Fix PUT of empty filename

This fixes the unit test but we should perhaps clarify what the intended
behaviour is when PUT'ing to an empty filename.

License: MIT
Signed-off-by: James Stanley <james@incoherency.co.uk>

core/corehttp/gateway_handler.go

@@ -427,32 +427,38 @@ func (i *gatewayHandler) putHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	rnode, err := i.node.DAG.Get(ctx, c)
-	if err != nil {
-		webError(w, "putHandler: Could not create DAG from request", err, http.StatusInternalServerError)
-		return
-	}
+	var newcid *cid.Cid
+	if newPath == "" {
+		// not inserting anything: directory tree is unchanged
+		newcid = c
+	} else {
+		rnode, err := i.node.DAG.Get(ctx, c)
+		if err != nil {
+			webError(w, "putHandler: Could not create DAG from request", err, http.StatusInternalServerError)
+			return
+		}
 
-	pbnd, ok := rnode.(*dag.ProtoNode)
-	if !ok {
-		webError(w, "Cannot read non protobuf nodes through gateway", dag.ErrNotProtobuf, http.StatusBadRequest)
-		return
-	}
+		pbnd, ok := rnode.(*dag.ProtoNode)
+		if !ok {
+			webError(w, "Cannot read non protobuf nodes through gateway", dag.ErrNotProtobuf, http.StatusBadRequest)
+			return
+		}
 
-	e := dagutils.NewDagEditor(pbnd, i.node.DAG)
-	err = e.InsertNodeAtPath(ctx, newPath, newnode, ft.EmptyDirNode)
-	if err != nil {
-		webError(w, "putHandler: InsertNodeAtPath failed", err, http.StatusInternalServerError)
-		return
-	}
+		e := dagutils.NewDagEditor(pbnd, i.node.DAG)
+		err = e.InsertNodeAtPath(ctx, newPath, newnode, ft.EmptyDirNode)
+		if err != nil {
+			webError(w, "putHandler: InsertNodeAtPath failed", err, http.StatusInternalServerError)
+			return
+		}
 
-	nnode, err := e.Finalize(ctx, i.node.DAG)
-	if err != nil {
-		webError(w, "putHandler: could not get node", err, http.StatusInternalServerError)
-		return
-	}
+		nnode, err := e.Finalize(ctx, i.node.DAG)
+		if err != nil {
+			webError(w, "putHandler: could not get node", err, http.StatusInternalServerError)
+			return
+		}
 
-	newcid := nnode.Cid()
+		newcid = nnode.Cid()
+	}
 
 	i.addUserHeaders(w) // ok, _now_ write user's headers.
 	w.Header().Set("IPFS-Hash", newcid.String())