[Feature Request] Add Context methods to get and set db

[ccollie]

pub fn selected_db(&self) -> i32 {
    unsafe { RedisModule_GetSelectedDb.unwrap()(self.ctx) }
}

pub fn select_db(&mut self, db: i32) -> Status {
    unsafe {
        match RedisModule_SelectDb.unwrap()(self.ctx, db) {
            0 => Status::Ok,
            _ => Status::Err,
        }
    }
}

[dmitrypol]

thanks for the PR. Could you provide a use case where this could be used?

[ccollie]

I'm developing a module which supports multiple dbs through a struct which manages per-db metadata. When I create an object, I need to add metadata to the specific db in which it is created. Similarly when an object is removed, the metadata needs to be cleaned up.

This segregation is necessary to support db specific indexing as well as the SWAPDB command.

These methods allow us to conveniently access the current db from command handlers, since that info is only available through Context

[ccollie]

See https://github.com/ccollie/valkey-timeseries/blob/main/src/series/index/mod.rs for my use-case. Pay attention to with_timeseries_index() and with_matched_series()