Parse string Guid NodeId as UUID (#1141) (#1311)

* Parse string Guid NodeId as UUID (#1141)

The following is the original :
FreeOpcUa/opcua-asyncio@0529ec7

* Fixed The Travis CI build failed

* Add test

The following is the original :
FreeOpcUa/opcua-asyncio@0529ec7

Co-authored-by: H.Tanaka <hirokazu.tanaka@users.noreply.github.com>

Author: gitseitanaka

examples/client-example.py

@@ -58,6 +58,7 @@ def event_notification(self, event):
         # get a specific node knowing its node id
         #var = client.get_node(ua.NodeId(1002, 2))
         #var = client.get_node("ns=3;i=2002")
+        #var = client.get_node("ns=2;g=1be5ba38-d004-46bd-aa3a-b5b87940c698")
         #print(var)
         #var.get_data_value() # get value of node as a DataValue object
         #var.get_value() # get value of node as a python builtin

opcua/ua/uatypes.py

@@ -362,7 +362,7 @@ def _from_string(string):
                 identifier = v
             elif k == "g":
                 ntype = NodeIdType.Guid
-                identifier = v
+                identifier = uuid.UUID("urn:uuid:{0}".format(v))
             elif k == "b":
                 ntype = NodeIdType.ByteString
                 identifier = v

tests/tests_common.py

@@ -897,3 +897,11 @@ def test_data_type_to_variant_type(self):
             }
         for dt, vdt in test_data.items():
             self.assertEqual(ua_utils.data_type_to_variant_type(self.opc.get_node(ua.NodeId(dt))), vdt)
+
+    def test_guid_node_id(self):
+        """
+        Test that a Node can be instantiated with a GUID string and that the NodeId ca be converted to binary.
+        """
+        node = Node(None, "ns=4;g=35d5f86f-2777-4550-9d48-b098f5ee285c")
+        binary_node_id = ua.ua_binary.nodeid_to_binary(node.nodeid)
+        assert type(binary_node_id) is bytes