Enhancing session management with Redis hashes

[mortensi]

Session management could be improved by modeling it as a hash as Spring does. This would reduce serialization/deserialization overheads and benefit from the latest hash-field expiration improvements in Redis 7.4. I would like to understand how to enhance flask-session to support the hash data model (while keeping backward compatibility with the current string format). So, as a summary, we would like to introduce:

• searchable sessions
• ability to find sessions open for a user (different devices)
• expiring data in the session before the session expires (may be useful to model those use cases where "you have 10 minutes" to complete a reservation or anything similar)
• analytics from anonymous sessions or authenticated sessions
• find sessions in a geographical area, or find sessions that are close to a location (e.g. in retail, sessions that are close to a shop)
• reduce the overhead to serialize or deserialize the entire session by just accessing the desired data
• ...

Any suggestion is welcome!