Add Maven Dependencies and Data Filter for Java Sessions

This page provides the steps required to add Maven Dependencies and defining filter for single-site and multi-site session providers to configure Web Sessions with NCache.

Prerequisites

Java

To learn about the standard packages necessary for java data caching and sessions, refer to the NCache Installation Guide.
To learn about the standard prerequisites required to work with all NCache client-side features, please refer to the given page on Client-Side API Prerequisites.

Defining Filter for Java Sessions

After adding the required Maven dependencies to your application, you need to add the filter in the deployment descriptor of your web application. The deployment descriptor is an XML file named web.xml located in the WEB-INF directory under the application root directory. To ensure correct session caching, apply this as the first filter in your deployment descriptor (as filters execute in the order defined in the deployment descriptor). The class file containing the filter implementation is as shown below:

com.alachisoft.ncache.web.sessionstate.NCacheSessionStoreProvider

To configure a filter, you must define it first under the <filter> tag and then provide a URL mapping for the filter using the <filter-mapping> tag. The following filter configuration means that the filter will be applied to all the URLs in a web application.

<filter>
    <filter-name>NCacheSessionProvider</filter-name>
    <filter-class>com.alachisoft.ncache.web.session.NCacheSessionProvider</filter-class>
</filter>
<filter-mapping>
    <filter-name>NCacheSessionProvider</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

You can configure the NCache session filter with the settings specified in the session.xml file located at %NCHOME%/config. You must specify the configPath with the filter initialization parameter to load the configuration settings.

<init-param>
    <param-name>configPath</param-name>
    <param-value>%NCHOME%/config</param-value>
</init-param>

Note

The value of the configPath must be the installation directory of NCache.

The following is an example of how the deployment descriptor should look like after defining the filter.

<session-config>
    <session-timeout>30</session-timeout>
</session-config>
<filter>
    <filter-name>NCacheSessionProvider</filter-name>
    <filter-class>com.alachisoft.ncache.web.session.NCacheSessionProvider</filter-class>
    <init-param>
        <param-name>configPath</param-name>
        <param-value>%NCHOME%/config</param-value>
    </init-param>
</filter>
<filter-mapping>
    <filter-name>NCacheSessionProvider</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>
<welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
</welcome-file-list>

You can configure the session module as single-regional or multi-regional.

Single-Site Session State Provider

For a single-regional session state provider, specify the session.xml as follows:

<?xml version="1.0" encoding="UTF-8"?>
<servlet-session-config>
    <cache id="demoCache"/>
    <log log-props="log4j.properties"/>
    <locking enable-session-locking="true" retries-count="2" retry-interval="500ms" lock-timeout="36000ms" empty-session-when-locked="false"/>
</servlet-session-config>

Multi-Site Session State Provider

You have to specify one primary and one secondary caches for each web farm in the session.xml file. The primary cache will be used for all local traffic and all the secondary caches will be used when a user is redirected to a different region. The sid-prefix defined for each cache in the session.xml file is added to the session id. This sid-prefix helps direct the client to the cache holding the session.

For the multi-regional session module, specify the following configuration in the session.xml file:

<servlet-session-config>
    <log log-props="log4j.properties"/>
    <locking enable-session-locking="true" retries-count="2" retry-interval="500ms" lock-timeout="36000ms" empty-session-when-locked="false"/>
    <multi-site-cache>
        <primary-cache id="LondonCache" sid-prefix="LDNC"/>
        <secondary-cache id="TokyoCache" sid-prefix="TKYC"/>
        <secondary-cache id="NewYorkCache" sid-prefix="NYKC"/>
    </multi-site-cache>
</servlet-session-config>