diff --git a/contentserver.graffle b/contentserver.graffle
index 6e61615..5176c77 100644
Binary files a/contentserver.graffle and b/contentserver.graffle differ
diff --git a/repo/loader.go b/repo/loader.go
index ac42e78..fa1cc4b 100644
--- a/repo/loader.go
+++ b/repo/loader.go
@@ -93,6 +93,7 @@ func (repo *Repo) _updateDimension(dimension string, newNode *content.RepoNode)
 
 	// ---------------------------------------------
 
+	// copy old datastructure to prevent concurrent map access
 	// collect other dimension in the Directory
 	newRepoDirectory := map[string]*Dimension{}
 	for d, D := range repo.Directory {
diff --git a/repo/repo.go b/repo/repo.go
index 9acbe89..ffe6146 100644
--- a/repo/repo.go
+++ b/repo/repo.go
@@ -96,6 +96,11 @@ func (repo *Repo) getNodes(nodeRequests map[string]*requests.Node, env *requests
 		path  = []*content.Item{}
 	)
 	for nodeName, nodeRequest := range nodeRequests {
+
+		if nodeName == "" || nodeRequest.ID == "" {
+			Log.Error("invalid node request", zap.Error(errors.New("nodeName or nodeRequest.ID empty")))
+			continue
+		}
 		Log.Debug("adding node", zap.String("name", nodeName), zap.String("requestID", nodeRequest.ID))
 
 		groups := env.Groups