[Liferay]liferay hooks overview and exercise

Hook overview

• Hooks were introduced in Liferay 5.1 as an alternate developmentapproach to the Liferay Extension Environment.
• Hooks are a type of Liferay Plugin and were designed to be smallerin size than the Extension Environment and more modular.
• Hooks were also designed to be hot-deployable.
• Over the last several versions of Liferay, the capabilities of Hookshave been expanded and are generally preferred over working in the ExtensionEnvironment or the EXT Plugin whenever possible.

HOOKS ADVANTAGES

• Hot deployable
  • Changes are made available as soon as they are deployed.
  • Changes are removed as soon as they are undeployed.
• Useful as a light weight customization archive. Examples:
  • Seven Cogs
  • Social Office
  • TweetRay

CUSTOMIZABLE ELEMENTS

• The following elements can be customized from a hook:
  • Change the configuration
  • Customize language keys
  • Add or overwrite JSP files
  • Indexer Post Processer
  • Provide custom services implementations
  • Override Struts Actions

CREATE TRAINING HOOK

1. Go to File → New → LiferayProject.
2. Project name: training
3. Display name: Training Hook
4. Select the SDK and Liferayruntime you have configured.
5. Select the Hook plug-in type.
6. Click Finish

LIFERAY-HOOK.XML

• At this point, we have created a Liferay Hook Plugin Project, but wehaven't actually created a Hook yet.

• Take a look at liferay-hook.xml, the descriptor of the hook.
• The liferay-hook.xml file is used to identify the types of hooks thatthis hook plugin will contain.
• To see a listing of the different types of hooks allowed, refer tohttp://www.liferay.com/dtd/liferay-hook_6_1_0.dtd.
• You can create different Hook Plugins for different purposes, or youcan combine several different Hooks into a single project.
• In this exercise, we will be adding several Hooks to a single HookPlugin project.

CUSTOMIZING PROPERTIES

• Ourfirst Hook will customize the portal.properties and implement a custompost-login action.

• Not all the properties can be modified yet by a hook — there is a limited set defined in the DTD that are most popular and applicable.
  • Default landing page, enable/disable public and private user pages, ...
  • Events(Startup, service, login, logout...etc), model listeners...
• Simplevalues are overwritten.
• Listvalues are appended.
• Properties can be overwritten in the portal.properties file defined in liferay-hook.xml.

CUSTOMIZING PROPERTIES

• Liferay Portal provides a pluggable mechanism whereby you canregister classes that get fired on pre-login and post-login.
• Event classes are specified in portal.propertiesby overriding the following key values:
  • login.events.pre
  • login.events.post
• To create a cookie with login info, we’ll create an event class andappend the class name tologin.events.post.

CREATE CUSTOM POST LOGIN ACTION

1. With the training-hookselected, click File → New → Liferay Hook.
2. Hook plug-in project: traininghook
3. Check the Portal propertiescheck box.
4. Click Next.
   1. 
      
5. Accept the default path for the Portal properties file.
6. Click the Add... button to Define actions to be executed on portal events.
7. For Event: click Select... and choose login.events.post and clickOK.
   1. For Class: click New and enter:
   2. Classname:  CreateCookieAction
8. Java Package:  com.liferay.training.events
9. Click Create, then Ok, then Finish.
   1. 
      
10. Replace the content of CreateCookieAction.java with snippet 01-CreateCookieAction.java
11. Save and deploy your hook.
    1. After login, you should see a line similar to the following in the console:
    • Added TRAINING_COOKIE value to response:companyId=10160,userId=10202
    • 
      

• You'l find that Liferay DeveloperStudio added one line into the portal.propertiesfile (docroot/WEB-INF/src):
  • login.events.post=com.liferay.training.events.CreateCookieAction
• This is telling the portal to callthe CreateCookieAction when a user islogged in.