Allow dirs to downloaded as tarballs

src/routes/apps.js

@@ -557,17 +557,18 @@ function downloadFile(req, res, next) {
 
     if (typeof req.query.file !== 'string' || !req.query.file) return next(new HttpError(400, 'file query argument must be provided'));
 
-    apps.downloadFile(req.params.id, req.query.file, function (error, result, info) {
+    apps.downloadFile(req.params.id, req.query.file, function (error, stream, info) {
         if (error && error.reason === AppsError.NOT_FOUND) return next(new HttpError(404, error.message));
         if (error) return next(new HttpError(500, error));
 
-        // TODO get real content type and size
-        res.writeHead(200, {
+        var headers = {
             'Content-Type': 'application/octet-stream',
-            'Content-Disposition': 'attachment; filename="' + info.filename + '"',
-            'Content-Length': info.size
-        });
+            'Content-Disposition': 'attachment; filename="' + info.filename + '"'
+        };
+        if (info.size) headers['Content-Length'] = info.size;
 
-        result.pipe(res);
+        res.writeHead(200, headers);
+
+        stream.pipe(res);
     });
 }