1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.shiro.session.mgt;
20
21 /**
22 * A ValidatingSessionManager is a SessionManager that can proactively validate any or all sessions
23 * that may be expired.
24 *
25 * @since 0.1
26 */
27 public interface ValidatingSessionManager extends SessionManager {
28
29 /**
30 * Performs session validation for all open/active sessions in the system (those that
31 * have not been stopped or expired), and validates each one. If a session is
32 * found to be invalid (e.g. it has expired), it is updated and saved to the EIS.
33 * <p/>
34 * This method is necessary in order to handle orphaned sessions and is expected to be run at
35 * a regular interval, such as once an hour, once a day or once a week, etc.
36 * The "best" frequency to run this method is entirely dependent upon the application
37 * and would be based on factors such as performance, average number of active users, hours of
38 * least activity, and other things.
39 * <p/>
40 * Most enterprise applications use a request/response programming model.
41 * This is obvious in the case of web applications due to the HTTP protocol, but it is
42 * equally true of remote client applications making remote method invocations. The server
43 * essentially sits idle and only "works" when responding to client requests and/or
44 * method invocations. This type of model is particularly efficient since it means the
45 * security system only has to validate a session during those cases. Such
46 * "lazy" behavior enables the system to lie stateless and/or idle and only incur
47 * overhead for session validation when necessary.
48 * <p/>
49 * However, if a client forgets to log-out, or in the event of a server failure, it is
50 * possible for sessions to be orphaned since no further requests would utilize that session.
51 * Because of these lower-probability cases, it might be required to regularly clean-up the sessions
52 * maintained by the system, especially if sessions are backed by a persistent data store.
53 * <p/>
54 * Even in applications that aren't primarily based on a request/response model,
55 * such as those that use enterprise asynchronous messaging (where data is pushed to
56 * a client without first receiving a client request), it is almost always acceptable to
57 * utilize this lazy approach and run this method at defined interval.
58 * <p/>
59 * Systems that want to proactively validate individual sessions may simply call the
60 * {@link #getSession(SessionKey) getSession(SessionKey)} method on any
61 * {@code ValidatingSessionManager} instance as that method is expected to
62 * validate the session before retrieving it. Note that even with proactive calls to {@code getSession},
63 * this {@code validateSessions()} method should be invoked regularly anyway to <em>guarantee</em> no
64 * orphans exist.
65 * <p/>
66 * <b>Note:</b> Shiro supports automatic execution of this method at a regular interval
67 * by using {@link SessionValidationScheduler}s. The Shiro default SecurityManager implementations
68 * needing session validation will create and use one by default if one is not provided by the
69 * application configuration.
70 */
71 void validateSessions();
72 }