Trait CacheStore 

pub trait CacheStore:
    Send
    + Sync
    + 'static {
    // Required methods
    fn get<'life0, 'life1, 'life2, 'async_trait>(
        &'life0 self,
        namespace: &'life1 str,
        key: &'life2 str,
    ) -> Pin<Box<dyn Future<Output = Result<Option<Vec<u8>>, Error>> + Send + 'async_trait>>
       where 'life0: 'async_trait,
             'life1: 'async_trait,
             'life2: 'async_trait,
             Self: 'async_trait;
    fn set<'life0, 'life1, 'life2, 'life3, 'async_trait>(
        &'life0 self,
        namespace: &'life1 str,
        key: &'life2 str,
        value: &'life3 [u8],
        ttl: Option<Duration>,
    ) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send + 'async_trait>>
       where 'life0: 'async_trait,
             'life1: 'async_trait,
             'life2: 'async_trait,
             'life3: 'async_trait,
             Self: 'async_trait;
    fn delete<'life0, 'life1, 'life2, 'async_trait>(
        &'life0 self,
        namespace: &'life1 str,
        key: &'life2 str,
    ) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send + 'async_trait>>
       where 'life0: 'async_trait,
             'life1: 'async_trait,
             'life2: 'async_trait,
             Self: 'async_trait;
    fn clear<'life0, 'life1, 'async_trait>(
        &'life0 self,
        namespace: &'life1 str,
    ) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send + 'async_trait>>
       where 'life0: 'async_trait,
             'life1: 'async_trait,
             Self: 'async_trait;

    // Provided method
    fn entry_count<'life0, 'life1, 'async_trait>(
        &'life0 self,
        _namespace: &'life1 str,
    ) -> Pin<Box<dyn Future<Output = Result<u64, Error>> + Send + 'async_trait>>
       where 'life0: 'async_trait,
             'life1: 'async_trait,
             Self: 'async_trait { ... }
}

Backend trait for pluggable cache storage.

Keys and values are opaque strings / bytes — the typed cache wrapper in whatsapp-rust handles serialization via serde.

Namespaces

Each logical cache uses a unique namespace string (e.g., "group", "device", "lid_pn_by_lid"). Implementations should use this to partition keys — for example, a Redis implementation might prefix keys as {namespace}:{key}.

Error handling

Cache operations are best-effort. The client falls back gracefully when cache reads fail (treats as miss) and logs warnings on write failures. Implementations should still return errors for observability.

Required Methods

fn get<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, namespace: &'life1 str, key: &'life2 str, ) -> Pin<Box<dyn Future<Output = Result<Option<Vec<u8>>, Error>> + Send + 'async_trait>>

where 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait, Self: 'async_trait,

Retrieve a cached value by namespace and key.

fn set<'life0, 'life1, 'life2, 'life3, 'async_trait>( &'life0 self, namespace: &'life1 str, key: &'life2 str, value: &'life3 [u8], ttl: Option<Duration>, ) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send + 'async_trait>>

where 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait, 'life3: 'async_trait, Self: 'async_trait,

Store a value with an optional TTL.

When ttl is None, the entry should persist until explicitly deleted or evicted by the implementation’s own policy.

fn delete<'life0, 'life1, 'life2, 'async_trait>( &'life0 self, namespace: &'life1 str, key: &'life2 str, ) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send + 'async_trait>>

where 'life0: 'async_trait, 'life1: 'async_trait, 'life2: 'async_trait, Self: 'async_trait,

Delete a single key from the given namespace.

fn clear<'life0, 'life1, 'async_trait>( &'life0 self, namespace: &'life1 str, ) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send + 'async_trait>>

where 'life0: 'async_trait, 'life1: 'async_trait, Self: 'async_trait,

Delete all keys in a namespace.

Provided Methods

fn entry_count<'life0, 'life1, 'async_trait>( &'life0 self, _namespace: &'life1 str, ) -> Pin<Box<dyn Future<Output = Result<u64, Error>> + Send + 'async_trait>>

where 'life0: 'async_trait, 'life1: 'async_trait, Self: 'async_trait,

Return the approximate number of entries in a namespace.

Used only for diagnostics. Implementations that cannot cheaply report counts should return Ok(0).

Implementors