event session

• session {Buffer}

The 'session' event is emitted on a client tls.TLSSocket when a new session or TLS ticket is available. This may or may not be before the handshake is complete, depending on the TLS protocol version that was negotiated. The event is not emitted on the server, or if a new session was not created, for example, when the connection was resumed. For some TLS protocol versions the event may be emitted multiple times, in which case all the sessions can be used for resumption.

On the client, the session can be provided to the session option of [tls.connect()][] to resume the connection.

See [Session Resumption][] for more information.

For TLSv1.2 and below, [tls.TLSSocket.getSession()][] can be called once the handshake is complete. For TLSv1.3, only ticket-based resumption is allowed by the protocol, multiple tickets are sent, and the tickets aren’t sent until after the handshake completes. So it is necessary to wait for the 'session' event to get a resumable session. Applications should use the 'session' event instead of getSession() to ensure they will work for all TLS versions. Applications that only expect to get or use one session should listen for this event only once:

tlsSocket.once('session', (session) => {
  // The session can be used immediately or later.
  tls.connect({
    session: session,
    // Other connect options...
  });
});