changes nextcloud 14 to determine mime-types from file content if the file exists and probably fixes some potential bugs

nextcloud-other-mime-type.patch

diff --git a/apps/dav/lib/Connector/Sabre/File.php b/apps/dav/lib/Connector/Sabre/File.php
index e46bdcb298..2401b7158a 100644
--- a/apps/dav/lib/Connector/Sabre/File.php
+++ b/apps/dav/lib/Connector/Sabre/File.php
@@ -165,7 +165,9 @@ class File extends Node implements IFile {
 				$this->changeLock(ILockingProvider::LOCK_EXCLUSIVE);
 			}
 
+
 			$target = $partStorage->fopen($internalPartPath, 'wb');
+
 			if ($target === false) {
 				\OC::$server->getLogger()->error('\OC\Files\Filesystem::fopen() failed', ['app' => 'webdav']);
 				// because we have no clue about the cause we can only throw back a 500/Internal Server Error
@@ -224,6 +226,9 @@ class File extends Node implements IFile {
 						throw new Exception('Could not rename part file to final file');
 					}
 				} catch (ForbiddenException $ex) {
+					# $partStorage->unlink did not remove the file
+					$localFile = $partStorage->getLocalFile($internalPartPath);
+					if(file_exists($localFile)) { unlink($localFile); }
 					throw new DAVForbiddenException($ex->getMessage(), $ex->getRetry());
 				} catch (\Exception $e) {
 					$partStorage->unlink($internalPartPath);
@@ -247,7 +252,7 @@ class File extends Node implements IFile {
 					$this->header('X-OC-MTime: accepted');
 				}
 			}
-					
+
 			if ($view) {
 				$this->emitPostHooks($exists);
 			}
diff --git a/apps/workflowengine/lib/Check/FileMimeType.php b/apps/workflowengine/lib/Check/FileMimeType.php
index bd94ec9d5b..c44d4d0d5f 100644
--- a/apps/workflowengine/lib/Check/FileMimeType.php
+++ b/apps/workflowengine/lib/Check/FileMimeType.php
@@ -72,9 +72,10 @@ class FileMimeType extends AbstractStringCheck {
 	 * @return string
 	 */
 	protected function getActualValue() {
-		if ($this->mimeType[$this->storage->getId()][$this->path] !== null) {
-			return $this->mimeType[$this->storage->getId()][$this->path];
-		}
+		# would read cached values. dont reuse old value after check for upload path that did not yet exist
+		#if ($this->mimeType[$this->storage->getId()][$this->path] !== null) {
+		#	return $this->mimeType[$this->storage->getId()][$this->path];
+		#}
 
 		if ($this->isWebDAVRequest()) {
 			// Creating a folder
@@ -85,10 +86,12 @@ class FileMimeType extends AbstractStringCheck {
 
 			if ($this->request->getMethod() === 'PUT' || $this->request->getMethod() === 'MOVE') {
 				if ($this->request->getMethod() === 'MOVE') {
-					$this->mimeType[$this->storage->getId()][$this->path] = $this->mimeTypeDetector->detectPath($this->path);
+					$this->mimeType[$this->storage->getId()][$this->path] = $this->mimeTypeDetector->detect($this->path);
 				} else {
-					$path = $this->request->getPathInfo();
-					$this->mimeType[$this->storage->getId()][$this->path] = $this->mimeTypeDetector->detectPath($path);
+					# path would be "webdav/filename" on upload and doesnt exist.
+					#$path = $this->request->getPathInfo();
+					#$this->mimeType[$this->storage->getId()][$this->path] = $this->mimeTypeDetector->detect($path);
+					$this->mimeType[$this->storage->getId()][$this->path] = $this->detectMimetypeFromPath();
 				}
 				return $this->mimeType[$this->storage->getId()][$this->path];
 			}
@@ -99,7 +102,7 @@ class FileMimeType extends AbstractStringCheck {
 					$path = substr($path, strlen('/webdav'));
 				}
 				$path = $this->path . $path;
-				$this->mimeType[$this->storage->getId()][$path] = $this->mimeTypeDetector->detectPath($path);
+				$this->mimeType[$this->storage->getId()][$path] = $this->mimeTypeDetector->detect($path);
 				return $this->mimeType[$this->storage->getId()][$path];
 			}
 		}
@@ -110,7 +113,7 @@ class FileMimeType extends AbstractStringCheck {
 				$mimeType = $files['type'][0];
 				if ($this->mimeType === 'application/octet-stream') {
 					// Maybe not...
-					$mimeTypeTest = $this->mimeTypeDetector->detectPath($files['name'][0]);
+					$mimeTypeTest = $this->mimeTypeDetector->detect($files['name'][0]);
 					if ($mimeTypeTest !== 'application/octet-stream' && $mimeTypeTest !== false) {
 						$mimeType = $mimeTypeTest;
 					} else {
@@ -125,10 +128,7 @@ class FileMimeType extends AbstractStringCheck {
 			}
 		}
 
-		$this->mimeType[$this->storage->getId()][$this->path] = $this->storage->getMimeType($this->path);
-		if ($this->mimeType[$this->storage->getId()][$this->path] === 'application/octet-stream') {
-			$this->mimeType[$this->storage->getId()][$this->path] = $this->detectMimetypeFromPath();
-		}
+		$this->mimeType[$this->storage->getId()][$this->path] = $this->detectMimetypeFromPath();
 
 		return $this->mimeType[$this->storage->getId()][$this->path];
 	}
@@ -137,11 +137,6 @@ class FileMimeType extends AbstractStringCheck {
 	 * @return string
 	 */
 	protected function detectMimetypeFromPath() {
-		$mimeType = $this->mimeTypeDetector->detectPath($this->path);
-		if ($mimeType !== 'application/octet-stream' && $mimeType !== false) {
-			return $mimeType;
-		}
-
 		if ($this->storage->instanceOfStorage('\OC\Files\Storage\Local')
 			|| $this->storage->instanceOfStorage('\OC\Files\Storage\Home')
 			|| $this->storage->instanceOfStorage('\OC\Files\ObjectStore\HomeObjectStoreStorage')) {
@@ -155,15 +150,19 @@ class FileMimeType extends AbstractStringCheck {
 
 			return 'application/octet-stream';
 		} else {
-			$handle = $this->storage->fopen($this->path, 'r');
-			$data = fread($handle, 8024);
-			fclose($handle);
-			$mimeType = $this->mimeTypeDetector->detectString($data);
-			if ($mimeType !== false) {
-				return $mimeType;
+			if(file_exists($this->path)) {
+				$handle = $this->storage->fopen($this->path, 'r');
+				$data = fread($handle, 8024);
+				fclose($handle);
+				$mimeType = $this->mimeTypeDetector->detectString($data);
+				if ($mimeType !== false) {
+					return $mimeType;
+				}
+				return 'application/octet-stream';
+			}
+			else {
+				return $this->storage->getMimeType($this->path);
 			}
-
-			return 'application/octet-stream';
 		}
 	}
 
diff --git a/lib/private/Files/Type/Detection.php b/lib/private/Files/Type/Detection.php
index 3207562763..5fecc86406 100644
--- a/lib/private/Files/Type/Detection.php
+++ b/lib/private/Files/Type/Detection.php
@@ -205,12 +205,16 @@ class Detection implements IMimeTypeDetector {
 			return "httpd/unix-directory";
 		}
 
-		$mimeType = $this->detectPath($path);
+		// dont try to test file content if file not existent
+		if (!file_exists($path)) {
+			return $this->detectPath($path);
+		}
 
-		if ($mimeType === 'application/octet-stream' and function_exists('finfo_open')
+		if (function_exists('finfo_open')
 			and function_exists('finfo_file') and $finfo = finfo_open(FILEINFO_MIME)
 		) {
 			$info = @strtolower(finfo_file($finfo, $path));
+
 			finfo_close($finfo);
 			if ($info) {
 				$mimeType = strpos($info, ';') !== false ? substr($info, 0, strpos($info, ';')) : $info;
@@ -219,11 +223,11 @@ class Detection implements IMimeTypeDetector {
 
 		}
 		$isWrapped = (strpos($path, '://') !== false) and (substr($path, 0, 7) === 'file://');
-		if (!$isWrapped and $mimeType === 'application/octet-stream' && function_exists("mime_content_type")) {
+		if (!$isWrapped && function_exists("mime_content_type")) {
 			// use mime magic extension if available
 			$mimeType = mime_content_type($path);
 		}
-		if (!$isWrapped and $mimeType === 'application/octet-stream' && \OC_Helper::canExecute("file")) {
+		if (!$isWrapped && \OC_Helper::canExecute("file")) {
 			// it looks like we have a 'file' command,
 			// lets see if it does have mime support
 			$path = escapeshellarg($path);
@@ -237,8 +241,13 @@ class Detection implements IMimeTypeDetector {
 			if (empty($mimeType)) {
 				$mimeType = 'application/octet-stream';
 			}
+		}
 
+		// check that result is a mime type. the various tools used can set it to error strings
+		if (!preg_match("/^[a-zA-Z0-9-]+\/[a-zA-Z0-9-]+$/", $mimeType)) {
+			$mimeType = 'application/octet-stream';
 		}
+
 		return $mimeType;
 	}