Garmin FIT files - The Garmin SDK

So I took the plunge on 7-16-2023 and downloaded version 21.115 of their SDK, release date June 20, 2023.

-rw-r--r-- 1 tom tom    9964330 Jul 16 17:42  FitSDKRelease_21.115.00.zip

The "C" subdirectory has an "examples directory with encode.c and decode.c. The code is provided along with Visual Studio "accessory files". It could be interesting (as an experiment) to copy the decode.c and the various support files into a directory and try to work up a Makefile to build it under linux and see how that develops.

It turned out to be a 5 minute job with no surprises:

# 7-16-2023
# Tom Trebisky

# Makefile for the Garmin SDK decode.c example under linux

OBJS = decode.o fit_convert.o fit_crc.o fit.o fit_example.o

decode:	$(OBJS)
	cc -o decode $(OBJS)

fit_product.c
fit_ram.c

 ./decode
usage: decode.exe 
./decode /home/tom/c.fit
Testing file conversion using /home/tom/c.fit file...
File is not FIT.

Digging a bit deeper, I see that two calls are made to FitConvert_Read
They return:

0 -- FIT_CONVERT_CONTINUE
5 -- FIT_CONVERT_DATA_TYPE_NOT_SUPPORTED

What about the Python code?

The file "decoder.py" has an entry point "read()" in the Decoder class.
Anyway, let's just try this before spending any time with possible buggy code:
I create the file "tom" in the "py" directory as follows:

#!/bin/python

from garmin_fit_sdk import Decoder, Stream

#path = "Activity.fit"
path = "/home/tom/c.fit"

stream = Stream.from_file(path)
decoder = Decoder(stream)
messages, errors = decoder.read()

print(errors)
print(messages)

Looking at decoder.py, this is nice clean code, well written, and a pleasure to look through.
I add to the above demo program:

!/bin/python

from garmin_fit_sdk import Decoder, Stream

path = "/home/tom/c.fit"

stream = Stream.from_file(path)
decoder = Decoder(stream)
messages, errors = decoder.read()

# list
ne = len(errors)
# hash
nm = len(messages)

print ( f"{ne} errors" )
print ( f"{nm} messages" )

print ( messages.keys())
# dict_keys(['file_id_mesgs', 'file_creator_mesgs', 'device_info_mesgs', 'record_mesgs', 'event_mesgs', 'lap_mesgs', 'session_mesgs', 'activity_mesgs'])

for k in messages.keys() :
    print ( f"{k} -- {len(messages[k])}" )
# file_id_mesgs -- 1
# file_creator_mesgs -- 1
# device_info_mesgs -- 1
# record_mesgs -- 1175
# event_mesgs -- 2
# lap_mesgs -- 1
# session_mesgs -- 1
# activity_mesgs -- 1

for m in messages["event_mesgs"] :
    print ( m )

rm = messages["record_mesgs"]
m = rm[0]
print ( m )

{'timestamp': datetime.datetime(2023, 7, 12, 20, 40, 30, tzinfo=datetime.timezone.utc), 'data': 0, 'event': 'timer', 'event_type': 'start', 'event_group': 0, 'timer_trigger': 'manual'}
{'timestamp': datetime.datetime(2023, 7, 13, 10, 25, 25, tzinfo=datetime.timezone.utc), 'data': 0, 'event': 'timer', 'event_type': 'stop_all', 'event_group': 0, 'timer_trigger': 'manual'}
{'timestamp': datetime.datetime(2023, 7, 12, 20, 40, 30, tzinfo=datetime.timezone.utc), 'position_lat': 378104392, 'position_long': -1322736078, 'enhanced_speed': 0.12, 'enhanced_altitude': 2211.2, 'altitude': 12607.0, 'speed': 65.535, 'temperature': 27}