BLE file like data transfer

Hi All,

We have a BSOM device that collects data points and saves them to an SD using Ricks Async Publish library, which then publishes the event if the device is connected to the cloud.

I am now looking to implement some functionality that would allow a user to connect to the BSOM via bluetooth and download this data from the SD card, then publish to our cloud via our phone app. (EDIT: Functionality only for cases where cellular signal is not available/reliable)

My initial thoughts are that I would have to modify the Async Publish library to also try to send the data via bluetooth. The only way I can think of doing this is to create a characteristic on the BSOM that starts notifying on request from the phone BLE, and the phone app just concatenates the data into a csv for upload.

Does anyone have any high level advice of the best way to approach this problem?