Struct TokenStoreFn 

pub struct TokenStoreFn<L, S> { /* private fields */ }

TokenStore backed by user-supplied load and save async closures.

This is the persistence layer primitive — it plugs into an existing strategy (e.g. AccessKeyStrategy) so that strategy can share its service-token cache across processes. For wiring in a complete acquisition pipeline (e.g. a JS-defined strategy across an FFI boundary), use AuthStrategyFn instead.

Closures deal in JSON strings — the on-the-wire form of Token — not the Token type itself. This keeps the caller’s signatures free of stack-auth internals and matches the natural shape of common storage substrates: a cookie value, a KV blob, a Redis string.

The closure return types are generic so async blocks / async || closures / async fn adapters all compose without boxing.

Secret-material handling. The JSON string passed to the save closure contains the bearer token verbatim (via SecretToken’s #[serde(transparent)] impl). Once the value crosses into the user’s closure, stack-auth has no control over zeroize semantics — implementations should treat the input as secret material and clear any local copies promptly. load wraps the returned string in Zeroizing internally, so the buffer is wiped after deserialisation. End-to-end protection at rest (e.g. encrypting the value before it ever leaves the worker) is tracked as a future EncryptedTokenStore decorator.

Implementations

impl<L, S> TokenStoreFn<L, S>

pub fn new(load: L, save: S) -> Self

Build a token store from a load closure (returns the stored JSON, or None if nothing is cached) and a save closure (persists the JSON).

See the module-level documentation for an example.

Trait Implementations

impl<L, LF, S, SF> TokenStore for TokenStoreFn<L, S>

where L: Fn() -> LF + Send + Sync, LF: Future<Output = Option<String>> + Send, S: Fn(String) -> SF + Send + Sync, SF: Future<Output = ()> + Send,

Available on non-WebAssembly only.

async fn load(&self) -> Option<Token>

Load the most recently saved token, or None if none has been stored (or the load failed). Errors are swallowed — the calling state machine falls back to fresh authentication when this returns None.

async fn save(&self, token: &Token)

Persist a token after a successful refresh or initial authentication. Best-effort — implementations should log on failure rather than returning an error.