This version is still in development and is not considered stable yet. For the latest stable version, please use Spring Session 3.1.7!

Spring Session - MongoDB Repositories

This guide describes how to use Spring Session backed by MongoDB.

The completed guide can be found in the mongo sample application.

Index

Updating Dependencies

Before you use Spring Session MongoDB, you must ensure to update your dependencies. We assume you are working with a working Spring Boot web application. If you are using Maven, ensure to add the following dependencies:

pom.xml

<dependencies>
	<!-- ... -->
	<dependency>
		<groupId>org.springframework.session</groupId>
		<artifactId>spring-session-data-mongodb</artifactId>
	</dependency>
</dependencies>

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.

All you have to do is to add the following Spring Configuration:

@Configuration(proxyBeanMethods = false)
@EnableMongoHttpSession (1)
public class HttpSessionConfig {

	@Bean
	public JdkMongoSessionConverter jdkMongoSessionConverter() {
		return new JdkMongoSessionConverter(Duration.ofMinutes(30)); (2)
	}

}

1	The `@EnableMongoHttpSession` annotation creates a Spring Bean with the name of `springSessionRepositoryFilter` that implements Filter. This filter is what replaces the default `HttpSession` with the MongoDB-backed bean.
2	Configures the session timeout to 30 minutes.

Configuring the MongoDB Connection

Spring Boot automatically creates a MongoClient that connects Spring Session to a MongoDB Server on localhost on port 27017 (default port). In a production environment you need to ensure to update your configuration to point to your MongoDB server. For example, you can include the following in your application.properties

src/main/resources/application.properties

spring.data.mongodb.host=mongo-srv
spring.data.mongodb.port=27018
spring.data.mongodb.database=prod

For more information, refer to Connecting to MongoDB portion of the Spring Boot 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. 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.

MongoDB Sample Application

The MongoDB Sample Application demonstrates how to use Spring Session to transparently leverage MongoDB to back a web application’s HttpSession when using Spring Boot.

Running the MongoDB Sample Application

You can run the sample by obtaining the source code and invoking the following command:

$ ./gradlew :samples:mongo:bootRun

You should now be able to access the application at localhost:8080/

Exploring the security Sample Application

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 your are logged in with the user entered previously. The user’s information is stored in MongoDB rather than Tomcat’s HttpSession implementation.

How does it work?

Instead of using Tomcat’s HttpSession, we are actually persisting the values in Mongo. Spring Session replaces the HttpSession with an implementation that is backed by Mongo. When Spring Security’s SecurityContextPersistenceFilter saves the SecurityContext to the HttpSession it is then persisted into Mongo.

When a new HttpSession is created, Spring Session creates a cookie named SESSION in your browser that contains the id of your session. Go ahead and view the cookies (click for help with Chrome or Firefox).

If you like, you can easily inspect the session using mongo client. For example, on a Linux based system you can type:

The sample application uses an embedded MongoDB instance that listens on a randomly allocated port. The port used by embedded MongoDB together with exact command to connect to it is logged during application startup.

$ mongo --port ...
> use test
> db.sessions.find().pretty()

Alternatively, you can also delete the explicit key. Enter the following into your terminal ensuring to replace 60f17293-839b-477c-bb92-07a9c3658843 with the value of your SESSION cookie:

> db.sessions.remove({"_id":"60f17293-839b-477c-bb92-07a9c3658843"})

Now visit the application at localhost:8080/ and observe that we are no longer authenticated.