In order to persist my access and refresh tokens, I needed a store. I think
using a database like SQLite may have been fine for this but was heavier weight
than what I wanted.
I decided to write a simple key-value store when the state is encoded and JSON
in a file called kv.json.
TODO:
- Support field nesting
- Support better error handling
- Support parameterizing the store path (i.e. ./kv.json)
