Question

We have different services deployed in DSS and we have a different way of caching:

• no cache
• 1 hour cache
• 1 day cache

Is there any way to set this caching directly to each dbs file without using the administration console?

Another way would be to set these three caches through a configuration file and then to refers to them from the dbs files.

The solution we are looking for, is without using the administration console.

Answer 1

It is indeed possible to configure caching for dataservices via a configuration file without using the management console. Each dataservice is deployed as form of a axis2 service. Therefore you can use the “services.xml” file which you would typically use to configure axis2 service related parameters, with dataservices too with a slight modification. That is, if the name of your dataservice is “TestDS” then you have to name your services.xml file as “TestDS_services.xml” and place it inside the dataservices deployment directory which can be located at “DSS_HOME/repository/deployment/server/dataservices”. Then you can include a caching policy having your own values as the parameters inside the aforementioned configuration file. Also it is important to note that, you can engage caching in three levels for a dataservies namely, per service group/per service/per operation.

A sample services.xml is show below.

<serviceGroup>
    <service name="TestDS">
        <!--parameter name="ServiceObjectSupplier">org.apache.axis2.engine.DefaultObjectSupplier</parameter-->
    <Description>Enabling caching through sevices.xml</Description>

    <operation name="op1">
        <messageReceiver class="org.wso2.carbon.dataservices.core.DBInOutMessageReceiver"/>
    <module ref="wso2caching"/>
        <wsp:Policy
            wsu:Id="WSO2CachingPolicy"
            xmlns:wsp="http://schemas.xmlsoap.org/ws/2004/09/policy"
            xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd">
        <wsch:CachingAssertion xmlns:wsch="http://www.wso2.org/ns/2007/06/commons/caching">
        <wsp:Policy>
            <wsp:All>
            <wsch:XMLIdentifier>org.wso2.caching.digest.DOMHASHGenerator</wsch:XMLIdentifier>
            <wsch:ExpireTime>70000</wsch:ExpireTime>
            <wsch:MaxCacheSize>1000</wsch:MaxCacheSize>
            <wsch:MaxMessageSize>1000</wsch:MaxMessageSize>
            </wsp:All>
        </wsp:Policy>
        </wsch:CachingAssertion>
        </wsp:Policy>
    </operation>

    <operation name="op2">
        <messageReceiver class="org.wso2.carbon.dataservices.core.DBInOutMessageReceiver"/>
    <module ref="wso2caching"/>
        <wsp:Policy
            wsu:Id="WSO2CachingPolicy"
            xmlns:wsp="http://schemas.xmlsoap.org/ws/2004/09/policy"
            xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd">
        <wsch:CachingAssertion xmlns:wsch="http://www.wso2.org/ns/2007/06/commons/caching">
        <wsp:Policy>
            <wsp:All>
            <wsch:XMLIdentifier>org.wso2.caching.digest.DOMHASHGenerator</wsch:XMLIdentifier>
            <wsch:ExpireTime>600000</wsch:ExpireTime>
            <wsch:MaxCacheSize>1000</wsch:MaxCacheSize>
            <wsch:MaxMessageSize>1000</wsch:MaxMessageSize>
            </wsp:All>
        </wsp:Policy>
        </wsch:CachingAssertion>
        </wsp:Policy>
    </operation>
        <operation name="op3">
        </operation>

    </service>
  </serviceGroup>

After placing your “data_service_name”_services.xml file inside the aforesaid directory, you have to comment out the following entry from the axis2.xml configuration file that can be located at “DSS_HOME/repository/conf” directory.

<listener class="org.wso2.carbon.core.deployment.DeploymentInterceptor">

Now you’re good to go with your deployment. Restart the server and you’ll be able to get the aforementioned functionality working.

NOTE: You would also want to be informed that a lot of improvements have been done on this space in DSS for our immediate upcoming DSS release. (DSS 3.0.0).

Regards,
Prabath