src/Util/ParseUrl.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2020, Friendica
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 namespace Friendica\Util;
  23
  24 use DOMDocument;
  25 use DOMXPath;
  26 use Friendica\Content\OEmbed;
  27 use Friendica\Core\Hook;
  28 use Friendica\Core\Logger;
  29 use Friendica\Database\Database;
  30 use Friendica\Database\DBA;
  31 use Friendica\DI;
  32 use Friendica\Network\HTTPException;
  33
  34 /**
  35  * Get information about a given URL
  36  *
  37  * Class with methods for extracting certain content from an url
  38  */
  39 class ParseUrl
  40 {
  41         const DEFAULT_EXPIRATION_FAILURE = 'now + 1 day';
  42         const DEFAULT_EXPIRATION_SUCCESS = 'now + 3 months';
  43
  44         /**
  45          * Maximum number of characters for the description
  46          */
  47         const MAX_DESC_COUNT = 250;
  48
  49         /**
  50          * Minimum number of characters for the description
  51          */
  52         const MIN_DESC_COUNT = 100;
  53
  54         /**
  55          * Fetch the content type of the given url
  56          * @param string $url URL of the page
  57          * @return array content type
  58          */
  59         public static function getContentType(string $url)
  60         {
  61                 $curlResult = DI::httpRequest()->head($url);
  62                 if (!$curlResult->isSuccess()) {
  63                         return [];
  64                 }
  65
  66                 $contenttype =  $curlResult->getHeader('Content-Type');
  67                 if (empty($contenttype)) {
  68                         return [];
  69                 }
  70
  71                 return explode('/', current(explode(';', $contenttype)));
  72         }
  73
  74         /**
  75          * Search for chached embeddable data of an url otherwise fetch it
  76          *
  77          * @param string $url         The url of the page which should be scraped
  78          * @param bool   $do_oembed   The false option is used by the function fetch_oembed()
  79          *                            to avoid endless loops
  80          *
  81          * @return array which contains needed data for embedding
  82          *    string 'url'      => The url of the parsed page
  83          *    string 'type'     => Content type
  84          *    string 'title'    => (optional) The title of the content
  85          *    string 'text'     => (optional) The description for the content
  86          *    string 'image'    => (optional) A preview image of the content
  87          *    array  'images'   => (optional) Array of preview pictures
  88          *    string 'keywords' => (optional) The tags which belong to the content
  89          *
  90          * @throws HTTPException\InternalServerErrorException
  91          * @see   ParseUrl::getSiteinfo() for more information about scraping
  92          * embeddable content
  93          */
  94         public static function getSiteinfoCached($url, $do_oembed = true): array
  95         {
  96                 if (empty($url)) {
  97                         return [
  98                                 'url' => '',
  99                                 'type' => 'error',
 100                         ];
 101                 }
 102
 103                 $urlHash = hash('sha256', $url);
 104
 105                 $parsed_url = DBA::selectFirst('parsed_url', ['content'],
 106                         ['url_hash' => $urlHash, 'oembed' => $do_oembed]
 107                 );
 108                 if (!empty($parsed_url['content'])) {
 109                         $data = unserialize($parsed_url['content']);
 110                         return $data;
 111                 }
 112
 113                 $data = self::getSiteinfo($url, $do_oembed);
 114
 115                 $expires = $data['expires'];
 116
 117                 unset($data['expires']);
 118
 119                 DI::dba()->insert(
 120                         'parsed_url',
 121                         [
 122                                 'url_hash' => $urlHash,
 123                                 'oembed'   => $do_oembed,
 124                                 'url'      => $url,
 125                                 'content'  => serialize($data),
 126                                 'created'  => DateTimeFormat::utcNow(),
 127                                 'expires'  => $expires,
 128                         ],
 129                         Database::INSERT_UPDATE
 130                 );
 131
 132                 return $data;
 133         }
 134
 135         /**
 136          * Parse a page for embeddable content information
 137          *
 138          * This method parses to url for meta data which can be used to embed
 139          * the content. If available it prioritizes Open Graph meta tags.
 140          * If this is not available it uses the twitter cards meta tags.
 141          * As fallback it uses standard html elements with meta informations
 142          * like \<title\>Awesome Title\</title\> or
 143          * \<meta name="description" content="An awesome description"\>
 144          *
 145          * @param string $url         The url of the page which should be scraped
 146          * @param bool   $do_oembed   The false option is used by the function fetch_oembed()
 147          *                            to avoid endless loops
 148          * @param int    $count       Internal counter to avoid endless loops
 149          *
 150          * @return array which contains needed data for embedding
 151          *    string 'url'      => The url of the parsed page
 152          *    string 'type'     => Content type (error, link, photo, image, audio, video)
 153          *    string 'title'    => (optional) The title of the content
 154          *    string 'text'     => (optional) The description for the content
 155          *    string 'image'    => (optional) A preview image of the content
 156          *    array  'images'   => (optional) Array of preview pictures
 157          *    string 'keywords' => (optional) The tags which belong to the content
 158          *
 159          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 160          * @todo  https://developers.google.com/+/plugins/snippet/
 161          * @verbatim
 162          * <meta itemprop="name" content="Awesome title">
 163          * <meta itemprop="description" content="An awesome description">
 164          * <meta itemprop="image" content="http://maple.libertreeproject.org/images/tree-icon.png">
 165          *
 166          * <body itemscope itemtype="http://schema.org/Product">
 167          *   <h1 itemprop="name">Shiny Trinket</h1>
 168          *   <img itemprop="image" src="{image-url}" />
 169          *   <p itemprop="description">Shiny trinkets are shiny.</p>
 170          * </body>
 171          * @endverbatim
 172          */
 173         public static function getSiteinfo($url, $do_oembed = true, $count = 1)
 174         {
 175                 if (empty($url)) {
 176                         return [
 177                                 'url' => '',
 178                                 'type' => 'error',
 179                         ];
 180                 }
 181
 182                 // Check if the URL does contain a scheme
 183                 $scheme = parse_url($url, PHP_URL_SCHEME);
 184
 185                 if ($scheme == '') {
 186                         $url = 'http://' . ltrim($url, '/');
 187                 }
 188
 189                 $url = trim($url, "'\"");
 190
 191                 $url = Network::stripTrackingQueryParams($url);
 192
 193                 $siteinfo = [
 194                         'url' => $url,
 195                         'type' => 'link',
 196                         'expires' => DateTimeFormat::utc(self::DEFAULT_EXPIRATION_FAILURE),
 197                 ];
 198
 199                 if ($count > 10) {
 200                         Logger::log('Endless loop detected for ' . $url, Logger::DEBUG);
 201                         return $siteinfo;
 202                 }
 203
 204                 $type = self::getContentType($url);
 205                 Logger::info('Got content-type', ['content-type' => $type, 'url' => $url]);
 206                 if (!empty($type) && in_array($type[0], ['image', 'video', 'audio'])) {
 207                         $siteinfo['type'] = $type[0];
 208                         return $siteinfo;
 209                 }
 210
 211                 if ((count($type) >= 2) && (($type[0] != 'text') || ($type[1] != 'html'))) {
 212                         Logger::info('Unparseable content-type, quitting here, ', ['content-type' => $type, 'url' => $url]);
 213                         return $siteinfo;
 214                 }
 215
 216                 $curlResult = DI::httpRequest()->get($url);
 217                 if (!$curlResult->isSuccess()) {
 218                         return $siteinfo;
 219                 }
 220
 221                 $siteinfo['expires'] = DateTimeFormat::utc(self::DEFAULT_EXPIRATION_SUCCESS);
 222
 223                 // If the file is too large then exit
 224                 if (($curlResult->getInfo()['download_content_length'] ?? 0) > 1000000) {
 225                         return $siteinfo;
 226                 }
 227
 228                 if ($cacheControlHeader = $curlResult->getHeader('Cache-Control')) {
 229                         if (preg_match('/max-age=([0-9]+)/i', $cacheControlHeader, $matches)) {
 230                                 $maxAge = max(86400, (int)array_pop($matches));
 231                                 $siteinfo['expires'] = DateTimeFormat::utc("now + $maxAge seconds");
 232                         }
 233                 }
 234
 235                 $header = $curlResult->getHeader();
 236                 $body = $curlResult->getBody();
 237
 238                 if ($do_oembed) {
 239                         $oembed_data = OEmbed::fetchURL($url, false, false);
 240
 241                         if (!empty($oembed_data->type)) {
 242                                 if (!in_array($oembed_data->type, ['error', 'rich', 'image', 'video', 'audio', ''])) {
 243                                         $siteinfo['type'] = $oembed_data->type;
 244                                 }
 245
 246                                 // See https://github.com/friendica/friendica/pull/5763#discussion_r217913178
 247                                 if ($siteinfo['type'] != 'photo') {
 248                                         if (!empty($oembed_data->title)) {
 249                                                 $siteinfo['title'] = trim($oembed_data->title);
 250                                         }
 251                                         if (!empty($oembed_data->description)) {
 252                                                 $siteinfo['text'] = trim($oembed_data->description);
 253                                         }
 254                                         if (!empty($oembed_data->author_name)) {
 255                                                 $siteinfo['author_name'] = trim($oembed_data->author_name);
 256                                         }
 257                                         if (!empty($oembed_data->author_url)) {
 258                                                 $siteinfo['author_url'] = trim($oembed_data->author_url);
 259                                         }
 260                                         if (!empty($oembed_data->provider_name)) {
 261                                                 $siteinfo['publisher_name'] = trim($oembed_data->provider_name);
 262                                         }
 263                                         if (!empty($oembed_data->provider_url)) {
 264                                                 $siteinfo['publisher_url'] = trim($oembed_data->provider_url);
 265                                         }
 266                                         if (!empty($oembed_data->thumbnail_url)) {
 267                                                 $siteinfo['image'] = $oembed_data->thumbnail_url;
 268                                         }
 269                                 }
 270                         }
 271                 }
 272
 273                 $charset = '';
 274                 // Look for a charset, first in headers
 275                 // Expected form: Content-Type: text/html; charset=ISO-8859-4
 276                 if (preg_match('/charset=([a-z0-9-_.\/]+)/i', $header, $matches)) {
 277                         $charset = trim(trim(trim(array_pop($matches)), ';,'));
 278                 }
 279
 280                 // Then in body that gets precedence
 281                 // Expected forms:
 282                 // - <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
 283                 // - <meta charset="utf-8">
 284                 // - <meta charset=utf-8>
 285                 // - <meta charSet="utf-8">
 286                 // We escape <style> and <script> tags since they can contain irrelevant charset information
 287                 // (see https://github.com/friendica/friendica/issues/9251#issuecomment-698636806)
 288                 Strings::performWithEscapedBlocks($body, '#<(?:style|script).*?</(?:style|script)>#ism', function ($body) use (&$charset) {
 289                         if (preg_match('/charset=["\']?([a-z0-9-_.\/]+)/i', $body, $matches)) {
 290                                 $charset = trim(trim(trim(array_pop($matches)), ';,'));
 291                         }
 292                 });
 293
 294                 $siteinfo['charset'] = $charset;
 295
 296                 if ($charset && strtoupper($charset) != 'UTF-8') {
 297                         // See https://github.com/friendica/friendica/issues/5470#issuecomment-418351211
 298                         $charset = str_ireplace('latin-1', 'latin1', $charset);
 299
 300                         Logger::log('detected charset ' . $charset, Logger::DEBUG);
 301                         $body = iconv($charset, 'UTF-8//TRANSLIT', $body);
 302                 }
 303
 304                 $body = mb_convert_encoding($body, 'HTML-ENTITIES', 'UTF-8');
 305
 306                 $doc = new DOMDocument();
 307                 @$doc->loadHTML($body);
 308
 309                 XML::deleteNode($doc, 'style');
 310                 XML::deleteNode($doc, 'option');
 311                 XML::deleteNode($doc, 'h1');
 312                 XML::deleteNode($doc, 'h2');
 313                 XML::deleteNode($doc, 'h3');
 314                 XML::deleteNode($doc, 'h4');
 315                 XML::deleteNode($doc, 'h5');
 316                 XML::deleteNode($doc, 'h6');
 317                 XML::deleteNode($doc, 'ol');
 318                 XML::deleteNode($doc, 'ul');
 319
 320                 $xpath = new DOMXPath($doc);
 321
 322                 $list = $xpath->query('//meta[@content]');
 323                 foreach ($list as $node) {
 324                         $meta_tag = [];
 325                         if ($node->attributes->length) {
 326                                 foreach ($node->attributes as $attribute) {
 327                                         $meta_tag[$attribute->name] = $attribute->value;
 328                                 }
 329                         }
 330
 331                         if (@$meta_tag['http-equiv'] == 'refresh') {
 332                                 $path = $meta_tag['content'];
 333                                 $pathinfo = explode(';', $path);
 334                                 $content = '';
 335                                 foreach ($pathinfo as $value) {
 336                                         if (substr(strtolower($value), 0, 4) == 'url=') {
 337                                                 $content = substr($value, 4);
 338                                         }
 339                                 }
 340                                 if ($content != '') {
 341                                         $siteinfo = self::getSiteinfo($content, $do_oembed, ++$count);
 342                                         return $siteinfo;
 343                                 }
 344                         }
 345                 }
 346
 347                 $list = $xpath->query('//title');
 348                 if ($list->length > 0) {
 349                         $siteinfo['title'] = trim($list->item(0)->nodeValue);
 350                 }
 351
 352                 $list = $xpath->query('//meta[@name]');
 353                 foreach ($list as $node) {
 354                         $meta_tag = [];
 355                         if ($node->attributes->length) {
 356                                 foreach ($node->attributes as $attribute) {
 357                                         $meta_tag[$attribute->name] = $attribute->value;
 358                                 }
 359                         }
 360
 361                         if (empty($meta_tag['content'])) {
 362                                 continue;
 363                         }
 364
 365                         $meta_tag['content'] = trim(html_entity_decode($meta_tag['content'], ENT_QUOTES, 'UTF-8'));
 366
 367                         switch (strtolower($meta_tag['name'])) {
 368                                 case 'fulltitle':
 369                                         $siteinfo['title'] = trim($meta_tag['content']);
 370                                         break;
 371                                 case 'description':
 372                                         $siteinfo['text'] = trim($meta_tag['content']);
 373                                         break;
 374                                 case 'thumbnail':
 375                                         $siteinfo['image'] = $meta_tag['content'];
 376                                         break;
 377                                 case 'twitter:image':
 378                                         $siteinfo['image'] = $meta_tag['content'];
 379                                         break;
 380                                 case 'twitter:image:src':
 381                                         $siteinfo['image'] = $meta_tag['content'];
 382                                         break;
 383                                 case 'twitter:card':
 384                                         // Detect photo pages
 385                                         if ($meta_tag['content'] == 'summary_large_image') {
 386                                                 $siteinfo['type'] = 'photo';
 387                                         }
 388                                         break;
 389                                 case 'twitter:description':
 390                                         $siteinfo['text'] = trim($meta_tag['content']);
 391                                         break;
 392                                 case 'twitter:title':
 393                                         $siteinfo['title'] = trim($meta_tag['content']);
 394                                         break;
 395                                 case 'dc.title':
 396                                         $siteinfo['title'] = trim($meta_tag['content']);
 397                                         break;
 398                                 case 'dc.description':
 399                                         $siteinfo['text'] = trim($meta_tag['content']);
 400                                         break;
 401                                 case 'dc.creator':
 402                                         $siteinfo['publisher_name'] = trim($meta_tag['content']);
 403                                         break;
 404                                 case 'keywords':
 405                                         $keywords = explode(',', $meta_tag['content']);
 406                                         break;
 407                                 case 'news_keywords':
 408                                         $keywords = explode(',', $meta_tag['content']);
 409                                         break;
 410                         }
 411                 }
 412
 413                 if (isset($keywords)) {
 414                         $siteinfo['keywords'] = [];
 415                         foreach ($keywords as $keyword) {
 416                                 if (!in_array(trim($keyword), $siteinfo['keywords'])) {
 417                                         $siteinfo['keywords'][] = trim($keyword);
 418                                 }
 419                         }
 420                 }
 421
 422                 $list = $xpath->query('//meta[@property]');
 423                 foreach ($list as $node) {
 424                         $meta_tag = [];
 425                         if ($node->attributes->length) {
 426                                 foreach ($node->attributes as $attribute) {
 427                                         $meta_tag[$attribute->name] = $attribute->value;
 428                                 }
 429                         }
 430
 431                         if (!empty($meta_tag['content'])) {
 432                                 $meta_tag['content'] = trim(html_entity_decode($meta_tag['content'], ENT_QUOTES, 'UTF-8'));
 433
 434                                 switch (strtolower($meta_tag['property'])) {
 435                                         case 'og:image':
 436                                                 $siteinfo['image'] = $meta_tag['content'];
 437                                                 break;
 438                                         case 'og:image:url':
 439                                                 $siteinfo['image'] = $meta_tag['content'];
 440                                                 break;
 441                                         case 'og:image:secure_url':
 442                                                 $siteinfo['image'] = $meta_tag['content'];
 443                                                 break;
 444                                         case 'og:title':
 445                                                 $siteinfo['title'] = trim($meta_tag['content']);
 446                                                 break;
 447                                         case 'og:description':
 448                                                 $siteinfo['text'] = trim($meta_tag['content']);
 449                                                 break;
 450                                         case 'og:site_name':
 451                                                 $siteinfo['publisher_name'] = trim($meta_tag['content']);
 452                                                 break;
 453                                         case 'twitter:description':
 454                                                 $siteinfo['text'] = trim($meta_tag['content']);
 455                                                 break;
 456                                         case 'twitter:title':
 457                                                 $siteinfo['title'] = trim($meta_tag['content']);
 458                                                 break;
 459                                         case 'twitter:image':
 460                                                 $siteinfo['image'] = $meta_tag['content'];
 461                                                 break;
 462                                 }
 463                         }
 464                 }
 465
 466                 $list = $xpath->query("//script[@type='application/ld+json']");
 467                 foreach ($list as $node) {
 468                         if (!empty($node->nodeValue)) {
 469                                 $nodevalue = html_entity_decode($node->nodeValue, ENT_COMPAT, 'UTF-8');
 470                                 if ($jsonld = json_decode($nodevalue, true)) {
 471                                         $siteinfo = self::parseParts($siteinfo, $jsonld);
 472                                 }
 473                         }
 474                 }
 475
 476                 // Prevent to have a photo type without an image
 477                 if ((empty($siteinfo['image']) || !empty($siteinfo['text'])) && ($siteinfo['type'] == 'photo')) {
 478                         $siteinfo['type'] = 'link';
 479                 }
 480
 481                 if (!empty($siteinfo['image'])) {
 482                         $siteinfo['images'] = $siteinfo['images'] ?? [];
 483                         array_unshift($siteinfo['images'], ['url' => $siteinfo['image']]);
 484                         unset($siteinfo['image']);
 485                 }
 486
 487                 $siteinfo = self::checkMedia($url, $siteinfo);
 488
 489                 if (!empty($siteinfo['text']) && mb_strlen($siteinfo['text']) > self::MAX_DESC_COUNT) {
 490                         $siteinfo['text'] = mb_substr($siteinfo['text'], 0, self::MAX_DESC_COUNT) . '…';
 491                         $pos = mb_strrpos($siteinfo['text'], '.');
 492                         if ($pos > self::MIN_DESC_COUNT) {
 493                                 $siteinfo['text'] = mb_substr($siteinfo['text'], 0, $pos + 1);
 494                         }
 495                 }
 496
 497                 Logger::info('Siteinfo fetched', ['url' => $url, 'siteinfo' => $siteinfo]);
 498
 499                 Hook::callAll('getsiteinfo', $siteinfo);
 500
 501                 return $siteinfo;
 502         }
 503
 504         /**
 505          * Check the attached media elements.
 506          * Fix existing data and add missing data.
 507          *
 508          * @param string $page_url
 509          * @param array $siteinfo
 510          * @return void
 511          */
 512         private static function checkMedia(string $page_url, array $siteinfo)
 513         {
 514                 if (!empty($siteinfo['images'])) {
 515                         array_walk($siteinfo['images'], function (&$image) use ($page_url) {
 516                                 // According to the specifications someone could place a picture url into the content field as well.
 517                                 // But this doesn't seem to happen in the wild, so we don't cover it here.
 518                                 $image['url'] = self::completeUrl($image['url'], $page_url);
 519                                 $photodata = Images::getInfoFromURLCached($image['url']);
 520                                 if (!empty($photodata) && ($photodata[0] > 50) && ($photodata[1] > 50)) {
 521                                         $image['src'] = $image['url'];
 522                                         $image['width'] = $photodata[0];
 523                                         $image['height'] = $photodata[1];
 524                                         $image['contenttype'] = $photodata['mime'];
 525                                         unset($image['url']);
 526                                         ksort($image);
 527                                 } else {
 528                                         $image = [];
 529                                 }
 530                         });
 531
 532                         $siteinfo['images'] = array_values(array_filter($siteinfo['images']));
 533                 }
 534
 535                 foreach (['audio', 'video'] as $element) {
 536                         if (!empty($siteinfo[$element])) {
 537                                 array_walk($siteinfo[$element], function (&$media) use ($page_url, &$siteinfo) {
 538                                         $url = '';
 539                                         $embed = '';
 540                                         $content = '';
 541                                         $contenttype = '';
 542                                         foreach (['embed', 'content', 'url'] as $field) {
 543                                                 if (!empty($media[$field])) {
 544                                                         $media[$field] = self::completeUrl($media[$field], $page_url);
 545                                                         $type = self::getContentType($media[$field]);
 546                                                         if ($type[0] == 'text') {
 547                                                                 if ($field == 'embed') {
 548                                                                         $embed = $media[$field];
 549                                                                 } else {
 550                                                                         $url = $media[$field];
 551                                                                 }
 552                                                         } elseif (!empty($type[0])) {
 553                                                                 $content = $media[$field];
 554                                                                 $contenttype = implode('/', $type);
 555                                                         }
 556                                                 }
 557                                                 unset($media[$field]);
 558                                         }
 559
 560                                         foreach (['image', 'preview'] as $field) {
 561                                                 if (!empty($media[$field])) {
 562                                                         $media[$field] = self::completeUrl($media[$field], $page_url);
 563                                                 }
 564                                         }
 565
 566                                         if (!empty($url)) {
 567                                                 $media['url'] = $url;
 568                                         }
 569                                         if (!empty($embed)) {
 570                                                 $media['embed'] = $embed;
 571                                                 if (!empty($media['main'])) {
 572                                                         $siteinfo['embed'] = $embed;
 573                                                 }
 574                                         }
 575                                         if (!empty($content)) {
 576                                                 $media['src'] = $content;
 577                                         }
 578                                         if (!empty($contenttype)) {
 579                                                 $media['contenttype'] = $contenttype;
 580                                         }
 581                                         if (empty($url) && empty($content) && empty($embed)) {
 582                                                 $media = [];
 583                                         }
 584                                         ksort($media);
 585                                 });
 586
 587                                 $siteinfo[$element] = array_values(array_filter($siteinfo[$element]));
 588                         }
 589                         if (empty($siteinfo[$element])) {
 590                                 unset($siteinfo[$element]);
 591                         }
 592                 }
 593                 return $siteinfo;
 594         }
 595
 596         /**
 597          * Convert tags from CSV to an array
 598          *
 599          * @param string $string Tags
 600          * @return array with formatted Hashtags
 601          */
 602         public static function convertTagsToArray($string)
 603         {
 604                 $arr_tags = str_getcsv($string);
 605                 if (count($arr_tags)) {
 606                         // add the # sign to every tag
 607                         array_walk($arr_tags, ["self", "arrAddHashes"]);
 608
 609                         return $arr_tags;
 610                 }
 611         }
 612
 613         /**
 614          * Add a hasht sign to a string
 615          *
 616          * This method is used as callback function
 617          *
 618          * @param string $tag The pure tag name
 619          * @param int    $k   Counter for internal use
 620          * @return void
 621          */
 622         private static function arrAddHashes(&$tag, $k)
 623         {
 624                 $tag = "#" . $tag;
 625         }
 626
 627         /**
 628          * Add a scheme to an url
 629          *
 630          * The src attribute of some html elements (e.g. images)
 631          * can miss the scheme so we need to add the correct
 632          * scheme
 633          *
 634          * @param string $url    The url which possibly does have
 635          *                       a missing scheme (a link to an image)
 636          * @param string $scheme The url with a correct scheme
 637          *                       (e.g. the url from the webpage which does contain the image)
 638          *
 639          * @return string The url with a scheme
 640          */
 641         private static function completeUrl($url, $scheme)
 642         {
 643                 $urlarr = parse_url($url);
 644
 645                 // If the url does allready have an scheme
 646                 // we can stop the process here
 647                 if (isset($urlarr["scheme"])) {
 648                         return($url);
 649                 }
 650
 651                 $schemearr = parse_url($scheme);
 652
 653                 $complete = $schemearr["scheme"]."://".$schemearr["host"];
 654
 655                 if (!empty($schemearr["port"])) {
 656                         $complete .= ":".$schemearr["port"];
 657                 }
 658
 659                 if (!empty($urlarr["path"])) {
 660                         if (strpos($urlarr["path"], "/") !== 0) {
 661                                 $complete .= "/";
 662                         }
 663
 664                         $complete .= $urlarr["path"];
 665                 }
 666
 667                 if (!empty($urlarr["query"])) {
 668                         $complete .= "?".$urlarr["query"];
 669                 }
 670
 671                 if (!empty($urlarr["fragment"])) {
 672                         $complete .= "#".$urlarr["fragment"];
 673                 }
 674
 675                 return($complete);
 676         }
 677
 678         /**
 679          * Parse the Json-Ld parts of a web page
 680          *
 681          * @param array $siteinfo
 682          * @param array $jsonld
 683          * @return array siteinfo
 684          */
 685         private static function parseParts(array $siteinfo, array $jsonld)
 686         {
 687                 if (!empty($jsonld['@graph']) && is_array($jsonld['@graph'])) {
 688                         foreach ($jsonld['@graph'] as $part) {
 689                                 $siteinfo = self::parseParts($siteinfo, $part);
 690                         }
 691                 } elseif (!empty($jsonld['@type'])) {
 692                         $siteinfo = self::parseJsonLd($siteinfo, $jsonld);
 693                 } elseif (!empty($jsonld)) {
 694                         $keys = array_keys($jsonld);
 695                         $numeric_keys = true;
 696                         foreach ($keys as $key) {
 697                                 if (!is_int($key)) {
 698                                         $numeric_keys = false;
 699                                 }
 700                         }
 701                         if ($numeric_keys) {
 702                                 foreach ($jsonld as $part) {
 703                                         $siteinfo = self::parseParts($siteinfo, $part);
 704                                 }
 705                         }
 706                 }
 707
 708                 return $siteinfo;
 709         }
 710
 711         /**
 712          * Improve the siteinfo with information from the provided JSON-LD information
 713          * @see https://jsonld.com/
 714          * @see https://schema.org/
 715          *
 716          * @param array $siteinfo
 717          * @param array $jsonld
 718          * @return array siteinfo
 719          */
 720         private static function parseJsonLd(array $siteinfo, array $jsonld)
 721         {
 722                 $type = JsonLD::fetchElement($jsonld, '@type');
 723                 if (empty($type)) {
 724                         Logger::info('Empty type', ['url' => $siteinfo['url']]);
 725                         return $siteinfo;
 726                 }
 727
 728                 // Silently ignore some types that aren't processed
 729                 if (in_array($type, ['SiteNavigationElement', 'JobPosting', 'CreativeWork', 'MusicAlbum',
 730                         'WPHeader', 'WPSideBar', 'WPFooter', 'LegalService', 'MusicRecording',
 731                         'ItemList', 'BreadcrumbList', 'Blog', 'Dataset', 'Product'])) {
 732                         return $siteinfo;
 733                 }
 734
 735                 switch ($type) {
 736                         case 'Article':
 737                         case 'AdvertiserContentArticle':
 738                         case 'NewsArticle':
 739                         case 'Report':
 740                         case 'SatiricalArticle':
 741                         case 'ScholarlyArticle':
 742                         case 'SocialMediaPosting':
 743                         case 'TechArticle':
 744                         case 'ReportageNewsArticle':
 745                         case 'SocialMediaPosting':
 746                         case 'BlogPosting':
 747                         case 'LiveBlogPosting':
 748                         case 'DiscussionForumPosting':
 749                                 return self::parseJsonLdArticle($siteinfo, $jsonld);
 750                         case 'WebPage':
 751                         case 'AboutPage':
 752                         case 'CheckoutPage':
 753                         case 'CollectionPage':
 754                         case 'ContactPage':
 755                         case 'FAQPage':
 756                         case 'ItemPage':
 757                         case 'MedicalWebPage':
 758                         case 'ProfilePage':
 759                         case 'QAPage':
 760                         case 'RealEstateListing':
 761                         case 'SearchResultsPage':
 762                         case 'MediaGallery':
 763                         case 'ImageGallery':
 764                         case 'VideoGallery':
 765                         case 'RadioEpisode':
 766                         case 'Event':
 767                                 return self::parseJsonLdWebPage($siteinfo, $jsonld);
 768                         case 'WebSite':
 769                                 return self::parseJsonLdWebSite($siteinfo, $jsonld);
 770                         case 'Organization':
 771                         case 'Airline':
 772                         case 'Consortium':
 773                         case 'Corporation':
 774                         case 'EducationalOrganization':
 775                         case 'FundingScheme':
 776                         case 'GovernmentOrganization':
 777                         case 'LibrarySystem':
 778                         case 'LocalBusiness':
 779                         case 'MedicalOrganization':
 780                         case 'NGO':
 781                         case 'NewsMediaOrganization':
 782                         case 'Project':
 783                         case 'SportsOrganization':
 784                         case 'WorkersUnion':
 785                                 return self::parseJsonLdWebOrganization($siteinfo, $jsonld);
 786                         case 'Person':
 787                         case 'Patient':
 788                         case 'PerformingGroup':
 789                         case 'DanceGroup';
 790                         case 'MusicGroup':
 791                         case 'TheaterGroup':
 792                                 return self::parseJsonLdWebPerson($siteinfo, $jsonld);
 793                         case 'AudioObject':
 794                         case 'Audio':
 795                                 return self::parseJsonLdMediaObject($siteinfo, $jsonld, 'audio');
 796                         case 'VideoObject':
 797                                 return self::parseJsonLdMediaObject($siteinfo, $jsonld, 'video');
 798                         case 'ImageObject':
 799                                 return self::parseJsonLdMediaObject($siteinfo, $jsonld, 'images');
 800                         default:
 801                                 Logger::info('Unknown type', ['type' => $type, 'url' => $siteinfo['url']]);
 802                                 return $siteinfo;
 803                 }
 804         }
 805
 806         /**
 807          * Fetch author and publisher data
 808          *
 809          * @param array $siteinfo
 810          * @param array $jsonld
 811          * @return array siteinfo
 812          */
 813         private static function parseJsonLdAuthor(array $siteinfo, array $jsonld)
 814         {
 815                 $jsonldinfo = [];
 816
 817                 if (!empty($jsonld['publisher']) && is_array($jsonld['publisher'])) {
 818                         $content = JsonLD::fetchElement($jsonld, 'publisher', 'name');
 819                         if (!empty($content) && is_string($content)) {
 820                                 $jsonldinfo['publisher_name'] = trim($content);
 821                         }
 822
 823                         $content = JsonLD::fetchElement($jsonld, 'publisher', 'url');
 824                         if (!empty($content) && is_string($content)) {
 825                                 $jsonldinfo['publisher_url'] = trim($content);
 826                         }
 827
 828                         $brand = JsonLD::fetchElement($jsonld, 'publisher', 'brand', '@type', 'Organization');
 829                         if (!empty($brand) && is_array($brand)) {
 830                                 $content = JsonLD::fetchElement($brand, 'name');
 831                                 if (!empty($content) && is_string($content)) {
 832                                         $jsonldinfo['publisher_name'] = trim($content);
 833                                 }
 834
 835                                 $content = JsonLD::fetchElement($brand, 'url');
 836                                 if (!empty($content) && is_string($content)) {
 837                                         $jsonldinfo['publisher_url'] = trim($content);
 838                                 }
 839
 840                                 $content = JsonLD::fetchElement($brand, 'logo', 'url');
 841                                 if (!empty($content) && is_string($content)) {
 842                                         $jsonldinfo['publisher_img'] = trim($content);
 843                                 }
 844                         }
 845
 846                         $logo = JsonLD::fetchElement($jsonld, 'publisher', 'logo');
 847                         if (!empty($logo) && is_array($logo)) {
 848                                 $content = JsonLD::fetchElement($logo, 'url');
 849                                 if (!empty($content) && is_string($content)) {
 850                                         $jsonldinfo['publisher_img'] = trim($content);
 851                                 }
 852                         }
 853                 } elseif (!empty($jsonld['publisher']) && is_string($jsonld['publisher'])) {
 854                         $jsonldinfo['publisher_name'] = trim($jsonld['publisher']);
 855                 }
 856
 857                 if (!empty($jsonld['author']) && is_array($jsonld['author'])) {
 858                         $content = JsonLD::fetchElement($jsonld, 'author', 'name');
 859                         if (!empty($content) && is_string($content)) {
 860                                 $jsonldinfo['author_name'] = trim($content);
 861                         }
 862
 863                         $content = JsonLD::fetchElement($jsonld, 'author', 'sameAs');
 864                         if (!empty($content) && is_string($content)) {
 865                                 $jsonldinfo['author_url'] = trim($content);
 866                         }
 867
 868                         $content = JsonLD::fetchElement($jsonld, 'author', 'url');
 869                         if (!empty($content) && is_string($content)) {
 870                                 $jsonldinfo['author_url'] = trim($content);
 871                         }
 872
 873                         $logo = JsonLD::fetchElement($jsonld, 'author', 'logo');
 874                         if (!empty($logo) && is_array($logo)) {
 875                                 $content = JsonLD::fetchElement($logo, 'url');
 876                                 if (!empty($content) && is_string($content)) {
 877                                         $jsonldinfo['author_img'] = trim($content);
 878                                 }
 879                         }
 880                 } elseif (!empty($jsonld['author']) && is_string($jsonld['author'])) {
 881                         $jsonldinfo['author_name'] = trim($jsonld['author']);
 882                 }
 883
 884                 Logger::info('Fetched Author information', ['fetched' => $jsonldinfo]);
 885
 886                 return array_merge($siteinfo, $jsonldinfo);
 887         }
 888
 889         /**
 890          * Fetch data from the provided JSON-LD Article type
 891          * @see https://schema.org/Article
 892          *
 893          * @param array $siteinfo
 894          * @param array $jsonld
 895          * @return array siteinfo
 896          */
 897         private static function parseJsonLdArticle(array $siteinfo, array $jsonld)
 898         {
 899                 $jsonldinfo = [];
 900
 901                 $content = JsonLD::fetchElement($jsonld, 'headline');
 902                 if (!empty($content) && is_string($content)) {
 903                         $jsonldinfo['title'] = trim($content);
 904                 }
 905
 906                 $content = JsonLD::fetchElement($jsonld, 'alternativeHeadline');
 907                 if (!empty($content) && is_string($content) && (($jsonldinfo['title'] ?? '') != trim($content))) {
 908                         $jsonldinfo['alternative_title'] = trim($content);
 909                 }
 910
 911                 $content = JsonLD::fetchElement($jsonld, 'description');
 912                 if (!empty($content) && is_string($content)) {
 913                         $jsonldinfo['text'] = trim($content);
 914                 }
 915
 916                 $content = JsonLD::fetchElement($jsonld, 'thumbnailUrl');
 917                 if (!empty($content)) {
 918                         $jsonldinfo['image'] = trim($content);
 919                 }
 920
 921                 $content = JsonLD::fetchElement($jsonld, 'image', 'url', '@type', 'ImageObject');
 922                 if (!empty($content) && is_string($content)) {
 923                         $jsonldinfo['image'] = trim($content);
 924                 }
 925
 926                 if (!empty($jsonld['keywords']) && !is_array($jsonld['keywords'])) {
 927                         $content = JsonLD::fetchElement($jsonld, 'keywords');
 928                         if (!empty($content)) {
 929                                 $siteinfo['keywords'] = [];
 930                                 $keywords = explode(',', $content);
 931                                 foreach ($keywords as $keyword) {
 932                                         $siteinfo['keywords'][] = trim($keyword);
 933                                 }
 934                         }
 935                 } else {
 936                         $content = JsonLD::fetchElementArray($jsonld, 'keywords');
 937                         if (!empty($content) && is_array($content)) {
 938                                 $jsonldinfo['keywords'] = $content;
 939                         }
 940                 }
 941
 942                 $jsonldinfo = self::parseJsonLdAuthor($jsonldinfo, $jsonld);
 943
 944                 Logger::info('Fetched article information', ['url' => $siteinfo['url'], 'fetched' => $jsonldinfo]);
 945
 946                 return array_merge($siteinfo, $jsonldinfo);
 947         }
 948
 949         /**
 950          * Fetch data from the provided JSON-LD WebPage type
 951          * @see https://schema.org/WebPage
 952          *
 953          * @param array $siteinfo
 954          * @param array $jsonld
 955          * @return array siteinfo
 956          */
 957         private static function parseJsonLdWebPage(array $siteinfo, array $jsonld)
 958         {
 959                 $jsonldinfo = [];
 960
 961                 $content = JsonLD::fetchElement($jsonld, 'name');
 962                 if (!empty($content)) {
 963                         $jsonldinfo['title'] = trim($content);
 964                 }
 965
 966                 $content = JsonLD::fetchElement($jsonld, 'description');
 967                 if (!empty($content)) {
 968                         $jsonldinfo['text'] = trim($content);
 969                 }
 970
 971                 $content = JsonLD::fetchElement($jsonld, 'image');
 972                 if (!empty($content)) {
 973                         $jsonldinfo['image'] = trim($content);
 974                 }
 975
 976                 $content = JsonLD::fetchElement($jsonld, 'thumbnailUrl');
 977                 if (!empty($content)) {
 978                         $jsonldinfo['image'] = trim($content);
 979                 }
 980
 981                 $jsonldinfo = self::parseJsonLdAuthor($jsonldinfo, $jsonld);
 982
 983                 Logger::info('Fetched WebPage information', ['url' => $siteinfo['url'], 'fetched' => $jsonldinfo]);
 984
 985                 return array_merge($siteinfo, $jsonldinfo);
 986         }
 987
 988         /**
 989          * Fetch data from the provided JSON-LD WebSite type
 990          * @see https://schema.org/WebSite
 991          *
 992          * @param array $siteinfo
 993          * @param array $jsonld
 994          * @return array siteinfo
 995          */
 996         private static function parseJsonLdWebSite(array $siteinfo, array $jsonld)
 997         {
 998                 $jsonldinfo = [];
 999
1000                 $content = JsonLD::fetchElement($jsonld, 'name');
1001                 if (!empty($content)) {
1002                         $jsonldinfo['publisher_name'] = trim($content);
1003                 }
1004
1005                 $content = JsonLD::fetchElement($jsonld, 'description');
1006                 if (!empty($content)) {
1007                         $jsonldinfo['publisher_description'] = trim($content);
1008                 }
1009
1010                 $content = JsonLD::fetchElement($jsonld, 'url');
1011                 if (!empty($content)) {
1012                         $jsonldinfo['publisher_url'] = trim($content);
1013                 }
1014
1015                 $content = JsonLD::fetchElement($jsonld, 'thumbnailUrl');
1016                 if (!empty($content)) {
1017                         $jsonldinfo['image'] = trim($content);
1018                 }
1019
1020                 $jsonldinfo = self::parseJsonLdAuthor($jsonldinfo, $jsonld);
1021
1022                 Logger::info('Fetched WebSite information', ['url' => $siteinfo['url'], 'fetched' => $jsonldinfo]);
1023                 return array_merge($siteinfo, $jsonldinfo);
1024         }
1025
1026         /**
1027          * Fetch data from the provided JSON-LD Organization type
1028          * @see https://schema.org/Organization
1029          *
1030          * @param array $siteinfo
1031          * @param array $jsonld
1032          * @return array siteinfo
1033          */
1034         private static function parseJsonLdWebOrganization(array $siteinfo, array $jsonld)
1035         {
1036                 $jsonldinfo = [];
1037
1038                 $content = JsonLD::fetchElement($jsonld, 'name');
1039                 if (!empty($content)) {
1040                         $jsonldinfo['publisher_name'] = trim($content);
1041                 }
1042
1043                 $content = JsonLD::fetchElement($jsonld, 'description');
1044                 if (!empty($content)) {
1045                         $jsonldinfo['publisher_description'] = trim($content);
1046                 }
1047
1048                 $content = JsonLD::fetchElement($jsonld, 'url');
1049                 if (!empty($content)) {
1050                         $jsonldinfo['publisher_url'] = trim($content);
1051                 }
1052
1053                 $content = JsonLD::fetchElement($jsonld, 'logo', 'url', '@type', 'ImageObject');
1054                 if (!empty($content)) {
1055                         $jsonldinfo['publisher_img'] = trim($content);
1056                 }
1057
1058                 $content = JsonLD::fetchElement($jsonld, 'brand', 'name', '@type', 'Organization');
1059                 if (!empty($content)) {
1060                         $jsonldinfo['publisher_name'] = trim($content);
1061                 }
1062
1063                 $content = JsonLD::fetchElement($jsonld, 'brand', 'url', '@type', 'Organization');
1064                 if (!empty($content)) {
1065                         $jsonldinfo['publisher_url'] = trim($content);
1066                 }
1067
1068                 Logger::info('Fetched Organization information', ['url' => $siteinfo['url'], 'fetched' => $jsonldinfo]);
1069                 return array_merge($siteinfo, $jsonldinfo);
1070         }
1071
1072         /**
1073          * Fetch data from the provided JSON-LD Person type
1074          * @see https://schema.org/Person
1075          *
1076          * @param array $siteinfo
1077          * @param array $jsonld
1078          * @return array siteinfo
1079          */
1080         private static function parseJsonLdWebPerson(array $siteinfo, array $jsonld)
1081         {
1082                 $jsonldinfo = [];
1083
1084                 $content = JsonLD::fetchElement($jsonld, 'name');
1085                 if (!empty($content)) {
1086                         $jsonldinfo['author_name'] = trim($content);
1087                 }
1088
1089                 $content = JsonLD::fetchElement($jsonld, 'description');
1090                 if (!empty($content)) {
1091                         $jsonldinfo['author_description'] = trim($content);
1092                 }
1093
1094                 $content = JsonLD::fetchElement($jsonld, 'sameAs');
1095                 if (!empty($content) && is_string($content)) {
1096                         $jsonldinfo['author_url'] = trim($content);
1097                 }
1098
1099                 $content = JsonLD::fetchElement($jsonld, 'url');
1100                 if (!empty($content)) {
1101                         $jsonldinfo['author_url'] = trim($content);
1102                 }
1103
1104                 $content = JsonLD::fetchElement($jsonld, 'image', 'url', '@type', 'ImageObject');
1105                 if (!empty($content)) {
1106                         $jsonldinfo['author_img'] = trim($content);
1107                 }
1108
1109                 Logger::info('Fetched Person information', ['url' => $siteinfo['url'], 'fetched' => $jsonldinfo]);
1110                 return array_merge($siteinfo, $jsonldinfo);
1111         }
1112
1113         /**
1114          * Fetch data from the provided JSON-LD MediaObject type
1115          * @see https://schema.org/MediaObject
1116          *
1117          * @param array $siteinfo
1118          * @param array $jsonld
1119          * @return array siteinfo
1120          */
1121         private static function parseJsonLdMediaObject(array $siteinfo, array $jsonld, string $name)
1122         {
1123                 $media = [];
1124
1125                 $content = JsonLD::fetchElement($jsonld, 'caption');
1126                 if (!empty($content)) {
1127                         $media['caption'] = trim($content);
1128                 }
1129
1130                 $content = JsonLD::fetchElement($jsonld, 'url');
1131                 if (!empty($content)) {
1132                         $media['url'] = trim($content);
1133                 }
1134
1135                 $content = JsonLD::fetchElement($jsonld, 'mainEntityOfPage');
1136                 if (!empty($content)) {
1137                         $media['main'] = Strings::compareLink($content, $siteinfo['url']);
1138                 }
1139
1140                 $content = JsonLD::fetchElement($jsonld, 'description');
1141                 if (!empty($content)) {
1142                         $media['description'] = trim($content);
1143                 }
1144
1145                 $content = JsonLD::fetchElement($jsonld, 'name');
1146                 if (!empty($content) && (($media['description'] ?? '') != trim($content))) {
1147                         $media['name'] = trim($content);
1148                 }
1149
1150                 $content = JsonLD::fetchElement($jsonld, 'contentUrl');
1151                 if (!empty($content)) {
1152                         $media['content'] = trim($content);
1153                 }
1154
1155                 $content = JsonLD::fetchElement($jsonld, 'embedUrl');
1156                 if (!empty($content)) {
1157                         $media['embed'] = trim($content);
1158                 }
1159
1160                 $content = JsonLD::fetchElement($jsonld, 'height');
1161                 if (!empty($content)) {
1162                         $media['height'] = trim($content);
1163                 }
1164
1165                 $content = JsonLD::fetchElement($jsonld, 'width');
1166                 if (!empty($content)) {
1167                         $media['width'] = trim($content);
1168                 }
1169
1170                 $content = JsonLD::fetchElement($jsonld, 'image');
1171                 if (!empty($content)) {
1172                         $media['image'] = trim($content);
1173                 }
1174
1175                 $content = JsonLD::fetchElement($jsonld, 'thumbnailUrl');
1176                 if (!empty($content) && (($media['image'] ?? '') != trim($content))) {
1177                         if (!empty($media['image'])) {
1178                                 $media['preview'] = trim($content);
1179                         } else {
1180                                 $media['image'] = trim($content);
1181                         }
1182                 }
1183
1184                 Logger::info('Fetched Media information', ['url' => $siteinfo['url'], 'fetched' => $media]);
1185                 $siteinfo[$name][] = $media;
1186                 return $siteinfo;
1187         }
1188 }