inc/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 * ------------------------------------------------------
   6 * Original URL: http://lab.arc90.com/experiments/readability/js/readability.js
   7 * Arc90's project URL: http://lab.arc90.com/experiments/readability/
   8 * JS Source: http://code.google.com/p/arc90labs-readability
   9 * Ported by: Keyvan Minoukadeh, http://www.keyvan.net
  10 * More information: http://fivefilters.org/content-only/
  11 * License: Apache License, Version 2.0
  12 * Requires: PHP5
  13 * Date: 2011-07-22
  14 *
  15 * Differences between the PHP port and the original
  16 * ------------------------------------------------------
  17 * Arc90's Readability is designed to run in the browser. It works on the DOM
  18 * tree (the parsed HTML) after the page's CSS styles have been applied and
  19 * Javascript code executed. This PHP port does not run inside a browser.
  20 * We use PHP's ability to parse HTML to build our DOM tree, but we cannot
  21 * rely on CSS or Javascript support. As such, the results will not always
  22 * match Arc90's Readability. (For example, if a web page contains CSS style
  23 * rules or Javascript code which hide certain HTML elements from display,
  24 * Arc90's Readability will dismiss those from consideration but our PHP port,
  25 * unable to understand CSS or Javascript, will not know any better.)
  26 *
  27 * Another significant difference is that the aim of Arc90's Readability is
  28 * to re-present the main content block of a given web page so users can
  29 * read it more easily in their browsers. Correct identification, clean up,
  30 * and separation of the content block is only a part of this process.
  31 * This PHP port is only concerned with this part, it does not include code
  32 * that relates to presentation in the browser - Arc90 already do
  33 * that extremely well, and for PDF output there's FiveFilters.org's
  34 * PDF Newspaper: http://fivefilters.org/pdf-newspaper/.
  35 *
  36 * Finally, this class contains methods that might be useful for developers
  37 * working on HTML document fragments. So without deviating too much from
  38 * the original code (which I don't want to do because it makes debugging
  39 * and updating more difficult), I've tried to make it a little more
  40 * developer friendly. You should be able to use the methods here on
  41 * existing DOMElement objects without passing an entire HTML document to
  42 * be parsed.
  43 */
  44
  45 // This class allows us to do JavaScript like assignements to innerHTML
  46 require_once(dirname(__FILE__).'/JSLikeHTMLElement.php');
  47
  48 // Alternative usage (for testing only!)
  49 // uncomment the lines below and call Readability.php in your browser
  50 // passing it the URL of the page you'd like content from, e.g.:
  51 // Readability.php?url=http://medialens.org/alerts/09/090615_the_guardian_climate.php
  52
  53 /*
  54 if (!isset($_GET['url']) || $_GET['url'] == '') {
  55         die('Please pass a URL to the script. E.g. Readability.php?url=bla.com/story.html');
  56 }
  57 $url = $_GET['url'];
  58 if (!preg_match('!^https?://!i', $url)) $url = 'http://'.$url;
  59 $html = file_get_contents($url);
  60 $r = new Readability($html, $url);
  61 $r->init();
  62 echo $r->articleContent->innerHTML;
  63 */
  64
  65
  66 class Readability
  67 {
  68         /* constants */
  69         const FLAG_STRIP_UNLIKELYS = 1;
  70         const FLAG_WEIGHT_CLASSES = 2;
  71         const FLAG_CLEAN_CONDITIONALLY = 4;
  72
  73         public $version = '1.7.1-without-multi-page';
  74         public $convertLinksToFootnotes = false;
  75         public $revertForcedParagraphElements = true;
  76         public $articleTitle;
  77         public $articleContent;
  78         public $dom;
  79         public $url = null; // optional - URL where HTML was retrieved
  80         public $debug = false;
  81         protected $body = null; //
  82         protected $bodyCache = null; // Cache the body HTML in case we need to re-use it later
  83         protected $flags = self::FLAG_CLEAN_CONDITIONALLY; // 1 | 2 | 4;   // Start with all flags set.
  84         protected $success = false; // indicates whether we were able to extract or not
  85
  86         /**
  87         * All of the regular expressions in use within readability.
  88         * Defined up here so we don't instantiate them repeatedly in loops.
  89         **/
  90         public $regexps = array(
  91                 'unlikelyCandidates' => '/combx|comment|comments|community|disqus|extra|foot|header|menu|remark|rss|shoutbox|sidebar|sponsor|ad-break|agegate|pagination|pager|popup|tweet|twitter/i',
  92                 'okMaybeItsACandidate' => '/and|article|body|column|main|shadow/i',
  93                 'positive' => '/article|body|content|entry|hentry|main|page|pagination|post|text|blog|story/i',
  94                 'negative' => '/combx|comment|comments|com-|contact|foot|footer|footnote|masthead|media|meta|outbrain|promo|related|scroll|shoutbox|sidebar|sponsor|shopping|tags|tool|widget/i',
  95                 'divToPElements' => '/<(a|blockquote|dl|div|ol|p|pre|table|ul)/i',
  96                 'replaceBrs' => '/(<br[^>]*>[ \n\r\t]*){2,}/i',
  97                 'replaceFonts' => '/<(\/?)font[^>]*>/i',
  98                 // 'trimRe' => '/^\s+|\s+$/g', // PHP has trim()
  99                 'normalize' => '/\s{2,}/',
 100                 'killBreaks' => '/(<br\s*\/?>(\s|&nbsp;?)*){1,}/',
 101                 'video' => '/http:\/\/(www\.)?(youtube|vimeo|dailymotion)\.com/i',
 102                 'skipFootnoteLink' => '/^\s*(\[?[a-z0-9]{1,2}\]?|^|edit|citation needed)\s*$/i'
 103         );
 104
 105         /**
 106         * Create instance of Readability
 107         * @param string UTF-8 encoded string
 108         * @param string (optional) URL associated with HTML (used for footnotes)
 109         */
 110         function __construct($html, $url=null)
 111         {
 112                 /* Turn all double br's into p's */
 113                 $html = preg_replace($this->regexps['replaceBrs'], '</p><p>', $html);
 114                 $html = preg_replace($this->regexps['replaceFonts'], '<$1span>', $html);
 115                 $html = mb_convert_encoding($html, 'HTML-ENTITIES', "UTF-8");
 116                 $this->dom = new DOMDocument();
 117                 $this->dom->preserveWhiteSpace = false;
 118                 $this->dom->registerNodeClass('DOMElement', 'JSLikeHTMLElement');
 119                 if (trim($html) == '') $html = '<html></html>';
 120                 @$this->dom->loadHTML($html);
 121                 $this->url = $url;
 122         }
 123
 124         /**
 125         * Get article title element
 126         * @return DOMElement
 127         */
 128         public function getTitle() {
 129                 return $this->articleTitle;
 130         }
 131
 132         /**
 133         * Get article content element
 134         * @return DOMElement
 135         */
 136         public function getContent() {
 137                 return $this->articleContent;
 138         }
 139
 140         /**
 141         * Runs readability.
 142         *
 143         * Workflow:
 144         *  1. Prep the document by removing script tags, css, etc.
 145         *  2. Build readability's DOM tree.
 146         *  3. Grab the article content from the current dom tree.
 147         *  4. Replace the current DOM tree with the new one.
 148         *  5. Read peacefully.
 149         *
 150         * @return boolean true if we found content, false otherwise
 151         **/
 152         public function init()
 153         {
 154                 if (!isset($this->dom->documentElement)) return false;
 155                 $this->removeScripts($this->dom);
 156                 //die($this->getInnerHTML($this->dom->documentElement));
 157
 158                 // Assume successful outcome
 159                 $this->success = true;
 160
 161                 $bodyElems = $this->dom->getElementsByTagName('body');
 162                 if ($bodyElems->length > 0) {
 163                         if ($this->bodyCache == null) {
 164                                 $this->bodyCache = $bodyElems->item(0)->innerHTML;
 165                         }
 166                         if ($this->body == null) {
 167                                 $this->body = $bodyElems->item(0);
 168                         }
 169                 }
 170
 171                 $this->prepDocument();
 172
 173                 //die($this->dom->documentElement->parentNode->nodeType);
 174                 //$this->setInnerHTML($this->dom->documentElement, $this->getInnerHTML($this->dom->documentElement));
 175                 //die($this->getInnerHTML($this->dom->documentElement));
 176
 177                 /* Build readability's DOM tree */
 178                 $overlay        = $this->dom->createElement('div');
 179                 $innerDiv       = $this->dom->createElement('div');
 180                 $articleTitle   = $this->getArticleTitle();
 181                 $articleContent = $this->grabArticle();
 182
 183                 if (!$articleContent) {
 184                         $this->success = false;
 185                         $articleContent = $this->dom->createElement('div');
 186                         $articleContent->setAttribute('id', 'readability-content');
 187                         $articleContent->innerHTML = '<p>Sorry, Readability was unable to parse this page for content.</p>';
 188                 }
 189
 190                 $overlay->setAttribute('id', 'readOverlay');
 191                 $innerDiv->setAttribute('id', 'readInner');
 192
 193                 /* Glue the structure of our document together. */
 194                 $innerDiv->appendChild($articleTitle);
 195                 $innerDiv->appendChild($articleContent);
 196                 $overlay->appendChild($innerDiv);
 197
 198                 /* Clear the old HTML, insert the new content. */
 199                 $this->body->innerHTML = '';
 200                 $this->body->appendChild($overlay);
 201                 //document.body.insertBefore(overlay, document.body.firstChild);
 202                 $this->body->removeAttribute('style');
 203
 204                 $this->postProcessContent($articleContent);
 205
 206                 // Set title and content instance variables
 207                 $this->articleTitle = $articleTitle;
 208                 $this->articleContent = $articleContent;
 209
 210                 return $this->success;
 211         }
 212
 213         /**
 214         * Debug
 215         */
 216         protected function dbg($msg) {
 217                 if ($this->debug) echo '* ',$msg, '<br />', "\n";
 218         }
 219
 220         /**
 221         * Run any post-process modifications to article content as necessary.
 222         *
 223         * @param DOMElement
 224         * @return void
 225         */
 226         public function postProcessContent($articleContent) {
 227                 if ($this->convertLinksToFootnotes && !preg_match('/wikipedia\.org/', @$this->url)) {
 228                         $this->addFootnotes($articleContent);
 229                 }
 230         }
 231
 232         /**
 233         * Get the article title as an H1.
 234         *
 235         * @return DOMElement
 236         */
 237         protected function getArticleTitle() {
 238                 $curTitle = '';
 239                 $origTitle = '';
 240
 241                 try {
 242                         $curTitle = $origTitle = $this->getInnerText($this->dom->getElementsByTagName('title')->item(0));
 243                 } catch(Exception $e) {}
 244
 245                 if (preg_match('/ [\|\-] /', $curTitle))
 246                 {
 247                         $curTitle = preg_replace('/(.*)[\|\-] .*/i', '$1', $origTitle);
 248
 249                         if (count(explode(' ', $curTitle)) < 3) {
 250                                 $curTitle = preg_replace('/[^\|\-]*[\|\-](.*)/i', '$1', $origTitle);
 251                         }
 252                 }
 253                 else if (strpos($curTitle, ': ') !== false)
 254                 {
 255                         $curTitle = preg_replace('/.*:(.*)/i', '$1', $origTitle);
 256
 257                         if (count(explode(' ', $curTitle)) < 3) {
 258                                 $curTitle = preg_replace('/[^:]*[:](.*)/i','$1', $origTitle);
 259                         }
 260                 }
 261                 else if(strlen($curTitle) > 150 || strlen($curTitle) < 15)
 262                 {
 263                         $hOnes = $this->dom->getElementsByTagName('h1');
 264                         if($hOnes->length == 1)
 265                         {
 266                                 $curTitle = $this->getInnerText($hOnes->item(0));
 267                         }
 268                 }
 269
 270                 $curTitle = trim($curTitle);
 271
 272                 if (count(explode(' ', $curTitle)) <= 4) {
 273                         $curTitle = $origTitle;
 274                 }
 275
 276                 $articleTitle = $this->dom->createElement('h1');
 277                 $articleTitle->innerHTML = $curTitle;
 278
 279                 return $articleTitle;
 280         }
 281
 282         /**
 283         * Prepare the HTML document for readability to scrape it.
 284         * This includes things like stripping javascript, CSS, and handling terrible markup.
 285         *
 286         * @return void
 287         **/
 288         protected function prepDocument() {
 289                 /**
 290                 * In some cases a body element can't be found (if the HTML is totally hosed for example)
 291                 * so we create a new body node and append it to the document.
 292                 */
 293                 if ($this->body == null)
 294                 {
 295                         $this->body = $this->dom->createElement('body');
 296                         $this->dom->documentElement->appendChild($this->body);
 297                 }
 298                 $this->body->setAttribute('id', 'readabilityBody');
 299
 300                 /* Remove all style tags in head */
 301                 $styleTags = $this->dom->getElementsByTagName('style');
 302                 for ($i = $styleTags->length-1; $i >= 0; $i--)
 303                 {
 304                         $styleTags->item($i)->parentNode->removeChild($styleTags->item($i));
 305                 }
 306
 307                 /* Turn all double br's into p's */
 308                 /* Note, this is pretty costly as far as processing goes. Maybe optimize later. */
 309                 //document.body.innerHTML = document.body.innerHTML.replace(readability.regexps.replaceBrs, '</p><p>').replace(readability.regexps.replaceFonts, '<$1span>');
 310                 // We do this in the constructor for PHP as that's when we have raw HTML - before parsing it into a DOM tree.
 311                 // Manipulating innerHTML as it's done in JS is not possible in PHP.
 312         }
 313
 314         /**
 315         * For easier reading, convert this document to have footnotes at the bottom rather than inline links.
 316         * @see http://www.roughtype.com/archives/2010/05/experiments_in.php
 317         *
 318         * @return void
 319         **/
 320         public function addFootnotes($articleContent) {
 321                 $footnotesWrapper = $this->dom->createElement('div');
 322                 $footnotesWrapper->setAttribute('id', 'readability-footnotes');
 323                 $footnotesWrapper->innerHTML = '<h3>References</h3>';
 324
 325                 $articleFootnotes = $this->dom->createElement('ol');
 326                 $articleFootnotes->setAttribute('id', 'readability-footnotes-list');
 327                 $footnotesWrapper->appendChild($articleFootnotes);
 328
 329                 $articleLinks = $articleContent->getElementsByTagName('a');
 330
 331                 $linkCount = 0;
 332                 for ($i = 0; $i < $articleLinks->length; $i++)
 333                 {
 334                         $articleLink  = $articleLinks->item($i);
 335                         $footnoteLink = $articleLink->cloneNode(true);
 336                         $refLink      = $this->dom->createElement('a');
 337                         $footnote     = $this->dom->createElement('li');
 338                         $linkDomain   = @parse_url($footnoteLink->getAttribute('href'), PHP_URL_HOST);
 339                         if (!$linkDomain && isset($this->url)) $linkDomain = @parse_url($this->url, PHP_URL_HOST);
 340                         //linkDomain   = footnoteLink.host ? footnoteLink.host : document.location.host,
 341                         $linkText     = $this->getInnerText($articleLink);
 342
 343                         if ((strpos($articleLink->getAttribute('class'), 'readability-DoNotFootnote') !== false) || preg_match($this->regexps['skipFootnoteLink'], $linkText)) {
 344                                 continue;
 345                         }
 346
 347                         $linkCount++;
 348
 349                         /** Add a superscript reference after the article link */
 350                         $refLink->setAttribute('href', '#readabilityFootnoteLink-' . $linkCount);
 351                         $refLink->innerHTML = '<small><sup>[' . $linkCount . ']</sup></small>';
 352                         $refLink->setAttribute('class', 'readability-DoNotFootnote');
 353                         $refLink->setAttribute('style', 'color: inherit;');
 354
 355                         //TODO: does this work or should we use DOMNode.isSameNode()?
 356                         if ($articleLink->parentNode->lastChild == $articleLink) {
 357                                 $articleLink->parentNode->appendChild($refLink);
 358                         } else {
 359                                 $articleLink->parentNode->insertBefore($refLink, $articleLink->nextSibling);
 360                         }
 361
 362                         $articleLink->setAttribute('style', 'color: inherit; text-decoration: none;');
 363                         $articleLink->setAttribute('name', 'readabilityLink-' . $linkCount);
 364
 365                         $footnote->innerHTML = '<small><sup><a href="#readabilityLink-' . $linkCount . '" title="Jump to Link in Article">^</a></sup></small> ';
 366
 367                         $footnoteLink->innerHTML = ($footnoteLink->getAttribute('title') != '' ? $footnoteLink->getAttribute('title') : $linkText);
 368                         $footnoteLink->setAttribute('name', 'readabilityFootnoteLink-' . $linkCount);
 369
 370                         $footnote->appendChild($footnoteLink);
 371                         if ($linkDomain) $footnote->innerHTML = $footnote->innerHTML . '<small> (' . $linkDomain . ')</small>';
 372
 373                         $articleFootnotes->appendChild($footnote);
 374                 }
 375
 376                 if ($linkCount > 0) {
 377                         $articleContent->appendChild($footnotesWrapper);
 378                 }
 379         }
 380
 381         /**
 382         * Reverts P elements with class 'readability-styled'
 383         * to text nodes - which is what they were before.
 384         *
 385         * @param DOMElement
 386         * @return void
 387         */
 388         function revertReadabilityStyledElements($articleContent) {
 389                 $xpath = new DOMXPath($articleContent->ownerDocument);
 390                 $elems = $xpath->query('.//p[@class="readability-styled"]', $articleContent);
 391                 //$elems = $articleContent->getElementsByTagName('p');
 392                 for ($i = $elems->length-1; $i >= 0; $i--) {
 393                         $e = $elems->item($i);
 394                         $e->parentNode->replaceChild($articleContent->ownerDocument->createTextNode($e->textContent), $e);
 395                         //if ($e->hasAttribute('class') && $e->getAttribute('class') == 'readability-styled') {
 396                         //      $e->parentNode->replaceChild($this->dom->createTextNode($e->textContent), $e);
 397                         //}
 398                 }
 399         }
 400
 401         /**
 402         * Prepare the article node for display. Clean out any inline styles,
 403         * iframes, forms, strip extraneous <p> tags, etc.
 404         *
 405         * @param DOMElement
 406         * @return void
 407         */
 408         function prepArticle($articleContent) {
 409                 $this->cleanStyles($articleContent);
 410                 $this->killBreaks($articleContent);
 411                 if ($this->revertForcedParagraphElements) {
 412                         $this->revertReadabilityStyledElements($articleContent);
 413                 }
 414
 415                 /* Clean out junk from the article content */
 416                 $this->cleanConditionally($articleContent, 'form');
 417                 $this->clean($articleContent, 'object');
 418                 $this->clean($articleContent, 'h1');
 419
 420                 /**
 421                 * If there is only one h2, they are probably using it
 422                 * as a header and not a subheader, so remove it since we already have a header.
 423                 ***/
 424                 if ($articleContent->getElementsByTagName('h2')->length == 1) {
 425                         $this->clean($articleContent, 'h2');
 426                 }
 427                 $this->clean($articleContent, 'iframe');
 428
 429                 $this->cleanHeaders($articleContent);
 430
 431                 /* Do these last as the previous stuff may have removed junk that will affect these */
 432                 $this->cleanConditionally($articleContent, 'table');
 433                 $this->cleanConditionally($articleContent, 'ul');
 434                 $this->cleanConditionally($articleContent, 'div');
 435
 436                 /* Remove extra paragraphs */
 437                 $articleParagraphs = $articleContent->getElementsByTagName('p');
 438                 for ($i = $articleParagraphs->length-1; $i >= 0; $i--)
 439                 {
 440                         $imgCount    = $articleParagraphs->item($i)->getElementsByTagName('img')->length;
 441                         $embedCount  = $articleParagraphs->item($i)->getElementsByTagName('embed')->length;
 442                         $objectCount = $articleParagraphs->item($i)->getElementsByTagName('object')->length;
 443
 444                         if ($imgCount === 0 && $embedCount === 0 && $objectCount === 0 && $this->getInnerText($articleParagraphs->item($i), false) == '')
 445                         {
 446                                 $articleParagraphs->item($i)->parentNode->removeChild($articleParagraphs->item($i));
 447                         }
 448                 }
 449
 450                 try {
 451                         $articleContent->innerHTML = preg_replace('/<br[^>]*>\s*<p/i', '<p', $articleContent->innerHTML);
 452                         //articleContent.innerHTML = articleContent.innerHTML.replace(/<br[^>]*>\s*<p/gi, '<p');
 453                 }
 454                 catch (Exception $e) {
 455                         $this->dbg("Cleaning innerHTML of breaks failed. This is an IE strict-block-elements bug. Ignoring.: " . $e);
 456                 }
 457         }
 458
 459         /**
 460         * Initialize a node with the readability object. Also checks the
 461         * className/id for special names to add to its score.
 462         *
 463         * @param Element
 464         * @return void
 465         **/
 466         protected function initializeNode($node) {
 467                 $readability = $this->dom->createAttribute('readability');
 468                 $readability->value = 0; // this is our contentScore
 469                 $node->setAttributeNode($readability);
 470
 471                 switch (strtoupper($node->tagName)) { // unsure if strtoupper is needed, but using it just in case
 472                         case 'DIV':
 473                                 $readability->value += 5;
 474                                 break;
 475
 476                         case 'PRE':
 477                         case 'TD':
 478                         case 'BLOCKQUOTE':
 479                                 $readability->value += 3;
 480                                 break;
 481
 482                         case 'ADDRESS':
 483                         case 'OL':
 484                         case 'UL':
 485                         case 'DL':
 486                         case 'DD':
 487                         case 'DT':
 488                         case 'LI':
 489                         case 'FORM':
 490                                 $readability->value -= 3;
 491                                 break;
 492
 493                         case 'H1':
 494                         case 'H2':
 495                         case 'H3':
 496                         case 'H4':
 497                         case 'H5':
 498                         case 'H6':
 499                         case 'TH':
 500                                 $readability->value -= 5;
 501                                 break;
 502                 }
 503                 $readability->value += $this->getClassWeight($node);
 504         }
 505
 506         /***
 507         * grabArticle - Using a variety of metrics (content score, classname, element types), find the content that is
 508         *               most likely to be the stuff a user wants to read. Then return it wrapped up in a div.
 509         *
 510         * @return DOMElement
 511         **/
 512         protected function grabArticle($page=null) {
 513                 $stripUnlikelyCandidates = $this->flagIsActive(self::FLAG_STRIP_UNLIKELYS);
 514                 if (!$page) $page = $this->dom;
 515                 $allElements = $page->getElementsByTagName('*');
 516                 /**
 517                 * First, node prepping. Trash nodes that look cruddy (like ones with the class name "comment", etc), and turn divs
 518                 * into P tags where they have been used inappropriately (as in, where they contain no other block level elements.)
 519                 *
 520                 * Note: Assignment from index for performance. See http://www.peachpit.com/articles/article.aspx?p=31567&seqNum=5
 521                 * TODO: Shouldn't this be a reverse traversal?
 522                 **/
 523                 $node = null;
 524                 $nodesToScore = array();
 525                 for ($nodeIndex = 0; ($node = $allElements->item($nodeIndex)); $nodeIndex++) {
 526                 //for ($nodeIndex=$targetList->length-1; $nodeIndex >= 0; $nodeIndex--) {
 527                         //$node = $targetList->item($nodeIndex);
 528                         $tagName = strtoupper($node->tagName);
 529                         /* Remove unlikely candidates */
 530                         if ($stripUnlikelyCandidates) {
 531                                 $unlikelyMatchString = $node->getAttribute('class') . $node->getAttribute('id');
 532                                 if (
 533                                         preg_match($this->regexps['unlikelyCandidates'], $unlikelyMatchString) &&
 534                                         !preg_match($this->regexps['okMaybeItsACandidate'], $unlikelyMatchString) &&
 535                                         $tagName != 'BODY'
 536                                 )
 537                                 {
 538                                         $this->dbg('Removing unlikely candidate - ' . $unlikelyMatchString);
 539                                         //$nodesToRemove[] = $node;
 540                                         $node->parentNode->removeChild($node);
 541                                         $nodeIndex--;
 542                                         continue;
 543                                 }
 544                         }
 545
 546                         if ($tagName == 'P' || $tagName == 'TD' || $tagName == 'PRE') {
 547                                 $nodesToScore[] = $node;
 548                         }
 549
 550                         /* Turn all divs that don't have children block level elements into p's */
 551                         if ($tagName == 'DIV') {
 552                                 if (!preg_match($this->regexps['divToPElements'], $node->innerHTML)) {
 553                                         //$this->dbg('Altering div to p');
 554                                         $newNode = $this->dom->createElement('p');
 555                                         try {
 556                                                 $newNode->innerHTML = $node->innerHTML;
 557                                                 //$nodesToReplace[] = array('new'=>$newNode, 'old'=>$node);
 558                                                 $node->parentNode->replaceChild($newNode, $node);
 559                                                 $nodeIndex--;
 560                                                 $nodesToScore[] = $node; // or $newNode?
 561                                         }
 562                                         catch(Exception $e) {
 563                                                 $this->dbg('Could not alter div to p, reverting back to div.: ' . $e);
 564                                         }
 565                                 }
 566                                 else
 567                                 {
 568                                         // EXPERIMENTAL
 569                                         // TODO: change these p elements back to text nodes after processing
 570                                         for ($i = 0, $il = $node->childNodes->length; $i < $il; $i++) {
 571                                                 $childNode = $node->childNodes->item($i);
 572                                                 if ($childNode->nodeType == 3) { // XML_TEXT_NODE
 573                                                         //$this->dbg('replacing text node with a p tag with the same content.');
 574                                                         $p = $this->dom->createElement('p');
 575                                                         $p->innerHTML = $childNode->nodeValue;
 576                                                         $p->setAttribute('style', 'display: inline;');
 577                                                         $p->setAttribute('class', 'readability-styled');
 578                                                         $childNode->parentNode->replaceChild($p, $childNode);
 579                                                 }
 580                                         }
 581                                 }
 582                         }
 583                 }
 584
 585                 /**
 586                 * Loop through all paragraphs, and assign a score to them based on how content-y they look.
 587                 * Then add their score to their parent node.
 588                 *
 589                 * A score is determined by things like number of commas, class names, etc. Maybe eventually link density.
 590                 **/
 591                 $candidates = array();
 592                 for ($pt=0; $pt < count($nodesToScore); $pt++) {
 593                         $parentNode      = $nodesToScore[$pt]->parentNode;
 594                         // $grandParentNode = $parentNode ? $parentNode->parentNode : null;
 595                         $grandParentNode = !$parentNode ? null : (($parentNode->parentNode instanceof DOMElement) ? $parentNode->parentNode : null);
 596                         $innerText       = $this->getInnerText($nodesToScore[$pt]);
 597
 598                         if (!$parentNode || !isset($parentNode->tagName)) {
 599                                 continue;
 600                         }
 601
 602                         /* If this paragraph is less than 25 characters, don't even count it. */
 603                         if(strlen($innerText) < 25) {
 604                                 continue;
 605                         }
 606
 607                         /* Initialize readability data for the parent. */
 608                         if (!$parentNode->hasAttribute('readability'))
 609                         {
 610                                 $this->initializeNode($parentNode);
 611                                 $candidates[] = $parentNode;
 612                         }
 613
 614                         /* Initialize readability data for the grandparent. */
 615                         if ($grandParentNode && !$grandParentNode->hasAttribute('readability') && isset($grandParentNode->tagName))
 616                         {
 617                                 $this->initializeNode($grandParentNode);
 618                                 $candidates[] = $grandParentNode;
 619                         }
 620
 621                         $contentScore = 0;
 622
 623                         /* Add a point for the paragraph itself as a base. */
 624                         $contentScore++;
 625
 626                         /* Add points for any commas within this paragraph */
 627                         $contentScore += count(explode(',', $innerText));
 628
 629                         /* For every 100 characters in this paragraph, add another point. Up to 3 points. */
 630                         $contentScore += min(floor(strlen($innerText) / 100), 3);
 631
 632                         /* Add the score to the parent. The grandparent gets half. */
 633                         $parentNode->getAttributeNode('readability')->value += $contentScore;
 634
 635                         if ($grandParentNode) {
 636                                 $grandParentNode->getAttributeNode('readability')->value += $contentScore/2;
 637                         }
 638                 }
 639
 640                 /**
 641                 * After we've calculated scores, loop through all of the possible candidate nodes we found
 642                 * and find the one with the highest score.
 643                 **/
 644                 $topCandidate = null;
 645                 for ($c=0, $cl=count($candidates); $c < $cl; $c++)
 646                 {
 647                         /**
 648                         * Scale the final candidates score based on link density. Good content should have a
 649                         * relatively small link density (5% or less) and be mostly unaffected by this operation.
 650                         **/
 651                         $readability = $candidates[$c]->getAttributeNode('readability');
 652                         $readability->value = $readability->value * (1-$this->getLinkDensity($candidates[$c]));
 653
 654                         $this->dbg('Candidate: ' . $candidates[$c]->tagName . ' (' . $candidates[$c]->getAttribute('class') . ':' . $candidates[$c]->getAttribute('id') . ') with score ' . $readability->value);
 655
 656                         if (!$topCandidate || $readability->value > (int)$topCandidate->getAttribute('readability')) {
 657                                 $topCandidate = $candidates[$c];
 658                         }
 659                 }
 660
 661                 /**
 662                 * If we still have no top candidate, just use the body as a last resort.
 663                 * We also have to copy the body node so it is something we can modify.
 664                 **/
 665                 if ($topCandidate === null || strtoupper($topCandidate->tagName) == 'BODY')
 666                 {
 667                         $topCandidate = $this->dom->createElement('div');
 668                         if ($page instanceof DOMDocument) {
 669                                 if (!isset($page->documentElement)) {
 670                                         // we don't have a body either? what a mess! :)
 671                                 } else {
 672                                         $topCandidate->innerHTML = $page->documentElement->innerHTML;
 673                                         $page->documentElement->innerHTML = '';
 674                                         $page->documentElement->appendChild($topCandidate);
 675                                 }
 676                         } else {
 677                                 $topCandidate->innerHTML = $page->innerHTML;
 678                                 $page->innerHTML = '';
 679                                 $page->appendChild($topCandidate);
 680                         }
 681                         $this->initializeNode($topCandidate);
 682                 }
 683
 684                 /**
 685                 * Now that we have the top candidate, look through its siblings for content that might also be related.
 686                 * Things like preambles, content split by ads that we removed, etc.
 687                 **/
 688                 $articleContent        = $this->dom->createElement('div');
 689                 $articleContent->setAttribute('id', 'readability-content');
 690                 $siblingScoreThreshold = max(10, ((int)$topCandidate->getAttribute('readability')) * 0.2);
 691                 $siblingNodes          = $topCandidate->parentNode->childNodes;
 692                 if (!isset($siblingNodes)) {
 693                         $siblingNodes = new stdClass;
 694                         $siblingNodes->length = 0;
 695                 }
 696
 697                 for ($s=0, $sl=$siblingNodes->length; $s < $sl; $s++)
 698                 {
 699                         $siblingNode = $siblingNodes->item($s);
 700                         $append      = false;
 701
 702                         $this->dbg('Looking at sibling node: ' . $siblingNode->nodeName . (($siblingNode->nodeType === XML_ELEMENT_NODE && $siblingNode->hasAttribute('readability')) ? (' with score ' . $siblingNode->getAttribute('readability')) : ''));
 703
 704                         //dbg('Sibling has score ' . ($siblingNode->readability ? siblingNode.readability.contentScore : 'Unknown'));
 705
 706                         if ($siblingNode === $topCandidate)
 707                         // or if ($siblingNode->isSameNode($topCandidate))
 708                         {
 709                                 $append = true;
 710                         }
 711
 712                         $contentBonus = 0;
 713                         /* Give a bonus if sibling nodes and top candidates have the example same classname */
 714                         if ($siblingNode->nodeType === XML_ELEMENT_NODE && $siblingNode->getAttribute('class') == $topCandidate->getAttribute('class') && $topCandidate->getAttribute('class') != '') {
 715                                 $contentBonus += ((int)$topCandidate->getAttribute('readability')) * 0.2;
 716                         }
 717
 718                         if ($siblingNode->nodeType === XML_ELEMENT_NODE && $siblingNode->hasAttribute('readability') && (((int)$siblingNode->getAttribute('readability')) + $contentBonus) >= $siblingScoreThreshold)
 719                         {
 720                                 $append = true;
 721                         }
 722
 723                         if (strtoupper($siblingNode->nodeName) == 'P') {
 724                                 $linkDensity = $this->getLinkDensity($siblingNode);
 725                                 $nodeContent = $this->getInnerText($siblingNode);
 726                                 $nodeLength  = strlen($nodeContent);
 727
 728                                 if ($nodeLength > 80 && $linkDensity < 0.25)
 729                                 {
 730                                         $append = true;
 731                                 }
 732                                 else if ($nodeLength < 80 && $linkDensity === 0 && preg_match('/\.( |$)/', $nodeContent))
 733                                 {
 734                                         $append = true;
 735                                 }
 736                         }
 737
 738                         /* Look for a special classname */
 739                         if ($siblingNode->nodeType === XML_ELEMENT_NODE && $siblingNode->hasAttribute('class') && $siblingNode->getAttribute('class') != '')
 740                         {
 741                                 if (preg_match($this->regexps['okMaybeItsACandidate'], $siblingNode->getAttribute('class'))) {
 742                                         $append = true;
 743                                 }
 744                         }
 745
 746                         /* Look for a special classname */
 747                         if ($siblingNode->nodeType === XML_ELEMENT_NODE && $siblingNode->hasAttribute('id') && $siblingNode->getAttribute('id') != '')
 748                         {
 749                                 if (preg_match($this->regexps['okMaybeItsACandidate'], $siblingNode->getAttribute('id'))) {
 750                                         $append = true;
 751                                 }
 752                         }
 753
 754
 755                         if ($append)
 756                         {
 757                                 $this->dbg('Appending node: ' . $siblingNode->nodeName);
 758
 759                                 $nodeToAppend = null;
 760                                 $sibNodeName = strtoupper($siblingNode->nodeName);
 761                                 if ($sibNodeName != 'DIV' && $sibNodeName != 'P') {
 762                                         /* 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. */
 763
 764                                         $this->dbg('Altering siblingNode of ' . $sibNodeName . ' to div.');
 765                                         $nodeToAppend = $this->dom->createElement('div');
 766                                         try {
 767                                                 $nodeToAppend->setAttribute('id', $siblingNode->getAttribute('id'));
 768                                                 $nodeToAppend->innerHTML = $siblingNode->innerHTML;
 769                                         }
 770                                         catch(Exception $e)
 771                                         {
 772                                                 $this->dbg('Could not alter siblingNode to div, reverting back to original.');
 773                                                 $nodeToAppend = $siblingNode;
 774                                                 $s--;
 775                                                 $sl--;
 776                                         }
 777                                 } else {
 778                                         $nodeToAppend = $siblingNode;
 779                                         $s--;
 780                                         $sl--;
 781                                 }
 782
 783                                 /* To ensure a node does not interfere with readability styles, remove its classnames */
 784                                 $nodeToAppend->removeAttribute('class');
 785
 786                                 /* Append sibling and subtract from our list because it removes the node when you append to another node */
 787                                 $articleContent->appendChild($nodeToAppend);
 788                         }
 789                 }
 790
 791                 /**
 792                 * So we have all of the content that we need. Now we clean it up for presentation.
 793                 **/
 794                 $this->prepArticle($articleContent);
 795
 796                 /**
 797                 * Now that we've gone through the full algorithm, check to see if we got any meaningful content.
 798                 * If we didn't, we may need to re-run grabArticle with different flags set. This gives us a higher
 799                 * likelihood of finding the content, and the sieve approach gives us a higher likelihood of
 800                 * finding the -right- content.
 801                 **/
 802                 if (strlen($this->getInnerText($articleContent, false)) < 250)
 803                 {
 804                         // 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
 805                         // in the meantime, we check and create an empty element if it's not there.
 806                         if (!isset($this->body->childNodes)) $this->body = $this->dom->createElement('body');
 807                         $this->body->innerHTML = $this->bodyCache;
 808
 809                         if ($this->flagIsActive(self::FLAG_STRIP_UNLIKELYS)) {
 810                                 $this->removeFlag(self::FLAG_STRIP_UNLIKELYS);
 811                                 return $this->grabArticle($this->body);
 812                         }
 813                         else if ($this->flagIsActive(self::FLAG_WEIGHT_CLASSES)) {
 814                                 $this->removeFlag(self::FLAG_WEIGHT_CLASSES);
 815                                 return $this->grabArticle($this->body);
 816                         }
 817                         else if ($this->flagIsActive(self::FLAG_CLEAN_CONDITIONALLY)) {
 818                                 $this->removeFlag(self::FLAG_CLEAN_CONDITIONALLY);
 819                                 return $this->grabArticle($this->body);
 820                         }
 821                         else {
 822                                 return false;
 823                         }
 824                 }
 825                 return $articleContent;
 826         }
 827
 828         /**
 829         * Remove script tags from document
 830         *
 831         * @param DOMElement
 832         * @return void
 833         */
 834         public function removeScripts($doc) {
 835                 $scripts = $doc->getElementsByTagName('script');
 836                 for($i = $scripts->length-1; $i >= 0; $i--)
 837                 {
 838                         $scripts->item($i)->parentNode->removeChild($scripts->item($i));
 839                 }
 840         }
 841
 842         /**
 843         * Get the inner text of a node.
 844         * This also strips out any excess whitespace to be found.
 845         *
 846         * @param DOMElement $
 847         * @param boolean $normalizeSpaces (default: true)
 848         * @return string
 849         **/
 850         public function getInnerText($e, $normalizeSpaces=true) {
 851                 $textContent = '';
 852
 853                 if (!isset($e->textContent) || $e->textContent == '') {
 854                         return '';
 855                 }
 856
 857                 $textContent = trim($e->textContent);
 858
 859                 if ($normalizeSpaces) {
 860                         return preg_replace($this->regexps['normalize'], ' ', $textContent);
 861                 } else {
 862                         return $textContent;
 863                 }
 864         }
 865
 866         /**
 867         * Get the number of times a string $s appears in the node $e.
 868         *
 869         * @param DOMElement $e
 870         * @param string - what to count. Default is ","
 871         * @return number (integer)
 872         **/
 873         public function getCharCount($e, $s=',') {
 874                 return substr_count($this->getInnerText($e), $s);
 875         }
 876
 877         /**
 878         * Remove the style attribute on every $e and under.
 879         *
 880         * @param DOMElement $e
 881         * @return void
 882         */
 883         public function cleanStyles($e) {
 884                 if (!is_object($e)) return;
 885                 $elems = $e->getElementsByTagName('*');
 886                 foreach ($elems as $elem) {
 887                         $elem->removeAttribute('style');
 888                 }
 889         }
 890
 891         /**
 892         * Get the density of links as a percentage of the content
 893         * This is the amount of text that is inside a link divided by the total text in the node.
 894         *
 895         * @param DOMElement $e
 896         * @return number (float)
 897         */
 898         public function getLinkDensity($e) {
 899                 $links      = $e->getElementsByTagName('a');
 900                 $textLength = strlen($this->getInnerText($e));
 901                 $linkLength = 0;
 902                 for ($i=0, $il=$links->length; $i < $il; $i++)
 903                 {
 904                         $linkLength += strlen($this->getInnerText($links->item($i)));
 905                 }
 906                 if ($textLength > 0) {
 907                         return $linkLength / $textLength;
 908                 } else {
 909                         return 0;
 910                 }
 911         }
 912
 913         /**
 914         * Get an elements class/id weight. Uses regular expressions to tell if this
 915         * element looks good or bad.
 916         *
 917         * @param DOMElement $e
 918         * @return number (Integer)
 919         */
 920         public function getClassWeight($e) {
 921                 if(!$this->flagIsActive(self::FLAG_WEIGHT_CLASSES)) {
 922                         return 0;
 923                 }
 924
 925                 $weight = 0;
 926
 927                 /* Look for a special classname */
 928                 if ($e->hasAttribute('class') && $e->getAttribute('class') != '')
 929                 {
 930                         if (preg_match($this->regexps['negative'], $e->getAttribute('class'))) {
 931                                 $weight -= 25;
 932                         }
 933                         if (preg_match($this->regexps['positive'], $e->getAttribute('class'))) {
 934                                 $weight += 25;
 935                         }
 936                 }
 937
 938                 /* Look for a special ID */
 939                 if ($e->hasAttribute('id') && $e->getAttribute('id') != '')
 940                 {
 941                         if (preg_match($this->regexps['negative'], $e->getAttribute('id'))) {
 942                                 $weight -= 25;
 943                         }
 944                         if (preg_match($this->regexps['positive'], $e->getAttribute('id'))) {
 945                                 $weight += 25;
 946                         }
 947                 }
 948                 return $weight;
 949         }
 950
 951         /**
 952         * Remove extraneous break tags from a node.
 953         *
 954         * @param DOMElement $node
 955         * @return void
 956         */
 957         public function killBreaks($node) {
 958                 $html = $node->innerHTML;
 959                 $html = preg_replace($this->regexps['killBreaks'], '<br />', $html);
 960                 $node->innerHTML = $html;
 961         }
 962
 963         /**
 964         * Clean a node of all elements of type "tag".
 965         * (Unless it's a youtube/vimeo video. People love movies.)
 966         *
 967         * @param DOMElement $e
 968         * @param string $tag
 969         * @return void
 970         */
 971         public function clean($e, $tag) {
 972                 $targetList = $e->getElementsByTagName($tag);
 973                 $isEmbed = ($tag == 'object' || $tag == 'embed');
 974
 975                 for ($y=$targetList->length-1; $y >= 0; $y--) {
 976                         /* Allow youtube and vimeo videos through as people usually want to see those. */
 977                         if ($isEmbed) {
 978                                 $attributeValues = '';
 979                                 for ($i=0, $il=$targetList->item($y)->attributes->length; $i < $il; $i++) {
 980                                         $attributeValues .= $targetList->item($y)->attributes->item($i)->value . '|'; // DOMAttr? (TODO: test)
 981                                 }
 982
 983                                 /* First, check the elements attributes to see if any of them contain youtube or vimeo */
 984                                 if (preg_match($this->regexps['video'], $attributeValues)) {
 985                                         continue;
 986                                 }
 987
 988                                 /* Then check the elements inside this element for the same. */
 989                                 if (preg_match($this->regexps['video'], $targetList->item($y)->innerHTML)) {
 990                                         continue;
 991                                 }
 992                         }
 993                         $targetList->item($y)->parentNode->removeChild($targetList->item($y));
 994                 }
 995         }
 996
 997         /**
 998         * Clean an element of all tags of type "tag" if they look fishy.
 999         * "Fishy" is an algorithm based on content length, classnames,
1000         * link density, number of images & embeds, etc.
1001         *
1002         * @param DOMElement $e
1003         * @param string $tag
1004         * @return void
1005         */
1006         public function cleanConditionally($e, $tag) {
1007                 if (!$this->flagIsActive(self::FLAG_CLEAN_CONDITIONALLY)) {
1008                         return;
1009                 }
1010
1011                 $tagsList = $e->getElementsByTagName($tag);
1012                 $curTagsLength = $tagsList->length;
1013
1014                 /**
1015                 * Gather counts for other typical elements embedded within.
1016                 * Traverse backwards so we can remove nodes at the same time without effecting the traversal.
1017                 *
1018                 * TODO: Consider taking into account original contentScore here.
1019                 */
1020                 for ($i=$curTagsLength-1; $i >= 0; $i--) {
1021                         $weight = $this->getClassWeight($tagsList->item($i));
1022                         $contentScore = ($tagsList->item($i)->hasAttribute('readability')) ? (int)$tagsList->item($i)->getAttribute('readability') : 0;
1023
1024                         $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')) : ''));
1025
1026                         if ($weight + $contentScore < 0) {
1027                                 $tagsList->item($i)->parentNode->removeChild($tagsList->item($i));
1028                         }
1029                         else if ( $this->getCharCount($tagsList->item($i), ',') < 10) {
1030                                 /**
1031                                 * If there are not very many commas, and the number of
1032                                 * non-paragraph elements is more than paragraphs or other ominous signs, remove the element.
1033                                 **/
1034                                 $p      = $tagsList->item($i)->getElementsByTagName('p')->length;
1035                                 $img    = $tagsList->item($i)->getElementsByTagName('img')->length;
1036                                 $li     = $tagsList->item($i)->getElementsByTagName('li')->length-100;
1037                                 $input  = $tagsList->item($i)->getElementsByTagName('input')->length;
1038
1039                                 $embedCount = 0;
1040                                 $embeds = $tagsList->item($i)->getElementsByTagName('embed');
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 ( $img > $p ) {
1052                                         $toRemove = true;
1053                                 } else if ($li > $p && $tag != 'ul' && $tag != 'ol') {
1054                                         $toRemove = true;
1055                                 } else if ( $input > floor($p/3) ) {
1056                                         $toRemove = true;
1057                                 } else if ($contentLength < 25 && ($img === 0 || $img > 2) ) {
1058                                         $toRemove = true;
1059                                 } else if($weight < 25 && $linkDensity > 0.2) {
1060                                         $toRemove = true;
1061                                 } else if($weight >= 25 && $linkDensity > 0.5) {
1062                                         $toRemove = true;
1063                                 } else if(($embedCount == 1 && $contentLength < 75) || $embedCount > 1) {
1064                                         $toRemove = true;
1065                                 }
1066
1067                                 if ($toRemove) {
1068                                         $tagsList->item($i)->parentNode->removeChild($tagsList->item($i));
1069                                 }
1070                         }
1071                 }
1072         }
1073
1074         /**
1075         * Clean out spurious headers from an Element. Checks things like classnames and link density.
1076         *
1077         * @param DOMElement $e
1078         * @return void
1079         */
1080         public function cleanHeaders($e) {
1081                 for ($headerIndex = 1; $headerIndex < 3; $headerIndex++) {
1082                         $headers = $e->getElementsByTagName('h' . $headerIndex);
1083                         for ($i=$headers->length-1; $i >=0; $i--) {
1084                                 if ($this->getClassWeight($headers->item($i)) < 0 || $this->getLinkDensity($headers->item($i)) > 0.33) {
1085                                         $headers->item($i)->parentNode->removeChild($headers->item($i));
1086                                 }
1087                         }
1088                 }
1089         }
1090
1091         public function flagIsActive($flag) {
1092                 return ($this->flags & $flag) > 0;
1093         }
1094
1095         public function addFlag($flag) {
1096                 $this->flags = $this->flags | $flag;
1097         }
1098
1099         public function removeFlag($flag) {
1100                 $this->flags = $this->flags & ~$flag;
1101         }
1102 }
1103 ?>