Python FIT SDK returns developer fields keyed by ordinal — is this intentional?

For better or worse this is a gap in the documentation. The "key" is added to the corresponding field_description_mesg. Each CIQ data field decides on their own values for the field_definition_number. Most will start at 0 or 1. So it is a combination of the field_definition_number and the developer_id that makes a unique fingerprint. The decoder tracks these unique fingerprints, the key, and uses the key to id the values.

The decoder returns the lists of developer_data_id and field_description mesgs, so that information is provided. The key that you see in the messages can be used to look up the field_description mesg. The developer_data_index in the field_description can be used to lookup the developer_data_id. 

There are are a few hops that need to be done, but it keeps the mesgs themselves from being bloated.

This is an example of a the key in a field_description mesg. The key is not an index, so you will need to search the field_description mesgs for a match. 

We will add this to the docs by the end of the quarter.

Hi Ben,

Thanks for the explanation!

Here's the Python code I implemented using the Garmin FIT SDK to resolve developer fields in case it's helpful to others: https://gist.github.com/mvilanova/461558f09c26612812f66a5c8d94d3e4

The key insight is using the mesg_listener callback to capture field_description messages and build a key-to-name mapping before other messages are processed.

Let me know if you have any feedback.

Thanks,

Marc