Performing a Custom Action

Hooks are useful for triggering custom actions on common portal events, like user log in or system start up. The actions for each of these events are defined in portal.properties, so we’ll need to extend this file to create a custom action. Hooks make this a simple task.

1. Create the directory example-hook/docroot/WEB-INF/src/com/liferay/sample/hook, and create the file LoginAction.java inside it with this content:

   package com.liferay.sample.hook;
   
   import com.liferay.portal.kernel.events.Action;
   import javax.servlet.http.HttpServletRequest;
   import javax.servlet.http.HttpServletResponse;
   
   public class LoginAction extends Action {
       public void run(HttpServletRequest req, HttpServletResponse res) {
           System.out.println("## My custom login action");
       }
   }
   

2. Create a portal.properties file inside example-hook/docroot/WEB-INF/src with this content:

   login.events.pre=com.liferay.sample.hook.LoginAction
   

3. Edit liferay-hook.xml inside example-hook/docroot/WEB-INF, adding the following line above <custom-jsp-dir>:

   <portal-properties>portal.properties</portal-properties>
   

4. Redeploy your hook. Once deployment is complete, log out and back in, and you should see your custom message, ## My custom login action, displayed in the terminal window running Liferay.

Custom action hook plugins aren’t limited to the log in event. You can define custom actions for other events, too. For actions that require access to the HttpServletRequest, extend com.liferay.portal.kernel.events.Action; for others, extend com.liferay.portal.struts.SimpleAction.

Important: For better forward compatibility, use hooks to customize Struts actions rather than Ext plugins. For more information, see the Properties Reference document.

Extending and overriding portal properties is just as easy, so let’s do that next.