API: torrents: remove useless isMultiFile property

It is only used to determine whether to use .tar extension when
download is requested. However, server sent Content-Disposition
header which already tells the browser the filename and it is
more accurate.

As such, remove this useless property.

client/src/javascript/components/modals/torrent-details-modal/TorrentContents.tsx

@@ -55,19 +55,14 @@ class TorrentContents extends React.Component<WrappedComponentProps> {
     event.preventDefault();
     const {baseURI} = ConfigStore;
     const link = document.createElement('a');
-    const {name} = TorrentStore.torrents[hash] || {};
 
-    if (name == null) {
-      return;
-    }
-
-    link.download = `${name}.tar`;
+    link.download = '';
     link.href = `${baseURI}api/torrents/${hash}/contents/${this.selectedIndices.join(',')}/data`;
     link.style.display = 'none';
 
-    document.body.appendChild(link); // Fix for Firefox 58+
-
+    document.body.appendChild(link);
     link.click();
+    document.body.removeChild(link);
   };
 
   handleFormChange = (hash: string, {event}: {event: Event | React.FormEvent<HTMLFormElement>}): void => {

client/src/javascript/components/torrent-list/TorrentListContextMenu.tsx

@@ -28,11 +28,14 @@ const handleTorrentDownload = (torrent: TorrentProperties, event: React.MouseEve
   event.preventDefault();
   const {baseURI} = ConfigStore;
   const link = document.createElement('a');
-  link.download = torrent.isMultiFile ? `${torrent.name}.tar` : torrent.name;
+
+  link.download = '';
   link.href = `${baseURI}api/torrents/${torrent.hash}/contents/all/data`;
   link.style.display = 'none';
+
   document.body.appendChild(link);
   link.click();
+  document.body.removeChild(link);
 };
 
 const handleItemClick = (action: TorrentContextMenuAction, event: React.MouseEvent): void => {

server/services/qBittorrent/clientGatewayService.ts

@@ -278,7 +278,6 @@ class QBittorrentClientGatewayService extends ClientGatewayService {
                 downTotal: info.downloaded,
                 eta: info.eta >= 8640000 ? -1 : info.eta,
                 hash: info.hash,
-                isMultiFile: false,
                 isPrivate: false,
                 message: '', // in tracker method
                 name: info.name,

server/services/rTorrent/constants/methodCallConfigs/torrentList.ts

@@ -26,10 +26,6 @@ const torrentListMethodCallConfigs = {
     methodCall: 'd.complete=',
     transformValue: booleanTransformer,
   },
-  isMultiFile: {
-    methodCall: 'd.is_multi_file=',
-    transformValue: booleanTransformer,
-  },
   isPrivate: {
     methodCall: 'd.is_private=',
     transformValue: booleanTransformer,

shared/types/Torrent.ts

@@ -39,7 +39,6 @@ export interface TorrentProperties {
   // Torrent ETA (seconds), -1 means infinity
   eta: number;
   hash: string;
-  isMultiFile: boolean;
   isPrivate: boolean;
   message: string;
   name: string;