xmlexport improve compat with xml schema (#380)

* xmlexport improve compat with xml schema

* revert changes to _extobj_to_etree, do fix argument member order in other pr

Author: bitkeeper

opcua/common/xmlexporter.py

@@ -236,6 +236,7 @@ def add_etree_variable(self, node):
         Add a UA variable element to the XML etree
         """
         var_el = self._add_node_common("UAVariable", node)
+        self._add_ref_els(var_el, node)
         self.add_variable_common(node, var_el)
 
         accesslevel = node.get_attribute(ua.AttributeIds.AccessLevel).Value.Value
@@ -254,7 +255,6 @@ def add_etree_variable(self, node):
         var = node.get_attribute(ua.AttributeIds.Historizing)
         if var.Value.Value:
             var_el.attrib["Historizing"] = 'true'
-        self._add_ref_els(var_el, node)
 
     def add_etree_variable_type(self, node):
         """
@@ -313,7 +313,8 @@ def _add_alias_els(self):
             ref_el = Et.SubElement(aliases_el, 'Alias', Alias=name)
             ref_el.text = nodeid.to_string()
 
-        self.etree.getroot().insert(0, aliases_el)
+        # insert behind the namespace element
+        self.etree.getroot().insert(1, aliases_el)
 
     def _add_ref_els(self, parent_el, obj):
         refs = obj.get_references()
@@ -351,6 +352,8 @@ def _val_to_etree(self, el, dtype, val):
         elif dtype == ua.NodeId(ua.ObjectIds.Guid):
             id_el = Et.SubElement(el, "uax:String")
             id_el.text = str(val)
+        elif dtype == ua.NodeId(ua.ObjectIds.Boolean):
+            el.text = 'true' if val else 'false'
         elif not hasattr(val, "ua_types"):
             if isinstance(val, bytes):
                 el.text = val.decode("utf-8")
@@ -392,7 +395,7 @@ def _value_to_etree(self, el, type_name, dtype, val):
             if dtype_base.NamespaceIndex == 0 and dtype_base.Identifier <= 21:
                 type_name = ua.ObjectIdNames[dtype_base.Identifier]
                 val_el = Et.SubElement(el, "uax:" + type_name)
-                self._val_to_etree(val_el, dtype, val)
+                self._val_to_etree(val_el, dtype_base, val)
             else:
                 self._extobj_to_etree(el, type_name, dtype, val)