Struct SessionData 

pub struct SessionData {
    pub version: u8,
    pub auth_state: AuthState,
    pub fingerprint: Option<String>,
    pub device_id: Option<DeviceId>,
    pub custom: Value,
}

The complete session payload stored in the session store.

All authentication state is captured here in a flat, serializable form. Session data is serialized as JSON once per request, not per field access.

Schema versioning

The version field is persisted with each session. When the library evolves and SessionData gains or removes fields, bump SESSION_DATA_VERSION and add a migration step in SessionData::migrate. The session layer calls migrate automatically on load, so existing sessions are upgraded in-place without requiring a coordinated session wipe.

Fields

version: u8

Schema version of this session data. Used for forward-compatible deserialization: if a newer library version adds fields, older sessions are migrated transparently on load.

auth_state: AuthState

Authentication state of the session principal.

fingerprint: Option<String>

Fingerprint identifying the expected client for this session.

Set automatically by SessionBinding when the session first becomes authenticated. Checked on every subsequent request: a mismatch invalidates the session (possible hijacking).

device_id: Option<DeviceId>

Opaque DeviceId resolved for the request that owns this session.

None when the device subsystem is disabled (the device feature is off) or when the request was handled before the device resolver had a chance to stamp it (the very first request on a brand-new browser, before any Device row exists).

Independent of fingerprint: fingerprint is a short-lived hijack guard recomputed on every request, whereas device_id references a long-lived row in the device store that may outlive any single session.

Carried ungated so the on-the-wire shape of SessionData does not diverge across feature configurations. See docs/identity/device.md.

custom: Value

Escape hatch for application-specific data stored alongside the session.

Implementations

impl SessionData

pub fn migrate(&mut self) -> bool

Migrate session data from an older schema version to the current version.

Called automatically by the session layer on load. Each version bump should add a migration step here. Returns true if a migration was applied (session should be re-saved).

Trait Implementations

impl Clone for SessionData

fn clone(&self) -> SessionData

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SessionData

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

Formats the value using the given formatter.

impl Default for SessionData

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for SessionData

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for SessionData

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Store<SessionId, SessionData> for MysqlSessionStore

Available on crate feature mysql only.

type Error = SqlStoreError

Backend-specific error. Use the shared StoreError enum for new backends; legacy wrappers may continue to surface SqlStoreError / ValkeyStoreError / PostgresStoreError until each is consolidated.

fn get( &self, key: &SessionId, ) -> impl Future<Output = Result<Option<SessionData>, Self::Error>> + Send

Fetch the value for key. Ok(None) when the key is absent (including TTL-expired); Err only on backend failure.

fn put( &self, key: &SessionId, value: &SessionData, ttl: Duration, ) -> impl Future<Output = Result<(), Self::Error>> + Send

Insert or replace the value at key with the given TTL.

fn delete( &self, key: &SessionId, ) -> impl Future<Output = Result<(), Self::Error>> + Send

Remove the entry at key. Idempotent; does not error if absent.

fn prune_expired(&self) -> impl Future<Output = Result<u64, Self::Error>> + Send

Bulk-evict every TTL-expired entry. Returns the number reclaimed. Backends with native TTL eviction (Valkey/Redis) may implement this as a no-op returning Ok(0); backends owning their own row table (SQLite, Postgres, in-memory) actually delete.

impl Store<SessionId, SessionData> for PostgresSessionStore

Available on crate feature postgres only.

type Error = SqlStoreError

Backend-specific error. Use the shared StoreError enum for new backends; legacy wrappers may continue to surface SqlStoreError / ValkeyStoreError / PostgresStoreError until each is consolidated.

fn get( &self, key: &SessionId, ) -> impl Future<Output = Result<Option<SessionData>, Self::Error>> + Send

Fetch the value for key. Ok(None) when the key is absent (including TTL-expired); Err only on backend failure.

fn put( &self, key: &SessionId, value: &SessionData, ttl: Duration, ) -> impl Future<Output = Result<(), Self::Error>> + Send

Insert or replace the value at key with the given TTL.

fn delete( &self, key: &SessionId, ) -> impl Future<Output = Result<(), Self::Error>> + Send

Remove the entry at key. Idempotent; does not error if absent.

fn prune_expired(&self) -> impl Future<Output = Result<u64, Self::Error>> + Send

Bulk-evict every TTL-expired entry. Returns the number reclaimed. Backends with native TTL eviction (Valkey/Redis) may implement this as a no-op returning Ok(0); backends owning their own row table (SQLite, Postgres, in-memory) actually delete.

impl Store<SessionId, SessionData> for SqliteSessionStore

Available on crate feature sqlite only.

type Error = SqlStoreError

Backend-specific error. Use the shared StoreError enum for new backends; legacy wrappers may continue to surface SqlStoreError / ValkeyStoreError / PostgresStoreError until each is consolidated.

fn get( &self, key: &SessionId, ) -> impl Future<Output = Result<Option<SessionData>, Self::Error>> + Send

Fetch the value for key. Ok(None) when the key is absent (including TTL-expired); Err only on backend failure.

fn put( &self, key: &SessionId, value: &SessionData, ttl: Duration, ) -> impl Future<Output = Result<(), Self::Error>> + Send

Insert or replace the value at key with the given TTL.

fn delete( &self, key: &SessionId, ) -> impl Future<Output = Result<(), Self::Error>> + Send

Remove the entry at key. Idempotent; does not error if absent.

fn prune_expired(&self) -> impl Future<Output = Result<u64, Self::Error>> + Send

Bulk-evict every TTL-expired entry. Returns the number reclaimed. Backends with native TTL eviction (Valkey/Redis) may implement this as a no-op returning Ok(0); backends owning their own row table (SQLite, Postgres, in-memory) actually delete.

impl Store<SessionId, SessionData> for ValkeySessionStore

Available on crate feature valkey only.

type Error = ValkeyStoreError

Backend-specific error. Use the shared StoreError enum for new backends; legacy wrappers may continue to surface SqlStoreError / ValkeyStoreError / PostgresStoreError until each is consolidated.

fn get( &self, key: &SessionId, ) -> impl Future<Output = Result<Option<SessionData>, Self::Error>> + Send

Fetch the value for key. Ok(None) when the key is absent (including TTL-expired); Err only on backend failure.

fn put( &self, key: &SessionId, value: &SessionData, ttl: Duration, ) -> impl Future<Output = Result<(), Self::Error>> + Send

Insert or replace the value at key with the given TTL.

fn delete( &self, key: &SessionId, ) -> impl Future<Output = Result<(), Self::Error>> + Send

Remove the entry at key. Idempotent; does not error if absent.

fn prune_expired(&self) -> impl Future<Output = Result<u64, Self::Error>> + Send

Bulk-evict every TTL-expired entry. Returns the number reclaimed. Backends with native TTL eviction (Valkey/Redis) may implement this as a no-op returning Ok(0); backends owning their own row table (SQLite, Postgres, in-memory) actually delete.