Converting StrutsActionWrappers to MVCCommands

Since Liferay Portal 6.1, developers could customize the Portal and Portlet Struts Actions using a Hook and StrutsActionWrappers. For example, the liferay-hook.xml file for a hook that overrode the login portlet’s login action had this entry:

<struts-action>
    <struts-action-path>/login/login</struts-action-path>
    <struts-action-impl>
    com.liferay.sample.hook.action.ExampleStrutsPortletAction
    </struts-action-impl>
</struts-action>

The liferay-hook.xml contains the struts mapping and the new class that overrides the default login action.

The wrapper could extend either BaseStrutsAction or BaseStrutsPortletAction, depending on whether the struts action was a portal or portlet action respectively.

Starting in Liferay DXP 7.0, this mechanism no longer applies for most of the portal portlets because they are no longer using Struts Actions, but instead use MVCCommands.

This tutorial demonstrates how to convert your existing StrutsActionWrappers to MVCCommands.

Converting Your old wrapper to MVCCommands

Converting StrutsActionWrappers to MVCCommands is easier than you may think.

As a review, legacy StrutsActionWrappers needed to implement all the methods, such as processAction, render, and serveResource, even if only one method was being customized. Each of these methods can now be customized independently, using different classes, making the logic simpler and easier to maintain. Depending on the method you customized in your StrutsActionWrapper, you need to use the matching MVCCommand shown below:

• processAction →  MVCActionCommand
• render → MVCRenderCommand
• serveResource → MVCResourceCommand

Look at the ExampleStrutsPortletAction class for a StrutsActionWrapper example. Depending on the actions overridden, the user must use different MVCCommands. In this example, the action and render were overridden, so in order to migrate to the new pattern, you would need to create two classes: MVCActionCommand and MVCRenderCommand.

Next you’ll need to determine the associated mapping that is used by the MVCCommand.

Mapping Your MVCCommand URLs

For most cases, the MVCCommand mapping is the same mapping defined in the legacy struts action.

Using the beginning login example once again, the struts-action-path mapping, /login/login, remains the same for the MVCCommand mapping in Liferay DXP 7.0, but some of the mappings may have changed. It’s best to check Liferay’s source code to determine the correct mapping.

Depending on the URL it is a different parameter:

• RenderURLs contain a parameter named mvcRenderCommandName. For example:

  <portlet:renderURL var="editEntryURL">
      <portlet:param name="mvcRenderCommandName" value="/hello/edit_entry" 
      />
      <portlet:param name="entryId" value="<%= String.valueOf(
      entry.getEntryId()) %>" />
  </portlet:renderURL>    
  

• ActionURLs are contained in the attribute name of the tag library or with the parameter ActionRequest.ACTION_NAME. For example:

  <portlet:actionURL name="/blogs/edit_entry" var="editEntryURL" />
  

• ResourceURLs are contained as the attribute id. For example:

  <portlet:resourceURL id="/login/captcha" var="captchaURL" />
  

Once you have this information, you can override the MVCCommand by following the instructions found in these sections of the Overriding MVC Commands tutorial:

• Overriding MVCActionCommands
• Overriding MVCResourceCommands
• Overriding MVCRenderCommands

Now you know how to convert your StrutsActionWrappers to MVCCommands!

Related Topics

Overriding MVC Commands