Fix: Linked Resources now working (coscine/issues#1616)

src/Tree/Controllers/TreeController.cs

@@ -83,7 +83,7 @@ namespace Coscine.Api.Tree.Controllers
         /// <param name="path">Path to the file</param>
         /// <returns> JSON Object with the metadata if ok, otherwise Statuscode 400 or 401 or 404</returns>
         [HttpGet("[controller]/{resourceId}/{*path}")]
-        public async Task<IActionResult> GetMetadata(string resourceId, string path)
+        public async Task<IActionResult> GetMetadata(string resourceId, string path = "")
         {
             var rawPath = path;
             path = $"/{path}";
@@ -167,12 +167,12 @@ namespace Coscine.Api.Tree.Controllers
                                     ["Download"] = new JObject
                                     {
                                         ["Method"] = "GET",
-                                        ["Url"] = resourceTypeDefinition?.GetEntryDownloadUrl(rawPath, null, resourceTypeOptions).Result.ToString()
+                                        ["Url"] = resourceTypeDefinition?.GetEntryDownloadUrl(rawPath, null, resourceTypeOptions).Result?.ToString()
                                     },
                                     ["Upload"] = new JObject
                                     {
                                         ["Method"] = "PUT",
-                                        ["Url"] = resourceTypeDefinition?.GetEntryStoreUrl(rawPath, null, resourceTypeOptions).Result.ToString()
+                                        ["Url"] = resourceTypeDefinition?.GetEntryStoreUrl(rawPath, null, resourceTypeOptions).Result?.ToString()
                                     }
                                 }
                             };