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 $regexps = array(
  91                 'unlikelyCandidates' => '/combx|comment|comments|community|disqus|extra|foot|header|menu|remark|rss|shoutbox|sidebar|sponsor|ad-break|agegate|pagination|pager|popup|tweet|twitter/i',
  92                 'okMaybeItsACandidate' => '/and|article|body|column|main|shadow/i',
  93                 'positive' => '/article|body|content|entry|hentry|main|page|pagination|post|text|blog|story|attachment/i',
  94                 'negative' => '/combx|comment|comments|com-|contact|foot|footer|footnote|masthead|media|meta|outbrain|promo|related|scroll|shoutbox|sidebar|sponsor|shopping|tags|tool|widget/i',
  95                 'divToPElements' => '/<(a|blockquote|dl|div|ol|p|pre|table|ul)/i',
  96                 'replaceBrs' => '/(<br[^>]*>[ \n\r\t]*){2,}/i',
  97                 'replaceFonts' => '/<(\/?)font[^>]*>/i',
  98                 // 'trimRe' => '/^\s+|\s+$/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                         return $this->success;
 189                 }
 190
 191                 $overlay->setAttribute('id', 'readOverlay');
 192                 $innerDiv->setAttribute('id', 'readInner');
 193
 194                 /* Glue the structure of our document together. */
 195                 $innerDiv->appendChild($articleTitle);
 196                 $innerDiv->appendChild($articleContent);
 197                 $overlay->appendChild($innerDiv);
 198
 199                 /* Clear the old HTML, insert the new content. */
 200                 $this->body->innerHTML = '';
 201                 $this->body->appendChild($overlay);
 202                 //document.body.insertBefore(overlay, document.body.firstChild);
 203                 $this->body->removeAttribute('style');
 204
 205                 $this->postProcessContent($articleContent);
 206
 207                 // Set title and content instance variables
 208                 $this->articleTitle = $articleTitle;
 209                 $this->articleContent = $articleContent;
 210
 211                 return $this->success;
 212         }
 213
 214         /**
 215         * Debug
 216         */
 217         protected function dbg($msg) {
 218                 if ($this->debug) echo '* ',$msg, '<br />', "\n";
 219         }
 220
 221         /**
 222         * Run any post-process modifications to article content as necessary.
 223         *
 224         * @param DOMElement
 225         * @return void
 226         */
 227         public function postProcessContent($articleContent) {
 228                 if ($this->convertLinksToFootnotes && !preg_match('/wikipedia\.org/', @$this->url)) {
 229                         $this->addFootnotes($articleContent);
 230                 }
 231         }
 232
 233         /**
 234         * Get the article title as an H1.
 235         *
 236         * @return DOMElement
 237         */
 238         protected function getArticleTitle() {
 239                 $curTitle = '';
 240                 $origTitle = '';
 241
 242                 try {
 243                         $curTitle = $origTitle = $this->getInnerText($this->dom->getElementsByTagName('title')->item(0));
 244                 } catch(Exception $e) {}
 245
 246                 if (preg_match('/ [\|\-] /', $curTitle))
 247                 {
 248                         $curTitle = preg_replace('/(.*)[\|\-] .*/i', '$1', $origTitle);
 249
 250                         if (count(explode(' ', $curTitle)) < 3) {
 251                                 $curTitle = preg_replace('/[^\|\-]*[\|\-](.*)/i', '$1', $origTitle);
 252                         }
 253                 }
 254                 else if (strpos($curTitle, ': ') !== false)
 255                 {
 256                         $curTitle = preg_replace('/.*:(.*)/i', '$1', $origTitle);
 257
 258                         if (count(explode(' ', $curTitle)) < 3) {
 259                                 $curTitle = preg_replace('/[^:]*[:](.*)/i','$1', $origTitle);
 260                         }
 261                 }
 262                 else if(strlen($curTitle) > 150 || strlen($curTitle) < 15)
 263                 {
 264                         $hOnes = $this->dom->getElementsByTagName('h1');
 265                         if($hOnes->length == 1)
 266                         {
 267                                 $curTitle = $this->getInnerText($hOnes->item(0));
 268                         }
 269                 }
 270
 271                 $curTitle = trim($curTitle);
 272
 273                 if (count(explode(' ', $curTitle)) <= 4) {
 274                         $curTitle = $origTitle;
 275                 }
 276
 277                 $articleTitle = $this->dom->createElement('h1');
 278                 $articleTitle->innerHTML = $curTitle;
 279
 280                 return $articleTitle;
 281         }
 282
 283         /**
 284         * Prepare the HTML document for readability to scrape it.
 285         * This includes things like stripping javascript, CSS, and handling terrible markup.
 286         *
 287         * @return void
 288         **/
 289         protected function prepDocument() {
 290                 /**
 291                 * In some cases a body element can't be found (if the HTML is totally hosed for example)
 292                 * so we create a new body node and append it to the document.
 293                 */
 294                 if ($this->body == null)
 295                 {
 296                         $this->body = $this->dom->createElement('body');
 297                         $this->dom->documentElement->appendChild($this->body);
 298                 }
 299                 $this->body->setAttribute('id', 'readabilityBody');
 300
 301                 /* Remove all style tags in head */
 302                 $styleTags = $this->dom->getElementsByTagName('style');
 303                 for ($i = $styleTags->length-1; $i >= 0; $i--)
 304                 {
 305                         $styleTags->item($i)->parentNode->removeChild($styleTags->item($i));
 306                 }
 307
 308                 /* Turn all double br's into p's */
 309                 /* Note, this is pretty costly as far as processing goes. Maybe optimize later. */
 310                 //document.body.innerHTML = document.body.innerHTML.replace(readability.regexps.replaceBrs, '</p><p>').replace(readability.regexps.replaceFonts, '<$1span>');
 311                 // We do this in the constructor for PHP as that's when we have raw HTML - before parsing it into a DOM tree.
 312                 // Manipulating innerHTML as it's done in JS is not possible in PHP.
 313         }
 314
 315         /**
 316         * For easier reading, convert this document to have footnotes at the bottom rather than inline links.
 317         * @see http://www.roughtype.com/archives/2010/05/experiments_in.php
 318         *
 319         * @return void
 320         **/
 321         public function addFootnotes($articleContent) {
 322                 $footnotesWrapper = $this->dom->createElement('div');
 323                 $footnotesWrapper->setAttribute('id', 'readability-footnotes');
 324                 $footnotesWrapper->innerHTML = '<h3>References</h3>';
 325
 326                 $articleFootnotes = $this->dom->createElement('ol');
 327                 $articleFootnotes->setAttribute('id', 'readability-footnotes-list');
 328                 $footnotesWrapper->appendChild($articleFootnotes);
 329
 330                 $articleLinks = $articleContent->getElementsByTagName('a');
 331
 332                 $linkCount = 0;
 333                 for ($i = 0; $i < $articleLinks->length; $i++)
 334                 {
 335                         $articleLink  = $articleLinks->item($i);
 336                         $footnoteLink = $articleLink->cloneNode(true);
 337                         $refLink      = $this->dom->createElement('a');
 338                         $footnote     = $this->dom->createElement('li');
 339                         $linkDomain   = @parse_url($footnoteLink->getAttribute('href'), PHP_URL_HOST);
 340                         if (!$linkDomain && isset($this->url)) $linkDomain = @parse_url($this->url, PHP_URL_HOST);
 341                         //linkDomain   = footnoteLink.host ? footnoteLink.host : document.location.host,
 342                         $linkText     = $this->getInnerText($articleLink);
 343
 344                         if ((strpos($articleLink->getAttribute('class'), 'readability-DoNotFootnote') !== false) || preg_match($this->regexps['skipFootnoteLink'], $linkText)) {
 345                                 continue;
 346                         }
 347
 348                         $linkCount++;
 349
 350                         /** Add a superscript reference after the article link */
 351                         $refLink->setAttribute('href', '#readabilityFootnoteLink-' . $linkCount);
 352                         $refLink->innerHTML = '<small><sup>[' . $linkCount . ']</sup></small>';
 353                         $refLink->setAttribute('class', 'readability-DoNotFootnote');
 354                         $refLink->setAttribute('style', 'color: inherit;');
 355
 356                         //TODO: does this work or should we use DOMNode.isSameNode()?
 357                         if ($articleLink->parentNode->lastChild == $articleLink) {
 358                                 $articleLink->parentNode->appendChild($refLink);
 359                         } else {
 360                                 $articleLink->parentNode->insertBefore($refLink, $articleLink->nextSibling);
 361                         }
 362
 363                         $articleLink->setAttribute('style', 'color: inherit; text-decoration: none;');
 364                         $articleLink->setAttribute('name', 'readabilityLink-' . $linkCount);
 365
 366                         $footnote->innerHTML = '<small><sup><a href="#readabilityLink-' . $linkCount . '" title="Jump to Link in Article">^</a></sup></small> ';
 367
 368                         $footnoteLink->innerHTML = ($footnoteLink->getAttribute('title') != '' ? $footnoteLink->getAttribute('title') : $linkText);
 369                         $footnoteLink->setAttribute('name', 'readabilityFootnoteLink-' . $linkCount);
 370
 371                         $footnote->appendChild($footnoteLink);
 372                         if ($linkDomain) $footnote->innerHTML = $footnote->innerHTML . '<small> (' . $linkDomain . ')</small>';
 373
 374                         $articleFootnotes->appendChild($footnote);
 375                 }
 376
 377                 if ($linkCount > 0) {
 378                         $articleContent->appendChild($footnotesWrapper);
 379                 }
 380         }
 381
 382         /**
 383         * Reverts P elements with class 'readability-styled'
 384         * to text nodes - which is what they were before.
 385         *
 386         * @param DOMElement
 387         * @return void
 388         */
 389         function revertReadabilityStyledElements($articleContent) {
 390                 $xpath = new DOMXPath($articleContent->ownerDocument);
 391                 $elems = $xpath->query('.//p[@class="readability-styled"]', $articleContent);
 392                 //$elems = $articleContent->getElementsByTagName('p');
 393                 for ($i = $elems->length-1; $i >= 0; $i--) {
 394                         $e = $elems->item($i);
 395                         $e->parentNode->replaceChild($articleContent->ownerDocument->createTextNode($e->textContent), $e);
 396                         //if ($e->hasAttribute('class') && $e->getAttribute('class') == 'readability-styled') {
 397                         //      $e->parentNode->replaceChild($this->dom->createTextNode($e->textContent), $e);
 398                         //}
 399                 }
 400         }
 401
 402         /**
 403         * Prepare the article node for display. Clean out any inline styles,
 404         * iframes, forms, strip extraneous <p> tags, etc.
 405         *
 406         * @param DOMElement
 407         * @return void
 408         */
 409         function prepArticle($articleContent) {
 410                 $this->cleanStyles($articleContent);
 411                 $this->killBreaks($articleContent);
 412                 if ($this->revertForcedParagraphElements) {
 413                         $this->revertReadabilityStyledElements($articleContent);
 414                 }
 415
 416                 /* Clean out junk from the article content */
 417                 $this->cleanConditionally($articleContent, 'form');
 418                 $this->clean($articleContent, 'object');
 419                 $this->clean($articleContent, 'h1');
 420
 421                 /**
 422                 * If there is only one h2, they are probably using it
 423                 * as a header and not a subheader, so remove it since we already have a header.
 424                 ***/
 425                 if ($articleContent->getElementsByTagName('h2')->length == 1) {
 426                         $this->clean($articleContent, 'h2');
 427                 }
 428                 $this->clean($articleContent, 'iframe');
 429
 430                 $this->cleanHeaders($articleContent);
 431
 432                 /* Do these last as the previous stuff may have removed junk that will affect these */
 433                 $this->cleanConditionally($articleContent, 'table');
 434                 $this->cleanConditionally($articleContent, 'ul');
 435                 $this->cleanConditionally($articleContent, 'div');
 436
 437                 /* Remove extra paragraphs */
 438                 $articleParagraphs = $articleContent->getElementsByTagName('p');
 439                 for ($i = $articleParagraphs->length-1; $i >= 0; $i--)
 440                 {
 441                         $imgCount    = $articleParagraphs->item($i)->getElementsByTagName('img')->length;
 442                         $embedCount  = $articleParagraphs->item($i)->getElementsByTagName('embed')->length;
 443                         $objectCount = $articleParagraphs->item($i)->getElementsByTagName('object')->length;
 444
 445                         if ($imgCount === 0 && $embedCount === 0 && $objectCount === 0 && $this->getInnerText($articleParagraphs->item($i), false) == '')
 446                         {
 447                                 $articleParagraphs->item($i)->parentNode->removeChild($articleParagraphs->item($i));
 448                         }
 449                 }
 450
 451                 try {
 452                         $articleContent->innerHTML = preg_replace('/<br[^>]*>\s*<p/i', '<p', $articleContent->innerHTML);
 453                         //articleContent.innerHTML = articleContent.innerHTML.replace(/<br[^>]*>\s*<p/gi, '<p');
 454                 }
 455                 catch (Exception $e) {
 456                         $this->dbg("Cleaning innerHTML of breaks failed. This is an IE strict-block-elements bug. Ignoring.: " . $e);
 457                 }
 458         }
 459
 460         /**
 461         * Initialize a node with the readability object. Also checks the
 462         * className/id for special names to add to its score.
 463         *
 464         * @param Element
 465         * @return void
 466         **/
 467         protected function initializeNode($node) {
 468                 $readability = $this->dom->createAttribute('readability');
 469                 $readability->value = 0; // this is our contentScore
 470                 $node->setAttributeNode($readability);
 471
 472                 switch (strtoupper($node->tagName)) { // unsure if strtoupper is needed, but using it just in case
 473                         case 'DIV':
 474                                 $readability->value += 5;
 475                                 break;
 476
 477                         case 'PRE':
 478                         case 'TD':
 479                         case 'BLOCKQUOTE':
 480                                 $readability->value += 3;
 481                                 break;
 482
 483                         case 'ADDRESS':
 484                         case 'OL':
 485                         case 'UL':
 486                         case 'DL':
 487                         case 'DD':
 488                         case 'DT':
 489                         case 'LI':
 490                         case 'FORM':
 491                                 $readability->value -= 3;
 492                                 break;
 493
 494                         case 'H1':
 495                         case 'H2':
 496                         case 'H3':
 497                         case 'H4':
 498                         case 'H5':
 499                         case 'H6':
 500                         case 'TH':
 501                                 $readability->value -= 5;
 502                                 break;
 503                 }
 504                 $readability->value += $this->getClassWeight($node);
 505         }
 506
 507         /***
 508         * grabArticle - Using a variety of metrics (content score, classname, element types), find the content that is
 509         *               most likely to be the stuff a user wants to read. Then return it wrapped up in a div.
 510         *
 511         * @return DOMElement
 512         **/
 513         protected function grabArticle($page=null) {
 514                 $stripUnlikelyCandidates = $this->flagIsActive(self::FLAG_STRIP_UNLIKELYS);
 515                 if (!$page) $page = $this->dom;
 516                 $allElements = $page->getElementsByTagName('*');
 517                 /**
 518                 * First, node prepping. Trash nodes that look cruddy (like ones with the class name "comment", etc), and turn divs
 519                 * into P tags where they have been used inappropriately (as in, where they contain no other block level elements.)
 520                 *
 521                 * Note: Assignment from index for performance. See http://www.peachpit.com/articles/article.aspx?p=31567&seqNum=5
 522                 * TODO: Shouldn't this be a reverse traversal?
 523                 **/
 524                 $node = null;
 525                 $nodesToScore = array();
 526                 for ($nodeIndex = 0; ($node = $allElements->item($nodeIndex)); $nodeIndex++) {
 527                 //for ($nodeIndex=$targetList->length-1; $nodeIndex >= 0; $nodeIndex--) {
 528                         //$node = $targetList->item($nodeIndex);
 529                         $tagName = strtoupper($node->tagName);
 530                         /* Remove unlikely candidates */
 531                         if ($stripUnlikelyCandidates) {
 532                                 $unlikelyMatchString = $node->getAttribute('class') . $node->getAttribute('id');
 533                                 if (
 534                                         preg_match($this->regexps['unlikelyCandidates'], $unlikelyMatchString) &&
 535                                         !preg_match($this->regexps['okMaybeItsACandidate'], $unlikelyMatchString) &&
 536                                         $tagName != 'BODY'
 537                                 )
 538                                 {
 539                                         $this->dbg('Removing unlikely candidate - ' . $unlikelyMatchString);
 540                                         //$nodesToRemove[] = $node;
 541                                         $node->parentNode->removeChild($node);
 542                                         $nodeIndex--;
 543                                         continue;
 544                                 }
 545                         }
 546
 547                         if ($tagName == 'P' || $tagName == 'TD' || $tagName == 'PRE') {
 548                                 $nodesToScore[] = $node;
 549                         }
 550
 551                         /* Turn all divs that don't have children block level elements into p's */
 552                         if ($tagName == 'DIV') {
 553                                 if (!preg_match($this->regexps['divToPElements'], $node->innerHTML)) {
 554                                         //$this->dbg('Altering div to p');
 555                                         $newNode = $this->dom->createElement('p');
 556                                         try {
 557                                                 $newNode->innerHTML = $node->innerHTML;
 558                                                 //$nodesToReplace[] = array('new'=>$newNode, 'old'=>$node);
 559                                                 $node->parentNode->replaceChild($newNode, $node);
 560                                                 $nodeIndex--;
 561                                                 $nodesToScore[] = $node; // or $newNode?
 562                                         }
 563                                         catch(Exception $e) {
 564                                                 $this->dbg('Could not alter div to p, reverting back to div.: ' . $e);
 565                                         }
 566                                 }
 567                                 else
 568                                 {
 569                                         // EXPERIMENTAL
 570                                         // TODO: change these p elements back to text nodes after processing
 571                                         for ($i = 0, $il = $node->childNodes->length; $i < $il; $i++) {
 572                                                 $childNode = $node->childNodes->item($i);
 573                                                 if ($childNode->nodeType == 3) { // XML_TEXT_NODE
 574                                                         //$this->dbg('replacing text node with a p tag with the same content.');
 575                                                         $p = $this->dom->createElement('p');
 576                                                         $p->innerHTML = $childNode->nodeValue;
 577                                                         $p->setAttribute('style', 'display: inline;');
 578                                                         $p->setAttribute('class', 'readability-styled');
 579                                                         $childNode->parentNode->replaceChild($p, $childNode);
 580                                                 }
 581                                         }
 582                                 }
 583                         }
 584                 }
 585
 586                 /**
 587                 * Loop through all paragraphs, and assign a score to them based on how content-y they look.
 588                 * Then add their score to their parent node.
 589                 *
 590                 * A score is determined by things like number of commas, class names, etc. Maybe eventually link density.
 591                 **/
 592                 $candidates = array();
 593                 for ($pt=0; $pt < count($nodesToScore); $pt++) {
 594                         $parentNode      = $nodesToScore[$pt]->parentNode;
 595                         // $grandParentNode = $parentNode ? $parentNode->parentNode : null;
 596                         $grandParentNode = !$parentNode ? null : (($parentNode->parentNode instanceof DOMElement) ? $parentNode->parentNode : null);
 597                         $innerText       = $this->getInnerText($nodesToScore[$pt]);
 598
 599                         if (!$parentNode || !isset($parentNode->tagName)) {
 600                                 continue;
 601                         }
 602
 603                         /* If this paragraph is less than 25 characters, don't even count it. */
 604                         if(strlen($innerText) < 25) {
 605                                 continue;
 606                         }
 607
 608                         /* Initialize readability data for the parent. */
 609                         if (!$parentNode->hasAttribute('readability'))
 610                         {
 611                                 $this->initializeNode($parentNode);
 612                                 $candidates[] = $parentNode;
 613                         }
 614
 615                         /* Initialize readability data for the grandparent. */
 616                         if ($grandParentNode && !$grandParentNode->hasAttribute('readability') && isset($grandParentNode->tagName))
 617                         {
 618                                 $this->initializeNode($grandParentNode);
 619                                 $candidates[] = $grandParentNode;
 620                         }
 621
 622                         $contentScore = 0;
 623
 624                         /* Add a point for the paragraph itself as a base. */
 625                         $contentScore++;
 626
 627                         /* Add points for any commas within this paragraph */
 628                         $contentScore += count(explode(',', $innerText));
 629
 630                         /* For every 100 characters in this paragraph, add another point. Up to 3 points. */
 631                         $contentScore += min(floor(strlen($innerText) / 100), 3);
 632
 633                         /* Add the score to the parent. The grandparent gets half. */
 634                         $parentNode->getAttributeNode('readability')->value += $contentScore;
 635
 636                         if ($grandParentNode) {
 637                                 $grandParentNode->getAttributeNode('readability')->value += $contentScore/2;
 638                         }
 639                 }
 640
 641                 /**
 642                 * After we've calculated scores, loop through all of the possible candidate nodes we found
 643                 * and find the one with the highest score.
 644                 **/
 645                 $topCandidate = null;
 646                 for ($c=0, $cl=count($candidates); $c < $cl; $c++)
 647                 {
 648                         /**
 649                         * Scale the final candidates score based on link density. Good content should have a
 650                         * relatively small link density (5% or less) and be mostly unaffected by this operation.
 651                         **/
 652                         $readability = $candidates[$c]->getAttributeNode('readability');
 653                         $readability->value = $readability->value * (1-$this->getLinkDensity($candidates[$c]));
 654
 655                         $this->dbg('Candidate: ' . $candidates[$c]->tagName . ' (' . $candidates[$c]->getAttribute('class') . ':' . $candidates[$c]->getAttribute('id') . ') with score ' . $readability->value);
 656
 657                         if (!$topCandidate || $readability->value > (int)$topCandidate->getAttribute('readability')) {
 658                                 $topCandidate = $candidates[$c];
 659                         }
 660                 }
 661
 662                 /**
 663                 * If we still have no top candidate, just use the body as a last resort.
 664                 * We also have to copy the body node so it is something we can modify.
 665                 **/
 666                 if ($topCandidate === null || strtoupper($topCandidate->tagName) == 'BODY')
 667                 {
 668                         $topCandidate = $this->dom->createElement('div');
 669                         if ($page instanceof DOMDocument) {
 670                                 if (!isset($page->documentElement)) {
 671                                         // we don't have a body either? what a mess! :)
 672                                 } else {
 673                                         $topCandidate->innerHTML = $page->documentElement->innerHTML;
 674                                         $page->documentElement->innerHTML = '';
 675                                         $page->documentElement->appendChild($topCandidate);
 676                                 }
 677                         } else {
 678                                 $topCandidate->innerHTML = $page->innerHTML;
 679                                 $page->innerHTML = '';
 680                                 $page->appendChild($topCandidate);
 681                         }
 682                         $this->initializeNode($topCandidate);
 683                 }
 684
 685                 /**
 686                 * Now that we have the top candidate, look through its siblings for content that might also be related.
 687                 * Things like preambles, content split by ads that we removed, etc.
 688                 **/
 689                 $articleContent        = $this->dom->createElement('div');
 690                 $articleContent->setAttribute('id', 'readability-content');
 691                 $siblingScoreThreshold = max(10, ((int)$topCandidate->getAttribute('readability')) * 0.2);
 692                 $siblingNodes          = $topCandidate->parentNode->childNodes;
 693                 if (!isset($siblingNodes)) {
 694                         $siblingNodes = new stdClass;
 695                         $siblingNodes->length = 0;
 696                 }
 697
 698                 for ($s=0, $sl=$siblingNodes->length; $s < $sl; $s++)
 699                 {
 700                         $siblingNode = $siblingNodes->item($s);
 701                         $append      = false;
 702
 703                         $this->dbg('Looking at sibling node: ' . $siblingNode->nodeName . (($siblingNode->nodeType === XML_ELEMENT_NODE && $siblingNode->hasAttribute('readability')) ? (' with score ' . $siblingNode->getAttribute('readability')) : ''));
 704
 705                         //dbg('Sibling has score ' . ($siblingNode->readability ? siblingNode.readability.contentScore : 'Unknown'));
 706
 707                         if ($siblingNode === $topCandidate)
 708                         // or if ($siblingNode->isSameNode($topCandidate))
 709                         {
 710                                 $append = true;
 711                         }
 712
 713                         $contentBonus = 0;
 714                         /* Give a bonus if sibling nodes and top candidates have the example same classname */
 715                         if ($siblingNode->nodeType === XML_ELEMENT_NODE && $siblingNode->getAttribute('class') == $topCandidate->getAttribute('class') && $topCandidate->getAttribute('class') != '') {
 716                                 $contentBonus += ((int)$topCandidate->getAttribute('readability')) * 0.2;
 717                         }
 718
 719                         if ($siblingNode->nodeType === XML_ELEMENT_NODE && $siblingNode->hasAttribute('readability') && (((int)$siblingNode->getAttribute('readability')) + $contentBonus) >= $siblingScoreThreshold)
 720                         {
 721                                 $append = true;
 722                         }
 723
 724                         if (strtoupper($siblingNode->nodeName) == 'P') {
 725                                 $linkDensity = $this->getLinkDensity($siblingNode);
 726                                 $nodeContent = $this->getInnerText($siblingNode);
 727                                 $nodeLength  = strlen($nodeContent);
 728
 729                                 if ($nodeLength > 80 && $linkDensity < 0.25)
 730                                 {
 731                                         $append = true;
 732                                 }
 733                                 else if ($nodeLength < 80 && $linkDensity === 0 && preg_match('/\.( |$)/', $nodeContent))
 734                                 {
 735                                         $append = true;
 736                                 }
 737                         }
 738
 739                         /* Look for a special classname */
 740                         if ($siblingNode->nodeType === XML_ELEMENT_NODE && $siblingNode->hasAttribute('class') && $siblingNode->getAttribute('class') != '')
 741                         {
 742                                 if (preg_match($this->regexps['okMaybeItsACandidate'], $siblingNode->getAttribute('class'))) {
 743                                         $append = true;
 744                                 }
 745                         }
 746
 747                         /* Look for a special classname */
 748                         if ($siblingNode->nodeType === XML_ELEMENT_NODE && $siblingNode->hasAttribute('id') && $siblingNode->getAttribute('id') != '')
 749                         {
 750                                 if (preg_match($this->regexps['okMaybeItsACandidate'], $siblingNode->getAttribute('id'))) {
 751                                         $append = true;
 752                                 }
 753                         }
 754
 755
 756                         if ($append)
 757                         {
 758                                 $this->dbg('Appending node: ' . $siblingNode->nodeName);
 759
 760                                 $nodeToAppend = null;
 761                                 $sibNodeName = strtoupper($siblingNode->nodeName);
 762                                 if ($sibNodeName != 'DIV' && $sibNodeName != 'P') {
 763                                         /* 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. */
 764
 765                                         $this->dbg('Altering siblingNode of ' . $sibNodeName . ' to div.');
 766                                         $nodeToAppend = $this->dom->createElement('div');
 767                                         try {
 768                                                 $nodeToAppend->setAttribute('id', $siblingNode->getAttribute('id'));
 769                                                 $nodeToAppend->innerHTML = $siblingNode->innerHTML;
 770                                         }
 771                                         catch(Exception $e)
 772                                         {
 773                                                 $this->dbg('Could not alter siblingNode to div, reverting back to original.');
 774                                                 $nodeToAppend = $siblingNode;
 775                                                 $s--;
 776                                                 $sl--;
 777                                         }
 778                                 } else {
 779                                         $nodeToAppend = $siblingNode;
 780                                         $s--;
 781                                         $sl--;
 782                                 }
 783
 784                                 /* To ensure a node does not interfere with readability styles, remove its classnames */
 785                                 $nodeToAppend->removeAttribute('class');
 786
 787                                 /* Append sibling and subtract from our list because it removes the node when you append to another node */
 788                                 $articleContent->appendChild($nodeToAppend);
 789                         }
 790                 }
 791
 792                 /**
 793                 * So we have all of the content that we need. Now we clean it up for presentation.
 794                 **/
 795                 $this->prepArticle($articleContent);
 796
 797                 /**
 798                 * Now that we've gone through the full algorithm, check to see if we got any meaningful content.
 799                 * If we didn't, we may need to re-run grabArticle with different flags set. This gives us a higher
 800                 * likelihood of finding the content, and the sieve approach gives us a higher likelihood of
 801                 * finding the -right- content.
 802                 **/
 803                 if (strlen($this->getInnerText($articleContent, false)) < 250)
 804                 {
 805                         // 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
 806                         // in the meantime, we check and create an empty element if it's not there.
 807                         if (!isset($this->body->childNodes)) $this->body = $this->dom->createElement('body');
 808                         $this->body->innerHTML = $this->bodyCache;
 809
 810                         if ($this->flagIsActive(self::FLAG_STRIP_UNLIKELYS)) {
 811                                 $this->removeFlag(self::FLAG_STRIP_UNLIKELYS);
 812                                 return $this->grabArticle($this->body);
 813                         }
 814                         else if ($this->flagIsActive(self::FLAG_WEIGHT_CLASSES)) {
 815                                 $this->removeFlag(self::FLAG_WEIGHT_CLASSES);
 816                                 return $this->grabArticle($this->body);
 817                         }
 818                         else if ($this->flagIsActive(self::FLAG_CLEAN_CONDITIONALLY)) {
 819                                 $this->removeFlag(self::FLAG_CLEAN_CONDITIONALLY);
 820                                 return $this->grabArticle($this->body);
 821                         }
 822                         else {
 823                                 return false;
 824                         }
 825                 }
 826                 return $articleContent;
 827         }
 828
 829         /**
 830         * Remove script tags from document
 831         *
 832         * @param DOMElement
 833         * @return void
 834         */
 835         public function removeScripts($doc) {
 836                 $scripts = $doc->getElementsByTagName('script');
 837                 for($i = $scripts->length-1; $i >= 0; $i--)
 838                 {
 839                         $scripts->item($i)->parentNode->removeChild($scripts->item($i));
 840                 }
 841         }
 842
 843         /**
 844         * Get the inner text of a node.
 845         * This also strips out any excess whitespace to be found.
 846         *
 847         * @param DOMElement $
 848         * @param boolean $normalizeSpaces (default: true)
 849         * @return string
 850         **/
 851         public function getInnerText($e, $normalizeSpaces=true) {
 852                 $textContent = '';
 853
 854                 if (!isset($e->textContent) || $e->textContent == '') {
 855                         return '';
 856                 }
 857
 858                 $textContent = trim($e->textContent);
 859
 860                 if ($normalizeSpaces) {
 861                         return preg_replace($this->regexps['normalize'], ' ', $textContent);
 862                 } else {
 863                         return $textContent;
 864                 }
 865         }
 866
 867         /**
 868         * Get the number of times a string $s appears in the node $e.
 869         *
 870         * @param DOMElement $e
 871         * @param string - what to count. Default is ","
 872         * @return number (integer)
 873         **/
 874         public function getCharCount($e, $s=',') {
 875                 return substr_count($this->getInnerText($e), $s);
 876         }
 877
 878         /**
 879         * Remove the style attribute on every $e and under.
 880         *
 881         * @param DOMElement $e
 882         * @return void
 883         */
 884         public function cleanStyles($e) {
 885                 if (!is_object($e)) return;
 886                 $elems = $e->getElementsByTagName('*');
 887                 foreach ($elems as $elem) {
 888                         $elem->removeAttribute('style');
 889                 }
 890         }
 891
 892         /**
 893         * Get the density of links as a percentage of the content
 894         * This is the amount of text that is inside a link divided by the total text in the node.
 895         *
 896         * @param DOMElement $e
 897         * @return number (float)
 898         */
 899         public function getLinkDensity($e) {
 900                 $links      = $e->getElementsByTagName('a');
 901                 $textLength = strlen($this->getInnerText($e));
 902                 $linkLength = 0;
 903                 for ($i=0, $il=$links->length; $i < $il; $i++)
 904                 {
 905                         $linkLength += strlen($this->getInnerText($links->item($i)));
 906                 }
 907                 if ($textLength > 0) {
 908                         return $linkLength / $textLength;
 909                 } else {
 910                         return 0;
 911                 }
 912         }
 913
 914         /**
 915         * Get an elements class/id weight. Uses regular expressions to tell if this
 916         * element looks good or bad.
 917         *
 918         * @param DOMElement $e
 919         * @return number (Integer)
 920         */
 921         public function getClassWeight($e) {
 922                 if(!$this->flagIsActive(self::FLAG_WEIGHT_CLASSES)) {
 923                         return 0;
 924                 }
 925
 926                 $weight = 0;
 927
 928                 /* Look for a special classname */
 929                 if ($e->hasAttribute('class') && $e->getAttribute('class') != '')
 930                 {
 931                         if (preg_match($this->regexps['negative'], $e->getAttribute('class'))) {
 932                                 $weight -= 25;
 933                         }
 934                         if (preg_match($this->regexps['positive'], $e->getAttribute('class'))) {
 935                                 $weight += 25;
 936                         }
 937                 }
 938
 939                 /* Look for a special ID */
 940                 if ($e->hasAttribute('id') && $e->getAttribute('id') != '')
 941                 {
 942                         if (preg_match($this->regexps['negative'], $e->getAttribute('id'))) {
 943                                 $weight -= 25;
 944                         }
 945                         if (preg_match($this->regexps['positive'], $e->getAttribute('id'))) {
 946                                 $weight += 25;
 947                         }
 948                 }
 949                 return $weight;
 950         }
 951
 952         /**
 953         * Remove extraneous break tags from a node.
 954         *
 955         * @param DOMElement $node
 956         * @return void
 957         */
 958         public function killBreaks($node) {
 959                 $html = $node->innerHTML;
 960                 $html = preg_replace($this->regexps['killBreaks'], '<br />', $html);
 961                 $node->innerHTML = $html;
 962         }
 963
 964         /**
 965         * Clean a node of all elements of type "tag".
 966         * (Unless it's a youtube/vimeo video. People love movies.)
 967         *
 968         * @param DOMElement $e
 969         * @param string $tag
 970         * @return void
 971         */
 972         public function clean($e, $tag) {
 973                 $targetList = $e->getElementsByTagName($tag);
 974                 $isEmbed = ($tag == 'object' || $tag == 'embed');
 975
 976                 for ($y=$targetList->length-1; $y >= 0; $y--) {
 977                         /* Allow youtube and vimeo videos through as people usually want to see those. */
 978                         if ($isEmbed) {
 979                                 $attributeValues = '';
 980                                 for ($i=0, $il=$targetList->item($y)->attributes->length; $i < $il; $i++) {
 981                                         $attributeValues .= $targetList->item($y)->attributes->item($i)->value . '|'; // DOMAttr? (TODO: test)
 982                                 }
 983
 984                                 /* First, check the elements attributes to see if any of them contain youtube or vimeo */
 985                                 if (preg_match($this->regexps['video'], $attributeValues)) {
 986                                         continue;
 987                                 }
 988
 989                                 /* Then check the elements inside this element for the same. */
 990                                 if (preg_match($this->regexps['video'], $targetList->item($y)->innerHTML)) {
 991                                         continue;
 992                                 }
 993                         }
 994                         $targetList->item($y)->parentNode->removeChild($targetList->item($y));
 995                 }
 996         }
 997
 998         /**
 999         * Clean an element of all tags of type "tag" if they look fishy.
1000         * "Fishy" is an algorithm based on content length, classnames,
1001         * link density, number of images & embeds, etc.
1002         *
1003         * @param DOMElement $e
1004         * @param string $tag
1005         * @return void
1006         */
1007         public function cleanConditionally($e, $tag) {
1008                 if (!$this->flagIsActive(self::FLAG_CLEAN_CONDITIONALLY)) {
1009                         return;
1010                 }
1011
1012                 $tagsList = $e->getElementsByTagName($tag);
1013                 $curTagsLength = $tagsList->length;
1014
1015                 /**
1016                 * Gather counts for other typical elements embedded within.
1017                 * Traverse backwards so we can remove nodes at the same time without effecting the traversal.
1018                 *
1019                 * TODO: Consider taking into account original contentScore here.
1020                 */
1021                 for ($i=$curTagsLength-1; $i >= 0; $i--) {
1022                         $weight = $this->getClassWeight($tagsList->item($i));
1023                         $contentScore = ($tagsList->item($i)->hasAttribute('readability')) ? (int)$tagsList->item($i)->getAttribute('readability') : 0;
1024
1025                         $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')) : ''));
1026
1027                         if ($weight + $contentScore < 0) {
1028                                 $tagsList->item($i)->parentNode->removeChild($tagsList->item($i));
1029                         }
1030                         else if ( $this->getCharCount($tagsList->item($i), ',') < 10) {
1031                                 /**
1032                                 * If there are not very many commas, and the number of
1033                                 * non-paragraph elements is more than paragraphs or other ominous signs, remove the element.
1034                                 **/
1035                                 $p      = $tagsList->item($i)->getElementsByTagName('p')->length;
1036                                 $img    = $tagsList->item($i)->getElementsByTagName('img')->length;
1037                                 $li     = $tagsList->item($i)->getElementsByTagName('li')->length-100;
1038                                 $input  = $tagsList->item($i)->getElementsByTagName('input')->length;
1039
1040                                 $embedCount = 0;
1041                                 $embeds = $tagsList->item($i)->getElementsByTagName('embed');
1042                                 for ($ei=0, $il=$embeds->length; $ei < $il; $ei++) {
1043                                         if (preg_match($this->regexps['video'], $embeds->item($ei)->getAttribute('src'))) {
1044                                         $embedCount++;
1045                                         }
1046                                 }
1047
1048                                 $linkDensity   = $this->getLinkDensity($tagsList->item($i));
1049                                 $contentLength = strlen($this->getInnerText($tagsList->item($i)));
1050                                 $toRemove      = false;
1051
1052                                 if ( $img > $p ) {
1053                                         $toRemove = true;
1054                                 } else if ($li > $p && $tag != 'ul' && $tag != 'ol') {
1055                                         $toRemove = true;
1056                                 } else if ( $input > floor($p/3) ) {
1057                                         $toRemove = true;
1058                                 } else if ($contentLength < 25 && ($img === 0 || $img > 2) ) {
1059                                         $toRemove = true;
1060                                 } else if($weight < 25 && $linkDensity > 0.2) {
1061                                         $toRemove = true;
1062                                 } else if($weight >= 25 && $linkDensity > 0.5) {
1063                                         $toRemove = true;
1064                                 } else if(($embedCount == 1 && $contentLength < 75) || $embedCount > 1) {
1065                                         $toRemove = true;
1066                                 }
1067
1068                                 if ($toRemove) {
1069                                         $tagsList->item($i)->parentNode->removeChild($tagsList->item($i));
1070                                 }
1071                         }
1072                 }
1073         }
1074
1075         /**
1076         * Clean out spurious headers from an Element. Checks things like classnames and link density.
1077         *
1078         * @param DOMElement $e
1079         * @return void
1080         */
1081         public function cleanHeaders($e) {
1082                 for ($headerIndex = 1; $headerIndex < 3; $headerIndex++) {
1083                         $headers = $e->getElementsByTagName('h' . $headerIndex);
1084                         for ($i=$headers->length-1; $i >=0; $i--) {
1085                                 if ($this->getClassWeight($headers->item($i)) < 0 || $this->getLinkDensity($headers->item($i)) > 0.33) {
1086                                         $headers->item($i)->parentNode->removeChild($headers->item($i));
1087                                 }
1088                         }
1089                 }
1090         }
1091
1092         public function flagIsActive($flag) {
1093                 return ($this->flags & $flag) > 0;
1094         }
1095
1096         public function addFlag($flag) {
1097                 $this->flags = $this->flags | $flag;
1098         }
1099
1100         public function removeFlag($flag) {
1101                 $this->flags = $this->flags & ~$flag;
1102         }
1103 }
1104 ?>