define checksum support in telegram specification; moved telegram v2 exception temporarily from parser to MBUSObject;

dsmr_parser/objects.py

@@ -12,26 +12,23 @@ class MBusObject(DSMRObject):
 
     @property
     def value(self):
+        # TODO temporary workaround for DSMR v2.2. Maybe use the same type of
+        # TODO object, but let the parse set them differently? So don't use
+        # TODO hardcoded indexes here.
+        if len(self.values) != 2:  # v2
+            return self.values[5]['value']
+        else:
             return self.values[1]['value']
 
     @property
     def unit(self):
-        return self.values[1]['unit']
+        # TODO temporary workaround for DSMR v2.2. Maybe use the same type of
-
+        # TODO object, but let the parse set them differently? So don't use
-
+        # TODO hardcoded indexes here.
-class MBusObjectV2_2(DSMRObject):
+        if len(self.values) != 2:  # v2
-
-    @property
-    def datetime(self):
-        return self.values[0]['value']
-
-    @property
-    def value(self):
-        return self.values[5]['value']
-
-    @property
-    def unit(self):
             return self.values[4]['value']
+        else:
+            return self.values[1]['unit']
 
 
 class CosemObject(DSMRObject):

dsmr_parser/parsers.py

@@ -3,7 +3,7 @@ import re
 
 from PyCRC.CRC16 import CRC16
 
-from dsmr_parser.objects import MBusObject, MBusObjectV2_2, CosemObject
+from dsmr_parser.objects import MBusObject, CosemObject
 from dsmr_parser.exceptions import ParseError, InvalidChecksumError
 
 logger = logging.getLogger(__name__)
@@ -11,14 +11,15 @@ logger = logging.getLogger(__name__)
 
 class TelegramParser(object):
 
-    def __init__(self, telegram_specification,
+    def __init__(self, telegram_specification, apply_checksum_validation=True):
-                 enable_checksum_validation=False):
         """
         :param telegram_specification: determines how the telegram is parsed
+        :param apply_checksum_validation: validate checksum if applicable for
+            telegram DSMR version (v4 and up).
         :type telegram_specification: dict
         """
         self.telegram_specification = telegram_specification
-        self.enable_checksum_validation = enable_checksum_validation
+        self.apply_checksum_validation = apply_checksum_validation
 
     def parse(self, telegram_data):
         """
@@ -32,19 +33,22 @@ class TelegramParser(object):
         :returns: Shortened example:
             {
                 ..
-                r'0-0:96\.1\.1': <CosemObject>,  # EQUIPMENT_IDENTIFIER
+                r'\d-\d:96\.1\.1.+?\r\n': <CosemObject>,  # EQUIPMENT_IDENTIFIER
-                r'1-0:1\.8\.1': <CosemObject>,   # ELECTRICITY_USED_TARIFF_1
+                r'\d-\d:1\.8\.1.+?\r\n': <CosemObject>,   # ELECTRICITY_USED_TARIFF_1
-                r'0-\d:24\.3\.0': <MBusObject>,  # GAS_METER_READING
+                r'\d-\d:24\.3\.0.+?\r\n.+?\r\n': <MBusObject>,  # GAS_METER_READING
                 ..
             }
+        :raises ParseError:
+        :raises InvalidChecksumError:
         """
 
-        if self.enable_checksum_validation:
+        if self.apply_checksum_validation \
+                and self.telegram_specification['checksum_support']:
             self.validate_checksum(telegram_data)
 
         telegram = {}
 
-        for signature, parser in self.telegram_specification.items():
+        for signature, parser in self.telegram_specification['objects'].items():
             match = re.search(signature, telegram_data, re.DOTALL)
 
             if match:
@@ -124,11 +128,7 @@ class MBusParser(DSMRObjectParser):
     """
 
     def parse(self, line):
-        values = self._parse(line)
+        return MBusObject(self._parse(line))
-        if len(values) == 2:
-            return MBusObject(values)
-        else:
-            return MBusObjectV2_2(values)
 
 
 class CosemParser(DSMRObjectParser):

dsmr_parser/telegram_specifications.py

@@ -14,6 +14,8 @@ how the telegram lines are parsed.
 """
 
 V2_2 = {
+    'checksum_support': False,
+    'objects': {
         obis.EQUIPMENT_IDENTIFIER: CosemParser(ValueParser(str)),
         obis.ELECTRICITY_USED_TARIFF_1: CosemParser(ValueParser(Decimal)),
         obis.ELECTRICITY_USED_TARIFF_2: CosemParser(ValueParser(Decimal)),
@@ -38,8 +40,11 @@ V2_2 = {
             ValueParser(Decimal),
         ),
     }
+}
 
 V4 = {
+    'checksum_support': True,
+    'objects': {
         obis.P1_MESSAGE_HEADER: CosemParser(ValueParser(str)),
         obis.P1_MESSAGE_TIMESTAMP: CosemParser(ValueParser(timestamp)),
         obis.ELECTRICITY_USED_TARIFF_1: CosemParser(ValueParser(Decimal)),
@@ -71,3 +76,4 @@ V4 = {
         obis.HOURLY_GAS_METER_READING: MBusParser(ValueParser(timestamp),
                                                   ValueParser(Decimal))
     }
+}

test/test_parse_v4_2.py

@@ -15,28 +15,6 @@ from test.example_telegrams import TELEGRAM_V4_2
 class TelegramParserV4_2Test(unittest.TestCase):
     """ Test parsing of a DSMR v4.2 telegram. """
 
-    def test_valid(self):
-        # No exception is raised.
-        TelegramParser.validate_checksum(TELEGRAM_V4_2)
-
-    def test_invalid(self):
-        # Remove the electricty used data value. This causes the checksum to
-        # not match anymore.
-        corrupted_telegram = TELEGRAM_V4_2.replace(
-            '1-0:1.8.1(001581.123*kWh)\r\n',
-            ''
-        )
-
-        with self.assertRaises(InvalidChecksumError):
-            TelegramParser.validate_checksum(corrupted_telegram)
-
-    def test_missing_checksum(self):
-        # Remove the checksum value causing a ParseError.
-        corrupted_telegram = TELEGRAM_V4_2.replace('!6796\r\n', '')
-
-        with self.assertRaises(ParseError):
-            TelegramParser.validate_checksum(corrupted_telegram)
-
     def test_parse(self):
         parser = TelegramParser(telegram_specifications.V4)
         result = parser.parse(TELEGRAM_V4_2)
@@ -219,3 +197,25 @@ class TelegramParserV4_2Test(unittest.TestCase):
 
         # VALVE_POSITION_GAS (0-x:24.4.0)
         # TODO to be implemented
+
+    def test_checksum_valid(self):
+        # No exception is raised.
+        TelegramParser.validate_checksum(TELEGRAM_V4_2)
+
+    def test_checksum_invalid(self):
+        # Remove the electricty used data value. This causes the checksum to
+        # not match anymore.
+        corrupted_telegram = TELEGRAM_V4_2.replace(
+            '1-0:1.8.1(001581.123*kWh)\r\n',
+            ''
+        )
+
+        with self.assertRaises(InvalidChecksumError):
+            TelegramParser.validate_checksum(corrupted_telegram)
+
+    def test_checksum_missing(self):
+        # Remove the checksum value causing a ParseError.
+        corrupted_telegram = TELEGRAM_V4_2.replace('!6796\r\n', '')
+
+        with self.assertRaises(ParseError):
+            TelegramParser.validate_checksum(corrupted_telegram)