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)
encoding = ord(data.read(1))
body = None
if encoding & (1 << 0):
length = Primitives.Int32.unpack(data)
if length < 1:
body = Buffer(b"")
else:
body = data.copy(length)
data.skip(length)
if typeid.Identifier == 0:
return ua.ExtensionObject()
if typeid in ua.extension_objects_by_typeid:
cls = ua.extension_objects_by_typeid[typeid]
if body is None:
raise UaError(f'parsing ExtensionObject {cls.__name__} without data')
return from_binary(cls, body)
e = ua.ExtensionObject()
e.TypeId = typeid
e.Encoding = encoding
if body is not None:
e.Body = body.read(len(body))
return e
def test_unknown_extension_object():
obj = ua.ExtensionObject()
obj.Body = b'example of data in custom format'
obj.TypeId = ua.NodeId.from_string('ns=3;i=42')
data = ua.utils.Buffer(extensionobject_to_binary(obj))
obj2 = extensionobject_from_binary(data)
assert type(obj2) == ua.ExtensionObject
assert obj2.TypeId == obj.TypeId
assert obj2.Body == b'example of data in custom format'
def test_empty_extension_object():
obj = ua.ExtensionObject()
obj2 = extensionobject_from_binary(
ua.utils.Buffer(extensionobject_to_binary(obj)))
assert type(obj) == type(obj2)
assert obj == obj2
