Access Controller Resolvers

In Lenya, the AccessController is chosen dynamically, depending on the requested URL. An AccessControllerResolver resolves the appropriate AccessController for a URL.

To obtain an AccessControllerResolver, the AccessControllerResolverSelector is used. A component which wants to obtain an AccessController asks the selector for the ComposableAccessControllerResolver. The ComposableAccessControllerResolver itself uses the selector to obtain its child AccessControllerResolvers.

<role name="org.apache.lenya.ac.AccessControllerResolverSelector"
    shorthand="access-controller-resolvers"
    default-class="org.apache.avalon.excalibur.component.ExcaliburComponentSelector">
  <hint shorthand="configurable"
      class="org.apache.lenya.ac.impl.ConfigurableAccessControllerResolver"/>
  <hint shorthand="publication"
      class="org.apache.lenya.cms.ac.PublicationAccessControllerResolver"/>
  <hint shorthand="composable"
      class="org.apache.lenya.ac.impl.ComposableAccessControllerResolver"/>
</role>

<access-controller-resolvers>
  <component-instance logger="lenya.ac.accesscontrollerresolver.publication"
    class="org.apache.lenya.cms.ac.PublicationAccessControllerResolver"
    name="publication">
  </component-instance>
  <component-instance logger="lenya.ac.accesscontrollerresolver.global"
    class="org.apache.lenya.ac.impl.ConfigurableAccessControllerResolver"
    name="global">
    <access-controller type="global"/>
  </component-instance>
  <component-instance logger="lenya.ac.accesscontrollerresolver.composable"
    class="org.apache.lenya.ac.impl.ComposableAccessControllerResolver"
    name="composable">
    <resolver type="publication"/>
    <resolver type="global"/>
  </component-instance>
</access-controller-resolvers>

The PublicationAccessControllerResolver looks for a config/ac.xconf file inside the publication. If you want to use multiple AccessControllers within your Lenya installation, just declare them in the cocoon-xconf.xsl file and choose the type in the config/ac.xconf file. The type attribute selects an AccessController from the definitions in cocoon.xconf.

You have to configure the complete AccessController in this file. For instance, if you want to use a BypassableAccessController together with a certain set of components, you declare it as follows:

<?xml version="1.0"?>
<access-controller type="bypassable">
  
  <accreditable-manager type="file">
    <parameter name="directory"
        value="context:///lenya/pubs/mypub/config/ac/passwd"/>
  </accreditable-manager>
  
  <policy-manager type="document">
    <policy-manager type="file">
      <parameter name="directory"
          value="context:///lenya/pubs/mypub/config/ac/policies"/>
    </policy-manager>
  </policy-manager>
  
  <authorizer type="policy"/>
  
  <authorizer type="usecase">
    <parameter name="configuration"
        value="context:///lenya/pubs/default/config/ac/usecase-policies.xml"/>
  </authorizer>
  
  <authorizer type="workflow"/>
  
</access-controller>

The ConfigurableAccessControllerResolver can be configured with an AccessController directly inside cocoon.xconf:

<component-instance logger="lenya.ac.accesscontrollerresolver"
    class="org.apache.lenya.ac.impl.ConfigurableAccessControllerResolver"
    name="global">
  <access-controller type="global"/>
</component-instance> 

The ComposableAccessControllerResolver is configured with a list of AccessControllerResolvers. Each one of these resolvers is invoked until one is successful. If no resolver finds an AccessController, the ComposableAccessControllerResolver returns null.

<component-instance logger="lenya.ac.accesscontrollerresolver"
    class="org.apache.lenya.ac.impl.ComposableAccessControllerResolver"
    name="composable">
  <resolver type="publication"/>
  <resolver type="global"/>
</component-instance>