wp-includes/SimplePie/Content/Type/Sniffer.php

   1 <?php
   2 /**
   3  * SimplePie
   4  *
   5  * A PHP-Based RSS and Atom Feed Framework.
   6  * Takes the hard work out of managing a complete RSS/Atom solution.
   7  *
   8  * Copyright (c) 2004-2012, Ryan Parman, Geoffrey Sneddon, Ryan McCue, and contributors
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without modification, are
  12  * permitted provided that the following conditions are met:
  13  *
  14  *      * Redistributions of source code must retain the above copyright notice, this list of
  15  *        conditions and the following disclaimer.
  16  *
  17  *      * Redistributions in binary form must reproduce the above copyright notice, this list
  18  *        of conditions and the following disclaimer in the documentation and/or other materials
  19  *        provided with the distribution.
  20  *
  21  *      * Neither the name of the SimplePie Team nor the names of its contributors may be used
  22  *        to endorse or promote products derived from this software without specific prior
  23  *        written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
  26  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
  27  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS
  28  * AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  30  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  31  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  32  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  33  * POSSIBILITY OF SUCH DAMAGE.
  34  *
  35  * @package SimplePie
  36  * @version 1.3.1
  37  * @copyright 2004-2012 Ryan Parman, Geoffrey Sneddon, Ryan McCue
  38  * @author Ryan Parman
  39  * @author Geoffrey Sneddon
  40  * @author Ryan McCue
  41  * @link http://simplepie.org/ SimplePie
  42  * @license http://www.opensource.org/licenses/bsd-license.php BSD License
  43  */
  44
  45
  46 /**
  47  * Content-type sniffing
  48  *
  49  * Based on the rules in http://tools.ietf.org/html/draft-abarth-mime-sniff-06
  50  *
  51  * This is used since we can't always trust Content-Type headers, and is based
  52  * upon the HTML5 parsing rules.
  53  *
  54  *
  55  * This class can be overloaded with {@see SimplePie::set_content_type_sniffer_class()}
  56  *
  57  * @package SimplePie
  58  * @subpackage HTTP
  59  */
  60 class SimplePie_Content_Type_Sniffer
  61 {
  62         /**
  63          * File object
  64          *
  65          * @var SimplePie_File
  66          */
  67         var $file;
  68
  69         /**
  70          * Create an instance of the class with the input file
  71          *
  72          * @param SimplePie_Content_Type_Sniffer $file Input file
  73          */
  74         public function __construct($file)
  75         {
  76                 $this->file = $file;
  77         }
  78
  79         /**
  80          * Get the Content-Type of the specified file
  81          *
  82          * @return string Actual Content-Type
  83          */
  84         public function get_type()
  85         {
  86                 if (isset($this->file->headers['content-type']))
  87                 {
  88                         if (!isset($this->file->headers['content-encoding'])
  89                                 && ($this->file->headers['content-type'] === 'text/plain'
  90                                         || $this->file->headers['content-type'] === 'text/plain; charset=ISO-8859-1'
  91                                         || $this->file->headers['content-type'] === 'text/plain; charset=iso-8859-1'
  92                                         || $this->file->headers['content-type'] === 'text/plain; charset=UTF-8'))
  93                         {
  94                                 return $this->text_or_binary();
  95                         }
  96
  97                         if (($pos = strpos($this->file->headers['content-type'], ';')) !== false)
  98                         {
  99                                 $official = substr($this->file->headers['content-type'], 0, $pos);
 100                         }
 101                         else
 102                         {
 103                                 $official = $this->file->headers['content-type'];
 104                         }
 105                         $official = trim(strtolower($official));
 106
 107                         if ($official === 'unknown/unknown'
 108                                 || $official === 'application/unknown')
 109                         {
 110                                 return $this->unknown();
 111                         }
 112                         elseif (substr($official, -4) === '+xml'
 113                                 || $official === 'text/xml'
 114                                 || $official === 'application/xml')
 115                         {
 116                                 return $official;
 117                         }
 118                         elseif (substr($official, 0, 6) === 'image/')
 119                         {
 120                                 if ($return = $this->image())
 121                                 {
 122                                         return $return;
 123                                 }
 124                                 else
 125                                 {
 126                                         return $official;
 127                                 }
 128                         }
 129                         elseif ($official === 'text/html')
 130                         {
 131                                 return $this->feed_or_html();
 132                         }
 133                         else
 134                         {
 135                                 return $official;
 136                         }
 137                 }
 138                 else
 139                 {
 140                         return $this->unknown();
 141                 }
 142         }
 143
 144         /**
 145          * Sniff text or binary
 146          *
 147          * @return string Actual Content-Type
 148          */
 149         public function text_or_binary()
 150         {
 151                 if (substr($this->file->body, 0, 2) === "\xFE\xFF"
 152                         || substr($this->file->body, 0, 2) === "\xFF\xFE"
 153                         || substr($this->file->body, 0, 4) === "\x00\x00\xFE\xFF"
 154                         || substr($this->file->body, 0, 3) === "\xEF\xBB\xBF")
 155                 {
 156                         return 'text/plain';
 157                 }
 158                 elseif (preg_match('/[\x00-\x08\x0E-\x1A\x1C-\x1F]/', $this->file->body))
 159                 {
 160                         return 'application/octect-stream';
 161                 }
 162                 else
 163                 {
 164                         return 'text/plain';
 165                 }
 166         }
 167
 168         /**
 169          * Sniff unknown
 170          *
 171          * @return string Actual Content-Type
 172          */
 173         public function unknown()
 174         {
 175                 $ws = strspn($this->file->body, "\x09\x0A\x0B\x0C\x0D\x20");
 176                 if (strtolower(substr($this->file->body, $ws, 14)) === '<!doctype html'
 177                         || strtolower(substr($this->file->body, $ws, 5)) === '<html'
 178                         || strtolower(substr($this->file->body, $ws, 7)) === '<script')
 179                 {
 180                         return 'text/html';
 181                 }
 182                 elseif (substr($this->file->body, 0, 5) === '%PDF-')
 183                 {
 184                         return 'application/pdf';
 185                 }
 186                 elseif (substr($this->file->body, 0, 11) === '%!PS-Adobe-')
 187                 {
 188                         return 'application/postscript';
 189                 }
 190                 elseif (substr($this->file->body, 0, 6) === 'GIF87a'
 191                         || substr($this->file->body, 0, 6) === 'GIF89a')
 192                 {
 193                         return 'image/gif';
 194                 }
 195                 elseif (substr($this->file->body, 0, 8) === "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A")
 196                 {
 197                         return 'image/png';
 198                 }
 199                 elseif (substr($this->file->body, 0, 3) === "\xFF\xD8\xFF")
 200                 {
 201                         return 'image/jpeg';
 202                 }
 203                 elseif (substr($this->file->body, 0, 2) === "\x42\x4D")
 204                 {
 205                         return 'image/bmp';
 206                 }
 207                 elseif (substr($this->file->body, 0, 4) === "\x00\x00\x01\x00")
 208                 {
 209                         return 'image/vnd.microsoft.icon';
 210                 }
 211                 else
 212                 {
 213                         return $this->text_or_binary();
 214                 }
 215         }
 216
 217         /**
 218          * Sniff images
 219          *
 220          * @return string Actual Content-Type
 221          */
 222         public function image()
 223         {
 224                 if (substr($this->file->body, 0, 6) === 'GIF87a'
 225                         || substr($this->file->body, 0, 6) === 'GIF89a')
 226                 {
 227                         return 'image/gif';
 228                 }
 229                 elseif (substr($this->file->body, 0, 8) === "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A")
 230                 {
 231                         return 'image/png';
 232                 }
 233                 elseif (substr($this->file->body, 0, 3) === "\xFF\xD8\xFF")
 234                 {
 235                         return 'image/jpeg';
 236                 }
 237                 elseif (substr($this->file->body, 0, 2) === "\x42\x4D")
 238                 {
 239                         return 'image/bmp';
 240                 }
 241                 elseif (substr($this->file->body, 0, 4) === "\x00\x00\x01\x00")
 242                 {
 243                         return 'image/vnd.microsoft.icon';
 244                 }
 245                 else
 246                 {
 247                         return false;
 248                 }
 249         }
 250
 251         /**
 252          * Sniff HTML
 253          *
 254          * @return string Actual Content-Type
 255          */
 256         public function feed_or_html()
 257         {
 258                 $len = strlen($this->file->body);
 259                 $pos = strspn($this->file->body, "\x09\x0A\x0D\x20");
 260
 261                 while ($pos < $len)
 262                 {
 263                         switch ($this->file->body[$pos])
 264                         {
 265                                 case "\x09":
 266                                 case "\x0A":
 267                                 case "\x0D":
 268                                 case "\x20":
 269                                         $pos += strspn($this->file->body, "\x09\x0A\x0D\x20", $pos);
 270                                         continue 2;
 271
 272                                 case '<':
 273                                         $pos++;
 274                                         break;
 275
 276                                 default:
 277                                         return 'text/html';
 278                         }
 279
 280                         if (substr($this->file->body, $pos, 3) === '!--')
 281                         {
 282                                 $pos += 3;
 283                                 if ($pos < $len && ($pos = strpos($this->file->body, '-->', $pos)) !== false)
 284                                 {
 285                                         $pos += 3;
 286                                 }
 287                                 else
 288                                 {
 289                                         return 'text/html';
 290                                 }
 291                         }
 292                         elseif (substr($this->file->body, $pos, 1) === '!')
 293                         {
 294                                 if ($pos < $len && ($pos = strpos($this->file->body, '>', $pos)) !== false)
 295                                 {
 296                                         $pos++;
 297                                 }
 298                                 else
 299                                 {
 300                                         return 'text/html';
 301                                 }
 302                         }
 303                         elseif (substr($this->file->body, $pos, 1) === '?')
 304                         {
 305                                 if ($pos < $len && ($pos = strpos($this->file->body, '?>', $pos)) !== false)
 306                                 {
 307                                         $pos += 2;
 308                                 }
 309                                 else
 310                                 {
 311                                         return 'text/html';
 312                                 }
 313                         }
 314                         elseif (substr($this->file->body, $pos, 3) === 'rss'
 315                                 || substr($this->file->body, $pos, 7) === 'rdf:RDF')
 316                         {
 317                                 return 'application/rss+xml';
 318                         }
 319                         elseif (substr($this->file->body, $pos, 4) === 'feed')
 320                         {
 321                                 return 'application/atom+xml';
 322                         }
 323                         else
 324                         {
 325                                 return 'text/html';
 326                         }
 327                 }
 328
 329                 return 'text/html';
 330         }
 331 }
 332