For the latest stable version, please use Spring Session 3.3.1! |
Spring Session - Spring Boot
This guide describes how to use Spring Session to transparently leverage Redis to back a web application’s HttpSession
when you use Spring Boot.
You can find the completed guide in the boot sample application. |
Updating Dependencies
Before you use Spring Session with Redis, you must ensure that you have the right dependencies. We assume you are working with a working Spring Boot web application.
<dependencies>
<!-- ... -->
<dependency>
<groupId>org.springframework.session</groupId>
<artifactId>spring-session-data-redis</artifactId>
</dependency>
</dependencies>
implementation("org.springframework.session:spring-session-data-redis")
Spring Boot provides dependency management for Spring Session modules, so you need not explicitly declare dependency version.
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 Redis is as simple as adding a single configuration property to your application.properties
, as the following listing shows:
spring.session.store-type=redis # Session store type.
Under the hood, Spring Boot applies configuration that is equivalent to manually adding @EnableRedisHttpSession
annotation.
This 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.
Further customization is possible by using application.properties
, as the following listing shows:
server.servlet.session.timeout= # Session timeout. If a duration suffix is not specified, seconds is used. spring.session.redis.flush-mode=on_save # Sessions flush mode. spring.session.redis.namespace=spring:session # Namespace for keys used to store sessions.
For more information, see the Spring Session portion of the Spring Boot documentation.
Configuring the Redis Connection
Spring Boot automatically creates a RedisConnectionFactory
that connects Spring Session to a Redis Server on localhost on port 6379 (default port).
In a production environment, you need to update your configuration to point to your Redis server.
For example, you can include the following in your application.properties:
spring.data.redis.host=localhost # Redis server host. spring.data.redis.password= # Login password of the redis server. spring.data.redis.port=6379 # Redis server port.
For more information, see the Connecting to Redis 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 (that is, Tomcat) uses our springSessionRepositoryFilter
for every request.
Fortunately, Spring Boot takes care of both of these steps for us.
Boot Sample Application
The Boot Sample Application demonstrates how to use Spring Session to transparently leverage Redis to back a web application’s HttpSession
when you use Spring Boot.
Running the Boot Sample Application
You can run the sample by obtaining the source code and invoking the following command:
$ ./gradlew :spring-session-sample-boot-redis:bootRun
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.
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You should now be able to access the application at localhost:8080/
Exploring the security
Sample Application
Now you can try using the application. Enter the following to log in:
-
Username user
-
Password password
Now click the Login button.
You should now see a message indicating you 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 by using redis-cli. For example, on a Linux based system you can type the following:
$ redis-cli keys '*' | xargs redis-cli del
The Redis documentation has instructions for installing redis-cli. |
Alternatively, you can also delete the explicit key.
To do so, enter the following 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 localhost:8080/ and observe that we are no longer authenticated.