PHP readfile_allow_large函数代码示例

//.........这里部分代码省略.........
        header('Content-Type: ' . $mimetype);
    }
    $lastmodified = is_object($file) ? $file->get_timemodified() : filemtime($file);
    header('Last-Modified: ' . gmdate('D, d M Y H:i:s', $lastmodified) . ' GMT');
    if (is_object($file)) {
        header('Etag: "' . $file->get_contenthash() . '"');
        if (isset($_SERVER['HTTP_IF_NONE_MATCH']) and trim($_SERVER['HTTP_IF_NONE_MATCH'], '"') === $file->get_contenthash()) {
            header('HTTP/1.1 304 Not Modified');
            return;
        }
    }
    // if etag present for stored file rely on it exclusively
    if (!empty($_SERVER['HTTP_IF_MODIFIED_SINCE']) and (empty($_SERVER['HTTP_IF_NONE_MATCH']) or !is_object($file))) {
        // get unixtime of request header; clip extra junk off first
        $since = strtotime(preg_replace('/;.*$/', '', $_SERVER["HTTP_IF_MODIFIED_SINCE"]));
        if ($since && $since >= $lastmodified) {
            header('HTTP/1.1 304 Not Modified');
            return;
        }
    }
    if ($accelerate and !empty($CFG->xsendfile)) {
        if (empty($CFG->disablebyteserving) and $mimetype !== 'text/plain') {
            header('Accept-Ranges: bytes');
        } else {
            header('Accept-Ranges: none');
        }
        if (is_object($file)) {
            $fs = get_file_storage();
            if ($fs->xsendfile($file->get_contenthash())) {
                return;
            }
        } else {
            require_once "{$CFG->libdir}/xsendfilelib.php";
            if (xsendfile($file)) {
                return;
            }
        }
    }
    $filesize = is_object($file) ? $file->get_filesize() : filesize($file);
    header('Last-Modified: ' . gmdate('D, d M Y H:i:s', $lastmodified) . ' GMT');
    if ($accelerate and empty($CFG->disablebyteserving) and $mimetype !== 'text/plain') {
        header('Accept-Ranges: bytes');
        if (!empty($_SERVER['HTTP_RANGE']) and strpos($_SERVER['HTTP_RANGE'], 'bytes=') !== FALSE) {
            // byteserving stuff - for acrobat reader and download accelerators
            // see: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35
            // inspired by: http://www.coneural.org/florian/papers/04_byteserving.php
            $ranges = false;
            if (preg_match_all('/(\\d*)-(\\d*)/', $_SERVER['HTTP_RANGE'], $ranges, PREG_SET_ORDER)) {
                foreach ($ranges as $key => $value) {
                    if ($ranges[$key][1] == '') {
                        //suffix case
                        $ranges[$key][1] = $filesize - $ranges[$key][2];
                        $ranges[$key][2] = $filesize - 1;
                    } else {
                        if ($ranges[$key][2] == '' || $ranges[$key][2] > $filesize - 1) {
                            //fix range length
                            $ranges[$key][2] = $filesize - 1;
                        }
                    }
                    if ($ranges[$key][2] != '' && $ranges[$key][2] < $ranges[$key][1]) {
                        //invalid byte-range ==> ignore header
                        $ranges = false;
                        break;
                    }
                    //prepare multipart header
                    $ranges[$key][0] = "\r\n--" . BYTESERVING_BOUNDARY . "\r\nContent-Type: {$mimetype}\r\n";
                    $ranges[$key][0] .= "Content-Range: bytes {$ranges[$key][1]}-{$ranges[$key][2]}/{$filesize}\r\n\r\n";
                }
            } else {
                $ranges = false;
            }
            if ($ranges) {
                if (is_object($file)) {
                    $handle = $file->get_content_file_handle();
                } else {
                    $handle = fopen($file, 'rb');
                }
                byteserving_send_file($handle, $mimetype, $ranges, $filesize);
            }
        }
    } else {
        // Do not byteserve
        header('Accept-Ranges: none');
    }
    header('Content-Length: ' . $filesize);
    if ($filesize > 10000000) {
        // for large files try to flush and close all buffers to conserve memory
        while (@ob_get_level()) {
            if (!@ob_end_flush()) {
                break;
            }
        }
    }
    // send the whole file content
    if (is_object($file)) {
        $file->readfile();
    } else {
        readfile_allow_large($file, $filesize);
    }
}

 /**
  * Dumps file content to page.
  */
 public function readfile()
 {
     $path = $this->get_content_file_location();
     if (!is_readable($path)) {
         if (!$this->fs->try_content_recovery($this) or !is_readable($path)) {
             throw new file_exception('storedfilecannotread', '', $path);
         }
     }
     readfile_allow_large($path, $this->get_filesize());
 }