make get_child use realtive path from spec as default, update examples

asyncua/common/node.py

@@ -574,14 +574,17 @@ async def get_child(
         """
         get a child specified by its path from this node.
         A path might be:
-        * a string representing a qualified name.
+        * a string representing a relative path as per UA spec
         * a qualified name
-        * a list of string
+        * a list of string representing browsenames (legacy)
         * a list of qualified names
         """
-        if isinstance(path, (ua.QualifiedName, str)):
-            path = [path]
-        rpath = self._make_relative_path(path)
+        if isinstance(path, str):
+            rpath = ua.RelativePath.from_string(path)
+        else:
+            if isinstance(path, ua.QualifiedName):
+                path = [path]
+            rpath = self._make_relative_path(path)
         bpath = ua.BrowsePath()
         bpath.StartingNode = self.nodeid
         bpath.RelativePath = rpath
@@ -600,16 +603,19 @@ async def get_children_by_path(
         """
         get children specified by their paths from this node.
         A path might be:
-        * a string representing a qualified name.
+        * a string representing a relative path as per UA spec
         * a qualified name
-        * a list of string
+        * a list of string representing browsenames (legacy)
         * a list of qualified names
         """
         bpaths: List[ua.BrowsePath] = []
         for path in paths:
-            if isinstance(path, (ua.QualifiedName, str)):
-                path = [path]
-            rpath = self._make_relative_path(path)
+            if isinstance(path, str):
+                rpath = ua.RelativePath.from_string(path)
+            else:
+                if isinstance(path, (ua.QualifiedName, str)):
+                    path = [path]
+                rpath = self._make_relative_path(path)
             bpath = ua.BrowsePath()
             bpath.StartingNode = self.nodeid
             bpath.RelativePath = rpath

examples/client-example.py

@@ -44,8 +44,8 @@ async def main():
         #await var.write_value(3.9) # set node value using implicit data type
 
         # Now getting a variable node using its browse path
-        myvar = await client.nodes.root.get_child(["0:Objects", "2:MyObject", "2:MyVariable"])
-        obj = await client.nodes.root.get_child(["0:Objects", "2:MyObject"])
+        myvar = await client.nodes.root.get_child("/Objects/2:MyObject/2:MyVariable")
+        obj = await client.nodes.root.get_child("Objects/2:MyObject")
         _logger.info("myvar is: %r", myvar)
 
         # subscribing to a variable node

examples/client-minimal.py

@@ -16,7 +16,7 @@ async def main():
 
         # Get the variable node for read / write
         var = await client.nodes.root.get_child(
-            ["0:Objects", f"{nsidx}:MyObject", f"{nsidx}:MyVariable"]
+            f"0:Objects/{nsidx}:MyObject/{nsidx}:MyVariable"
         )
         value = await var.read_value()
         print(f"Value of MyVariable ({var}): {value}")

examples/client-subscription.py

@@ -30,7 +30,7 @@ async def main():
     client = Client(url='opc.tcp://localhost:4840/freeopcua/server/')
     async with client:
         idx = await client.get_namespace_index(uri="http://examples.freeopcua.github.io")
-        var = await client.nodes.objects.get_child([f"{idx}:MyObject", f"{idx}:MyVariable"])
+        var = await client.nodes.objects.get_child(f"{idx}:MyObject/{idx}:MyVariable")
         handler = SubscriptionHandler()
         # We create a Client Subscription.
         subscription = await client.create_subscription(500, handler)

tests/test_common.py

@@ -442,16 +442,16 @@ async def test_browse_references(opc):
 
 async def test_browsename_with_spaces(opc):
     o = opc.opc.nodes.objects
-    v = await o.add_variable(3, "BNVariable with spaces and %&+?/", 1.3)
-    v2 = await o.get_child("3:BNVariable with spaces and %&+?/")
+    v = await o.add_variable(3, "BNVariable with spaces and %+?", 1.3)
+    v2 = await o.get_child("/3:BNVariable with spaces and %+?")
     assert v == v2
     await opc.opc.delete_nodes([v])
 
 
 async def test_non_existing_path(opc):
     root = opc.opc.nodes.root
     with pytest.raises(ua.UaStatusCodeError):
-        await root.get_child(["0:Objects", "0:Server", "0:nonexistingnode"])
+        await root.get_child("0:Objects/0:Server/0:nonexistingnode")
 
 
 async def test_bad_attribute(opc):
@@ -463,7 +463,7 @@ async def test_bad_attribute(opc):
 async def test_get_node_by_nodeid(opc):
     root = opc.opc.nodes.root
     server_time_node = await root.get_child(
-        ["0:Objects", "0:Server", "0:ServerStatus", "0:CurrentTime"]
+        "/Objects/Server/ServerStatus.CurrentTime"
     )
     correct = opc.opc.get_node(ua.NodeId(ua.ObjectIds.Server_ServerStatus_CurrentTime))
     assert server_time_node == correct
@@ -657,13 +657,13 @@ async def test_same_browse_name(opc):
     o2 = await f.add_object("ns=2;i=204;", "2:MyBName")
     v2 = await o2.add_variable("ns=2;i=205;", "2:MyBNameTarget", 2.0)
     nodes = await objects.get_child(
-        ["2:MyBNameFolder", "2:MyBName", "2:MyBNameTarget"], return_all=True
+        "/2:MyBNameFolder/2:MyBName/2:MyBNameTarget", return_all=True
     )
     assert len(nodes) == 2
     assert nodes[0] == v
     assert nodes[1] == v2
     [nodes] = await objects.get_children_by_path(
-        [["2:MyBNameFolder", "2:MyBName", "2:MyBNameTarget"]]
+        ["/2:MyBNameFolder/2:MyBName/2:MyBNameTarget"]
     )
     assert len(nodes) == 2
     assert nodes[0] == v