optimize detection of xml-data

document.py

@@ -1041,6 +1041,30 @@ class Incoming(metaclass=PoolMeta):
                 msg='cannot convert %(val)s' % {
                     'val': date_string}))
 
+    def _facturx_get_level(self, xml_data):
+        """ detect level and flavour of factur-x file,
+
+        Args:
+            xml_data (xml-tree): xml-tree
+
+        Raises:
+            UserError: if unexpected error message from facturx
+
+        Returns:
+            tuple: (flavour, level)
+        """
+        try:
+            fx_flavour = facturx.get_flavor(xml_data)
+            fx_level = facturx.get_level(xml_data)
+        except ValueError as e1:
+            fx_flavour = fx_level = None
+            if not str(e1).startswith(
+                    'This XML is not a Factur-X nor Order-X XML'):
+                raise UserError(gettext(
+                    'document_incoming_invoice_xml.msg_convert_error',
+                    msg=str(e1)))
+        return (fx_flavour, fx_level)
+
     def _facturx_detect_content(self):
         """ check xml-data against xsd of XRechnung and FacturX,
             begin with extended, goto minimal, then xrechnung
@@ -1066,14 +1090,18 @@ class Incoming(metaclass=PoolMeta):
                 msg='content-type "%(mime)s" not supported' % {
                     'mime': self.mime_type}))
 
-        fx_flavour = facturx.get_flavor(xml_data)
+        (fx_flavour, fx_level) = self._facturx_get_level(xml_data)
-        fx_level = facturx.get_level(xml_data)
-
         for xsdpath, xsdtype, funcname in xml_types:
+            # skip factur-x validation if library was not able to detect
+            # level and flavour of xml-file
+            if xsdtype.lower().startswith('factur-x') and (
+                    not fx_flavour) and (not fx_level):
+                continue
+
+            # fast forward to known xml-type
             if fx_flavour == 'factur-x' and fx_level:
                 if not (xsdtype.lower().startswith('factur-x') and
                         xsdtype.lower().endswith(fx_level)):
-                    # skip check if xml-content is already known
                     continue
 
             fname = os.path.join(*[os.path.split(__file__)[0]] + xsdpath)