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
333