Http Range requests support in downloads

Http range requests support is required for video preview

apps/files/ajax/download.php

@@ -50,4 +50,13 @@ if(isset($_GET['downloadStartSecret'])
 	setcookie('ocDownloadStarted', $_GET['downloadStartSecret'], time() + 20, '/');
 }
 
-OC_Files::get($dir, $files_list, $_SERVER['REQUEST_METHOD'] == 'HEAD');
+$server_params = array( 'head' => \OC::$server->getRequest()->getMethod() == 'HEAD' );
+
+/**
+ * Http range requests support
+ */
+if (isset($_SERVER['HTTP_RANGE'])) {
+	$server_params['range'] = \OC::$server->getRequest()->getHeader('Range');
+}
+
+OC_Files::get($dir, $files_list, $server_params);

apps/files_sharing/lib/controllers/sharecontroller.php

@@ -484,16 +484,25 @@ class ShareController extends Controller {
 
 		$this->emitAccessShareHook($share);
 
+		$server_params = array( 'head' => $this->request->getMethod() == 'HEAD' );
+
+		/**
+		 * Http range requests support
+		 */
+		if (isset($_SERVER['HTTP_RANGE'])) {
+			$server_params['range'] = $this->request->getHeader('Range');
+		}
+
 		// download selected files
 		if (!is_null($files) && $files !== '') {
 			// FIXME: The exit is required here because otherwise the AppFramework is trying to add headers as well
 			// after dispatching the request which results in a "Cannot modify header information" notice.
-			OC_Files::get($originalSharePath, $files_list, $_SERVER['REQUEST_METHOD'] == 'HEAD');
+			OC_Files::get($originalSharePath, $files_list, $server_params);
 			exit();
 		} else {
 			// FIXME: The exit is required here because otherwise the AppFramework is trying to add headers as well
 			// after dispatching the request which results in a "Cannot modify header information" notice.
-			OC_Files::get(dirname($originalSharePath), basename($originalSharePath), $_SERVER['REQUEST_METHOD'] == 'HEAD');
+			OC_Files::get(dirname($originalSharePath), basename($originalSharePath), $server_params);
 			exit();
 		}
 	}

lib/private/Files/View.php

@@ -53,6 +53,7 @@ use OCP\Files\InvalidCharacterInPathException;
 use OCP\Files\InvalidPathException;
 use OCP\Files\NotFoundException;
 use OCP\Files\ReservedWordException;
+use OCP\Files\UnseekableException;
 use OCP\Files\Storage\ILockingStorage;
 use OCP\IUser;
 use OCP\Lock\ILockingProvider;
@@ -423,6 +424,39 @@ class View {
 		return false;
 	}
 
+	/**
+	 * @param string $path
+	 * @param int $from 
+	 * @param int $to
+	 * @return bool|mixed
+	 * @throws \OCP\Files\InvalidPathException, \OCP\Files\UnseekableException
+	 */
+	public function readfilePart($path, $from, $to) {
+		$this->assertPathLength($path);
+		@ob_end_clean();
+		$handle = $this->fopen($path, 'rb');
+		if ($handle) {
+			if (fseek($handle, $from) === 0) {
+			    $chunkSize = 8192; // 8 kB chunks
+			    $end = $to + 1;
+			    while (!feof($handle) && ftell($handle) < $end) {
+				$len = $end-ftell($handle);
+				if ($len > $chunkSize) { 
+				    $len = $chunkSize; 
+				}
+				echo fread($handle, $len);
+				flush();
+			    }
+			    $size = ftell($handle) - $from;
+			    return $size;
+			}
+			else {
+			    throw new \OCP\Files\UnseekableException('fseek error');
+			}
+		}
+		return false;
+	}
+
 	/**
 	 * @param string $path
 	 * @return mixed

lib/private/legacy/files.php

@@ -16,6 +16,7 @@
  * @author Thomas Müller <thomas.mueller@tmit.eu>
  * @author Victor Dubiniuk <dubiniuk@owncloud.com>
  * @author Vincent Petry <pvince81@owncloud.com>
+ * @author Piotr Filiciak <piotr@filiciak.pl>
  *
  * @copyright Copyright (c) 2016, ownCloud, Inc.
  * @license AGPL-3.0
@@ -49,20 +50,48 @@ class OC_Files {
 
 	const UPLOAD_MIN_LIMIT_BYTES = 1048576; // 1 MiB
 
+
+	private static $MULTIPART_BOUNDARY = '';
+
+	/**
+	 * @return string
+	 */
+	private static function getBoundary() {
+		if (empty(self::$MULTIPART_BOUNDARY)) {
+			self::$MULTIPART_BOUNDARY = md5(mt_rand());
+		}
+		return self::$MULTIPART_BOUNDARY;
+	}
+
 	/**
 	 * @param string $filename
 	 * @param string $name
+	 * @param array $rangeArray ('from'=>int,'to'=>int), ...
 	 */
-	private static function sendHeaders($filename, $name) {
+	private static function sendHeaders($filename, $name, array $rangeArray) {
 		OC_Response::setContentDispositionHeader($name, 'attachment');
-		header('Content-Transfer-Encoding: binary');
+		header('Content-Transfer-Encoding: binary', true);
 		OC_Response::disableCaching();
 		$fileSize = \OC\Files\Filesystem::filesize($filename);
 		$type = \OC::$server->getMimeTypeDetector()->getSecureMimeType(\OC\Files\Filesystem::getMimeType($filename));
-		header('Content-Type: '.$type);
 		if ($fileSize > -1) {
-			OC_Response::setContentLengthHeader($fileSize);
+			if (!empty($rangeArray)) {
+			    header('HTTP/1.1 206 Partial Content', true);
+			    header('Accept-Ranges: bytes', true);
+			    if (count($rangeArray) > 1) {
+				$type = 'multipart/byteranges; boundary='.self::getBoundary();
+				// no Content-Length header here
+			    }
+			    else {
+				header(sprintf('Content-Range: bytes %d-%d/%d', $rangeArray[0]['from'], $rangeArray[0]['to'], $fileSize), true);
+				OC_Response::setContentLengthHeader($rangeArray[0]['to'] - $rangeArray[0]['from'] + 1);
+			    }
+			}
+			else {
+			    OC_Response::setContentLengthHeader($fileSize);
+			}
 		}
+		header('Content-Type: '.$type, true);
 	}
 
 	/**
@@ -70,9 +99,9 @@ class OC_Files {
 	 *
 	 * @param string $dir
 	 * @param string $files ; separated list of files to download
-	 * @param boolean $onlyHeader ; boolean to only send header of the request
+	 * @param array $params ; 'head' boolean to only send header of the request ; 'range' http range header
 	 */
-	public static function get($dir, $files, $onlyHeader = false) {
+	public static function get($dir, $files, $params = array( 'head' => false )) {
 
 		$view = \OC\Files\Filesystem::getView();
 		$getType = self::FILE;
@@ -86,7 +115,7 @@ class OC_Files {
 			if (!is_array($files)) {
 				$filename = $dir . '/' . $files;
 				if (!$view->is_dir($filename)) {
-					self::getSingleFile($view, $dir, $files, $onlyHeader);
+					self::getSingleFile($view, $dir, $files, $params);
 					return;
 				}
 			}
@@ -156,19 +185,78 @@ class OC_Files {
 		}
 	}
 
+	/**
+	 * @param string $rangeHeaderPos
+	 * @param int $fileSize
+	 * @return array $rangeArray ('from'=>int,'to'=>int), ...
+	 */
+	private static function parseHttpRangeHeader($rangeHeaderPos, $fileSize) {
+		$rArray=split(',', $rangeHeaderPos);
+		$minOffset = 0;
+		$ind = 0;
+
+		$rangeArray = array();
+
+		foreach ($rArray as $value) {
+			$ranges = explode('-', $value);
+			if (is_numeric($ranges[0])) {
+				if ($ranges[0] < $minOffset) { // case: bytes=500-700,601-999
+					$ranges[0] = $minOffset;
+				}
+				if ($ind > 0 && $rangeArray[$ind-1]['to']+1 == $ranges[0]) { // case: bytes=500-600,601-999
+					$ind--;
+					$ranges[0] = $rangeArray[$ind]['from'];
+				}
+			}
+
+			if (is_numeric($ranges[0]) && is_numeric($ranges[1]) && $ranges[0] < $fileSize && $ranges[0] <= $ranges[1]) {
+				// case: x-x
+				if ($ranges[1] >= $fileSize) {
+					$ranges[1] = $fileSize-1;
+				}
+				$rangeArray[$ind++] = array( 'from' => $ranges[0], 'to' => $ranges[1], 'size' => $fileSize );
+				$minOffset = $ranges[1] + 1;
+				if ($minOffset >= $fileSize) {
+					break;
+				}
+			}
+			elseif (is_numeric($ranges[0]) && $ranges[0] < $fileSize) {
+				// case: x-
+				$rangeArray[$ind++] = array( 'from' => $ranges[0], 'to' => $fileSize-1, 'size' => $fileSize );
+				break;
+			}
+			elseif (is_numeric($ranges[1])) {
+				// case: -x
+				if ($ranges[1] > $fileSize) {
+					$ranges[1] = $fileSize;
+				}
+				$rangeArray[$ind++] = array( 'from' => $fileSize-$ranges[1], 'to' => $fileSize-1, 'size' => $fileSize );
+				break;
+			}
+		}
+		return $rangeArray;
+	}
+
 	/**
 	 * @param View $view
 	 * @param string $name
 	 * @param string $dir
-	 * @param boolean $onlyHeader
+	 * @param array $params ; 'head' boolean to only send header of the request ; 'range' http range header
 	 */
-	private static function getSingleFile($view, $dir, $name, $onlyHeader) {
+	private static function getSingleFile($view, $dir, $name, $params) {
 		$filename = $dir . '/' . $name;
 		OC_Util::obEnd();
 		$view->lockFile($filename, ILockingProvider::LOCK_SHARED);
+		
+		$rangeArray = array();
 
+		if (isset($params['range']) && substr($params['range'], 0, 6) === 'bytes=') {
+			$rangeArray = self::parseHttpRangeHeader(substr($params['range'], 6), 
+								 \OC\Files\Filesystem::filesize($filename));
+		}
+		
 		if (\OC\Files\Filesystem::isReadable($filename)) {
-			self::sendHeaders($filename, $name);
+			self::sendHeaders($filename, $name, $rangeArray);
 		} elseif (!\OC\Files\Filesystem::file_exists($filename)) {
 			header("HTTP/1.0 404 Not Found");
 			$tmpl = new OC_Template('', '404', 'guest');
@@ -178,10 +266,41 @@ class OC_Files {
 			header("HTTP/1.0 403 Forbidden");
 			die('403 Forbidden');
 		}
-		if ($onlyHeader) {
+		if (isset($params['head']) && $params['head']) {
 			return;
 		}
-		$view->readfile($filename);
+		if (!empty($rangeArray)) {
+			try {
+			    if (count($rangeArray) == 1) {
+				$view->readfilePart($filename, $rangeArray[0]['from'], $rangeArray[0]['to']);
+			    }
+			    else {
+				// check if file is seekable (if not throw UnseekableException)
+				// we have to check it before body contents
+				$view->readfilePart($filename, $rangeArray[0]['size'], $rangeArray[0]['size']);
+
+				$type = \OC::$server->getMimeTypeDetector()->getSecureMimeType(\OC\Files\Filesystem::getMimeType($filename));
+
+				foreach ($rangeArray as $range) {
+				    echo "\r\n--".self::getBoundary()."\r\n".
+				         "Content-type: ".$type."\r\n".
+				         "Content-range: bytes ".$range['from']."-".$range['to']."/".$range['size']."\r\n\r\n";
+				    $view->readfilePart($filename, $range['from'], $range['to']);
+				}
+				echo "\r\n--".self::getBoundary()."--\r\n";
+			    }
+			} catch (\OCP\Files\UnseekableException $ex) {
+			    // file is unseekable
+			    header_remove('Accept-Ranges');
+			    header_remove('Content-Range');
+			    header("HTTP/1.1 200 OK");
+			    self::sendHeaders($filename, $name, array());
+			    $view->readfile($filename);
+			}
+		}
+		else {
+		    $view->readfile($filename);
+		}
 	}
 
 	/**

lib/public/Files/UnseekableException.php

@@ -0,0 +1,34 @@
+<?php
+/**
+ * @author Piotr Filiciak <piotr@filiciak.pl>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+/**
+ * Public interface of ownCloud for apps to use.
+ * Files/UnseekableException class
+ */
+
+// use OCP namespace for all classes that are considered public.
+// This means that they should be used by apps instead of the internal ownCloud classes
+namespace OCP\Files;
+
+/**
+ * Exception for seek problem
+ */
+class UnseekableException extends \Exception {}