[FIXED] Start a session from a given id in spring

Issue

How can I create a session in a spring mvc application from a given ID instead of a generated one?

I want to fixate the session. The fixation will be started by a trusted ui service. This trusted service forwards all requests. Thus the fixation can't begin in browser. It is not intended to do it without this ui service.

Providing a HttpSessionIdResolver bean does not work, since it only changes the location in HTTP response. Eg Session ID in HTTP header after authorization.

Are there any solutions without creating a shadow session management?

Session is required for keycloak integration. Guess it's not possible to use keycloak in stateless mode.

Thanks in advance

Solution

It is possible to fixate a session with spring-session.

@Configuration
@EnableSpringHttpSession
public class SessionConfig {

  @Bean
  public HttpSessionIdResolver httpSessionIdResolver() {
    return new HttpSessionIdResolver() {
      public List<String> resolveSessionIds(HttpServletRequest request) {
        final var sessionId = request.getHeader("X-SessionId");
        request.setAttribute(SessionConfig.class.getName() + "SessionIdAttr", sessionId);
        return List.of(sessionId);
      }

      public void setSessionId(HttpServletRequest request, HttpServletResponse response, String sessionId) {}
      public void expireSession(HttpServletRequest request, HttpServletResponse response) {}
    };
  }

  @Bean
  public SessionRepository<MapSession> sessionRepository() {
    return new MapSessionRepository(new HashMap<>()) {
      @Override
      public MapSession createSession() {
        var sessionId =
            (String)RequestContextHolder
                .currentRequestAttributes()
                .getAttribute(SessionConfig.class.getName()+"SessionIdAttr", 0);
        final var session = super.createSession();
        if (sessionId != null) {
          session.setId(sessionId);
        }
        return session;
      }
    };
}

In #resolveSessionIds() you can read the ID and store for later use. createSession() is called when no session has been found and a new one is required. Here you can create the session with previously remembered ID in MapSession#setId(String).

Even if is possible, IMO it is not a good idea. There might be other architectural solutions/problems.

Answered By - Paul
Answer Checked By - David Goodson (JavaFixing Volunteer)