make automatic decoding of custom structs really work on client

Author: oroulet

opcua/client/client.py

@@ -540,7 +540,7 @@ def import_and_register_structures(self, nodes=None):
         If no no node is given, attemps to import variables from all nodes under
         "0:OPC Binary"
         the code is generated and imported on the fly. If you know the structures
-        are not going to be modified it is safer to copy the generated files
+        are not going to be modified it might be interresting to copy the generated files
         and include them in you code
         """
         if nodes is None:
@@ -549,22 +549,29 @@ def import_and_register_structures(self, nodes=None):
                 if desc.BrowseName != ua.QualifiedName("Opc.Ua"):
                     nodes.append(self.get_node(desc.NodeId))
         self.logger.info("Importing structures from nodes: %s", nodes)
-
+        
+        structs_dict = {}
         for node in nodes:
             xml = node.get_value()
             xml = xml.decode("utf-8")
-            #with open("titi.xml", "w") as f:
-                #f.write(xml)
             name = "structures_" + node.get_browse_name().Name
             gen = StructGenerator()
             gen.make_model_from_string(xml)
-            structs_dict = gen.save_and_import(name + ".py")
-            # register classes
-            for desc in node.get_children_descriptions():
-                if desc.BrowseName.Name in structs_dict:
-                    self.logger.info("registring new structure: %: %s", desc.NodeId, desc.BrowseName.Name)
-                    ua.extension_object_classes[desc.NodeId] = structs_dict[desc.BrowseName.Name]
-                    ua.extension_object_ids[desc.BrowseName.Name] = desc.NodeId
+            gen.save_and_import(name + ".py", append_to=structs_dict)
+
+        # register classes
+        for desc in self.nodes.base_structure_type.get_children_descriptions():
+            # FIXME: maybe we should look recursively at children
+            # FIXME: we should get enoding and description but this is too 
+            # expensive. we take a shorcut and assume that browsename of struct 
+            # is the same as the name of the data type structure
+            if desc.BrowseName.Name in structs_dict:
+                struct_node = self.get_node(desc.NodeId)
+                refs = struct_node.get_references(ua.ObjectIds.HasEncoding, ua.BrowseDirection.Forward)
+                for ref in refs:
+                    if "Binary" in ref.BrowseName.Name:
+                        ua.register_extension_object(desc.BrowseName.Name, ref.NodeId, structs_dict[desc.BrowseName.Name])
+
 
 
 

opcua/common/shortcuts.py

@@ -25,3 +25,4 @@ def __init__(self, server):
         self.object_types = Node(server, ObjectIds.ObjectTypesFolder)
         self.namespace_array = Node(server, ObjectIds.Server_NamespaceArray)
         self.opc_binary = Node(server, ObjectIds.OPCBinarySchema_TypeSystem)
+        self.base_structure_type = Node(server, ObjectIds.Structure)

opcua/common/structures_generator.py

@@ -166,13 +166,23 @@ def save_to_file(self, path):
             _file.write(struct.get_code())
         _file.close()
 
-    def save_and_import(self, path):
+    def save_and_import(self, path, append_to=None):
+        """
+        save the new structures to a python file which be used later
+        import the result and return resulting classes in a dict
+        if append_to is a dict, the classes are added to the dict
+        """
         self.save_to_file(path)
         name = os.path.basename(path)
         name = os.path.splitext(name)[0]
         mymodule = importlib.import_module(name)
-        mydict = {struct.name: getattr(mymodule, struct.name) for struct in self.model}
-        return mydict
+        if append_to is None:
+            result = {}
+        else:
+            result = append_to
+        for struct in self.model:
+            result[struct.name] = getattr(mymodule, struct.name)
+        return result
 
     def get_structures(self):
         ld = {}

opcua/ua/ua_binary.py

@@ -264,7 +264,7 @@ def pack_uatype(vtype, value):
         # dependency loop: classes in uaprotocol_auto use Variant defined in this file,
         # but Variant can contain any object from uaprotocol_auto as ExtensionObject.
         # Using local import to avoid import loop
-        from opcua.ua.uaprotocol_auto import extensionobject_to_binary
+        from opcua.ua import extensionobject_to_binary
         return extensionobject_to_binary(value)
     else:
         try:
@@ -283,7 +283,7 @@ def unpack_uatype(vtype, data):
         # dependency loop: classes in uaprotocol_auto use Variant defined in this file,
         # but Variant can contain any object from uaprotocol_auto as ExtensionObject.
         # Using local import to avoid import loop
-        from opcua.ua.uaprotocol_auto import extensionobject_from_binary
+        from opcua.ua import extensionobject_from_binary
         return extensionobject_from_binary(data)
     else:
         from opcua.ua import uatypes

opcua/ua/uatypes.py

@@ -1,8 +1,10 @@
 """
 implement ua datatypes
 """
+
+import logging
 import struct
-from enum import Enum, IntEnum, EnumMeta
+from enum import Enum, IntEnum
 from datetime import datetime
 import sys
 import os
@@ -19,6 +21,9 @@
 from opcua.common.utils import Buffer
 
 
+logger = logging.getLogger(__name__)
+
+
 if sys.version_info.major > 2:
     unicode = str
 def get_win_epoch():
@@ -1106,12 +1111,20 @@ def get_default_value(vtype):
 extension_object_ids = {}
 
 
+def register_extension_object(name, nodeid, class_type):
+    """
+    """
+    logger.warning("registring new extension object: %s %s %s", name, nodeid, class_type)
+    extension_object_classes[nodeid] = class_type
+    extension_object_ids[name] = nodeid
+
+
 def extensionobject_from_binary(data):
     """
     Convert binary-coded ExtensionObject to a Python object.
     Returns an object, or None if TypeId is zero
     """
-    TypeId = NodeId.from_binary(data)
+    typeid = NodeId.from_binary(data)
     Encoding = ord(data.read(1))
     body = None
     if Encoding & (1 << 0):
@@ -1121,16 +1134,16 @@ def extensionobject_from_binary(data):
         else:
             body = data.copy(length)
             data.skip(length)
-    if TypeId.Identifier == 0:
+    if typeid.Identifier == 0:
         return None
-    elif TypeId in extension_object_classes:
-        klass = extension_object_classes[TypeId]
+    elif typeid in extension_object_classes:
+        klass = extension_object_classes[typeid]
         if body is None:
             raise UaError("parsing ExtensionObject {0} without data".format(klass.__name__))
         return klass.from_binary(body)
     else:
         e = ExtensionObject()
-        e.TypeId = TypeId
+        e.TypeId = typeid
         e.Encoding = Encoding
         if body is not None:
             e.Body = body.read(len(body))