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   1  <?php
   2  
   3  declare(strict_types=1);
   4  /**
   5   * SimplePie
   6   *
   7   * A PHP-Based RSS and Atom Feed Framework.
   8   * Takes the hard work out of managing a complete RSS/Atom solution.
   9   *
  10   * Copyright (c) 2004-2022, Ryan Parman, Sam Sneddon, Ryan McCue, and contributors
  11   * All rights reserved.
  12   *
  13   * Redistribution and use in source and binary forms, with or without modification, are
  14   * permitted provided that the following conditions are met:
  15   *
  16   *     * Redistributions of source code must retain the above copyright notice, this list of
  17   *       conditions and the following disclaimer.
  18   *
  19   *     * Redistributions in binary form must reproduce the above copyright notice, this list
  20   *       of conditions and the following disclaimer in the documentation and/or other materials
  21   *       provided with the distribution.
  22   *
  23   *     * Neither the name of the SimplePie Team nor the names of its contributors may be used
  24   *       to endorse or promote products derived from this software without specific prior
  25   *       written permission.
  26   *
  27   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
  28   * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
  29   * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS
  30   * AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  31   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  32   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  33   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  34   * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  35   * POSSIBILITY OF SUCH DAMAGE.
  36   *
  37   * @package SimplePie
  38   * @copyright 2004-2016 Ryan Parman, Sam Sneddon, Ryan McCue
  39   * @author Ryan Parman
  40   * @author Sam Sneddon
  41   * @author Ryan McCue
  42   * @link http://simplepie.org/ SimplePie
  43   * @license http://www.opensource.org/licenses/bsd-license.php BSD License
  44   */
  45  
  46  namespace SimplePie\Content\Type;
  47  
  48  /**
  49   * Content-type sniffing
  50   *
  51   * Based on the rules in http://tools.ietf.org/html/draft-abarth-mime-sniff-06
  52   *
  53   * This is used since we can't always trust Content-Type headers, and is based
  54   * upon the HTML5 parsing rules.
  55   *
  56   *
  57   * This class can be overloaded with {@see \SimplePie\SimplePie::set_content_type_sniffer_class()}
  58   *
  59   * @package SimplePie
  60   * @subpackage HTTP
  61   */
  62  class Sniffer
  63  {
  64      /**
  65       * File object
  66       *
  67       * @var \SimplePie\File
  68       */
  69      public $file;
  70  
  71      /**
  72       * Create an instance of the class with the input file
  73       *
  74       * @param Sniffer $file Input file
  75       */
  76      public function __construct($file)
  77      {
  78          $this->file = $file;
  79      }
  80  
  81      /**
  82       * Get the Content-Type of the specified file
  83       *
  84       * @return string Actual Content-Type
  85       */
  86      public function get_type()
  87      {
  88          if (isset($this->file->headers['content-type'])) {
  89              if (!isset($this->file->headers['content-encoding'])
  90                  && ($this->file->headers['content-type'] === 'text/plain'
  91                      || $this->file->headers['content-type'] === 'text/plain; charset=ISO-8859-1'
  92                      || $this->file->headers['content-type'] === 'text/plain; charset=iso-8859-1'
  93                      || $this->file->headers['content-type'] === 'text/plain; charset=UTF-8')) {
  94                  return $this->text_or_binary();
  95              }
  96  
  97              if (($pos = strpos($this->file->headers['content-type'], ';')) !== false) {
  98                  $official = substr($this->file->headers['content-type'], 0, $pos);
  99              } else {
 100                  $official = $this->file->headers['content-type'];
 101              }
 102              $official = trim(strtolower($official));
 103  
 104              if ($official === 'unknown/unknown'
 105                  || $official === 'application/unknown') {
 106                  return $this->unknown();
 107              } elseif (substr($official, -4) === '+xml'
 108                  || $official === 'text/xml'
 109                  || $official === 'application/xml') {
 110                  return $official;
 111              } elseif (substr($official, 0, 6) === 'image/') {
 112                  if ($return = $this->image()) {
 113                      return $return;
 114                  }
 115  
 116                  return $official;
 117              } elseif ($official === 'text/html') {
 118                  return $this->feed_or_html();
 119              }
 120  
 121              return $official;
 122          }
 123  
 124          return $this->unknown();
 125      }
 126  
 127      /**
 128       * Sniff text or binary
 129       *
 130       * @return string Actual Content-Type
 131       */
 132      public function text_or_binary()
 133      {
 134          if (substr($this->file->body, 0, 2) === "\xFE\xFF"
 135              || substr($this->file->body, 0, 2) === "\xFF\xFE"
 136              || substr($this->file->body, 0, 4) === "\x00\x00\xFE\xFF"
 137              || substr($this->file->body, 0, 3) === "\xEF\xBB\xBF") {
 138              return 'text/plain';
 139          } elseif (preg_match('/[\x00-\x08\x0E-\x1A\x1C-\x1F]/', $this->file->body)) {
 140              return 'application/octet-stream';
 141          }
 142  
 143          return 'text/plain';
 144      }
 145  
 146      /**
 147       * Sniff unknown
 148       *
 149       * @return string Actual Content-Type
 150       */
 151      public function unknown()
 152      {
 153          $ws = strspn($this->file->body, "\x09\x0A\x0B\x0C\x0D\x20");
 154          if (strtolower(substr($this->file->body, $ws, 14)) === '<!doctype html'
 155              || strtolower(substr($this->file->body, $ws, 5)) === '<html'
 156              || strtolower(substr($this->file->body, $ws, 7)) === '<script') {
 157              return 'text/html';
 158          } elseif (substr($this->file->body, 0, 5) === '%PDF-') {
 159              return 'application/pdf';
 160          } elseif (substr($this->file->body, 0, 11) === '%!PS-Adobe-') {
 161              return 'application/postscript';
 162          } elseif (substr($this->file->body, 0, 6) === 'GIF87a'
 163              || substr($this->file->body, 0, 6) === 'GIF89a') {
 164              return 'image/gif';
 165          } elseif (substr($this->file->body, 0, 8) === "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A") {
 166              return 'image/png';
 167          } elseif (substr($this->file->body, 0, 3) === "\xFF\xD8\xFF") {
 168              return 'image/jpeg';
 169          } elseif (substr($this->file->body, 0, 2) === "\x42\x4D") {
 170              return 'image/bmp';
 171          } elseif (substr($this->file->body, 0, 4) === "\x00\x00\x01\x00") {
 172              return 'image/vnd.microsoft.icon';
 173          }
 174  
 175          return $this->text_or_binary();
 176      }
 177  
 178      /**
 179       * Sniff images
 180       *
 181       * @return string Actual Content-Type
 182       */
 183      public function image()
 184      {
 185          if (substr($this->file->body, 0, 6) === 'GIF87a'
 186              || substr($this->file->body, 0, 6) === 'GIF89a') {
 187              return 'image/gif';
 188          } elseif (substr($this->file->body, 0, 8) === "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A") {
 189              return 'image/png';
 190          } elseif (substr($this->file->body, 0, 3) === "\xFF\xD8\xFF") {
 191              return 'image/jpeg';
 192          } elseif (substr($this->file->body, 0, 2) === "\x42\x4D") {
 193              return 'image/bmp';
 194          } elseif (substr($this->file->body, 0, 4) === "\x00\x00\x01\x00") {
 195              return 'image/vnd.microsoft.icon';
 196          }
 197  
 198          return false;
 199      }
 200  
 201      /**
 202       * Sniff HTML
 203       *
 204       * @return string Actual Content-Type
 205       */
 206      public function feed_or_html()
 207      {
 208          $len = strlen($this->file->body);
 209          $pos = strspn($this->file->body, "\x09\x0A\x0D\x20\xEF\xBB\xBF");
 210  
 211          while ($pos < $len) {
 212              switch ($this->file->body[$pos]) {
 213                  case "\x09":
 214                  case "\x0A":
 215                  case "\x0D":
 216                  case "\x20":
 217                      $pos += strspn($this->file->body, "\x09\x0A\x0D\x20", $pos);
 218                      continue 2;
 219  
 220                  case '<':
 221                      $pos++;
 222                      break;
 223  
 224                  default:
 225                      return 'text/html';
 226              }
 227  
 228              if (substr($this->file->body, $pos, 3) === '!--') {
 229                  $pos += 3;
 230                  if ($pos < $len && ($pos = strpos($this->file->body, '-->', $pos)) !== false) {
 231                      $pos += 3;
 232                  } else {
 233                      return 'text/html';
 234                  }
 235              } elseif (substr($this->file->body, $pos, 1) === '!') {
 236                  if ($pos < $len && ($pos = strpos($this->file->body, '>', $pos)) !== false) {
 237                      $pos++;
 238                  } else {
 239                      return 'text/html';
 240                  }
 241              } elseif (substr($this->file->body, $pos, 1) === '?') {
 242                  if ($pos < $len && ($pos = strpos($this->file->body, '?>', $pos)) !== false) {
 243                      $pos += 2;
 244                  } else {
 245                      return 'text/html';
 246                  }
 247              } elseif (substr($this->file->body, $pos, 3) === 'rss'
 248                  || substr($this->file->body, $pos, 7) === 'rdf:RDF') {
 249                  return 'application/rss+xml';
 250              } elseif (substr($this->file->body, $pos, 4) === 'feed') {
 251                  return 'application/atom+xml';
 252              } else {
 253                  return 'text/html';
 254              }
 255          }
 256  
 257          return 'text/html';
 258      }
 259  }
 260  
 261  class_alias('SimplePie\Content\Type\Sniffer', 'SimplePie_Content_Type_Sniffer');