Struct IdempotencyStore 

pub struct IdempotencyStore { /* private fields */ }

In-memory Idempotency-Key store. Bounded by capacity (default 10_000 entries — generous for the high-traffic banking POST case); once full, the oldest entry is evicted on insert.

Implementations

impl IdempotencyStore

pub fn new(capacity: usize, retention: Duration) -> Self

pub fn len(&self) -> usize

pub fn is_empty(&self) -> bool

pub fn hash_prefix_hex(hash: &[u8; 32]) -> String

Hex-encode the first 8 bytes of a SHA-256 digest. Enough entropy for adopter-side correlation, doesn’t leak the full hash (defense-in-depth).

pub fn hash_body(body: &[u8]) -> [u8; 32]

Compute the canonical body hash. We hash the raw bytes the client sent — adopters submitting JSON with whitespace differences will hash DIFFERENTLY, which is the safer default (the client must canonicalize on its side if it wants semantic equality). Matches Stripe’s behavior.

pub fn lookup( &mut self, key: &IdempotencyCacheKey, request_body_hash: &[u8; 32], ) -> IdempotencyVerdict

Look up a cached entry. Three-way verdict:

• Miss: no entry for this key.
• Hit(entry): entry found, body hash matches — replay.
• Conflict: entry found, body hash MISMATCH — return 422. Expired entries are evicted lazily and reported as Miss.

pub fn insert(&mut self, key: IdempotencyCacheKey, entry: IdempotencyEntry)

Insert (or overwrite) an entry. Caller is responsible for only caching successful responses (the gate in dynamic_endpoint_handler only caches 2xx — preserving the semantic that retries genuinely retry execution on failure).

pub fn reap_expired(&mut self) -> usize

Sweep expired entries. Returns the number reaped. Intended to be called periodically by a server task to bound memory.

pub fn set_retention(&mut self, retention: Duration)

Reconfigure retention (for tests + per-endpoint future tuning).

Trait Implementations

impl Debug for IdempotencyStore

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for IdempotencyStore

fn default() -> Self

Returns the “default value” for a type.