Spring Session provides an API and implementations for managing a user’s session information.
1. Introduction
Spring Session provides an API and implementations for managing a user’s session information. It also provides transparent integration with:
-
HttpSession - allows replacing the HttpSession in an application container (i.e. Tomcat) neutral way. Additional features include:
-
Clustered Sessions - Spring Session makes it trivial to support clustered sessions without being tied to an application container specific solution.
-
Multiple Browser Sessions - Spring Session supports managing multiple users' sessions in a single browser instance (i.e. multiple authenticated accounts similar to Google).
-
RESTful APIs - Spring Session allows providing session ids in headers to work with RESTful APIs
-
-
WebSocket - provides the ability to keep the
HttpSession
alive when receiving WebSocket messages
2. What’s New in 1.3
Below are the highlights of what is new in Spring Session 1.3. You can find a complete list of what’s new by referring to the changelogs of 1.3.0.M1, 1.3.0.M2, 1.3.0.RC1, and 1.3.0.RELEASE.
-
First class support for Hazelcast
-
First class support for Spring Security’s concurrent session management
-
GenericJackson2JsonRedisSerializer sample with Spring Security’s new Jackson Support
-
Guides now use Lettuce
-
spring.session.cleanup.cron.expression
can be used to override the cleanup task’s cron expression -
Lots of performance improvements and bug fixes
3. Samples and Guides (Start Here)
If you are looking to get started with Spring Session, the best place to start is our Sample Applications.
Source | Description | Guide |
---|---|---|
Demonstrates how to use Spring Session to replace the |
||
Demonstrates how to use Spring Session to replace the |
||
Demonstrates how to use Spring Session to find sessions by username. |
||
Demonstrates how to use Spring Session with WebSockets. |
||
Demonstrates how to use Spring Session to replace the |
TBD |
Source | Description | Guide |
---|---|---|
Demonstrates how to use Spring Session to replace the |
||
Demonstrates how to use Spring Session to replace the |
||
Demonstrates how to use Spring Session to replace the |
||
Demonstrates how to use Spring Session and customize the cookie. |
||
Demonstrates how to use Spring Session with an existing Spring Security application. |
||
Demonstrates how to use Spring Session in a REST application to support authenticating with a header. |
||
Demonstrates how to use Spring Session to manage multiple simultaneous browser sessions (i.e Google Accounts). |
Source | Description | Guide |
---|---|---|
Demonstrates how to use Spring Session to replace the |
||
Demonstrates how to use Spring Session to replace the |
Source | Description | Guide |
---|---|---|
Demonstrates how to use Spring Session with Grails 3. |
||
Demonstrates how to use Spring Session with Hazelcast in a Java EE application. |
TBD |
4. HttpSession Integration
Spring Session provides transparent integration with HttpSession
.
This means that developers can switch the HttpSession
implementation out with an implementation that is backed by Spring Session.
4.1. Why Spring Session & HttpSession?
We have already mentioned that Spring Session provides transparent integration with HttpSession
, but what benefits do we get out of this?
-
Clustered Sessions - Spring Session makes it trivial to support clustered sessions without being tied to an application container specific solution.
-
Multiple Browser Sessions - Spring Session supports managing multiple users' sessions in a single browser instance (i.e. multiple authenticated accounts similar to Google).
-
RESTful APIs - Spring Session allows providing session ids in headers to work with RESTful APIs
4.2. HttpSession with Redis
Using Spring Session with HttpSession
is enabled by adding a Servlet Filter before anything that uses the HttpSession
.
You can choose from enabling this using either:
4.2.1. Redis Java Based Configuration
This section describes how to use Redis to back HttpSession
using Java based configuration.
The HttpSession Sample provides a working sample on how to integrate Spring Session and HttpSession using Java configuration.
You can read the basic steps for integration below, but you are encouraged to follow along with the detailed HttpSession Guide when integrating with your own application.
|
Spring Java Configuration
After adding the required dependencies, we can create our Spring configuration.
The Spring configuration is responsible for creating a Servlet Filter that replaces the HttpSession
implementation with an implementation backed by Spring Session.
Add the following Spring Configuration:
@EnableRedisHttpSession (1)
public class Config {
@Bean
public LettuceConnectionFactory connectionFactory() {
return new LettuceConnectionFactory(); (2)
}
}
1 | The @EnableRedisHttpSession annotation creates a Spring Bean with the name of springSessionRepositoryFilter that implements Filter.
The filter is what is in charge of replacing the HttpSession implementation to be backed by Spring Session.
In this instance Spring Session is backed by Redis. |
2 | We create a RedisConnectionFactory that connects Spring Session to the Redis Server.
We configure the connection to connect to localhost on the default port (6379)
For more information on configuring Spring Data Redis, refer to the reference documentation. |
Java Servlet Container Initialization
Our Spring Configuration created a Spring Bean named springSessionRepositoryFilter
that implements Filter
.
The springSessionRepositoryFilter
bean is responsible for replacing the HttpSession
with a custom implementation that is backed by Spring Session.
In order for our Filter
to do its magic, Spring needs to load our Config
class.
Last we need to ensure that our Servlet Container (i.e. Tomcat) uses our springSessionRepositoryFilter
for every request.
Fortunately, Spring Session provides a utility class named AbstractHttpSessionApplicationInitializer
both of these steps extremely easy.
You can find an example below:
public class Initializer extends AbstractHttpSessionApplicationInitializer { (1)
public Initializer() {
super(Config.class); (2)
}
}
The name of our class (Initializer) does not matter. What is important is that we extend AbstractHttpSessionApplicationInitializer .
|
1 | The first step is to extend AbstractHttpSessionApplicationInitializer .
This ensures that the Spring Bean by the name springSessionRepositoryFilter is registered with our Servlet Container for every request. |
2 | AbstractHttpSessionApplicationInitializer also provides a mechanism to easily ensure Spring loads our Config . |
4.2.2. Redis XML Based Configuration
This section describes how to use Redis to back HttpSession
using XML based configuration.
The HttpSession XML Sample provides a working sample on how to integrate Spring Session and HttpSession using XML configuration.
You can read the basic steps for integration below, but you are encouraged to follow along with the detailed HttpSession XML Guide when integrating with your own application.
|
Spring XML Configuration
After adding the required dependencies, we can create our Spring configuration.
The Spring configuration is responsible for creating a Servlet Filter that replaces the HttpSession
implementation with an implementation backed by Spring Session.
Add the following Spring Configuration:
(1)
<context:annotation-config/>
<bean class="org.springframework.session.data.redis.config.annotation.web.http.RedisHttpSessionConfiguration"/>
(2)
<bean class="org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory"/>
1 | We use the combination of <context:annotation-config/> and RedisHttpSessionConfiguration because Spring Session does not yet provide XML Namespace support (see gh-104).
This creates a Spring Bean with the name of springSessionRepositoryFilter that implements Filter.
The filter is what is in charge of replacing the HttpSession implementation to be backed by Spring Session.
In this instance Spring Session is backed by Redis. |
2 | We create a RedisConnectionFactory that connects Spring Session to the Redis Server.
We configure the connection to connect to localhost on the default port (6379)
For more information on configuring Spring Data Redis, refer to the reference documentation. |
XML Servlet Container Initialization
Our Spring Configuration created a Spring Bean named springSessionRepositoryFilter
that implements Filter
.
The springSessionRepositoryFilter
bean is responsible for replacing the HttpSession
with a custom implementation that is backed by Spring Session.
In order for our Filter
to do its magic, we need to instruct Spring to load our session.xml
configuration.
We do this with the following configuration:
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
/WEB-INF/spring/*.xml
</param-value>
</context-param>
<listener>
<listener-class>
org.springframework.web.context.ContextLoaderListener
</listener-class>
</listener>
The ContextLoaderListener reads the contextConfigLocation and picks up our session.xml configuration.
Last we need to ensure that our Servlet Container (i.e. Tomcat) uses our springSessionRepositoryFilter
for every request.
The following snippet performs this last step for us:
<filter>
<filter-name>springSessionRepositoryFilter</filter-name>
<filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
</filter>
<filter-mapping>
<filter-name>springSessionRepositoryFilter</filter-name>
<url-pattern>/*</url-pattern>
<dispatcher>REQUEST</dispatcher>
<dispatcher>ERROR</dispatcher>
</filter-mapping>
The DelegatingFilterProxy will look up a Bean by the name of springSessionRepositoryFilter
and cast it to a Filter
.
For every request that DelegatingFilterProxy
is invoked, the springSessionRepositoryFilter
will be invoked.
4.3. HttpSession with JDBC
Using Spring Session with HttpSession
is enabled by adding a Servlet Filter before anything that uses the HttpSession
.
You can choose from enabling this using either:
4.3.1. JDBC Java Based Configuration
This section describes how to use a relational database to back HttpSession
using Java based configuration.
The HttpSession JDBC Sample provides a working sample on how to integrate Spring Session and HttpSession using Java configuration.
You can read the basic steps for integration below, but you are encouraged to follow along with the detailed HttpSession JDBC Guide when integrating with your own application.
|
Spring Java Configuration
After adding the required dependencies, we can create our Spring configuration.
The Spring configuration is responsible for creating a Servlet Filter that replaces the HttpSession
implementation with an implementation backed by Spring Session.
Add the following Spring Configuration:
@EnableJdbcHttpSession (1)
public class Config {
@Bean
public EmbeddedDatabase dataSource() {
return new EmbeddedDatabaseBuilder() (2)
.setType(EmbeddedDatabaseType.H2)
.addScript("org/springframework/session/jdbc/schema-h2.sql").build();
}
@Bean
public PlatformTransactionManager transactionManager(DataSource dataSource) {
return new DataSourceTransactionManager(dataSource); (3)
}
}
1 | The @EnableJdbcHttpSession annotation creates a Spring Bean with the name of springSessionRepositoryFilter that implements Filter.
The filter is what is in charge of replacing the HttpSession implementation to be backed by Spring Session.
In this instance Spring Session is backed by a relational database. |
2 | We create a dataSource that connects Spring Session to an embedded instance of H2 database.
We configure the H2 database to create database tables using the SQL script which is included in Spring Session. |
3 | We create a transactionManager that manages transactions for previously configured dataSource . |
For additional information on how to configure data access related concerns, please refer to the Spring Framework Reference Documentation.
Java Servlet Container Initialization
Our Spring Configuration created a Spring Bean named springSessionRepositoryFilter
that implements Filter
.
The springSessionRepositoryFilter
bean is responsible for replacing the HttpSession
with a custom implementation that is backed by Spring Session.
In order for our Filter
to do its magic, Spring needs to load our Config
class.
Last we need to ensure that our Servlet Container (i.e. Tomcat) uses our springSessionRepositoryFilter
for every request.
Fortunately, Spring Session provides a utility class named AbstractHttpSessionApplicationInitializer
both of these steps extremely easy.
You can find an example below:
public class Initializer extends AbstractHttpSessionApplicationInitializer { (1)
public Initializer() {
super(Config.class); (2)
}
}
The name of our class (Initializer) does not matter. What is important is that we extend AbstractHttpSessionApplicationInitializer .
|
1 | The first step is to extend AbstractHttpSessionApplicationInitializer .
This ensures that the Spring Bean by the name springSessionRepositoryFilter is registered with our Servlet Container for every request. |
2 | AbstractHttpSessionApplicationInitializer also provides a mechanism to easily ensure Spring loads our Config . |
4.3.2. JDBC XML Based Configuration
This section describes how to use a relational database to back HttpSession
using XML based configuration.
The HttpSession JDBC XML Sample provides a working sample on how to integrate Spring Session and HttpSession using XML configuration.
You can read the basic steps for integration below, but you are encouraged to follow along with the detailed HttpSession JDBC XML Guide when integrating with your own application.
|
Spring XML Configuration
After adding the required dependencies, we can create our Spring configuration.
The Spring configuration is responsible for creating a Servlet Filter that replaces the HttpSession
implementation with an implementation backed by Spring Session.
Add the following Spring Configuration:
(1)
<context:annotation-config/>
<bean class="org.springframework.session.jdbc.config.annotation.web.http.JdbcHttpSessionConfiguration"/>
(2)
<jdbc:embedded-database id="dataSource" database-name="testdb" type="H2">
<jdbc:script location="classpath:org/springframework/session/jdbc/schema-h2.sql"/>
</jdbc:embedded-database>
(3)
<bean class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<constructor-arg ref="dataSource"/>
</bean>
1 | We use the combination of <context:annotation-config/> and JdbcHttpSessionConfiguration because Spring Session does not yet provide XML Namespace support (see gh-104).
This creates a Spring Bean with the name of springSessionRepositoryFilter that implements Filter.
The filter is what is in charge of replacing the HttpSession implementation to be backed by Spring Session.
In this instance Spring Session is backed by a relational database. |
2 | We create a dataSource that connects Spring Session to an embedded instance of H2 database.
We configure the H2 database to create database tables using the SQL script which is included in Spring Session. |
3 | We create a transactionManager that manages transactions for previously configured dataSource . |
For additional information on how to configure data access related concerns, please refer to the Spring Framework Reference Documentation.
XML Servlet Container Initialization
Our Spring Configuration created a Spring Bean named springSessionRepositoryFilter
that implements Filter
.
The springSessionRepositoryFilter
bean is responsible for replacing the HttpSession
with a custom implementation that is backed by Spring Session.
In order for our Filter
to do its magic, we need to instruct Spring to load our session.xml
configuration.
We do this with the following configuration:
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
/WEB-INF/spring/*.xml
</param-value>
</context-param>
<listener>
<listener-class>
org.springframework.web.context.ContextLoaderListener
</listener-class>
</listener>
The ContextLoaderListener reads the contextConfigLocation and picks up our session.xml configuration.
Last we need to ensure that our Servlet Container (i.e. Tomcat) uses our springSessionRepositoryFilter
for every request.
The following snippet performs this last step for us:
<filter>
<filter-name>springSessionRepositoryFilter</filter-name>
<filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
</filter>
<filter-mapping>
<filter-name>springSessionRepositoryFilter</filter-name>
<url-pattern>/*</url-pattern>
<dispatcher>REQUEST</dispatcher>
<dispatcher>ERROR</dispatcher>
</filter-mapping>
The DelegatingFilterProxy will look up a Bean by the name of springSessionRepositoryFilter
and cast it to a Filter
.
For every request that DelegatingFilterProxy
is invoked, the springSessionRepositoryFilter
will be invoked.
4.3.3. JDBC Spring Boot Based Configuration
This section describes how to use a relational database to back HttpSession
when using Spring Boot.
The HttpSession JDBC Spring Boot Sample provides a working sample on how to integrate Spring Session and HttpSession using Spring Boot.
You can read the basic steps for integration below, but you are encouraged to follow along with the detailed HttpSession JDBC Spring Boot Guide when integrating with your own application.
|
Spring Boot Configuration
After adding the required dependencies, we can create our Spring Boot configuration.
Thanks to first-class auto configuration support, setting up Spring Session backed by a relational database is as simple as adding a single configuration property to your application.properties
:
spring.session.store-type=jdbc
Under the hood, Spring Boot will apply configuration that is equivalent to manually adding @EnableJdbcHttpSession
annotation.
This creates a Spring Bean with the name of springSessionRepositoryFilter
that implements Filter.
The filter is what is in charge of replacing the HttpSession
implementation to be backed by Spring Session.
Further customization is possible using application.properties
:
server.session.timeout= # Session timeout in seconds. spring.session.jdbc.initializer.enabled= # Create the required session tables on startup if necessary. Enabled automatically if the default table name is set or a custom schema is configured. spring.session.jdbc.schema=classpath:org/springframework/session/jdbc/schema-@@platform@@.sql # Path to the SQL file to use to initialize the database schema. spring.session.jdbc.table-name=SPRING_SESSION # Name of database table used to store sessions.
For more information, refer to Spring Session portion of the Spring Boot documentation.
Configuring the DataSource
Spring Boot automatically creates a DataSource
that connects Spring Session to an embedded instance of H2 database.
In a production environment you need to ensure to update your configuration to point to your relational database.
For example, you can include the following in your application.properties
spring.datasource.url=jdbc:postgresql://localhost:5432/myapp spring.datasource.username=myapp spring.datasource.password=secret
For more information, refer to Configure a DataSource portion of the Spring Boot documentation.
Servlet Container Initialization
Our Spring Boot Configuration created a Spring Bean named springSessionRepositoryFilter
that implements Filter
.
The springSessionRepositoryFilter
bean is responsible for replacing the HttpSession
with a custom implementation that is backed by Spring Session.
In order for our Filter
to do its magic, Spring needs to load our Config
class.
Last we need to ensure that our Servlet Container (i.e. Tomcat) uses our springSessionRepositoryFilter
for every request.
Fortunately, Spring Boot takes care of both of these steps for us.
4.4. HttpSession with Hazelcast
Using Spring Session with HttpSession
is enabled by adding a Servlet Filter before anything that uses the HttpSession
.
This section describes how to use Hazelcast to back HttpSession
using Java based configuration.
The Hazelcast Spring Sample provides a working sample on how to integrate Spring Session and HttpSession using Java configuration.
You can read the basic steps for integration below, but you are encouraged to follow along with the detailed Hazelcast Spring Guide when integrating with your own application.
|
4.4.1. Spring Configuration
After adding the required dependencies, we can create our Spring configuration.
The Spring configuration is responsible for creating a Servlet Filter that replaces the HttpSession
implementation with an implementation backed by Spring Session.
Add the following Spring Configuration:
@EnableHazelcastHttpSession (1)
@Configuration
public class HazelcastHttpSessionConfig {
@Bean
public HazelcastInstance hazelcastInstance() {
MapAttributeConfig attributeConfig = new MapAttributeConfig()
.setName(HazelcastSessionRepository.PRINCIPAL_NAME_ATTRIBUTE)
.setExtractor(PrincipalNameExtractor.class.getName());
Config config = new Config();
config.getMapConfig("spring:session:sessions") (2)
.addMapAttributeConfig(attributeConfig)
.addMapIndexConfig(new MapIndexConfig(
HazelcastSessionRepository.PRINCIPAL_NAME_ATTRIBUTE, false));
return Hazelcast.newHazelcastInstance(config); (3)
}
}
1 | The @EnableHazelcastHttpSession annotation creates a Spring Bean with the name of springSessionRepositoryFilter that implements Filter.
The filter is what is in charge of replacing the HttpSession implementation to be backed by Spring Session.
In this instance Spring Session is backed by Hazelcast. |
2 | In order to support retrieval of sessions by principal name index, appropriate ValueExtractor needs to be registered.
Spring Session provides PrincipalNameExtractor for this purpose. |
3 | We create a HazelcastInstance that connects Spring Session to Hazelcast.
By default, an embedded instance of Hazelcast is started and connected to by the application.
For more information on configuring Hazelcast, refer to the reference documentation. |
4.4.2. Servlet Container Initialization
Our Spring Configuration created a Spring Bean named springSessionRepositoryFilter
that implements Filter
.
The springSessionRepositoryFilter
bean is responsible for replacing the HttpSession
with a custom implementation that is backed by Spring Session.
In order for our Filter
to do its magic, Spring needs to load our SessionConfig
class.
Since our application is already loading Spring configuration using our SecurityInitializer
class, we can simply add our SessionConfig
class to it.
public class SecurityInitializer extends AbstractSecurityWebApplicationInitializer {
public SecurityInitializer() {
super(SecurityConfig.class, SessionConfig.class);
}
}
Last we need to ensure that our Servlet Container (i.e. Tomcat) uses our springSessionRepositoryFilter
for every request.
It is extremely important that Spring Session’s springSessionRepositoryFilter
is invoked before Spring Security’s springSecurityFilterChain
.
This ensures that the HttpSession
that Spring Security uses is backed by Spring Session.
Fortunately, Spring Session provides a utility class named AbstractHttpSessionApplicationInitializer
that makes this extremely easy.
You can find an example below:
public class Initializer extends AbstractHttpSessionApplicationInitializer {
}
The name of our class (Initializer) does not matter. What is important is that we extend AbstractHttpSessionApplicationInitializer .
|
By extending AbstractHttpSessionApplicationInitializer
we ensure that the Spring Bean by the name springSessionRepositoryFilter
is registered with our Servlet Container for every request before Spring Security’s springSecurityFilterChain
.
4.5. How HttpSession Integration Works
Fortunately both HttpSession
and HttpServletRequest
(the API for obtaining an HttpSession
) are both interfaces.
This means that we can provide our own implementations for each of these APIs.
This section describes how Spring Session provides transparent integration with HttpSession . The intent is so that user’s can understand what is happening under the covers. This functionality is already integrated and you do NOT need to implement this logic yourself.
|
First we create a custom HttpServletRequest
that returns a custom implementation of HttpSession
.
It looks something like the following:
public class SessionRepositoryRequestWrapper extends HttpServletRequestWrapper {
public SessionRepositoryRequestWrapper(HttpServletRequest original) {
super(original);
}
public HttpSession getSession() {
return getSession(true);
}
public HttpSession getSession(boolean createNew) {
// create an HttpSession implementation from Spring Session
}
// ... other methods delegate to the original HttpServletRequest ...
}
Any method that returns an HttpSession
is overridden.
All other methods are implemented by HttpServletRequestWrapper
and simply delegate to the original HttpServletRequest
implementation.
We replace the HttpServletRequest
implementation using a servlet Filter
called SessionRepositoryFilter
.
The pseudocode can be found below:
public class SessionRepositoryFilter implements Filter {
public doFilter(ServletRequest request, ServletResponse response, FilterChain chain) {
HttpServletRequest httpRequest = (HttpServletRequest) request;
SessionRepositoryRequestWrapper customRequest =
new SessionRepositoryRequestWrapper(httpRequest);
chain.doFilter(customRequest, response, chain);
}
// ...
}
By passing in a custom HttpServletRequest
implementation into the FilterChain
we ensure that anything invoked after our Filter
uses the custom HttpSession
implementation.
This highlights why it is important that Spring Session’s SessionRepositoryFilter
must be placed before anything that interacts with the HttpSession
.
4.6. Multiple HttpSessions in Single Browser
Spring Session has the ability to support multiple sessions in a single browser instance. This provides the ability to support authenticating with multiple users in the same browser instance (i.e. Google Accounts).
The Manage Multiple Users Guide provides a complete working example of managing multiple users in the same browser instance. You can follow the basic steps for integration below, but you are encouraged to follow along with the detailed Manage Multiple Users Guide when integrating with your own application. |
Let’s take a look at how Spring Session keeps track of multiple sessions.
4.6.1. Managing a Single Session
Spring Session keeps track of the HttpSession
by adding a value to a cookie named SESSION.
For example, the SESSION cookie might have a value of:
7e8383a4-082c-4ffe-a4bc-c40fd3363c5e
4.6.2. Adding a Session
We can add another session by requesting a URL that contains a special parameter in it. By default the parameter name is _s. For example, the following URL would create a new session:
The parameter value does not indicate the actual session id. This is important because we never want to allow the session id to be determined by a client to avoid session fixation attacks. Additionally, we do not want the session id to be leaked since it is sent as a query parameter. Remember sensitive information should only be transmitted as a header or in the body of the request. |
Rather than creating the URL ourselves, we can utilize the HttpSessionManager
to do this for us.
We can obtain the HttpSessionManager
from the HttpServletRequest
using the following:
HttpSessionManager sessionManager = (HttpSessionManager) httpRequest
.getAttribute(HttpSessionManager.class.getName());
We can now use it to create a URL to add another session.
String addAlias = unauthenticatedAlias == null ? (1)
sessionManager.getNewSessionAlias(httpRequest)
: (2)
unauthenticatedAlias; (3)
String addAccountUrl = sessionManager.encodeURL(contextPath, addAlias); (4)
1 | We have an existing variable named unauthenticatedAlias .
The value is an alias that points to an existing unauthenticated session.
If no such session exists, the value is null.
This ensures if we have an existing unauthenticated session that we use it instead of creating a new session. |
2 | If all of our sessions are already associated to a user, we create a new session alias. |
3 | If there is an existing session that is not associated to a user, we use its session alias. |
4 | Finally, we create the add account URL. The URL contains a session alias that either points to an existing unauthenticated session or is an alias that is unused thus signaling to create a new session associated to that alias. |
Now our SESSION cookie looks something like this:
0 7e8383a4-082c-4ffe-a4bc-c40fd3363c5e 1 1d526d4a-c462-45a4-93d9-84a39b6d44ad
Such that:
-
There is a session with the id 7e8383a4-082c-4ffe-a4bc-c40fd3363c5e
-
The alias for this session is 0. For example, if the URL is http://localhost:8080/?_s=0 this alias would be used.
-
This is the default session. This means that if no session alias is specified, then this session is used. For example, if the URL is http://localhost:8080/ this session would be used.
-
-
There is a session with the id 1d526d4a-c462-45a4-93d9-84a39b6d44ad
-
The alias for this session is 1. If the session alias is 1, then this session is used. For example, if the URL is http://localhost:8080/?_s=1 this alias would be used.
-
4.6.3. Automatic Session Alias Inclusion with encodeURL
The nice thing about specifying the session alias in the URL is that we can have multiple tabs open with different active sessions. The bad thing is that we need to include the session alias in every URL of our application. Fortunately, Spring Session will automatically include the session alias in any URL that passes through HttpServletResponse#encodeURL(java.lang.String)
This means that if you are using standard tag libraries the session alias is automatically included in the URL. For example, if we are currently using the session with the alias of 1, then the following:
-->
<c:url value="/link.jsp" var="linkUrl"/>
<a id="navLink" href="${linkUrl}">Link</a>
will output a link of:
<a id="navLink" href="/link.jsp?_s=1">Link</a>
4.7. HttpSession & RESTful APIs
Spring Session can work with RESTful APIs by allowing the session to be provided in a header.
The REST Sample provides a working sample on how to use Spring Session in a REST application to support authenticating with a header. You can follow the basic steps for integration below, but you are encouraged to follow along with the detailed REST Guide when integrating with your own application. |
4.7.1. Spring Configuration
After adding the required dependencies, we can create our Spring configuration.
The Spring configuration is responsible for creating a Servlet Filter that replaces the HttpSession
implementation with an implementation backed by Spring Session.
Add the following Spring Configuration:
@Configuration
@EnableRedisHttpSession (1)
public class HttpSessionConfig {
@Bean
public LettuceConnectionFactory connectionFactory() {
return new LettuceConnectionFactory(); (2)
}
@Bean
public HttpSessionStrategy httpSessionStrategy() {
return new HeaderHttpSessionStrategy(); (3)
}
}
1 | The @EnableRedisHttpSession annotation creates a Spring Bean with the name of springSessionRepositoryFilter that implements Filter .
The filter is what is in charge of replacing the HttpSession implementation to be backed by Spring Session.
In this instance Spring Session is backed by Redis. |
2 | We create a RedisConnectionFactory that connects Spring Session to the Redis Server.
We configure the connection to connect to localhost on the default port (6379)
For more information on configuring Spring Data Redis, refer to the reference documentation. |
3 | We customize Spring Session’s HttpSession integration to use HTTP headers to convey the current session information instead of cookies. |
4.7.2. Servlet Container Initialization
Our Spring Configuration created a Spring Bean named springSessionRepositoryFilter
that implements Filter
.
The springSessionRepositoryFilter
bean is responsible for replacing the HttpSession
with a custom implementation that is backed by Spring Session.
In order for our Filter
to do its magic, Spring needs to load our Config
class. We provide the configuration in our Spring MvcInitializer
as shown below:
@Override
protected Class<?>[] getRootConfigClasses() {
return new Class[] { SecurityConfig.class, HttpSessionConfig.class };
}
Last we need to ensure that our Servlet Container (i.e. Tomcat) uses our springSessionRepositoryFilter
for every request.
Fortunately, Spring Session provides a utility class named AbstractHttpSessionApplicationInitializer
that makes this extremely easy. Simply extend the class with the default constructor as shown below:
public class Initializer extends AbstractHttpSessionApplicationInitializer {
}
The name of our class (Initializer) does not matter. What is important is that we extend AbstractHttpSessionApplicationInitializer .
|
4.8. HttpSessionListener
Spring Session supports HttpSessionListener
by translating SessionDestroyedEvent
and SessionCreatedEvent
into HttpSessionEvent
by declaring SessionEventHttpSessionListenerAdapter
.
To use this support, you need to:
-
Ensure your
SessionRepository
implementation supports and is configured to fireSessionDestroyedEvent
andSessionCreatedEvent
. -
Configure
SessionEventHttpSessionListenerAdapter
as a Spring bean. -
Inject every
HttpSessionListener
into theSessionEventHttpSessionListenerAdapter
If you are using the configuration support documented in HttpSession with Redis, then all you need to do is register every HttpSessionListener
as a bean.
For example, assume you want to support Spring Security’s concurrency control and need to use HttpSessionEventPublisher
you can simply add HttpSessionEventPublisher
as a bean.
In Java configuration, this might look like:
@Configuration
@EnableRedisHttpSession
public class RedisHttpSessionConfig {
@Bean
public HttpSessionEventPublisher httpSessionEventPublisher() {
return new HttpSessionEventPublisher();
}
// ...
}
In XML configuration, this might look like:
<bean class="org.springframework.security.web.session.HttpSessionEventPublisher"/>
5. WebSocket Integration
Spring Session provides transparent integration with Spring’s WebSocket support.
Spring Session’s WebSocket support only works with Spring’s WebSocket support. Specifically it does not work with using JSR-356 directly. This is due to the fact that JSR-356 does not have a mechanism for intercepting incoming WebSocket messages. |
5.1. Why Spring Session & WebSockets?
So why do we need Spring Session when using WebSockets?
Consider an email application that does much of its work through HTTP requests.
However, there is also a chat application embedded within it that works over WebSocket APIs.
If a user is actively chatting with someone, we should not timeout the HttpSession
since this would be pretty poor user experience.
However, this is exactly what JSR-356 does.
Another issue is that according to JSR-356 if the HttpSession
times out any WebSocket that was created with that HttpSession and an authenticated user should be forcibly closed.
This means that if we are actively chatting in our application and are not using the HttpSession, then we will also disconnect from our conversation!
5.2. WebSocket Usage
The WebSocket Sample provides a working sample on how to integrate Spring Session with WebSockets. You can follow the basic steps for integration below, but you are encouraged to follow along with the detailed WebSocket Guide when integrating with your own application:
5.2.1. HttpSession Integration
Before using WebSocket integration, you should be sure that you have HttpSession Integration working first.
5.2.2. Spring Configuration
In a typical Spring WebSocket application users would extend AbstractWebSocketMessageBrokerConfigurer
.
For example, the configuration might look something like the following:
@Configuration
@EnableScheduling
@EnableWebSocketMessageBroker
public class WebSocketConfig extends AbstractWebSocketMessageBrokerConfigurer {
public void registerStompEndpoints(StompEndpointRegistry registry) {
registry.addEndpoint("/messages").withSockJS();
}
@Override
public void configureMessageBroker(MessageBrokerRegistry registry) {
registry.enableSimpleBroker("/queue/", "/topic/");
registry.setApplicationDestinationPrefixes("/app");
}
}
We can easily update our configuration to use Spring Session’s WebSocket support. For example:
@Configuration
@EnableScheduling
@EnableWebSocketMessageBroker
public class WebSocketConfig
extends AbstractSessionWebSocketMessageBrokerConfigurer<ExpiringSession> { (1)
protected void configureStompEndpoints(StompEndpointRegistry registry) { (2)
registry.addEndpoint("/messages").withSockJS();
}
public void configureMessageBroker(MessageBrokerRegistry registry) {
registry.enableSimpleBroker("/queue/", "/topic/");
registry.setApplicationDestinationPrefixes("/app");
}
}
To hook in the Spring Session support we only need to change two things:
1 | Instead of extending AbstractWebSocketMessageBrokerConfigurer we extend AbstractSessionWebSocketMessageBrokerConfigurer |
2 | We rename the registerStompEndpoints method to configureStompEndpoints |
What does AbstractSessionWebSocketMessageBrokerConfigurer
do behind the scenes?
-
WebSocketConnectHandlerDecoratorFactory
is added as aWebSocketHandlerDecoratorFactory
toWebSocketTransportRegistration
. This ensures a customSessionConnectEvent
is fired that contains theWebSocketSession
. TheWebSocketSession
is necessary to terminate any WebSocket connections that are still open when a Spring Session is terminated. -
SessionRepositoryMessageInterceptor
is added as aHandshakeInterceptor
to everyStompWebSocketEndpointRegistration
. This ensures that the Session is added to the WebSocket properties to enable updating the last accessed time. -
SessionRepositoryMessageInterceptor
is added as aChannelInterceptor
to our inboundChannelRegistration
. This ensures that every time an inbound message is received, that the last accessed time of our Spring Session is updated. -
WebSocketRegistryListener
is created as a Spring Bean. This ensures that we have a mapping of all of the Session id to the corresponding WebSocket connections. By maintaining this mapping, we can close all the WebSocket connections when a Spring Session (HttpSession) is terminated.
6. Spring Security Integration
Spring Session provides integration with Spring Security.
6.1. Spring Security Remember-Me Support
Spring Session provides integration with Spring Security’s Remember-Me Authentication. The support will:
-
Change the session expiration length
-
Ensure the session cookie expires at
Integer.MAX_VALUE
. The cookie expiration is set to the largest possible value because the cookie is only set when the session is created. If it were set to the same value as the session expiration, then the session would get renewed when the user used it but the cookie expiration would not be updated causing the expiration to be fixed.
To configure Spring Session with Spring Security in Java Configuration use the following as a guide:
@Override
protected void configure(HttpSecurity http) throws Exception {
http
// ... additional configuration ...
.rememberMe()
.rememberMeServices(rememberMeServices());
}
@Bean
RememberMeServices rememberMeServices() {
SpringSessionRememberMeServices rememberMeServices =
new SpringSessionRememberMeServices();
// optionally customize
rememberMeServices.setAlwaysRemember(true);
return rememberMeServices;
}
An XML based configuration would look something like this:
<security:http>
<!-- ... -->
<security:form-login />
<security:remember-me services-ref="rememberMeServices"/>
</security:http>
<bean id="rememberMeServices"
class="org.springframework.session.security.web.authentication.SpringSessionRememberMeServices"
p:alwaysRemember="true"/>
6.2. Spring Security Concurrent Session Control
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.
When using Spring Security’s Java config DSL, you can configure the custom SessionRegistry
through the
SessionManagementConfigurer
like this:
@Configuration
public class SecurityConfiguration extends WebSecurityConfigurerAdapter {
@Autowired
private FindByIndexNameSessionRepository<ExpiringSession> sessionRepository;
@Override
protected void configure(HttpSecurity http) throws Exception {
// @formatter:off
http
// other config goes here...
.sessionManagement()
.maximumSessions(2)
.sessionRegistry(sessionRegistry());
// @formatter:on
}
@Bean
SpringSessionBackedSessionRegistry sessionRegistry() {
return new SpringSessionBackedSessionRegistry<ExpiringSession>(
this.sessionRepository);
}
}
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:
<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>
This assumes that your Spring Session SessionRegistry
bean is called sessionRegistry
, which is the name used by all
SpringHttpSessionConfiguration
subclasses.
6.3. 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.
7. API Documentation
You can browse the complete Javadoc online. The key APIs are described below:
7.1. Session
A Session
is a simplified Map
of name value pairs.
Typical usage might look like the following:
public class RepositoryDemo<S extends Session> {
private SessionRepository<S> repository; (1)
public void demo() {
S toSave = this.repository.createSession(); (2)
(3)
User rwinch = new User("rwinch");
toSave.setAttribute(ATTR_USER, rwinch);
this.repository.save(toSave); (4)
S session = this.repository.getSession(toSave.getId()); (5)
(6)
User user = session.getAttribute(ATTR_USER);
assertThat(user).isEqualTo(rwinch);
}
// ... setter methods ...
}
1 | We create a SessionRepository instance with a generic type, S , that extends Session . The generic type is defined in our class. |
2 | We create a new Session using our SessionRepository and assign it to a variable of type S . |
3 | We interact with the Session . In our example, we demonstrate saving a User to the Session . |
4 | We now save the Session . This is why we needed the generic type S . The SessionRepository only allows saving Session instances that were created or retrieved using the same SessionRepository . This allows for the SessionRepository to make implementation specific optimizations (i.e. only writing attributes that have changed). |
5 | We retrieve the Session from the SessionRepository . |
6 | We obtain the persisted User from our Session without the need for explicitly casting our attribute. |
7.2. ExpiringSession
An ExpiringSession
extends a Session
by providing attributes related to the Session
instance’s expiration.
If there is no need to interact with the expiration information, prefer using the more simple Session
API.
Typical usage might look like the following:
public class ExpiringRepositoryDemo<S extends ExpiringSession> {
private SessionRepository<S> repository; (1)
public void demo() {
S toSave = this.repository.createSession(); (2)
// ...
toSave.setMaxInactiveIntervalInSeconds(30); (3)
this.repository.save(toSave); (4)
S session = this.repository.getSession(toSave.getId()); (5)
// ...
}
// ... setter methods ...
}
1 | We create a SessionRepository instance with a generic type, S , that extends ExpiringSession . The generic type is defined in our class. |
2 | We create a new ExpiringSession using our SessionRepository and assign it to a variable of type S . |
3 | We interact with the ExpiringSession .
In our example, we demonstrate updating the amount of time the ExpiringSession can be inactive before it expires. |
4 | We now save the ExpiringSession .
This is why we needed the generic type S .
The SessionRepository only allows saving ExpiringSession instances that were created or retrieved using the same SessionRepository .
This allows for the SessionRepository to make implementation specific optimizations (i.e. only writing attributes that have changed).
The last accessed time is automatically updated when the ExpiringSession is saved. |
5 | We retrieve the ExpiringSession from the SessionRepository .
If the ExpiringSession were expired, the result would be null. |
7.3. SessionRepository
A SessionRepository
is in charge of creating, retrieving, and persisting Session
instances.
If possible, developers should not interact directly with a SessionRepository
or a Session
.
Instead, developers should prefer interacting with SessionRepository
and Session
indirectly through the HttpSession and WebSocket integration.
7.4. FindByIndexNameSessionRepository
Spring Session’s most basic API for using a Session
is the SessionRepository
.
This API is intentionally very simple, so that it is easy to provide additional implementations with basic functionality.
Some SessionRepository
implementations may choose to implement FindByIndexNameSessionRepository
also.
For example, Spring’s Redis support implements FindByIndexNameSessionRepository
.
The FindByIndexNameSessionRepository
adds a single method to look up all the sessions for a particular user.
This is done by ensuring that the session attribute with the name FindByIndexNameSessionRepository.PRINCIPAL_NAME_INDEX_NAME
is populated with the username.
It is the responsibility of the developer to ensure the attribute is populated since Spring Session is not aware of the authentication mechanism being used.
An example of how this might be used can be seen below:
String username = "username";
this.session.setAttribute(
FindByIndexNameSessionRepository.PRINCIPAL_NAME_INDEX_NAME, username);
Some implementations of |
Once the session is indexed, it can be found using the following:
String username = "username";
Map<String, Session> sessionIdToSession = this.sessionRepository
.findByIndexNameAndIndexValue(
FindByIndexNameSessionRepository.PRINCIPAL_NAME_INDEX_NAME,
username);
7.5. EnableSpringHttpSession
The @EnableSpringHttpSession
annotation can be added to an @Configuration
class to expose the SessionRepositoryFilter
as a bean named "springSessionRepositoryFilter".
In order to leverage the annotation, a single SessionRepository
bean must be provided.
For example:
@EnableSpringHttpSession
@Configuration
public class SpringHttpSessionConfig {
@Bean
public MapSessionRepository sessionRepository() {
return new MapSessionRepository();
}
}
It is important to note that no infrastructure for session expirations is configured for you out of the box. This is because things like session expiration are highly implementation dependent. This means if you require cleaning up expired sessions, you are responsible for cleaning up the expired sessions.
7.6. RedisOperationsSessionRepository
RedisOperationsSessionRepository
is a SessionRepository
that is implemented using Spring Data’s RedisOperations
.
In a web environment, this is typically used in combination with SessionRepositoryFilter
.
The implementation supports SessionDestroyedEvent
and SessionCreatedEvent
through SessionMessageListener
.
7.6.1. Instantiating a RedisOperationsSessionRepository
A typical example of how to create a new instance can be seen below:
LettuceConnectionFactory factory = new LettuceConnectionFactory();
SessionRepository<? extends ExpiringSession> repository = new RedisOperationsSessionRepository(
factory);
For additional information on how to create a RedisConnectionFactory
, refer to the Spring Data Redis Reference.
7.6.2. EnableRedisHttpSession
In a web environment, the simplest way to create a new RedisOperationsSessionRepository
is to use @EnableRedisHttpSession
.
Complete example usage can be found in the Samples and Guides (Start Here)
You can use the following attributes to customize the configuration:
-
maxInactiveIntervalInSeconds - the amount of time before the session will expire in seconds
-
redisNamespace - allows configuring an application specific namespace for the sessions. Redis keys and channel ids will start with the prefix of
spring:session:<redisNamespace>:
. -
redisFlushMode - allows specifying when data will be written to Redis. The default is only when
save
is invoked onSessionRepository
. A value ofRedisFlushMode.IMMEDIATE
will write to Redis as soon as possible.
7.6.3. Redis TaskExecutor
RedisOperationsSessionRepository
is subscribed to receive events from redis using a RedisMessageListenerContainer
.
You can customize the way those events are dispatched, by creating a Bean named springSessionRedisTaskExecutor
and/or a Bean springSessionRedisSubscriptionExecutor
.
More details on configuring redis task executors can be found here.
7.6.4. Storage Details
The sections below outline how Redis is updated for each operation. An example of creating a new session can be found below. The subsequent sections describe the details.
HMSET spring:session:sessions:33fdd1b6-b496-4b33-9f7d-df96679d32fe creationTime 1404360000000 \ maxInactiveInterval 1800 \ lastAccessedTime 1404360000000 \ sessionAttr:attrName someAttrValue \ sessionAttr2:attrName someAttrValue2 EXPIRE spring:session:sessions:33fdd1b6-b496-4b33-9f7d-df96679d32fe 2100 APPEND spring:session:sessions:expires:33fdd1b6-b496-4b33-9f7d-df96679d32fe "" EXPIRE spring:session:sessions:expires:33fdd1b6-b496-4b33-9f7d-df96679d32fe 1800 SADD spring:session:expirations:1439245080000 expires:33fdd1b6-b496-4b33-9f7d-df96679d32fe EXPIRE spring:session:expirations1439245080000 2100
Saving a Session
Each session is stored in Redis as a Hash. Each session is set and updated using the HMSET command. An example of how each session is stored can be seen below.
HMSET spring:session:sessions:33fdd1b6-b496-4b33-9f7d-df96679d32fe creationTime 1404360000000 \ maxInactiveInterval 1800 \ lastAccessedTime 1404360000000 \ sessionAttr:attrName someAttrValue \ sessionAttr2:attrName someAttrValue2
In this example, the session following statements are true about the session:
-
The session id is 33fdd1b6-b496-4b33-9f7d-df96679d32fe
-
The session was created at 1404360000000 in milliseconds since midnight of 1/1/1970 GMT.
-
The session expires in 1800 seconds (30 minutes).
-
The session was last accessed at 1404360000000 in milliseconds since midnight of 1/1/1970 GMT.
-
The session has two attributes. The first is "attrName" with the value of "someAttrValue". The second session attribute is named "attrName2" with the value of "someAttrValue2".
Optimized Writes
The Session
instances managed by RedisOperationsSessionRepository
keeps track of the properties that have changed and only updates those.
This means if an attribute is written once and read many times we only need to write that attribute once.
For example, assume the session attribute "sessionAttr2" from earlier was updated.
The following would be executed upon saving:
HMSET spring:session:sessions:33fdd1b6-b496-4b33-9f7d-df96679d32fe sessionAttr:attrName2 newValue
Session Expiration
An expiration is associated to each session using the EXPIRE command based upon the ExpiringSession.getMaxInactiveInterval()
.
For example:
EXPIRE spring:session:sessions:33fdd1b6-b496-4b33-9f7d-df96679d32fe 2100
You will note that the expiration that is set is 5 minutes after the session actually expires. This is necessary so that the value of the session can be accessed when the session expires. An expiration is set on the session itself five minutes after it actually expires to ensure it is cleaned up, but only after we perform any necessary processing.
The |
Spring Session relies on the delete and expired keyspace notifications from Redis to fire a SessionDeletedEvent and SessionExpiredEvent respectively.
It is the SessionDeletedEvent
or SessionExpiredEvent
that ensures resources associated with the Session are cleaned up.
For example, when using Spring Session’s WebSocket support the Redis expired or delete event is what triggers any WebSocket connections associated with the session to be closed.
Expiration is not tracked directly on the session key itself since this would mean the session data would no longer be available. Instead a special session expires key is used. In our example the expires key is:
APPEND spring:session:sessions:expires:33fdd1b6-b496-4b33-9f7d-df96679d32fe "" EXPIRE spring:session:sessions:expires:33fdd1b6-b496-4b33-9f7d-df96679d32fe 1800
When a session expires key is deleted or expires, the keyspace notification triggers a lookup of the actual session and a SessionDestroyedEvent is fired.
One problem with relying on Redis expiration exclusively is that Redis makes no guarantee of when the expired event will be fired if they key has not been accessed. Specifically the background task that Redis uses to clean up expired keys is a low priority task and may not trigger the key expiration. For additional details see Timing of expired events section in the Redis documentation.
To circumvent the fact that expired events are not guaranteed to happen we can ensure that each key is accessed when it is expected to expire. This means that if the TTL is expired on the key, Redis will remove the key and fire the expired event when we try to access they key.
For this reason, each session expiration is also tracked to the nearest minute. This allows a background task to access the potentially expired sessions to ensure that Redis expired events are fired in a more deterministic fashion. For example:
SADD spring:session:expirations:1439245080000 expires:33fdd1b6-b496-4b33-9f7d-df96679d32fe EXPIRE spring:session:expirations1439245080000 2100
The background task will then use these mappings to explicitly request each key. By accessing they key, rather than deleting it, we ensure that Redis deletes the key for us only if the TTL is expired.
We do not explicitly delete the keys since in some instances there may be a race condition that incorrectly identifies a key as expired when it is not. Short of using distributed locks (which would kill our performance) there is no way to ensure the consistency of the expiration mapping. By simply accessing the key, we ensure that the key is only removed if the TTL on that key is expired. |
7.6.5. SessionDeletedEvent and SessionExpiredEvent
SessionDeletedEvent
and SessionExpiredEvent
are both types of SessionDestroyedEvent
.
RedisOperationsSessionRepository
supports firing a SessionDeletedEvent
whenever a Session
is deleted or a SessionExpiredEvent
when it expires.
This is necessary to ensure resources associated with the Session
are properly cleaned up.
For example, when integrating with WebSockets the SessionDestroyedEvent
is in charge of closing any active WebSocket connections.
Firing SessionDeletedEvent
or SessionExpiredEvent
is made available through the SessionMessageListener
which listens to Redis Keyspace events.
In order for this to work, Redis Keyspace events for Generic commands and Expired events needs to be enabled.
For example:
redis-cli config set notify-keyspace-events Egx
If you are using @EnableRedisHttpSession
the SessionMessageListener
and enabling the necessary Redis Keyspace events is done automatically.
However, in a secured Redis enviornment the config command is disabled.
This means that Spring Session cannot configure Redis Keyspace events for you.
To disable the automatic configuration add ConfigureRedisAction.NO_OP
as a bean.
For example, Java Configuration can use the following:
@Bean
public static ConfigureRedisAction configureRedisAction() {
return ConfigureRedisAction.NO_OP;
}
XML Configuration can use the following:
<util:constant
static-field="org.springframework.session.data.redis.config.ConfigureRedisAction.NO_OP"/>
7.6.6. SessionCreatedEvent
When a session is created an event is sent to Redis with the channel of spring:session:channel:created:33fdd1b6-b496-4b33-9f7d-df96679d32fe
such that 33fdd1b6-b496-4b33-9f7d-df96679d32fe
is the session id. The body of the event will be the session that was created.
If registered as a MessageListener (default), then RedisOperationsSessionRepository
will then translate the Redis message into a SessionCreatedEvent
.
7.6.7. Viewing the Session in Redis
After installing redis-cli, you can inspect the values in Redis using the redis-cli. For example, enter the following into a terminal:
$ redis-cli
redis 127.0.0.1:6379> keys *
1) "spring:session:sessions:4fc39ce3-63b3-4e17-b1c4-5e1ed96fb021" (1)
2) "spring:session:expirations:1418772300000" (2)
1 | The suffix of this key is the session identifier of the Spring Session. |
2 | This key contains all the session ids that should be deleted at the time 1418772300000 . |
You can also view the attributes of each session.
redis 127.0.0.1:6379> hkeys spring:session:sessions:4fc39ce3-63b3-4e17-b1c4-5e1ed96fb021
1) "lastAccessedTime"
2) "creationTime"
3) "maxInactiveInterval"
4) "sessionAttr:username"
redis 127.0.0.1:6379> hget spring:session:sessions:4fc39ce3-63b3-4e17-b1c4-5e1ed96fb021 sessionAttr:username
"\xac\xed\x00\x05t\x00\x03rob"
7.7. MapSessionRepository
The MapSessionRepository
allows for persisting ExpiringSession
in a Map
with the key being the ExpiringSession
id and the value being the ExpiringSession
.
The implementation can be used with a ConcurrentHashMap
as a testing or convenience mechanism.
Alternatively, it can be used with distributed Map
implementations. For example, it can be used with Hazelcast.
7.7.1. Instantiating MapSessionRepository
Creating a new instance is as simple as:
SessionRepository<? extends ExpiringSession> repository = new MapSessionRepository();
7.7.2. Using Spring Session and Hazlecast
The Hazelcast Sample is a complete application demonstrating using Spring Session with Hazelcast.
To run it use the following:
./gradlew :samples:hazelcast:tomcatRun
The Hazelcast Spring Sample is a complete application demonstrating using Spring Session with Hazelcast and Spring Security.
It includes example Hazelcast MapListener
implementations that support firing SessionCreatedEvent
, SessionDeletedEvent
and SessionExpiredEvent
.
To run it use the following:
./gradlew :samples:hazelcast-spring:tomcatRun
7.8. JdbcOperationsSessionRepository
JdbcOperationsSessionRepository
is a SessionRepository
implementation that uses Spring’s JdbcOperations
to store sessions in a relational database.
In a web environment, this is typically used in combination with SessionRepositoryFilter
.
Please note that this implementation does not support publishing of session events.
7.8.1. Instantiating a JdbcOperationsSessionRepository
A typical example of how to create a new instance can be seen below:
JdbcTemplate jdbcTemplate = new JdbcTemplate();
// ... configure JdbcTemplate ...
PlatformTransactionManager transactionManager = new DataSourceTransactionManager();
// ... configure transactionManager ...
SessionRepository<? extends ExpiringSession> repository =
new JdbcOperationsSessionRepository(jdbcTemplate, transactionManager);
For additional information on how to create and configure JdbcTemplate
and PlatformTransactionManager
, refer to the Spring Framework Reference Documentation.
7.8.2. EnableJdbcHttpSession
In a web environment, the simplest way to create a new JdbcOperationsSessionRepository
is to use @EnableJdbcHttpSession
.
Complete example usage can be found in the Samples and Guides (Start Here)
You can use the following attributes to customize the configuration:
-
tableName - the name of database table used by Spring Session to store sessions
-
maxInactiveIntervalInSeconds - the amount of time before the session will expire in seconds
Custom LobHandler
You can customize the BLOB handling by creating a Bean named springSessionLobHandler
that implements LobHandler
.
Custom ConversionService
You can customize the default serialization and deserialization of the session by providing a ConversionService
instance.
When working in a typical Spring environment, the default ConversionService
Bean (named conversionService
) will be automatically picked up and used for serialization and deserialization.
However, you can override the default ConversionService
by providing a Bean named springSessionConversionService
.
7.8.3. Storage Details
By default, this implementation uses SPRING_SESSION
and SPRING_SESSION_ATTRIBUTES
tables to store sessions.
Note that the table name can be easily customized as already described. In that case the table used to store attributes will be named using the provided table name, suffixed with _ATTRIBUTES
.
If further customizations are needed, SQL queries used by the repository can be customized using set*Query
setter methods. In this case you need to manually configure the sessionRepository
bean.
Due to the differences between the various database vendors, especially when it comes to storing binary data, make sure to use SQL script specific to your database.
Scripts for most major database vendors are packaged as org/springframework/session/jdbc/schema-*.sql
, where *
is the target database type.
For example, with PostgreSQL database you would use the following schema script:
CREATE TABLE SPRING_SESSION (
SESSION_ID CHAR(36) NOT NULL,
CREATION_TIME BIGINT NOT NULL,
LAST_ACCESS_TIME BIGINT NOT NULL,
MAX_INACTIVE_INTERVAL INT NOT NULL,
PRINCIPAL_NAME VARCHAR(100),
CONSTRAINT SPRING_SESSION_PK PRIMARY KEY (SESSION_ID)
);
CREATE INDEX SPRING_SESSION_IX1 ON SPRING_SESSION (LAST_ACCESS_TIME);
CREATE TABLE SPRING_SESSION_ATTRIBUTES (
SESSION_ID CHAR(36) NOT NULL,
ATTRIBUTE_NAME VARCHAR(200) NOT NULL,
ATTRIBUTE_BYTES BYTEA NOT NULL,
CONSTRAINT SPRING_SESSION_ATTRIBUTES_PK PRIMARY KEY (SESSION_ID, ATTRIBUTE_NAME),
CONSTRAINT SPRING_SESSION_ATTRIBUTES_FK FOREIGN KEY (SESSION_ID) REFERENCES SPRING_SESSION(SESSION_ID) ON DELETE CASCADE
);
CREATE INDEX SPRING_SESSION_ATTRIBUTES_IX1 ON SPRING_SESSION_ATTRIBUTES (SESSION_ID);
And with MySQL database:
CREATE TABLE SPRING_SESSION (
SESSION_ID CHAR(36) NOT NULL,
CREATION_TIME BIGINT NOT NULL,
LAST_ACCESS_TIME BIGINT NOT NULL,
MAX_INACTIVE_INTERVAL INT NOT NULL,
PRINCIPAL_NAME VARCHAR(100),
CONSTRAINT SPRING_SESSION_PK PRIMARY KEY (SESSION_ID)
) ENGINE=InnoDB;
CREATE INDEX SPRING_SESSION_IX1 ON SPRING_SESSION (LAST_ACCESS_TIME);
CREATE TABLE SPRING_SESSION_ATTRIBUTES (
SESSION_ID CHAR(36) NOT NULL,
ATTRIBUTE_NAME VARCHAR(200) NOT NULL,
ATTRIBUTE_BYTES BLOB NOT NULL,
CONSTRAINT SPRING_SESSION_ATTRIBUTES_PK PRIMARY KEY (SESSION_ID, ATTRIBUTE_NAME),
CONSTRAINT SPRING_SESSION_ATTRIBUTES_FK FOREIGN KEY (SESSION_ID) REFERENCES SPRING_SESSION(SESSION_ID) ON DELETE CASCADE
) ENGINE=InnoDB;
CREATE INDEX SPRING_SESSION_ATTRIBUTES_IX1 ON SPRING_SESSION_ATTRIBUTES (SESSION_ID);
7.8.4. Transaction management
All JDBC operations in JdbcOperationsSessionRepository
are executed in a transactional manner.
Transactions are executed with propagation set to REQUIRES_NEW
in order to avoid unexpected behavior due to interference with existing transactions (for example, executing save
operation in a thread that already participates in a read-only transaction).
7.9. HazelcastSessionRepository
HazelcastSessionRepository
is a SessionRepository
implementation that stores sessions in Hazelcast’s distributed IMap
.
In a web environment, this is typically used in combination with SessionRepositoryFilter
.
7.9.1. Instantiating a HazelcastSessionRepository
A typical example of how to create a new instance can be seen below:
Config config = new Config();
// ... configure Hazelcast ...
HazelcastInstance hazelcastInstance = Hazelcast.newHazelcastInstance(config);
IMap<String, MapSession> sessions = hazelcastInstance
.getMap("spring:session:sessions");
HazelcastSessionRepository repository =
new HazelcastSessionRepository(sessions);
For additional information on how to create and configure Hazelcast instance, refer to the Hazelcast documentation.
7.9.2. EnableHazelcastHttpSession
If you wish to use Hazelcast as your backing source for the SessionRepository
, then the @EnableHazelcastHttpSession
annotation
can be added to an @Configuration
class. This extends the functionality provided by the @EnableSpringHttpSession
annotation but makes the SessionRepository
for you in Hazelcast.
You must provide a single HazelcastInstance
bean for the configuration to work.
Complete configuration example can be found in the Samples and Guides (Start Here)
7.9.3. Basic Customization
You can use the following attributes on @EnableHazelcastHttpSession
to customize the configuration:
-
maxInactiveIntervalInSeconds - the amount of time before the session will expire in seconds. Default is 1800 seconds (30 minutes)
-
sessionMapName - the name of the distributed
Map
that will be used in Hazelcast to store the session data.
7.9.4. Session Events
Using a MapListener
to respond to entries being added, evicted, and removed from the distributed Map
, these events will trigger
publishing SessionCreatedEvent
, SessionExpiredEvent
, and SessionDeletedEvent
events respectively using the ApplicationEventPublisher
.
7.9.5. Storage Details
Sessions will be stored in a distributed IMap
in Hazelcast.
The IMap
interface methods will be used to get()
and put()
Sessions.
Additionally, values()
method is used to support FindByIndexNameSessionRepository#findByIndexNameAndIndexValue
operation, together with appropriate ValueExtractor
that needs to be registered with Hazelcast. Refer to Hazelcast Spring Sample for more details on this configuration.
The expiration of a session in the IMap
is handled by Hazelcast’s support for setting the time to live on an entry when it is put()
into the IMap
. Entries (sessions) that have been idle longer than the time to live will be automatically removed from the IMap
.
You shouldn’t need to configure any settings such as max-idle-seconds
or time-to-live-seconds
for the IMap
within the Hazelcast configuration.
Note that if you use Hazelcast’s MapStore
to persist your sessions IMap
there are some limitations when reloading the sessions from MapStore
:
-
reload triggers
EntryAddedListener
which results inSessionCreatedEvent
being re-published -
reload uses default TTL for a given
IMap
which results in sessions losing their original TTL
8. Spring Session Community
We are glad to consider you a part of our community. Please find additional information below.
8.1. Support
You can get help by asking questions on StackOverflow with the tag spring-session. Similarly we encourage helping others by answering questions on StackOverflow.
8.2. Source Code
Our source code can be found on github at https://github.com/spring-projects/spring-session/
8.3. Issue Tracking
We track issues in github issues at https://github.com/spring-projects/spring-session/issues
8.4. Contributing
We appreciate Pull Requests.
8.5. License
Spring Session is Open Source software released under the Apache 2.0 license.
9. Minimum Requirements
The minimum requirements for Spring Session are:
-
Java 5+
-
If you are running in a Servlet Container (not required), Servlet 2.5+
-
If you are using other Spring libraries (not required), the minimum required version is Spring 3.2.14. While we re-run all unit tests against Spring 3.2.x, we recommend using the latest Spring 4.x version when possible.
-
@EnableRedisHttpSession
requires Redis 2.8+. This is necessary to support Session Expiration
At its core Spring Session only has a required dependency on |