'SPARTNMessage' object has no attribute 'authInd'

[tammoweb]

Hi,
I'm trying to receive the PointPerfect data stream via NTRIP and parse it with SPARTNReader in real time.
Receiving works but the error messages "Unknown protocol b'\xa5'" and "'SPARTNMessage' object has no attribute 'authInd'" appear alternately when i try to print the parsed data.

Error:
Unknown protocol b'\xf1'
Unknown protocol b'\x88'
'SPARTNMessage' object has no attribute 'authInd'
Unknown protocol b'A'
Unknown protocol b','
Unknown protocol b'Y'
Unknown protocol b'\x05'
Unknown protocol b'_'
Unknown protocol b'\xe3'
Unknown protocol b'\x80'
Unknown protocol b'\xac'
Unknown protocol b'\xf1'
Unknown protocol b'\xca'
Unknown protocol b'='
Unknown protocol b'\x9d'
Unknown protocol b'\x06'
Unknown protocol b'p'
Unknown protocol b'`'
Unknown protocol b'\xe3'
Unknown protocol b'\xb6'
'SPARTNMessage' object has no attribute 'authInd'

`
self._socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

try:

	while True:

		key = "930d847b779b126863c8b3b2766ae7cc"
		basedate = 451169309

		try:
			spr = SPARTNReader(self._socket, decode=True, key=key, basedate=basedate)
			for _, parsed in spr:
				print(parsed)

		except Exception as e:
			print(e)
			continue

`

[semuadmin]

Hi @tammoweb ,

It's not clear from the code snippet above how you're accessing the NTRIP service, but a few observations...

1. In order to properly receive NTRIP data from a caster, you need to use an NTRIP client - simply streaming from a socket won't necessarily work. Proprietary NTRIP services typically require a userid and password to access the datastream.
2. The Thingstream SPARTN NTRIP service requires a paid subscription in order to obtain the necessary NTRIP userid (aka "client-id") and password - it's not a free service.
3. Unlike their MQTT and L-Band SPARTN services, the Thingstream SPARTN NTRIP payload is not encrypted (eaf=0), so if you want to decode the payload, use decode=1 and set the key to any arbitrary hexadecimal value e.g. key=abcd1234.

Once you have the relevant login credentials and region code, try using the gnssntripclient installed with pygnssutils e.g.:

python3 -m pip install --upgrade pygnssutils
gnssntripclient --server ppntrip.services.u-blox.com --port 2102 --https 1 --mountpoint EU --datatype spartn --ntripuser your-thingstream-client-id --ntrippassword "yourthingstreampassword" --spartndecode 1 --spartnkey abcd1234 --verbosity 2

2024-09-25 11:18:34.182 - INFO - pygnssutils.gnssntripclient - Streaming spartn data from ppntrip.services.u-blox.com:2102/EU ...
2024-09-25 11:18:34.183 - INFO - pygnssutils.gnssntripclient - Message received: SPARTN-1X-OCB-GLO
2024-09-25 11:18:34.183 - INFO - pygnssutils.gnssntripclient - Message received: SPARTN-1X-OCB-BEI
2024-09-25 11:18:34.184 - INFO - pygnssutils.gnssntripclient - Message received: SPARTN-1X-OCB-GAL
2024-09-25 11:18:34.184 - INFO - pygnssutils.gnssntripclient - Message received: SPARTN-1X-OCB-GPS
... etc.

(use --verbosity 3 to see the full payload at the terminal)

To use the GNSSNTRIPClient class as part of a Python script, see the example here: https://github.com/semuconsulting/pyspartn/blob/main/examples/spartn_ntrip_client.py

[semuadmin]

As a general tip, if you want to invoke SPARTNReader within a while True loop, it's probably best to instantiate the SPARTNReader class outside the while loop and use a simple read() (rather than the iterator) within the loop - i.e. something like this...

import socket
from pyspartn import SPARTNReader

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as stream:
    stream.connect((url, port))
    parser = SPARTNReader(
        stream,
        decode=True,
        key="abcd1234",
    )

    while True:
        try:
            raw_data, parsed_data = parser.read()
            if parsed_data is not None:
                print(parsed_data)
        except Exception as err:
            print(err)
            continue

[tammoweb]

Hi @semuadmin, thanks for your quick response.

I use the read_data method as an NTRIP client. The class is assigned user, password, etc. when instantiated.

def read_data(self):

        while True:
            time.sleep(0.1)

            logging.info("Mountpoint: Main loop started.")

            caster = self.caster
            port = int(self.port)

            if caster is None or port is None:
                logging.error("Mountpoint: Caster settings incorrect!")
                sys.exit(0)

            if (self.user == "" or
                    self.password == ""):
                logging.error("Mountpoint: User and/or password are missing!")
                sys.exit(0)

            reconnectTry = 1
            maxReconnections = 1

            try:
                while reconnectTry <= maxReconnections:
                    print(self.getName(), ": NTRIP main loop")

                    found_header = False

                    self._socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

                    error_indicator = self._socket.connect_ex((caster, port))

                    if error_indicator == 0:

                        self._socket.settimeout(10)
                        self._socket.sendall(self.getMountPointBytes())

                        while not found_header: 


                            casterResponse = self._socket.recv(4096)
                            header_lines = casterResponse.decode('utf-8').split("\r\n")

                            for line in header_lines:
                                if line == "":
                                    if not found_header:
                                        found_header = True
                                else:
                                    continue

                            for line in header_lines:
                                if line.find("SOURCETABLE") >= 0:
                                    logging.warning("Mountpoint: Mountpoint does not exist!")
                                    sys.exit(0)
                                elif line.find("401 Unauthorized") >= 0:
                                    logging.warning("Mountpoint: Unauthorized request!")
                                    sys.exit(0)
                                elif line.find("404 Not found") >= 0:
                                    logging.warning("Mountpoint: Mountpoint does not exist!")
                                    sys.exit(0)
                                elif line.find("ICY 200 OK") >= 0:
                                    self._socket.sendall(self.getGGABytes())
                                elif line.find("HTTP/1.0 200 OK") >= 0:
                                    self._socket.sendall(self.getGGABytes())
                                elif line.find("HTTP/1.1 200 OK") >= 0:
                                    self._socket.sendall(self.getGGABytes())

                        try:
                            basedate = 451169309
                            key = "abcd1234"
                            parser = SPARTNReader(self._socket, decode=1, key=key, basedate=basedate)

                                    
                            while True:
                                try:  
                                    raw_data, parsed_data = parser.read()
                                    if parsed_data is not None:
                                        print(parsed_data)

                                    

                                except Exception as e:
                                    print(e)
                                    continue

                        except socket.timeout:
                            print(self.getName() + ": Exception 'socket.timeout'")
                            self._socket.close()  # See: https://docs.python.org/3/howto/sockets.html
                            time.sleep(60)
                            break
                        except socket.error:
                            print(self.getName() + ": Exception 'socket.error'")
                            self._socket.close()
                            time.sleep(60)
                            break

                    time.sleep(5)

            except KeyboardInterrupt:
                if self._socket:
                    self._socket.close()

            except Exception as e:
                print("General exception:")
                print(e)
                if self._socket:
                    self._socket.close()
                    time.sleep(60)
                continue

            if self._socket:
                self._socket.close()

            time.sleep(5)

Your tip with instantiation outside the loop solved the "Unknown protocol" problem. But I still get the following error message:

'SPARTNMessage' object has no attribute 'authInd'

[semuadmin]

The authInd attribute is part of the SPARTN transport layer and is only present if the payload is encrypted i.e. eaf=1. As I mention above, in the case of the ThingStream PointPerfect SPARTN NTRIP service the payload is NOT encrypted so SPARTNMessage.authInd will not exist. I'm unclear why the code would be attempting to access it. Are you using the latest version of pyspartn (v1.0.3)?

(very early versions of pyspartn did have a problem with NTRIP streams but this was resolved way back in v.0.2.1-alpha)