Merge branch 'Issue/2122-retrieveWithoutFile' into 'dev'

Fix: Metadata can be retrieved without a file present

See merge request !72

src/Tree/Controllers/TreeController.cs

@@ -157,6 +157,12 @@ namespace Coscine.Api.Tree.Controllers
                 var resourceTypeInformation = resourceTypeDefinition.GetResourceTypeInformation().Result;
                 var metadataInfos = new List<ResourceEntry>(fileInfos);
 
+                // Add to metadata infos, if no "physical" file for it exists
+                if (!metadataInfos.Any((metadataInfo) => metadataInfo.Key == path))
+                {
+                    metadataInfos.Add(new ResourceEntry(path, true, 0, GenerateId(resourceId, path).AbsoluteUri, null, DateTime.Now, DateTime.Now));
+                }
+
                 var graphs = new List<object>();
                 int metadataCount = 0;
                 foreach (var info in metadataInfos)