1<?php
2
3/**
4 * Utilities for handling HTTP related tasks
5 *
6 * @license    GPL 2 (http://www.gnu.org/licenses/gpl.html)
7 * @author     Andreas Gohr <andi@splitbrain.org>
8 */
9
10define('HTTP_MULTIPART_BOUNDARY', 'D0KuW1K1B0uNDARY');
11define('HTTP_HEADER_LF', "\r\n");
12define('HTTP_CHUNK_SIZE', 16 * 1024);
13
14/**
15 * Checks and sets HTTP headers for conditional HTTP requests
16 *
17 * @param int $timestamp lastmodified time of the cache file
18 * @returns  void or exits with previously header() commands executed
19 * @link     http://simonwillison.net/2003/Apr/23/conditionalGet/
20 *
21 * @author   Simon Willison <swillison@gmail.com>
22 */
23function http_conditionalRequest($timestamp)
24{
25    global $INPUT;
26
27    // A PHP implementation of conditional get, see
28    //   http://fishbowl.pastiche.org/2002/10/21/http_conditional_get_for_rss_hackers/
29    $last_modified = substr(gmdate('r', $timestamp), 0, -5) . 'GMT';
30    $etag = '"' . md5($last_modified) . '"';
31    // Send the headers
32    header("Last-Modified: $last_modified");
33    header("ETag: $etag");
34    // See if the client has provided the required headers
35    $if_modified_since = $INPUT->server->filter('stripslashes')->str('HTTP_IF_MODIFIED_SINCE', false);
36    $if_none_match = $INPUT->server->filter('stripslashes')->str('HTTP_IF_NONE_MATCH', false);
37
38    if (!$if_modified_since && !$if_none_match) {
39        return;
40    }
41
42    // At least one of the headers is there - check them
43    if ($if_none_match && $if_none_match != $etag) {
44        return; // etag is there but doesn't match
45    }
46
47    if ($if_modified_since && $if_modified_since != $last_modified) {
48        return; // if-modified-since is there but doesn't match
49    }
50
51    // Nothing has changed since their last request - serve a 304 and exit
52    header('HTTP/1.0 304 Not Modified');
53
54    // don't produce output, even if compression is on
55    @ob_end_clean();
56    exit;
57}
58
59/**
60 * Let the webserver send the given file via x-sendfile method
61 *
62 * @param string $file absolute path of file to send
63 * @returns  void or exits with previous header() commands executed
64 * @author Chris Smith <chris@jalakai.co.uk>
65 *
66 */
67function http_sendfile($file)
68{
69    global $conf;
70
71    //use x-sendfile header to pass the delivery to compatible web servers
72    if ($conf['xsendfile'] == 1) {
73        header("X-LIGHTTPD-send-file: $file");
74        ob_end_clean();
75        exit;
76    } elseif ($conf['xsendfile'] == 2) {
77        header("X-Sendfile: $file");
78        ob_end_clean();
79        exit;
80    } elseif ($conf['xsendfile'] == 3) {
81        // FS#2388 nginx just needs the relative path.
82        $file = DOKU_REL . substr($file, strlen(fullpath(DOKU_INC)) + 1);
83        header("X-Accel-Redirect: $file");
84        ob_end_clean();
85        exit;
86    }
87}
88
89/**
90 * Send file contents supporting rangeRequests
91 *
92 * This function exits the running script
93 *
94 * @param resource $fh - file handle for an already open file
95 * @param int $size - size of the whole file
96 * @param int $mime - MIME type of the file
97 *
98 * @author Andreas Gohr <andi@splitbrain.org>
99 */
100function http_rangeRequest($fh, $size, $mime)
101{
102    global $INPUT;
103
104    $ranges = [];
105    $isrange = false;
106
107    header('Accept-Ranges: bytes');
108
109    if (!$INPUT->server->has('HTTP_RANGE')) {
110        // no range requested - send the whole file
111        $ranges[] = [0, $size, $size];
112    } else {
113        $t = explode('=', $INPUT->server->str('HTTP_RANGE'));
114        if (!$t[0] == 'bytes') {
115            // we only understand byte ranges - send the whole file
116            $ranges[] = [0, $size, $size];
117        } else {
118            $isrange = true;
119            // handle multiple ranges
120            $r = explode(',', $t[1]);
121            foreach ($r as $x) {
122                $p = explode('-', $x);
123                $start = (int)$p[0];
124                $end = (int)$p[1];
125                if (!$end) $end = $size - 1;
126                if ($start > $end || $start > $size || $end > $size) {
127                    header('HTTP/1.1 416 Requested Range Not Satisfiable');
128                    echo 'Bad Range Request!';
129                    exit;
130                }
131                $len = $end - $start + 1;
132                $ranges[] = [$start, $end, $len];
133            }
134        }
135    }
136    $parts = count($ranges);
137
138    // now send the type and length headers
139    if (!$isrange) {
140        header("Content-Type: $mime", true);
141    } else {
142        header('HTTP/1.1 206 Partial Content');
143        if ($parts == 1) {
144            header("Content-Type: $mime", true);
145        } else {
146            header('Content-Type: multipart/byteranges; boundary=' . HTTP_MULTIPART_BOUNDARY, true);
147        }
148    }
149
150    // send all ranges
151    for ($i = 0; $i < $parts; $i++) {
152        [$start, $end, $len] = $ranges[$i];
153
154        // multipart or normal headers
155        if ($parts > 1) {
156            echo HTTP_HEADER_LF . '--' . HTTP_MULTIPART_BOUNDARY . HTTP_HEADER_LF;
157            echo "Content-Type: $mime" . HTTP_HEADER_LF;
158            echo "Content-Range: bytes $start-$end/$size" . HTTP_HEADER_LF;
159            echo HTTP_HEADER_LF;
160        } else {
161            header("Content-Length: $len");
162            if ($isrange) {
163                header("Content-Range: bytes $start-$end/$size");
164            }
165        }
166
167        // send file content
168        fseek($fh, $start); //seek to start of range
169        $chunk = ($len > HTTP_CHUNK_SIZE) ? HTTP_CHUNK_SIZE : $len;
170        while (!feof($fh) && $chunk > 0) {
171            @set_time_limit(30); // large files can take a lot of time
172            echo fread($fh, $chunk);
173            flush();
174            $len -= $chunk;
175            $chunk = ($len > HTTP_CHUNK_SIZE) ? HTTP_CHUNK_SIZE : $len;
176        }
177    }
178    if ($parts > 1) {
179        echo HTTP_HEADER_LF . '--' . HTTP_MULTIPART_BOUNDARY . '--' . HTTP_HEADER_LF;
180    }
181
182    // everything should be done here, exit (or return if testing)
183    if (defined('SIMPLE_TEST')) return;
184    exit;
185}
186
187/**
188 * Check for a gzipped version and create if necessary
189 *
190 * return true if there exists a gzip version of the uncompressed file
191 * (samepath/samefilename.sameext.gz) created after the uncompressed file
192 *
193 * @param string $uncompressed_file
194 * @return bool
195 * @author Chris Smith <chris.eureka@jalakai.co.uk>
196 *
197 */
198function http_gzip_valid($uncompressed_file)
199{
200    if (!DOKU_HAS_GZIP) return false;
201
202    $gzip = $uncompressed_file . '.gz';
203    if (filemtime($gzip) < filemtime($uncompressed_file)) {    // filemtime returns false (0) if file doesn't exist
204        return copy($uncompressed_file, 'compress.zlib://' . $gzip);
205    }
206
207    return true;
208}
209
210/**
211 * Set HTTP headers and echo cachefile, if useable
212 *
213 * This function handles output of cacheable resource files. It ses the needed
214 * HTTP headers. If a useable cache is present, it is passed to the web server
215 * and the script is terminated.
216 *
217 * @param string $cache cache file name
218 * @param bool $cache_ok if cache can be used
219 */
220function http_cached($cache, $cache_ok)
221{
222    global $conf;
223
224    // check cache age & handle conditional request
225    // since the resource files are timestamped, we can use a long max age: 1 year
226    header('Cache-Control: public, max-age=31536000');
227    header('Pragma: public');
228    if ($cache_ok) {
229        http_conditionalRequest(filemtime($cache));
230        if ($conf['allowdebug']) header("X-CacheUsed: $cache");
231
232        // finally send output
233        if ($conf['gzip_output'] && http_gzip_valid($cache)) {
234            header('Vary: Accept-Encoding');
235            header('Content-Encoding: gzip');
236            readfile($cache . ".gz");
237        } else {
238            http_sendfile($cache);
239            readfile($cache);
240        }
241        exit;
242    }
243
244    http_conditionalRequest(time());
245}
246
247/**
248 * Cache content and print it
249 *
250 * @param string $file file name
251 * @param string $content
252 */
253function http_cached_finish($file, $content)
254{
255    global $conf;
256
257    // save cache file
258    io_saveFile($file, $content);
259    if (DOKU_HAS_GZIP) io_saveFile("$file.gz", $content);
260
261    // finally send output
262    if ($conf['gzip_output'] && DOKU_HAS_GZIP) {
263        header('Vary: Accept-Encoding');
264        header('Content-Encoding: gzip');
265        echo gzencode($content, 9, FORCE_GZIP);
266    } else {
267        echo $content;
268    }
269}
270
271/**
272 * Fetches raw, unparsed POST data
273 *
274 * @return string
275 */
276function http_get_raw_post_data()
277{
278    static $postData = null;
279    if ($postData === null) {
280        $postData = file_get_contents('php://input');
281    }
282    return $postData;
283}
284
285/**
286 * Set the HTTP response status and takes care of the used PHP SAPI
287 *
288 * Inspired by CodeIgniter's set_status_header function
289 *
290 * @param int $code
291 * @param string $text
292 */
293function http_status($code = 200, $text = '')
294{
295    global $INPUT;
296
297    static $stati = [
298        200 => 'OK',
299        201 => 'Created',
300        202 => 'Accepted',
301        203 => 'Non-Authoritative Information',
302        204 => 'No Content',
303        205 => 'Reset Content',
304        206 => 'Partial Content',
305        300 => 'Multiple Choices',
306        301 => 'Moved Permanently',
307        302 => 'Found',
308        304 => 'Not Modified',
309        305 => 'Use Proxy',
310        307 => 'Temporary Redirect',
311        400 => 'Bad Request',
312        401 => 'Unauthorized',
313        403 => 'Forbidden',
314        404 => 'Not Found',
315        405 => 'Method Not Allowed',
316        406 => 'Not Acceptable',
317        407 => 'Proxy Authentication Required',
318        408 => 'Request Timeout',
319        409 => 'Conflict',
320        410 => 'Gone',
321        411 => 'Length Required',
322        412 => 'Precondition Failed',
323        413 => 'Request Entity Too Large',
324        414 => 'Request-URI Too Long',
325        415 => 'Unsupported Media Type',
326        416 => 'Requested Range Not Satisfiable',
327        417 => 'Expectation Failed',
328        500 => 'Internal Server Error',
329        501 => 'Not Implemented',
330        502 => 'Bad Gateway',
331        503 => 'Service Unavailable',
332        504 => 'Gateway Timeout',
333        505 => 'HTTP Version Not Supported'
334    ];
335
336    if ($text == '' && isset($stati[$code])) {
337        $text = $stati[$code];
338    }
339
340    $server_protocol = $INPUT->server->str('SERVER_PROTOCOL', false);
341
342    if (str_starts_with(PHP_SAPI, 'cgi') || defined('SIMPLE_TEST')) {
343        header("Status: {$code} {$text}", true);
344    } elseif ($server_protocol == 'HTTP/1.1' || $server_protocol == 'HTTP/1.0') {
345        header($server_protocol . " {$code} {$text}", true, $code);
346    } else {
347        header("HTTP/1.1 {$code} {$text}", true, $code);
348    }
349}
350