Spring security session registry (#473)

*  Spring Security Concurrent Session Integration #65

 add SpringSessionBackedSessionRegistry

*  Spring Security Concurrent Session Integration #65

 add documentation

*  Spring Security Concurrent Session Integration #65

support marking SessionInformations as expired before deleting the Session

docs/src/docs/asciidoc/index.adoc

@@ -505,6 +505,43 @@ Before using WebSocket integration, you should be sure that you have <<httpsessi
 
 include::guides/websocket.adoc[tags=config,leveloffset=+2]
 
+[[spring-security-concurrent-sessions]]
+== Spring Security Integration
+
+Spring Session provides integration with Spring Security to support its concurrent session control.
+This allows limiting the number of active sessions that a single user can have concurrently, but unlike the default
+Spring Security support this will also work in a clustered environment. This is done by providing a custom
+implementation of Spring Security's `SessionRegistry` interface.
+
+[[spring-security-concurrent-sessions-how]]
+=== Configuring Spring Security's concurrent session management
+
+When using Spring Security's Java config DSL, you can configure the custom `SessionRegistry` through the
+`SessionManagementConfigurer` like this:
+[source,java,indent=0]
+----
+include::{docs-test-dir}docs/security/SecurityConfiguration.java[tags=class]
+----
+
+This assumes that you've also configured Spring Session to provide a `FindByIndexNameSessionRepository` that
+returns `ExpiringSession` instances.
+
+When using XML configuration, it would look something like this:
+[source,xml,indent=0]
+----
+include::{docs-test-resources-dir}docs/security/security-config.xml[tags=config]
+----
+
+This assumes that your Spring Session `SessionRegistry` bean is called `sessionRegistry`, which is the name used by all
+`SpringHttpSessionConfiguration` subclasses except for the one for MongoDB: there it's called `mongoSessionRepository`.
+
+[[spring-security-concurrent-sessions-limitations]]
+=== Limitations
+
+Spring Session's implementation of Spring Security's `SessionRegistry` interface does not support the `getAllPrincipals`
+method, as this information cannot be retrieved using Spring Session. This method is never called by Spring Security,
+so this only affects applications that access the `SessionRegistry` themselves.
+
 [[api]]
 == API Documentation
 
@@ -837,7 +874,7 @@ For example, Java Configuration can use the following:
 include::{docs-test-dir}docs/RedisHttpSessionConfigurationNoOpConfigureRedisActionTests.java[tags=configure-redis-action]
 ----
 
-XML Configuraiton can use the following:
+XML Configuration can use the following:
 
 [source,xml,indent=0]
 ----

docs/src/test/java/docs/security/SecurityConfiguration.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2014-2016 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package docs.security;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
+import org.springframework.session.ExpiringSession;
+import org.springframework.session.FindByIndexNameSessionRepository;
+import org.springframework.session.security.SpringSessionBackedSessionRegistry;
+
+/**
+ * @author Joris Kuipers
+ */
+// tag::class[]
+@Configuration
+public class SecurityConfiguration extends WebSecurityConfigurerAdapter {
+
+	@Autowired
+	FindByIndexNameSessionRepository<ExpiringSession> sessionRepository;
+
+	@Override
+	protected void configure(HttpSecurity http) throws Exception {
+		http
+			// other config goes here...
+			.sessionManagement()
+				.maximumSessions(2)
+				.sessionRegistry(sessionRegistry());
+	}
+
+	@Bean
+	SpringSessionBackedSessionRegistry sessionRegistry() {
+		return new SpringSessionBackedSessionRegistry(this.sessionRepository);
+	}
+}
+// end::class[]

docs/src/test/resources/docs/security/security-config.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans"
+	   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	   xmlns:security="http://www.springframework.org/schema/security"
+	   xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
+						   http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security.xsd">
+
+	<!-- tag::config[] -->
+	<security:http>
+		<!-- other config goes here... -->
+		<security:session-management>
+			<security:concurrency-control max-sessions="2" session-registry-ref="sessionRegistry"
+		</security:session-management>
+	</security:http>
+
+	<bean id="sessionRegistry"
+		  class="org.springframework.session.security.SpringSessionBackedSessionRegistry">
+		<constructor-arg ref="sessionRepository"/>
+	</bean>
+	<!-- end::config[] -->
+
+</beans>