Struct SessionCache 

pub struct SessionCache { /* private fields */ }

Thread-safe in-memory TLS session cache

Stores session tickets for TLS 1.3 resumption. This enables clients to reconnect without performing full handshakes, reducing latency by 50-70%.

Pass the same cache (in an Arc) to every TlsClient::connect_with_session call: the TLS layer stores the server’s session tickets in it and offers them on the next connection to the same server name. Those TLS tickets are kept in a rustls session store bounded by max_entries and expire as the server’s ticket lifetime says; default_ttl applies to entries added with store.

rustls only resumes a session with the same certificate verifier that checked the original connection, so the cache also keeps the TLS client configuration built for each distinct TlsClientConfig and reuses it. Certificate, key and CA files are therefore read on the first connection with a given configuration; call clear after replacing those files.

Implementations

impl SessionCache

pub fn new(max_entries: usize, default_ttl: Duration) -> Self

Create a new session cache

Arguments

• max_entries - Maximum number of sessions to cache (e.g., 1000)
• default_ttl - Default time-to-live for each session (e.g., 1 hour)

Example

let cache = SessionCache::new(1000, Duration::from_secs(3600));

pub async fn store<S: Into<String>>(&self, session_id: S, ticket: Vec<u8>)

Store a session ticket in the cache

This is typically called by the TLS layer after establishing a connection. Automatically manages eviction when cache is full.

Arguments

• session_id - Unique session identifier
• ticket - Serialized TLS session ticket

pub async fn get(&self, session_id: &str) -> Option<Arc<Vec<u8>>>

Retrieve a session ticket from the cache

Returns the ticket if found and not expired, None otherwise.

Example

if let Some(ticket) = cache.get("session-123").await {
    // Use ticket for resumption
}

pub async fn clear(&self)

Clear all sessions from the cache

pub async fn stats(&self) -> SessionCacheStats

Get current cache statistics

Trait Implementations

impl Clone for SessionCache

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.