Spring Session and Spring Security
This guide describes how to use Spring Session along with Spring Security. It assumes you have already applied Spring Security to your application.
| You can find the completed guide in the security sample application. |
Updating Dependencies
Before you use Spring Session, you must update your dependencies. If you use Maven, you must add the following dependencies:
<dependencies>
<!-- ... -->
<dependency>
<groupId>org.springframework.session</groupId>
<artifactId>spring-session-data-redis</artifactId>
<version>2.6.0-SNAPSHOT</version>
<type>pom</type>
</dependency>
<dependency>
<groupId>io.lettuce</groupId>
<artifactId>lettuce-core</artifactId>
<version>6.1.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>5.3.9</version>
</dependency>
</dependencies>Since we are using a SNAPSHOT version, we need to add the Spring Snapshot Maven Repository. You must have the following in your pom.xml:
<repositories>
<!-- ... -->
<repository>
<id>spring-snapshot</id>
<url>https://repo.spring.io/libs-snapshot</url>
</repository>
</repositories>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.
To do so, add the following Spring Configuration:
@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 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, see the reference documentation. |
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.
Since our application is already loading Spring configuration by using our SecurityInitializer class, we can add our configuration class to it.
The following example shows how to do so:
public class SecurityInitializer extends AbstractSecurityWebApplicationInitializer {
public SecurityInitializer() {
super(SecurityConfig.class, Config.class);
}
}Last, we need to ensure that our Servlet Container (that is, 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 doing so easy.
The following example shows how to do so:
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 named springSessionRepositoryFilter is registered with our Servlet Container for every request before Spring Security’s springSecurityFilterChain .
security Sample Application
This section describes how to work with the security sample application.
Running the security Sample Application
You can run the sample by obtaining the source code and invoking the following command:
$ ./gradlew :spring-session-sample-javaconfig-security:tomcatRun
For the sample to work, you must install Redis 2.8+ on localhost and run it with the default port (6379).
Alternatively, you can update the RedisConnectionFactory to point to a Redis server.
Another option is to use Docker to run Redis on localhost.
See Docker Redis repository for detailed instructions.
|
You should now be able to access the application at http://localhost:8080/
Exploring the security Sample Application
Now you can use the application. Enter the following to log in:
-
Username user
-
Password password
Now click the Login button.
You should now see a message indicating your are logged in with the user entered previously.
The user’s information is stored in Redis rather than Tomcat’s HttpSession implementation.
How Does It Work?
Instead of using Tomcat’s HttpSession, we persist the values in Redis.
Spring Session replaces the HttpSession with an implementation that is backed by Redis.
When Spring Security’s SecurityContextPersistenceFilter saves the SecurityContext to the HttpSession, it is then persisted into Redis.
When a new HttpSession is created, Spring Session creates a cookie named SESSION in your browser.
That cookie contains the ID of your session.
You can view the cookies (with Chrome or Firefox).
You can remove the session using redis-cli. For example, on a Linux-based system you can type the following command:
$ redis-cli keys '*' | xargs redis-cli del
| The Redis documentation has instructions for installing redis-cli. |
Alternatively, you can also delete the explicit key.
Enter the following command into your terminal, being sure to replace 7e8383a4-082c-4ffe-a4bc-c40fd3363c5e with the value of your SESSION cookie:
$ redis-cli del spring:session:sessions:7e8383a4-082c-4ffe-a4bc-c40fd3363c5e
Now you can visit the application at http://localhost:8080/ and see that we are no longer authenticated.