Initial QSfera import

Server/services/collaboration/pkg/helpers/cs3.go

@@ -0,0 +1,17 @@
+package helpers
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+
+	providerv1beta1 "github.com/cs3org/go-cs3apis/cs3/storage/provider/v1beta1"
+	"github.com/opencloud-eu/reva/v2/pkg/storagespace"
+)
+
+// HashResourceId builds a urlsafe and stable file reference that can be used for proxy routing,
+// so that all sessions on one file end on the same office server
+func HashResourceId(resourceId *providerv1beta1.ResourceId) string {
+	c := sha256.New()
+	c.Write([]byte(storagespace.FormatResourceID(resourceId)))
+	return hex.EncodeToString(c.Sum(nil))
+}