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