This guide describes how to configure Apache Geode as a provider in Spring Session to transparently manage
a Web application’s javax.servlet.http.HttpSession using XML configuration.
| The completed guide can be found in the HttpSession with Apache Geode (P2P) using XML Sample Application. |
1. Updating Dependencies
Before using Spring Session, you must ensure that the required dependencies are included.
If you are using Maven, include the following dependencies in your pom.xml:
<dependencies>
<!-- ... -->
<dependency>
<groupId>org.springframework.session</groupId>
<artifactId>spring-session-data-geode</artifactId>
<version>2.1.2.RELEASE</version>
<type>pom</type>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-web</artifactId>
<version>5.1.3.RELEASE</version>
</dependency>
</dependencies>2. Spring XML Configuration
After adding the required dependencies and repository declarations, we can create the Spring configuration.
The Spring configuration is responsible for creating a Servlet Filter that replaces the
javax.servlet.http.HttpSession with an implementation backed by Spring Session and Apache Geode.
Add the following Spring configuration:
<context:annotation-config/>
<context:property-placeholder/>
(1)
<util:properties id="gemfireProperties">
<prop key="name">SpringSessionDataGeodeXmlP2pSample</prop>
<prop key="log-level">${spring.data.gemfire.cache.log-level:error}</prop>
</util:properties>
(2)
<gfe:cache properties-ref="gemfireProperties"/>
(3)
<bean class="org.springframework.session.data.gemfire.config.annotation.web.http.GemFireHttpSessionConfiguration"
p:maxInactiveIntervalInSeconds="30"/>| 1 | (Optional) First, we can include a Properties bean to configure certain aspects of the Apache Geode peer Cache
using {data-store-docs}/reference/topics/gemfire_properties.html[Pivotal GemFire Properties]. In this case, we are just
setting Apache Geode’s “log-level” using an application-specific System property, defaulting to “warning”
if unspecified. |
| 2 | We must configure an Apache Geode peer Cache instance. We initialize it with the Apache Geode properties. |
| 3 | Finally, we enable Spring Session functionality by registering an instance of GemFireHttpSessionConfiguration. |
| For more information on configuring Spring Data for Apache Geode, refer to the {sdg-docs}[Reference Guide]. |
3. XML Servlet Container Initialization
The Spring XML Configuration created a Spring bean named springSessionRepositoryFilter
that implements javax.servlet.Filter. The springSessionRepositoryFilter bean is responsible for replacing the
javax.servlet.http.HttpSession with a custom implementation that is backed by Spring Session and Apache Geode.
In order for our Filter to do its magic, we need to instruct Spring to load our session.xml configuration file.
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 context parameter value and picks up our session.xml configuration file.
Finally, we need to ensure that our Servlet container (i.e. Tomcat) uses our springSessionRepositoryFilter
for every HTTP 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 HTTP request
the DelegatingFilterProxy is invoked, delegating to the springSessionRepositoryFilter.
4. HttpSession with Apache Geode (P2P) using XML Sample Application
4.1. Running the Apache Geode XML Sample Application
You can run the sample by obtaining the source code and invoking the following command:
$ ./gradlew :spring-session-sample-xml-gemfire-p2p:tomcatRun
You should now be able to access the application at http://localhost:8080/.
4.2. Exploring the Apache Geode XML Sample Application
Try using the application. Fill out the form with the following information:
-
Attribute Name: username
-
Attribute Value: john
Now click the Set Attribute button. You should now see the values displayed in the table.
4.3. How does it work?
We interact with the standard HttpSession in the SessionServlet shown below:
public class SessionServlet extends HttpServlet {
private static final long serialVersionUID = 2878267318695777395L;
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String attributeName = request.getParameter("attributeName");
String attributeValue = request.getParameter("attributeValue");
request.getSession().setAttribute(attributeName, attributeValue);
response.sendRedirect(request.getContextPath() + "/");
}
}Instead of using Tomcat’s HttpSession, we are actually persisting the session in Apache Geode.