $this->clean($articleContent, 'h2');
 433         }
 434         $this->clean($articleContent, 'iframe');
 435
 436         $this->cleanHeaders($articleContent);
 437
 438         /* Do these last as the previous stuff may have removed junk that will affect these */
 439         $this->cleanConditionally($articleContent, 'table');
 440         $this->cleanConditionally($articleContent, 'ul');
 441         $this->cleanConditionally($articleContent, 'div');
 442
 443         /* Remove extra paragraphs */
 444         $articleParagraphs = $articleContent->getElementsByTagName('p');
 445         for ($i = $articleParagraphs->length-1; $i >= 0; $i--)
 446         {
 447             $imgCount    = $articleParagraphs->item($i)->getElementsByTagName('img')->length;
 448             $embedCount  = $articleParagraphs->item($i)->getElementsByTagName('embed')->length;
 449             $objectCount = $articleParagraphs->item($i)->getElementsByTagName('object')->length;
 450             $iframeCount = $articleParagraphs->item($i)->getElementsByTagName('iframe')->length;
 451
 452             if ($imgCount === 0 && $embedCount === 0 && $objectCount === 0 && $iframeCount === 0 && $this->getInnerText($articleParagraphs->item($i), false) == '')
 453             {
 454                 $articleParagraphs->item($i)->parentNode->removeChild($articleParagraphs->item($i));
 455             }
 456         }
 457
 458         try {
 459             $articleContent->innerHTML = preg_replace('/<br[^>]*>\s*<p/i', '<p', $articleContent->innerHTML);
 460             //articleContent.innerHTML = articleContent.innerHTML.replace(/<br[^>]*>\s*<p/gi, '<p');
 461         }
 462         catch (Exception $e) {
 463             $this->dbg("Cleaning innerHTML of breaks failed. This is an IE strict-block-elements bug. Ignoring.: " . $e);
 464         }
 465     }
 466
 467     /**
 468     * Initialize a node with the readability object. Also checks the
 469     * className/id for special names to add to its score.
 470     *
 471     * @param Element
 472     * @return void
 473     **/
 474     protected function initializeNode($node) {
 475         $readability = $this->dom->createAttribute('readability');
 476         $readability->value = 0; // this is our contentScore
 477         $node->setAttributeNode($readability);
 478
 479         switch (strtoupper($node->tagName)) { // unsure if strtoupper is needed, but using it just in case
 480             case 'DIV':
 481                 $readability->value += 5;
 482                 break;
 483
 484             case 'PRE':
 485             case 'TD':
 486             case 'BLOCKQUOTE':
 487                 $readability->value += 3;
 488                 break;
 489
 490             case 'ADDRESS':
 491             case 'OL':
 492             case 'UL':
 493             case 'DL':
 494             case 'DD':
 495             case 'DT':
 496             case 'LI':
 497             case 'FORM':
 498                 $readability->value -= 3;
 499                 break;
 500
 501             case 'H1':
 502             case 'H2':
 503             case 'H3':
 504             case 'H4':
 505             case 'H5':
 506             case 'H6':
 507             case 'TH':
 508                 $readability->value -= 5;
 509                 break;
 510         }
 511         $readability->value += $this->getClassWeight($node);
 512     }
 513
 514     /***
 515     * grabArticle - Using a variety of metrics (content score, classname, element types), find the content that is
 516     *               most likely to be the stuff a user wants to read. Then return it wrapped up in a div.
 517     *
 518     * @return DOMElement
 519     **/
 520     protected function grabArticle($page=null) {
 521         $stripUnlikelyCandidates = $this->flagIsActive(self::FLAG_STRIP_UNLIKELYS);
 522         if (!$page) $page = $this->dom;
 523         $allElements = $page->getElementsByTagName('*');
 524         /**
 525         * First, node prepping. Trash nodes that look cruddy (like ones with the class name "comment", etc), and turn divs
 526         * into P tags where they have been used inappropriately (as in, where they contain no other block level elements.)
 527         *
 528         * Note: Assignment from index for performance. See http://www.peachpit.com/articles/article.aspx?p=31567&seqNum=5
 529         * TODO: Shouldn't this be a reverse traversal?
 530         **/
 531         $node = null;
 532         $nodesToScore = array();
 533         for ($nodeIndex = 0; ($node = $allElements->item($nodeIndex)); $nodeIndex++) {
 534         //for ($nodeIndex=$targetList->length-1; $nodeIndex >= 0; $nodeIndex--) {
 535             //$node = $targetList->item($nodeIndex);
 536             $tagName = strtoupper($node->tagName);
 537             /* Remove unlikely candidates */
 538             if ($stripUnlikelyCandidates) {
 539                 $unlikelyMatchString = $node->getAttribute('class') . $node->getAttribute('id');
 540                 if (
 541                     preg_match($this->regexps['unlikelyCandidates'], $unlikelyMatchString) &&
 542                     !preg_match($this->regexps['okMaybeItsACandidate'], $unlikelyMatchString) &&
 543                     $tagName != 'BODY'
 544                 )
 545                 {
 546                     $this->dbg('Removing unlikely candidate - ' . $unlikelyMatchString);
 547                     //$nodesToRemove[] = $node;
 548                     $node->parentNode->removeChild($node);
 549                     $nodeIndex--;
 550                     continue;
 551                 }
 552             }
 553
 554             if ($tagName == 'P' || $tagName == 'TD' || $tagName == 'PRE') {
 555                 $nodesToScore[] = $node;
 556             }
 557
 558             /* Turn all divs that don't have children block level elements into p's */
 559             if ($tagName == 'DIV') {
 560                 if (!preg_match($this->regexps['divToPElements'], $node->innerHTML)) {
 561                     //$this->dbg('Altering div to p');
 562                     $newNode = $this->dom->createElement('p');
 563                     try {
 564                         $newNode->innerHTML = $node->innerHTML;
 565                         //$nodesToReplace[] = array('new'=>$newNode, 'old'=>$node);
 566                         $node->parentNode->replaceChild($newNode, $node);
 567                         $nodeIndex--;
 568                         $nodesToScore[] = $node; // or $newNode?
 569                     }
 570                     catch(Exception $e) {
 571                         $this->dbg('Could not alter div to p, reverting back to div.: ' . $e);
 572                     }
 573                 }
 574                 else
 575                 {
 576                     /* EXPERIMENTAL */
 577                     // TODO: change these p elements back to text nodes after processing
 578                     for ($i = 0, $il = $node->childNodes->length; $i < $il; $i++) {
 579                         $childNode = $node->childNodes->item($i);
 580                         if ($childNode->nodeType == 3) { // XML_TEXT_NODE
 581                             //$this->dbg('replacing text node with a p tag with the same content.');
 582                             $p = $this->dom->createElement('p');
 583                             $p->innerHTML = $childNode->nodeValue;
 584                             $p->setAttribute('style', 'display: inline;');
 585                             $p->setAttribute('class', 'readability-styled');
 586                             $childNode->parentNode->replaceChild($p, $childNode);
 587                         }
 588                     }
 589                 }
 590             }
 591         }
 592
 593         /**
 594         * Loop through all paragraphs, and assign a score to them based on how content-y they look.
 595         * Then add their score to their parent node.
 596         *
 597         * A score is determined by things like number of commas, class names, etc. Maybe eventually link density.
 598         **/
 599         $candidates = array();
 600         for ($pt=0; $pt < count($nodesToScore); $pt++) {
 601             $parentNode      = $nodesToScore[$pt]->parentNode;
 602             // $grandParentNode = $parentNode ? $parentNode->parentNode : null;
 603             $grandParentNode = !$parentNode ? null : (($parentNode->parentNode instanceof DOMElement) ? $parentNode->parentNode : null);
 604             $innerText       = $this->getInnerText($nodesToScore[$pt]);
 605
 606             if (!$parentNode || !isset($parentNode->tagName)) {
 607                 continue;
 608             }
 609
 610             /* If this paragraph is less than 25 characters, don't even count it. */
 611             if(strlen($innerText) < 25) {
 612                 continue;
 613             }
 614
 615             /* Initialize readability data for the parent. */
 616             if (!$parentNode->hasAttribute('readability'))
 617             {
 618                 $this->initializeNode($parentNode);
 619                 $candidates[] = $parentNode;
 620             }
 621
 622             /* Initialize readability data for the grandparent. */
 623             if ($grandParentNode && !$grandParentNode->hasAttribute('readability') && isset($grandParentNode->tagName))
 624             {
 625                 $this->initializeNode($grandParentNode);
 626                 $candidates[] = $grandParentNode;
 627             }
 628
 629             $contentScore = 0;
 630
 631             /* Add a point for the paragraph itself as a base. */
 632             $contentScore++;
 633
 634             /* Add points for any commas within this paragraph */
 635             $contentScore += count(explode(',', $innerText));
 636
 637             /* For every 100 characters in this paragraph, add another point. Up to 3 points. */
 638             $contentScore += min(floor(strlen($innerText) / 100), 3);
 639
 640             /* Add the score to the parent. The grandparent gets half. */
 641             $parentNode->getAttributeNode('readability')->value += $contentScore;
 642
 643             if ($grandParentNode) {
 644                 $grandParentNode->getAttributeNode('readability')->value += $contentScore/2;
 645             }
 646         }
 647
 648         /**
 649         * After we've calculated scores, loop through all of the possible candidate nodes we found
 650         * and find the one with the highest score.
 651         **/
 652         $topCandidate = null;
 653         for ($c=0, $cl=count($candidates); $c < $cl; $c++)
 654         {
 655             /**
 656             * Scale the final candidates score based on link density. Good content should have a
 657             * relatively small link density (5% or less) and be mostly unaffected by this operation.
 658             **/
 659             $readability = $candidates[$c]->getAttributeNode('readability');
 660             $readability->value = $readability->value * (1-$this->getLinkDensity($candidates[$c]));
 661
 662             $this->dbg('Candidate: ' . $candidates[$c]->tagName . ' (' . $candidates[$c]->getAttribute('class') . ':' . $candidates[$c]->getAttribute('id') . ') with score ' . $readability->value);
 663
 664             if (!$topCandidate || $readability->value > (int)$topCandidate->getAttribute('readability')) {
 665                 $topCandidate = $candidates[$c];
 666             }
 667         }
 668
 669         /**
 670         * If we still have no top candidate, just use the body as a last resort.
 671         * We also have to copy the body node so it is something we can modify.
 672         **/
 673         if ($topCandidate === null || strtoupper($topCandidate->tagName) == 'BODY')
 674         {
 675             $topCandidate = $this->dom->createElement('div');
 676             if ($page instanceof DOMDocument) {
 677                 if (!isset($page->documentElement)) {
 678                     // we don't have a body either? what a mess! :)
 679                 } else {
 680                     $topCandidate->innerHTML = $page->documentElement->innerHTML;
 681                     $page->documentElement->innerHTML = '';
 682                     $page->documentElement->appendChild($topCandidate);
 683                 }
 684             } else {
 685                 $topCandidate->innerHTML = $page->innerHTML;
 686                 $page->innerHTML = '';
 687                 $page->appendChild($topCandidate);
 688             }
 689             $this->initializeNode($topCandidate);
 690         }
 691
 692         /**
 693         * Now that we have the top candidate, look through its siblings for content that might also be related.
 694         * Things like preambles, content split by ads that we removed, etc.
 695         **/
 696         $articleContent        = $this->dom->createElement('div');
 697         $articleContent->setAttribute('id', 'readability-content');
 698         $siblingScoreThreshold = max(10, ((int)$topCandidate->getAttribute('readability')) * 0.2);
 699         $siblingNodes          = $topCandidate->parentNode->childNodes;
 700         if (!isset($siblingNodes)) {
 701             $siblingNodes = new stdClass;
 702             $siblingNodes->length = 0;
 703         }
 704
 705         for ($s=0, $sl=$siblingNodes->length; $s < $sl; $s++)
 706         {
 707             $siblingNode = $siblingNodes->item($s);
 708             $append      = false;
 709
 710             $this->dbg('Looking at sibling node: ' . $siblingNode->nodeName . (($siblingNode->nodeType === XML_ELEMENT_NODE && $siblingNode->hasAttribute('readability')) ? (' with score ' . $siblingNode->getAttribute('readability')) : ''));
 711
 712             //dbg('Sibling has score ' . ($siblingNode->readability ? siblingNode.readability.contentScore : 'Unknown'));
 713
 714             if ($siblingNode === $topCandidate)
 715             // or if ($siblingNode->isSameNode($topCandidate))
 716             {
 717                 $append = true;
 718             }
 719
 720             $contentBonus = 0;
 721             /* Give a bonus if sibling nodes and top candidates have the example same classname */
 722             if ($siblingNode->nodeType === XML_ELEMENT_NODE && $siblingNode->getAttribute('class') == $topCandidate->getAttribute('class') && $topCandidate->getAttribute('class') != '') {
 723                 $contentBonus += ((int)$topCandidate->getAttribute('readability')) * 0.2;
 724             }
 725
 726             if ($siblingNode->nodeType === XML_ELEMENT_NODE && $siblingNode->hasAttribute('readability') && (((int)$siblingNode->getAttribute('readability')) + $contentBonus) >= $siblingScoreThreshold)
 727             {
 728                 $append = true;
 729             }
 730
 731             if (strtoupper($siblingNode->nodeName) == 'P') {
 732                 $linkDensity = $this->getLinkDensity($siblingNode);
 733                 $nodeContent = $this->getInnerText($siblingNode);
 734                 $nodeLength  = strlen($nodeContent);
 735
 736                 if ($nodeLength > 80 && $linkDensity < 0.25)
 737                 {
 738                     $append = true;
 739                 }
 740                 else if ($nodeLength < 80 && $linkDensity === 0 && preg_match('/\.( |$)/', $nodeContent))
 741                 {
 742                     $append = true;
 743                 }
 744             }
 745
 746             if ($append)
 747             {
 748                 $this->dbg('Appending node: ' . $siblingNode->nodeName);
 749
 750                 $nodeToAppend = null;
 751                 $sibNodeName = strtoupper($siblingNode->nodeName);
 752                 if ($sibNodeName != 'DIV' && $sibNodeName != 'P') {
 753                     /* We have a node that isn't a common block level element, like a form or td tag. Turn it into a div so it doesn't get filtered out later by accident. */
 754
 755                     $this->dbg('Altering siblingNode of ' . $sibNodeName . ' to div.');
 756                     $nodeToAppend = $this->dom->createElement('div');
 757                     try {
 758                         $nodeToAppend->setAttribute('id', $siblingNode->getAttribute('id'));
 759                         $nodeToAppend->innerHTML = $siblingNode->innerHTML;
 760                     }
 761                     catch(Exception $e)
 762                     {
 763                         $this->dbg('Could not alter siblingNode to div, reverting back to original.');
 764                         $nodeToAppend = $siblingNode;
 765                         $s--;
 766                         $sl--;
 767                     }
 768                 } else {
 769                     $nodeToAppend = $siblingNode;
 770                     $s--;
 771                     $sl--;
 772                 }
 773
 774                 /* To ensure a node does not interfere with readability styles, remove its classnames */
 775                 $nodeToAppend->removeAttribute('class');
 776
 777                 /* Append sibling and subtract from our list because it removes the node when you append to another node */
 778                 $articleContent->appendChild($nodeToAppend);
 779             }
 780         }
 781
 782         /**
 783         * So we have all of the content that we need. Now we clean it up for presentation.
 784         **/
 785         $this->prepArticle($articleContent);
 786
 787         /**
 788         * Now that we've gone through the full algorithm, check to see if we got any meaningful content.
 789         * If we didn't, we may need to re-run grabArticle with different flags set. This gives us a higher
 790         * likelihood of finding the content, and the sieve approach gives us a higher likelihood of
 791         * finding the -right- content.
 792         **/
 793         if (strlen($this->getInnerText($articleContent, false)) < 250)
 794         {
 795             // TODO: find out why element disappears sometimes, e.g. for this URL http://www.businessinsider.com/6-hedge-fund-etfs-for-average-investors-2011-7
 796             // in the meantime, we check and create an empty element if it's not there.
 797             if (!isset($this->body->childNodes)) $this->body = $this->dom->createElement('body');
 798             $this->body->innerHTML = $this->bodyCache;
 799
 800             if ($this->flagIsActive(self::FLAG_STRIP_UNLIKELYS)) {
 801                 $this->removeFlag(self::FLAG_STRIP_UNLIKELYS);
 802                 return $this->grabArticle($this->body);
 803             }
 804             else if ($this->flagIsActive(self::FLAG_WEIGHT_CLASSES)) {
 805                 $this->removeFlag(self::FLAG_WEIGHT_CLASSES);
 806                 return $this->grabArticle($this->body);
 807             }
 808             else if ($this->flagIsActive(self::FLAG_CLEAN_CONDITIONALLY)) {
 809                 $this->removeFlag(self::FLAG_CLEAN_CONDITIONALLY);
 810                 return $this->grabArticle($this->body);
 811             }
 812             else {
 813                 return false;
 814             }
 815         }
 816         return $articleContent;
 817     }
 818
 819     /**
 820     * Remove script tags from document
 821     *
 822     * @param DOMElement
 823     * @return void
 824     */
 825     public function removeScripts($doc) {
 826         $scripts = $doc->getElementsByTagName('script');
 827         for($i = $scripts->length-1; $i >= 0; $i--)
 828         {
 829             $scripts->item($i)->parentNode->removeChild($scripts->item($i));
 830         }
 831     }
 832
 833     /**
 834     * Get the inner text of a node.
 835     * This also strips out any excess whitespace to be found.
 836     *
 837     * @param DOMElement $
 838     * @param boolean $normalizeSpaces (default: true)
 839     * @return string
 840     **/
 841     public function getInnerText($e, $normalizeSpaces=true) {
 842         $textContent = '';
 843
 844         if (!isset($e->textContent) || $e->textContent == '') {
 845             return '';
 846         }
 847
 848         $textContent = trim($e->textContent);
 849
 850         if ($normalizeSpaces) {
 851             return preg_replace($this->regexps['normalize'], ' ', $textContent);
 852         } else {
 853             return $textContent;
 854         }
 855     }
 856
 857     /**
 858     * Get the number of times a string $s appears in the node $e.
 859     *
 860     * @param DOMElement $e
 861     * @param string - what to count. Default is ","
 862     * @return number (integer)
 863     **/
 864     public function getCharCount($e, $s=',') {
 865         return substr_count($this->getInnerText($e), $s);
 866     }
 867
 868     /**
 869     * Remove the style attribute on every $e and under.
 870     *
 871     * @param DOMElement $e
 872     * @return void
 873     */
 874     public function cleanStyles($e) {
 875         if (!is_object($e)) return;
 876         $elems = $e->getElementsByTagName('*');
 877         foreach ($elems as $elem) {
 878             $elem->removeAttribute('style');
 879         }
 880     }
 881
 882     /**
 883     * Get the density of links as a percentage of the content
 884     * This is the amount of text that is inside a link divided by the total text in the node.
 885     *
 886     * @param DOMElement $e
 887     * @return number (float)
 888     */
 889     public function getLinkDensity($e) {
 890         $links      = $e->getElementsByTagName('a');
 891         $textLength = strlen($this->getInnerText($e));
 892         $linkLength = 0;
 893         for ($i=0, $il=$links->length; $i < $il; $i++)
 894         {
 895             $linkLength += strlen($this->getInnerText($links->item($i)));
 896         }
 897         if ($textLength > 0) {
 898             return $linkLength / $textLength;
 899         } else {
 900             return 0;
 901         }
 902     }
 903
 904     /**
 905     * Get an elements class/id weight. Uses regular expressions to tell if this
 906     * element looks good or bad.
 907     *
 908     * @param DOMElement $e
 909     * @return number (Integer)
 910     */
 911     public function getClassWeight($e) {
 912         if(!$this->flagIsActive(self::FLAG_WEIGHT_CLASSES)) {
 913             return 0;
 914         }
 915
 916         $weight = 0;
 917
 918         /* Look for a special classname */
 919         if ($e->hasAttribute('class') && $e->getAttribute('class') != '')
 920         {
 921             if (preg_match($this->regexps['negative'], $e->getAttribute('class'))) {
 922                 $weight -= 25;
 923             }
 924             if (preg_match($this->regexps['positive'], $e->getAttribute('class'))) {
 925                 $weight += 25;
 926             }
 927         }
 928
 929         /* Look for a special ID */
 930         if ($e->hasAttribute('id') && $e->getAttribute('id') != '')
 931         {
 932             if (preg_match($this->regexps['negative'], $e->getAttribute('id'))) {
 933                 $weight -= 25;
 934             }
 935             if (preg_match($this->regexps['positive'], $e->getAttribute('id'))) {
 936                 $weight += 25;
 937             }
 938         }
 939         return $weight;
 940     }
 941
 942     /**
 943     * Remove extraneous break tags from a node.
 944     *
 945     * @param DOMElement $node
 946     * @return void
 947     */
 948     public function killBreaks($node) {
 949         $html = $node->innerHTML;
 950         $html = preg_replace($this->regexps['killBreaks'], '<br />', $html);
 951         $node->innerHTML = $html;
 952     }
 953
 954     /**
 955     * Clean a node of all elements of type "tag".
 956     * (Unless it's a youtube/vimeo video. People love movies.)
 957     *
 958     * Updated 2012-09-18 to preserve youtube/vimeo iframes
 959     *
 960     * @param DOMElement $e
 961     * @param string $tag
 962     * @return void
 963     */
 964     public function clean($e, $tag) {
 965         $targetList = $e->getElementsByTagName($tag);
 966         $isEmbed = ($tag == 'iframe' || $tag == 'object' || $tag == 'embed');
 967
 968         for ($y=$targetList->length-1; $y >= 0; $y--) {
 969             /* Allow youtube and vimeo videos through as people usually want to see those. */
 970             if ($isEmbed) {
 971                 $attributeValues = '';
 972                 for ($i=0, $il=$targetList->item($y)->attributes->length; $i < $il; $i++) {
 973                     $attributeValues .= $targetList->item($y)->attributes->item($i)->value . '|'; // DOMAttr? (TODO: test)
 974                 }
 975
 976                 /* First, check the elements attributes to see if any of them contain youtube or vimeo */
 977                 if (preg_match($this->regexps['video'], $attributeValues)) {
 978                     continue;
 979                 }
 980
 981                 /* Then check the elements inside this element for the same. */
 982                 if (preg_match($this->regexps['video'], $targetList->item($y)->innerHTML)) {
 983                     continue;
 984                 }
 985             }
 986             $targetList->item($y)->parentNode->removeChild($targetList->item($y));
 987         }
 988     }
 989
 990     /**
 991     * Clean an element of all tags of type "tag" if they look fishy.
 992     * "Fishy" is an algorithm based on content length, classnames,
 993     * link density, number of images & embeds, etc.
 994     *
 995     * @param DOMElement $e
 996     * @param string $tag
 997     * @return void
 998     */
 999     public function cleanConditionally($e, $tag) {
1000         if (!$this->flagIsActive(self::FLAG_CLEAN_CONDITIONALLY)) {
1001             return;
1002         }
1003
1004         $tagsList = $e->getElementsByTagName($tag);
1005         $curTagsLength = $tagsList->length;
1006
1007         /**
1008         * Gather counts for other typical elements embedded within.
1009         * Traverse backwards so we can remove nodes at the same time without effecting the traversal.
1010         *
1011         * TODO: Consider taking into account original contentScore here.
1012         */
1013         for ($i=$curTagsLength-1; $i >= 0; $i--) {
1014             $weight = $this->getClassWeight($tagsList->item($i));
1015             $contentScore = ($tagsList->item($i)->hasAttribute('readability')) ? (int)$tagsList->item($i)->getAttribute('readability') : 0;
1016
1017             $this->dbg('Cleaning Conditionally ' . $tagsList->item($i)->tagName . ' (' . $tagsList->item($i)->getAttribute('class') . ':' . $tagsList->item($i)->getAttribute('id') . ')' . (($tagsList->item($i)->hasAttribute('readability')) ? (' with score ' . $tagsList->item($i)->getAttribute('readability')) : ''));
1018
1019             if ($weight + $contentScore < 0) {
1020                 $tagsList->item($i)->parentNode->removeChild($tagsList->item($i));
1021             }
1022             else if ( $this->getCharCount($tagsList->item($i), ',') < 10) {
1023                 /**
1024                 * If there are not very many commas, and the number of
1025                 * non-paragraph elements is more than paragraphs or other ominous signs, remove the element.
1026                 **/
1027                 $p      = $tagsList->item($i)->getElementsByTagName('p')->length;
1028                 $img    = $tagsList->item($i)->getElementsByTagName('img')->length;
1029                 $li     = $tagsList->item($i)->getElementsByTagName('li')->length-100;
1030                 $input  = $tagsList->item($i)->getElementsByTagName('input')->length;
1031                 $a      = $tagsList->item($i)->getElementsByTagName('a')->length;
1032
1033                 $embedCount = 0;
1034                 $embeds = $tagsList->item($i)->getElementsByTagName('embed');
1035                 for ($ei=0, $il=$embeds->length; $ei < $il; $ei++) {
1036                     if (preg_match($this->regexps['video'], $embeds->item($ei)->getAttribute('src'))) {
1037                         $embedCount++;
1038                     }
1039                 }
1040                 $embeds = $tagsList->item($i)->getElementsByTagName('iframe');
1041                 for ($ei=0, $il=$embeds->length; $ei < $il; $ei++) {
1042                     if (preg_match($this->regexps['video'], $embeds->item($ei)->getAttribute('src'))) {
1043                         $embedCount++;
1044                     }
1045                 }
1046
1047                 $linkDensity   = $this->getLinkDensity($tagsList->item($i));
1048                 $contentLength = strlen($this->getInnerText($tagsList->item($i)));
1049                 $toRemove      = false;
1050
1051                 if ($this->lightClean) {
1052                     $this->dbg('Light clean...');
1053                     if ( ($img > $p) && ($img > 4) ) {
1054                         $this->dbg(' more than 4 images and more image elements than paragraph elements');
1055                         $toRemove = true;
1056                     } else if ($li > $p && $tag != 'ul' && $tag != 'ol') {
1057                         $this->dbg(' too many <li> elements, and parent is not <ul> or <ol>');
1058                         $toRemove = true;
1059                     } else if ( $input > floor($p/3) ) {
1060                         $this->dbg(' too many <input> elements');
1061                         $toRemove = true;
1062                     } else if ($contentLength < 25 && ($embedCount === 0 && ($img === 0 || $img > 2))) {
1063                         $this->dbg(' content length less than 25 chars, 0 embeds and either 0 images or more than 2 images');
1064                         $toRemove = true;
1065                     } else if($weight < 25 && $linkDensity > 0.2) {
1066                         $this->dbg(' weight smaller than 25 and link density above 0.2');
1067                         $toRemove = true;
1068                     } else if($a > 2 && ($weight >= 25 && $linkDensity > 0.5)) {
1069                         $this->dbg(' more than 2 links and weight above 25 but link density greater than 0.5');
1070                         $toRemove = true;
1071                     } else if($embedCount > 3) {
1072                         $this->dbg(' more than 3 embeds');
1073                         $toRemove = true;
1074                     }
1075                 } else {
1076                     $this->dbg('Standard clean...');
1077                     if ( $img > $p ) {
1078                         $this->dbg(' more image elements than paragraph elements');
1079                         $toRemove = true;
1080                     } else if ($li > $p && $tag != 'ul' && $tag != 'ol') {
1081                         $this->dbg(' too many <li> elements, and parent is not <ul> or <ol>');
1082                         $toRemove = true;
1083                     } else if ( $input > floor($p/3) ) {
1084                         $this->dbg(' too many <input> elements');
1085                         $toRemove = true;
1086                     } else if ($contentLength < 25 && ($img === 0 || $img > 2) ) {
1087                         $this->dbg(' content length less than 25 chars and 0 images, or more than 2 images');
1088                         $toRemove = true;
1089                     } else if($weight < 25 && $linkDensity > 0.2) {
1090                         $this->dbg(' weight smaller than 25 and link density above 0.2');
1091                         $toRemove = true;
1092                     } else if($weight >= 25 && $linkDensity > 0.5) {
1093                         $this->dbg(' weight above 25 but link density greater than 0.5');
1094                         $toRemove = true;
1095                     } else if(($embedCount == 1 && $contentLength < 75) || $embedCount > 1) {
1096                         $this->dbg(' 1 embed and content length smaller than 75 chars, or more than one embed');
1097                         $toRemove = true;
1098                     }
1099                 }
1100
1101                 if ($toRemove) {
1102                     //$this->dbg('Removing: '.$tagsList->item($i)->innerHTML);
1103                     $tagsList->item($i)->parentNode->removeChild($tagsList->item($i));
1104                 }
1105             }
1106         }
1107     }
1108
1109     /**
1110     * Clean out spurious headers from an Element. Checks things like classnames and link density.
1111     *
1112     * @param DOMElement $e
1113     * @return void
1114     */
1115     public function cleanHeaders($e) {
1116         for ($headerIndex = 1; $headerIndex < 3; $headerIndex++) {
1117             $headers = $e->getElementsByTagName('h' . $headerIndex);
1118             for ($i=$headers->length-1; $i >=0; $i--) {
1119                 if ($this->getClassWeight($headers->item($i)) < 0 || $this->getLinkDensity($headers->item($i)) > 0.33) {
1120                     $headers->item($i)->parentNode->removeChild($headers->item($i));
1121                 }
1122             }
1123         }
1124     }
1125
1126     public function flagIsActive($flag) {
1127         return ($this->flags & $flag) > 0;
1128     }
1129
1130     public function addFlag($flag) {
1131         $this->flags = $this->flags | $flag;
1132     }
1133
1134     public function removeFlag($flag) {
1135         $this->flags = $this->flags & ~$flag;
1136     }
1137 }