Add a configuration switch for enabled preview mimetypes

1 files changed, 35 insertions, 12 deletions

diff --git a/lib/private/preview.php b/lib/private/preview.php
index b04cc2b8564..9d44d00e686 100755
--- a/lib/private/preview.php
+++ b/lib/private/preview.php
@@ -13,7 +13,6 @@
  */
 namespace OC;
 
-use OC\Files\Filesystem;
 use OC\Preview\Provider;
 use OCP\Files\NotFoundException;
 
@@ -23,7 +22,6 @@ require_once 'preview/mp3.php';
 require_once 'preview/pdf.php';
 require_once 'preview/svg.php';
 require_once 'preview/txt.php';
-require_once 'preview/unknown.php';
 require_once 'preview/office.php';
 require_once 'preview/tiff.php';
 
@@ -62,6 +60,7 @@ class Preview {
 	//preview providers
 	static private $providers = array();
 	static private $registeredProviders = array();
+	static private $enabledProviders = array();
 
 	/**
 	 * @var \OCP\Files\FileInfo
@@ -669,12 +668,39 @@ class Preview {
 	}
 
 	/**
-	 * register a new preview provider to be used
+	 * Register a new preview provider to be used
+	 * @param $class
 	 * @param array $options
-	 * @return void
 	 */
 	public static function registerProvider($class, $options = array()) {
-		self::$registeredProviders[] = array('class' => $class, 'options' => $options);
+		/**
+		 * Only register providers that have been explicitly enabled
+		 *
+		 * The following providers are enabled by default:
+		 *  - OC\Preview\Image
+		 *  - OC\Preview\MP3
+		 *  - OC\Preview\TXT
+		 *  - OC\Preview\MarkDown
+		 *
+		 * The following providers are disabled by default due to performance or privacy concerns:
+		 *  - OC\Preview\Office
+		 *  - OC\Preview\SVG
+		 *  - OC\Preview\Movies
+		 *  - OC\Preview\PDF
+		 *  - OC\Preview\Tiff
+		 */
+		if(empty(self::$enabledProviders)) {
+			self::$enabledProviders = \OC::$server->getConfig()->getSystemValue('enabledPreviewProviders', array(
+				'OC\Preview\Image',
+				'OC\Preview\MP3',
+				'OC\Preview\TXT',
+				'OC\Preview\MarkDown',
+			));
+		}
+
+		if(in_array($class, self::$enabledProviders)) {
+			self::$registeredProviders[] = array('class' => $class, 'options' => $options);
+		}
 	}
 
 	/**
@@ -682,9 +708,8 @@ class Preview {
 	 * @return void
 	 */
 	private static function initProviders() {
-		if (!\OC_Config::getValue('enable_previews', true)) {
-			$provider = new Preview\Unknown(array());
-			self::$providers = array($provider->getMimeType() => $provider);
+		if (!\OC::$server->getConfig()->getSystemValue('enable_previews', true)) {
+			self::$providers = array();
 			return;
 		}
 
@@ -698,12 +723,12 @@ class Preview {
 
 			/** @var $object Provider */
 			$object = new $class($options);
-
 			self::$providers[$object->getMimeType()] = $object;
 		}
 
 		$keys = array_map('strlen', array_keys(self::$providers));
 		array_multisort($keys, SORT_DESC, self::$providers);
+
 	}
 
 	public static function post_write($args) {
@@ -758,9 +783,7 @@ class Preview {
 			self::initProviders();
 		}
 
-		//remove last element because it has the mimetype *
-		$providers = array_slice(self::$providers, 0, -1);
-		foreach ($providers as $supportedMimeType => $provider) {
+		foreach (self::$providers as $supportedMimeType => $provider) {
 			/**
 			 * @var \OC\Preview\Provider $provider
 			 */