When indexing a shared folder, it enable to add the value of the dc:source property to wl:isExposedAs. It is possible to apply a transformation on the value to be copied. To let this work, it's need to add a context file in either your tomcat or liferay configuration and to let this service use the URL of your server as exposition pattern.
Homepage POM file JAR file Javadoc'org.ow2.weblab.webservices:local-file-exposer:2.0'