/**
* Outputs a file that can be paused and resumed by the client (by following the partial content spec)
*
* Additionally, this function will also set up correct file headers (Content-Type, Content-Disposition, etc)
* or can return them as an array if $returnheader is set to TRUE.
* In this case no fileoutput will be generated. You can use Loops\Misc::readpartialfile to actually send the file.
*
* The Content-Disposition header will always be set to 'attachment'. 'servefiles' purpose is to provide
* a resumeable download. If you want to send inline content, use PHPs readfile and header functions instead.
*
* $filename or $mimetype can be also set to a boolean. If boolean TRUE, values will be infered from the $file.
* If set to FALSE, values will NOT be included in the headers.
* i.e. no filename="..." in Content-Disposition and/or no Content-Type header.
*
* If the file and headers have been sent, -1 is returned, thus not genarating additional output.
* In case of an error, a http status code is generated (4xx, 5xx series) and returned.
* You can conveniently use this funcion in the action method of loops elements:
* <code>
* use Loops\Misc;
*
* public function action($parameter) {
* return Misc::servefile("example.png");
* }
* </code>
*
* This function will raise an exeption if there is already data in an outbut buffer or headers were already sent.
*
* @todo Do not rely on $_SERVER variable for the partial spec
*
* @param string $file The physical location of the file (must be understood by fopen)
* @param bool|string $filename An alternate filename that is sent in Content-Disposition (must be an UTF-8 string or bool)
* @param bool|string $mimetype The mimetype that is used for the Content-Type header.
* @param bool $returnheader If set to TRUE, headers will be returned as an array (no output is generated)
* @param resource $context The context passed to fopen.
* @return int|array An http status code or an array of headers
*/
public static function servefile($file, $filename = TRUE, $mimetype = TRUE, $returnheader = FALSE, $force = FALSE, $context = NULL)
{
if (headers_sent()) {
throw new Exception("Can't serve file because output headers have already been sent.");
}
if (!$force) {
if (!@file_exists($file)) {
return 404;
}
if (!@is_readable($file)) {
return 403;
}
}
//detect mimetype - note that spl fileobject does not support this over data urls for some reason
if ($mimetype === TRUE) {
$mimetype = "application/octet-stream";
if ($finfo = finfo_open(FILEINFO_MIME_TYPE)) {
if ($type = finfo_file($finfo, $file)) {
$mimetype = $type;
}
finfo_close($finfo);
}
}
//open file
if (!$file instanceof SplFileObject) {
$file = new SplFileObject($file);
}
//get size
$filesize = $file->getSize();
//get requested range from header
$range = FALSE;
if (isset($_SERVER["HTTP_RANGE"])) {
$range = $_SERVER["HTTP_RANGE"];
} else {
if (isset($_SERVER["HTTP_CONTENT_RANGE"])) {
$range = $_SERVER["HTTP_CONTENT_RANGE"];
} else {
if (function_exists('apache_request_headers')) {
$headers = apache_request_headers();
foreach ($headers as $key => $value) {
if (strtolower($key) == "range") {
$range = $value;
break;
}
}
}
}
}
//partial information
$partial = FALSE;
if ($range) {
if (strpos($range, '=') === FALSE) {
return 400;
}
list($param, $range) = explode('=', $range, 2);
if (strtolower(trim($param)) != 'bytes') {
// Bad request - range unit is not 'bytes'
return 400;
}
$range = explode(',', $range);
$range = explode('-', $range[0]);
// We only deal with the first requested range
if (count($range) != 2) {
// Bad request - 'bytes' parameter is not valid
return 400;
}
if ($range[0] === '') {
// First number missing, return last $range[1] bytes
$offset = $filesize - intval($range[1]);
if ($offset && $offset < $filesize) {
$partial = [$offset, $filesize - 1];
} else {
return 416;
}
} else {
if ($range[1] === '') {
// Second number missing, return from byte $range[0] to end
$offset = intval($range[0]);
if ($offset < $filesize) {
$partial = [$offset, $filesize - 1];
} else {
return 416;
}
} else {
// Both numbers present, return specific range
$offset1 = intval($range[0]);
$offset2 = intval($range[1]);
if ($offset1 < $filesize && $offset2 < $filesize) {
$partial = [$offset1, $offset2];
} else {
return 416;
}
}
}
}
if ($filename) {
if ($filename === TRUE) {
$filename = basename($file);
}
// get user-agent from header
$useragent = FALSE;
if (isset($_SERVER["HTTP_USER_AGENT"])) {
$useragent = $_SERVER["HTTP_USER_AGENT"];
} else {
if (function_exists('apache_request_headers')) {
$headers = apache_request_headers();
foreach ($headers as $key => $value) {
if (strtolower($key) == "user-agent") {
$useragent = $value;
break;
}
}
}
}
//we need to get a cross browser compatible filename for the header. oh boy....
//lets trust the following stack overflow question:
// http://stackoverflow.com/questions/93551/how-to-encode-the-filename-parameter-of-content-disposition-header-in-http
if ($useragent && preg_match("/IE [5678]\\./", $useragent)) {
$filename = " filename=" . urlencode($filename);
} else {
if ($useragent && preg_match("/Safari/", $useragent)) {
$filename = " filename={$filename}";
} else {
if ($useragent && preg_match("/[^a-zA-Z0-9_\\.]/", $filename)) {
$filename = " filename=\"{$filename}\"; filename*=UTF-8''" . urlencode($filename);
} else {
$filename = " filename=\"{$filename}\";";
}
}
}
}
//create output headers
$length = $partial ? $partial[1] - $partial[0] + 1 : $filesize;
$headers = array();
$headers[] = "Content-Type: {$mimetype}";
$headers[] = "Content-Disposition: attachment;{$filename}";
$headers[] = "Content-Length: {$length}";
$headers[] = "Accept-Ranges: bytes";
if ($partial) {
$headers[] = "Content-Range: bytes {$partial['0']}-{$partial['1']}/{$filesize}";
}
if ($returnheader) {
return $headers;
}
//actual output happens from now on
//set status code and header
if (!$context) {
$context = Loops::getCurrentLoops();
}
if ($partial) {
$context->response->setStatusCode(206);
}
foreach ($headers as $line) {
$context->response->addHeader($line);
}
$context->response->setHeader();
if ($filesize) {
if ($partial) {
$bytes = Misc::readPartialFile($file, $partial[0], $partial[1], $context);
} else {
$bytes = $file->fpassthru();
}
//if no output was generated, the above functions failed and we have to/can recover
if (!$bytes) {
//remove previously set headers
foreach ($headers as $line) {
$context->response->removeHeader($line);
}
return 500;
}
}
//do not generate output
return -1;
}
