parse unknown message IDs

.vscode/settings.json

@@ -4,5 +4,5 @@
     "editor.formatOnSave": true,
     "modulename": "${workspaceFolderBasename}",
     "distname": "${workspaceFolderBasename}",
-    "moduleversion": "1.0.40",
+    "moduleversion": "1.0.41",
 }

README.md

@@ -126,7 +126,7 @@ with open('nmeadata.log', 'rb') as stream:
     print(parsed_data)
 ```
 
-Example - Socket input (using iterator):
+* Socket input (using iterator):
 
 ```python
 import socket
@@ -186,6 +186,18 @@ print(latlon2dmm((msg.lat, msg.lon)))
 ('52°37.2378′N', '2°9.6072′W')
 ```
 
+If the NMEA sentence type is unrecognised or not yet implemented (*e.g. due to definition not yet being in the public domain*) and the `VALMSGID` validation flag is *NOT* set,
+ `NMEAMessage` will parse the message to a NOMINAL structure e.g.:
+
+```python
+from pynmeagps import NMEAReader, VALCKSUM
+msg = NMEAReader.parse('$GNACN,103607.00,ECN,E,A,W,A,test,C*67\r\n', validate=VALCKSUM)
+print(msg)
+```
+```
+<NMEA(GNACN, NOMINAL, field_01=103607.00, field_02=ECN, field_03=E, field_04=A, field_05=W, field_06=A, field_07=test, field_08=C)>
+```
+
 ---
 ## <a name="generating">Generating</a>
 
@@ -195,9 +207,9 @@ class pynmeagps.nmeamessage.NMEAMessage(talker: str, msgID: str, msgmode: int, *
 
 You can create an `NMEAMessage` object by calling the constructor with the following parameters:
 1. talker (must be a valid talker from `pynmeagps.NMEA_TALKERS`)
-1. message id (must be a valid id from `pynmeagps.NMEA_MSGIDS` or `pynmeagps.NMEA_MSGIDS_PROP`)
-2. msgmode (0=GET, 1=SET, 2=POLL)
-3. (optional) a series of keyword parameters representing the message payload
+2. message id (must be a valid id from `pynmeagps.NMEA_MSGIDS` or `pynmeagps.NMEA_MSGIDS_PROP`)
+3. msgmode (0=GET, 1=SET, 2=POLL)
+4. (optional) a series of keyword parameters representing the message payload
 
 The 'msgmode' parameter signifies whether the message payload refers to a:
 

RELEASE_NOTES.md

@@ -1,8 +1,42 @@
 # pynmeagps Release Notes
 
+### RELEASE 1.0.41
+
+ENHANCEMENTS:
+
+1. Enhance NMEAMessage to parse unrecognised* NMEA sentence types to a nominal `<NMEA(TTXXX, NOMINAL, field_01=x...)>` message structure if `VALMSGID` validation flag is *not* set, rather than raise a `NMEAParseMessage` error e.g.:
+
+   A. with the `VALMSGID` flag *not* set (*the new default behaviour*):
+
+   ```shell
+   from pynmeagps import NMEAReader
+   msg = NMEAReader.parse("$GNACN,103607.00,ECN,E,A,W,A,test,C*67\r\n")
+   print(msg)
+   ```
+   ```
+   <NMEA(GNACN, NOMINAL, field_01=103607.00, field_02=ECN, field_03=E, field_04=A, field_05=W, field_06=A, field_07=test, field_08=C)>
+   ```
+
+   B. with the `VALMSGID flag` set:
+
+   ```shell
+   from pynmeagps import NMEAReader, VALMSGID
+   msg = NMEAReader.parse("$GNACN,103607.00,ECN,E,A,W,A,test,C*67\r\n", validate=VALMSGID)
+   print(msg)
+   ```
+   ```
+   pynmeagps.exceptions.NMEAParseError: Unknown msgID GNACN, msgmode GET.
+   ```
+
+   \* unrecognised message types include those with unknown or invalid NMEA msgIDs (*but valid payloads and checksums*), or valid NMEA sentences whose payload definitions are not yet in the public domain (e.g. those currently commented-out in [`NMEA_MSGIDS`](https://github.com/semuconsulting/pynmeagps/blob/master/src/pynmeagps/nmeatypes_core.py#L207)).
+
+1. Add NMEA ALF sentence definition.
+1. Add `validate` argument to `NMEAMessage` and carry forward from `NMEAReader`
+1. Add logger to `NMEAMessage`.
+
 ### RELEASE 1.0.40
 
-CHANGES:
+ENHANCEMENTS:
 
 1. Add area() helper method to calculate spherical area of bounding box.
 1. Sphinx documentation and docstrings enhanced to include global constants and decodes.

pyproject.toml

@@ -7,7 +7,7 @@ name = "pynmeagps"
 authors = [{ name = "semuadmin", email = "[email protected]" }]
 maintainers = [{ name = "semuadmin", email = "[email protected]" }]
 description = "NMEA protocol parser and generator"
-version = "1.0.40"
+version = "1.0.41"
 license = { file = "LICENSE" }
 readme = "README.md"
 requires-python = ">=3.8"

src/pynmeagps/_version.py

@@ -8,4 +8,4 @@
 :license: BSD 3-Clause
 """
 
-__version__ = "1.0.40"
+__version__ = "1.0.41"

src/pynmeagps/nmeamessage.py

@@ -12,6 +12,7 @@
 
 import struct
 from datetime import datetime, timezone
+from logging import getLogger
 
 import pynmeagps.exceptions as nme
 import pynmeagps.nmeatypes_core as nmt
@@ -33,7 +34,13 @@ class NMEAMessage:
     """NMEA GNSS/GPS Message Class."""
 
     def __init__(
-        self, talker: str, msgID: str, msgmode: int, hpnmeamode: bool = False, **kwargs
+        self,
+        talker: str,
+        msgID: str,
+        msgmode: int,
+        hpnmeamode: bool = False,
+        validate: int = nmt.VALCKSUM,
+        **kwargs,
     ):
         """Constructor.
 
@@ -47,12 +54,16 @@ def __init__(
         :param str msgID: message ID e.g. "GGA"
         :param int msgmode: mode (0=GET, 1=SET, 2=POLL)
         :param bool hpnmeamode: high precision lat/lon mode (7dp rather than 5dp) (False)
+        :param int validate: validation flags - VALNONE (0), VALCKSUM (1), VALMSGID (2) (1)
         :param kwargs: keyword arg(s) representing all or some payload attributes
         :raises: NMEAMessageError
         """
 
         # object is mutable during initialisation only
         super().__setattr__("_immutable", False)
+        self._logger = getLogger(__name__)
+        self._validate = validate
+        self._nominal = False  # flag for unrecognised NMEA sentence types
 
         if msgmode not in (0, 1, 2):
             raise nme.NMEAMessageError(
@@ -65,9 +76,10 @@ def __init__(
             and msgID not in (nmt.NMEA_MSGIDS_PROP)
             and msgID not in (nmt.PROP_MSGIDS)
         ):
-            raise nme.NMEAMessageError(
-                f"Unknown msgID {talker}{msgID}, msgmode {('GET','SET','POLL')[msgmode]}."
-            )
+            if self._validate & nmt.VALMSGID:
+                raise nme.NMEAMessageError(
+                    f"Unknown msgID {talker}{msgID}, msgmode {('GET','SET','POLL')[msgmode]}."
+                )
 
         self._mode = msgmode
         # high precision NMEA mode returns NMEA lat/lon to 7dp rather than 5dp
@@ -93,6 +105,10 @@ def _do_attributes(self, **kwargs):
             self._payload = kwargs.get("payload", [])
             self._checksum = kwargs.get("checksum", None)
             pdict = self._get_dict(**kwargs)  # get payload definition dict
+            if pdict is None:  # definition not yet implemented
+                if "payload" in kwargs:
+                    self._set_attribute_nominal(kwargs["payload"])
+                return
             for key in pdict.keys():  # process each attribute in dict
                 (pindex, gindex) = self._set_attribute(
                     pindex, pdict, key, gindex, **kwargs
@@ -238,6 +254,17 @@ def _set_attribute_single(
 
         return pindex
 
+    def _set_attribute_nominal(self, payload: list):
+        """
+        Set nominal attributes for unrecognised NMEA sentence types.
+
+        :param list payload: payload as list
+        """
+
+        self._nominal = True
+        for i, fld in enumerate(payload):
+            setattr(self, f"field_{i+1:02d}", fld)
+
     def _get_dict(self, **kwargs) -> dict:
         """
         Get payload dictionary.
@@ -268,9 +295,10 @@ def _get_dict(self, **kwargs) -> dict:
                 return nms.NMEA_PAYLOADS_SET[key]
             return nmg.NMEA_PAYLOADS_GET[key]
         except KeyError as err:
-            raise nme.NMEAMessageError(
-                f"Unknown msgID {key} msgmode {('GET', 'SET', 'POLL')[self._mode]}."
-            ) from err
+            erm = f"Unknown msgID {key} msgmode {('GET', 'SET', 'POLL')[self._mode]}."
+            if self._validate & nmt.VALMSGID:
+                raise nme.NMEAMessageError(erm) from err
+            return None  # message not yet implemented
 
     def _calc_num_repeats(
         self, attd: dict, payload: list, pindex: int, pindexend: int = 0
@@ -300,6 +328,8 @@ def __str__(self) -> str:
 
         stg = f"<NMEA({self.identity}"
         stg += ", "
+        if self._nominal:
+            stg += "NOMINAL, "
         for i, att in enumerate(self.__dict__):
             if att[0] != "_":  # only show public attributes
                 val = self.__dict__[att]

src/pynmeagps/nmeareader.py

@@ -250,10 +250,15 @@ def parse(
                         f" - should be {ccksum}."
                     )
             return NMEAMessage(
-                talker, msgid, msgmode, payload=payload, checksum=checksum
+                talker,
+                msgid,
+                msgmode,
+                payload=payload,
+                checksum=checksum,
+                validate=validate,
             )
 
         except nme.NMEAMessageError as err:
-            if not validate & VALMSGID:
-                return None
-            raise nme.NMEAParseError(err)
+            if validate & VALMSGID:
+                raise nme.NMEAParseError(err)
+            return None