3.5 library(http/http_session): HTTP Session management
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Availability::- use_module(library(http/http_session)).
Source[det]http_close_session(+SessionID)
Closes an HTTP session. This predicate can be called from any thread to terminate a session. It uses the broadcast/1 service with the message below. 
http_session(end(SessionId, Peer))

The broadcast is done before the session data is destroyed and the listen-handlers are executed in context of the session that is being closed. Here is an example that destroys a Prolog thread that is associated to a thread: 

:- listen(http_session(end(SessionId, _Peer)),
          kill_session_thread(SessionID)).

kill_session_thread(SessionID) :-
        http_session_data(thread(ThreadID)),
        thread_signal(ThreadID, throw(session_closed)).

Succeed without any effect if SessionID does not refer to an active session.

If http_close_session/1 is called from a handler operating in the current session and the CGI stream is still in state header, this predicate emits a Set-Cookie to expire the cookie.

Errors
type_error(atom, SessionID)
See also
listen/2 for acting upon closed sessions