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One of the primary ways of extending the functionality of Liferay Portal is by the use of plugins. Plugin is an umbrella term for installable portlet, theme, layout template, hook, Ext and web module Java EE .war files. Though Liferay comes bundled with a number of functional portlets, themes, layout templates, hooks and web modules, plugins provide a means of extending Liferay to be able to do almost anything.

Portlets

Portlets are small web applications that run in a portion of a web page. The heart of any portal implementation is its portlets, because all of the functionality of a portal resides in its portlets. Liferay’s core is a portlet container. The container’s job is to manage the portal’s pages and to aggregate the set of portlets that are to appear on any particular page. This means the core doesn’t contain application code. Instead, all of the features and functionality of your portal application must reside in its portlets.

Portlet applications, like servlet applications, have become a Java standard which various portal server vendors have implemented. The JSR-168 standard defines the portlet 1.0 specification and the JSR-286 standard defines the portlet 2.0 specification. A Java standard portlet should be deployable on any portlet container which supports the standard. Portlets are placed on the page in a certain order by the end user and are served up dynamically by the portal server. This means certain givens that apply to servlet-based projects, such as control over URLs or access to the HttpServletRequest object, don’t apply in portlet projects, because the portal server generates these objects dynamically.

Portal applications come generally in two flavors: 1) portlets can be written to provide small amounts of functionality and then aggregated by the portal server into a larger application or 2) whole applications can be written to reside in only one or a few portlet windows. The choice is up to those designing the application. The developer only has to worry about what happens inside of the portlet itself; the portal server handles building out the page as it is presented to the user.

Most developers nowadays like to use certain frameworks to develop their applications, because those frameworks provide both functionality and structure to a project. For example, Struts enforces the Model-View-Controller design pattern and provides lots of functionality, such as custom tags and form validation, that make it easier for a developer to implement certain standard features. With Liferay, developers are free to use all of the leading frameworks in the Java EE space, including Struts, Spring MVC and Java Server Faces. This allows developers familiar with those frameworks to more easily implement portlets and also facilitates the quick porting of an application using those frameworks over to a portlet implementation.

Additionally, Liferay allows for the consuming of PHP and Ruby applications as portlets so you do not need to be a Java developer in order to take advantage of Liferay’s built-in features (such as user management, sites, organizations, page building and content management). You can also use scripting languages such as Groovy if you wish. You can use the Plugins SDK to deploy your PHP or Ruby application as a portlet and it will run seamlessly inside of Liferay. We have plenty of examples of this; to see them, check out the Plugins SDK from Liferay’s public code repository.

Does your organization make use of any Enterprise Planning (ERP) software that exposes its data via web services? You could write a portlet plugin for Liferay that can consume that data and display it as part of a dashboard page for your users. Do you subscribe to a stock service? You could pull stock quotes from that service and display them on your page, instead of using Liferay’s built-in Stocks portlet. Do you have a need to combine the functionality of two or more servlet-based applications on one page? You could make them into portlet plugins and have Liferay display them in whatever layout you want. Do you have existing Struts, Spring MVC or JSF applications you want to integrate with your portal? It is a straightforward task to migrate these applications into Liferay, then they can take advantage of the layout, security and administration infrastructure that Liferay provides.

Themes

marketplace-envision-theme.png

Figure 15.15: Envision Theme from Liferay’s Theme Repository

Themes are hot deployable plugins which can completely transform the look and feel of the portal. Most organizations have their own look and feel standards which go across all of the web sites and web applications in the infrastructure. Liferay makes it possible for a site designer to create a theme plugin which can be installed, allowing for the complete transformation of the portal to whatever look and feel is needed. There are lots of available theme plugins on Liferay’s web site and more are being added every day. This makes it easier for those who wish to develop themes for Liferay, as you can now choose a theme which most closely resembles what you want to do and then customize it. This is much easier than starting a theme from scratch. You can learn more about theme development in Liferay in Action or the Liferay Development Guide.

marketplace-murali-theme.png

Figure 15.16: Murali Theme from Liferay’s Theme Repository

Layout Templates

Layout Templates are ways of choosing how your portlets will be arranged on a page. They make up the body of your page, the large area into which you can drag and drop portlets. Liferay Portal comes with several built-in layout templates. If you have a complex page layout (especially for your home page), you may wish to create a custom layout template of your own. This is covered in Liferay in Action and the Liferay Development Guide.

Hook Plugins

Hook plugins were introduced with Liferay 5.2. As the name implies, they allow “hooking” into Liferay’s core functionality. This means they enable developers to override or replace functionality that is in the core of the system. You can hook into the eventing system, model listeners and portal properties. You can also override Liferay’s core JSPs with your own. Hooks are very powerful and have been designed to replace most of the reasons for using the extension environment with something that is easier to use and hot deployable.

Web Plugins

Web plugins are regular Java EE web modules designed to work with Liferay. Liferay supports integration with various Enterprise Service Bus (ESB) implementations, as well as Single Sign-On implementations, workflow engines, and so on. These are implemented as web modules used by Liferay portlets to provide functionality.

OSGi Bundles

OSGi (Open Services Gateway initiative) is a framework for developing modular Java applications. Liferay 6.2 introduced support for the OSGi module framework. It hosts an OSGi runtime and allows administrators to deploy OSGi bundles to Liferay. OSGi web application bundles are very similar to standard web application archives except that they must include additional metadata so that they can operate in an OSGi framework. The OSGi specification does not require a specific file extension for web application bundles but they typically have a .jar file extension. Sometimes a .war file extension is used instead.

Deploying an OSGi bundle to Liferay is easy: just copy the bundle to your [Liferay Home]/data/osgi/modules directory. Undeploying is just as easy: just remove the bundle from the [Liferay Home]/data/osgi/modules directory. Note: If you copy an OSGi bundle to your [Liferay Home]/deploy directory, Liferay automatically copies it to your [Liferay Home]/data/osgi/modules directory.

To test Liferay’s OSGi module framework and deploy mechanism, you can use the test-module-framework-shared bundle from Liferay’s plugin repository on Github: test-module-framework-shared. In order to deploy the module framework test plugin from a clone of the liferay-plugins repository, you should first add the following lines to your build.[username].properties file in your liferay-plugins directory. If this file doesn’t exist yet, create it.

liferay.home=[path-to-your-liferay-installation]
auto.deploy.dir=${liferay.home}/deploy

Then navigate to the liferay-plugins/shared/test-module-framework-shared directory in a terminal and run ant deploy. Of course, Apache Ant must be installed on your system for this to work. When the test-module-framework-shared bundle has been deployed, the following message appears in the console:

Activate Test Component

When you remove the test-module-framework-shared bundle from the ${LIFERAY_HOME}/data/osgi/deploy directory, another message appears:

Deactivate Test Component

If you’d like to customize your Liferay Portal instance’s module framework behavior, please refer to the Module Framework section of the portal.properties file. For example, you can set a comma-delimited list of directories to scan for modules to deploy, specify how to often to scan the directories for changes, etc. Remember not to make customizations to the portal.properties file itself but to instead add customized properties to a portal-ext.properties file in your Liferay Home directory.

Configuring Plugins

Liferay Portal has a section of the Control Panel called Plugins Configuration, which you can find under the Apps heading of the Control Panel. The Plugins Configuration section not only allows you to see what plugins are installed on your portal, but also enables you to configure which portal roles can access certain plugins. It also allows you to activate or deactivate portlet plugins. From the Control Panel, click on Plugins Configuration to find an interface which allows you to view and manage installed portlet, theme, and layout template plugins.

The default view of the Plugins Configuration section shows which plugins are already installed on the system. For portlet plugins, you can click on the plugin’s name to view whether or not it’s active and to view or configure the portlet’s permissions. You don’t have to uninstall a plugin to prevent users from accessing the plugin’s functionality; instead, you can deactivate the plugin. To deactivate a plugin, click on the plugin’s name in the Plugins Configuration section of the Control Panel and remove the flag from the Active checkbox. Then click Save. To reactive the plugin later, just flag the Active checkbox again and click Save.

On the Portlet Plugins tab, you have to click on a specific portlet in order to view the plugin’s active/inactive status and to configure the portlet’s permissions. The active/inactive status doesn’t apply to themes or layout templates: if a theme or layout template has been installed, then it’s available for use. The Theme and Layout Template Plugins tabs of the Plugins Configuration section directly display which portal roles can access them.

marketplace-plugins-installation-portlet-tab.png

Figure 15.17: Plugins Installation Portlet Tab Default View

It’s easy to browse through the lists of installed plugins since the plugins are listed alphabetically. You can also change the number of items per page and navigate to a specific page if you know where a particular plugin appears in the list. This is a standard feature of Liferay and you will see it in most of Liferay’s portlets.

Note that the Plugins Configuration section of the Control Panel is for basic configuration: it allows you to active or deactivate portlet plugins, view the existing permissions configuration for various plugins and/or modify the configurations for existing roles. If you need to add permissions to new roles for certain portlets, use the Roles section of the Control Panel and the ActionsDefine Permissions button. Next, let’s learn how to install plugins manually.

Installing Plugins Manually

Installing plugins manually is not quite as easy as installing plugins via the Marketplace interface but it’s still quite simple. There are several scenarios in which you would need to install plugins manually rather than from Liferay’s repositories:

  • Your server is firewalled without access to the Internet. This makes it impossible for your instance of Liferay to connect to the plugin repositories.

  • You are installing portlets which you have either purchased from a vendor, downloaded separately or developed yourself.

  • For security reasons, you do not want to allow portal administrators to install plugins from the Internet before they are evaluated.

You can still use the Control Panel to install plugins that are not available from the online repositories. This is by far the easiest way to install plugins.

If your server is firewalled, you will not be able to install plugins directly from the Liferay Marketplace. Instead, you will need to download the .lpkg file (in the case of a Marketplace app) or .war file (in the case of an individual plugin). Then navigate to the Control Panel and click on App Manager under the Apps heading. Then click on Install. This gives you a simple interface for installing an .lpkg or .war file containing an app or plugin to your Liferay Portal. Use the File Upload option to browse to and install from a local .lpkg or .war file. Use the URL option to install from a remote .lpkg or .war file.

marketplace-plugin-installer-upload-file.png

Figure 15.18: Installing a Plugin Manually

That’s all the information the App Manager needs in order to deploy your portlet, theme, layout template, hook, or web plugin. Click the Install button and your plugin will be uploaded to the server and deployed. If it is a portlet, theme, or layout template you should see it in the appropriate tab of the Plugins Configuration interface.

If you do not wish to use the App Manager to deploy plugins, you can also deploy them at the operating system level. The first time Liferay starts, it creates a hot deploy folder which is, by default, created inside the Liferay Home folder. This folder generally resides one directory up from where your application server is installed, though it may be elsewhere depending on which application server you are running. To find out where the Liferay Home folder is for your application server, please see the article on your server in this guide’s Installation and Setup section. The first time Liferay is launched, it creates a folder structure in Liferay Home to house various configuration and administrative data. One of the folders it creates is called deploy. If you copy a portlet or theme plugin into this folder, Liferay hot deploys it and makes it available for use just as though you’d installed it via App Manager in the Control Panel. In fact, this is what the App Manager does behind the scenes.

You can change the defaults for this directory structure so it is stored anywhere you like by modifying the appropriate properties in your portal-ext.properties file. Please see the above section on the portal-ext.properties file for more information.

To have Liferay hot deploy a plugin, copy the plugin into your hot deploy folder, which by default is in [Liferay Home]/deploy. If you are watching the Liferay console, you should see messages like the following:

16:11:47,616 INFO [PortletAutoDeployListener:71] Copying portlets for
/Users/stephenkostas/java/liferay/bundles/liferay-portal-6.0.4/deploy/weather-portlet-6.0.4.1.war

Expanding:
/Users/stephenkostas/java/liferay/bundles/liferay-portal-6.0.4/deploy/weather-portlet-6.0.4.1.war
into
/Users/stephenkostas/java/liferay/bundles/liferay-portal-6.0.4/tomcat-6.0.26/temp/20100729161147694

Copying 1 file to
/Users/stephenkostas/java/liferay/bundles/liferay-portal-6.0.4/tomcat-6.0.26/temp/20100729161147694/WEB-INF

Copying 1 file to
/Users/stephenkostas/java/liferay/bundles/liferay-portal-6.0.4/tomcat-6.0.26/temp/20100729161147694/WEB-INF/classes

Copying 1 file to
/Users/stephenkostas/java/liferay/bundles/liferay-portal-6.0.4/tomcat-6.0.26/temp/20100729161147694/WEB-INF/classes

Copying 1 file to
/Users/stephenkostas/java/liferay/bundles/liferay-portal-6.0.4/tomcat-6.0.26/temp/20100729161147694/META-INF

Copying 37 files to
/Users/stephenkostas/java/liferay/bundles/liferay-portal-6.0.4/tomcat-6.0.26/webapps/weather-portlet

Copying 1 file to
/Users/stephenkostas/java/liferay/bundles/liferay-portal-6.0.4/tomcat-6.0.26/webapps/weather-portlet

Deleting directory
/Users/stephenkostas/java/liferay/bundles/liferay-portal-6.0.4/tomcat-6.0.26/temp/20100729161147694

16:11:48,072 INFO [PortletAutoDeployListener:81] Portlets for
/Users/stephenkostas/java/liferay/bundles/liferay-portal-6.0.4/deploy/weather-portlet-6.0.4.1.war
copied successfully. Deployment will start in a few seconds.

Jul 29, 2010 4:11:50 PM org.apache.catalina.startup.HostConfig
deployDirectory

INFO: Deploying web application directory weather-portlet

16:11:50,585 INFO [PortletHotDeployListener:222] Registering portlets
for weather-portlet

16:11:50,784 INFO [PortletHotDeployListener:371] 1 portlet for
weather-portlet is available for use

The available for use message means your plugin was installed correctly and is available for use in the portal.

Plugin Troubleshooting

Sometimes plugins fail to install. There can be different reasons for installation failure based on several factors, including

  • Liferay configuration

  • The container upon which Liferay is running

  • Changing the configuration options in multiple places

  • How Liferay is being launched

You can often tell whether or not you have a plugin deployment problem by looking at the Liferay server console. If the hot deploy listener recognizes the plugin, you’ll see a plugin copied successfully message. If this message is not followed up by an available for use message then you have an issue with your plugin deployment configuration, probably due to one of the factors listed above.

Let’s take a look at each of these factors.

Liferay Configuration Issues

Liferay by default comes as a bundle or as a .war file. Though every effort has been made to make the .war file as generic as possible, sometimes the default settings are inappropriate for the container upon which Liferay is running. Most of these problems were resolved in Liferay 4.3.5 with the addition of code that allows Liferay to determine which application server it is running on and adjust the way it deploys plugins as a result. If you have upgraded from one of these older versions, you may still have settings in your portal.ext.properties file that are no longer needed. One of these settings is the manual override of the default value of auto.deploy.dest.dir.

In versions of Liferay prior to 4.3.5, there is a property called auto.deploy.dest.dir that defines the folder where plugins are deployed after the hot deploy utilities have finished preparing them. This folder maps to a folder the container defines as an auto-deploy or a hot deploy folder. By default in older versions of Liferay, this property is set to ../webapps. This default value works for Tomcat containers (if Tomcat has been launched from its bin folder) but will not work for other containers that define their hot deploy folders in a different place. In newer versions of Liferay, this value is automatically set to the default for the application server upon which Liferay is running.

For example, Glassfish defines the hot deploy folder as a folder called autodeploy inside of the domain folder in which your server is running. By default, this is in <Glassfish Home>/domains/domain1/autodeploy. JBoss defines the hot deploy folder as a root folder inside the particular server configuration you are using. By default, this is in <JBoss Home>/server/default/deploy. WebLogic defines this folder inside of the domain directory. By default, this is in <Bea Home>/user_projects/domains/<domain name>/autodeploy.

The best thing to do when upgrading to newer versions of Liferay Portal is to remove this property altogether. It is not needed, as the autodetection of the container handles the hot deploy location. If, for whatever reason, you need to customize the location of the hot deploy folder, follow the instructions below.

You will first need to determine where the hot deploy folder is for the container you are running. Consult your product documentation for this. Once you have this value, there are two places in which you can set it: in the portal-ext.properties file and in the Plugin Installer portlet.

To change this setting in the portal-ext.properties file, browse to where Liferay was deployed in your application server. Inside of this folder should be a WEB-INF/classes folder. Here you will find the portal-ext.properties file. Open this file in a text editor and look for the property auto.deploy.dest.dir. If it does not appear in the file, you can add it. The safest way to set this property, as we will see later, is to define the property using an absolute path from the root of your file system to your application server’s hot deploy folder. For example, if you are using Glassfish, and you have the server installed in /java/glassfish, your auto.deploy.dest.dir property would look like the following:

auto.deploy.dest.dir=/java/glassfish/domains/domain1/autodeploy

Remember, if you are on a Windows system, use forward slashes instead of back slashes, like so:

auto.deploy.dest.dir=C:/java/glassfish/domains/domain1/autodeploy

Save the file and then restart your container. Now plugins should install correctly.

If you are having hot deploy trouble in Liferay versions 4.3.5 and greater, it is possible the administrator of your application server has changed the default folder for auto deploy in your application server. In this case, you would want to set auto.deploy.dest.dir to the customized folder location as you would with older versions of Liferay. In Liferay 4.3.5 and greater, this setting still exists but is blank. Add the property to your portal-ext.properties file and set its value to the fully qualified path to the auto deploy folder configured in your application server.

Deploy Issues for Specific Containers

Some containers, such as WebSphere┬«, don’t have a hot deploy feature. Unfortunately, these containers do not work with Liferay’s hot deploy system. But this does not mean you cannot install plugins on these containers. You can deploy plugins manually using the application server’s deployment tools. Liferay is able to pick up the portlet plugins once they get deployed to the container manually, especially if you add it to the same Enterprise Application project that was created for Liferay.

When Liferay hot deploys portlet and theme .war files, it sometimes makes modifications to those files right before deployment. In order to successfully deploy plugins using an application server vendor’s tools, you will want to run your plugins through this process before you attempt to deploy them.

Navigate back to the Configuration tab of the Plugin Installer. Enter the location you would like plugin .war files to be copied to after they are processed by Liferay’s plugin installer process into the Destination Directory field. You will use this as a staging directory for your plugins before you install them manually with your server’s deployment tools. When you are finished, click Save.

Now you can deploy plugins using the Plugin Installer portlet or by dropping .war files into your auto deploy directory. Liferay will pick up the files, modify them and then copy the result into the destination directory you have configured. You may then deploy them from here to your application server.

Example: WebSphere ® Application Server

  1. If you don’t have one already, create a portal-ext.properties file in the Liferay Home folder of your Liferay installation. Add the following directive to it:

    auto.deploy.dest.dir=${liferay.home}/websphere-deploy

  2. Create a folder called websphere-deploy inside your $LIFERAY_HOME folder. This is the folder where the Lucene index, Jackrabbit config and deploy folders are.

  3. Make sure the web.xml file inside the plugin you want to install has the following context parameter in it:

    <context-param\>
    
    <param-name\>com.ibm.websphere.portletcontainer.PortletDeploymentEnabled</param-name\>
    
    <param-value\>false</param-value\>
    
    </context-param\>
    

    Liferay versions 5.2.2 and higher will automatically inject this into the web.xml file on WebSphere containers.

  4. The WebSphere deploy occurs in two steps. You will first use Liferay’s tools to “pre-deploy” the file and then use WebSphere’s tools to do the actual deployment. This is because Liferay makes deployment-time modifications to the plugins right before they are actually deployed to the application server. For other application servers, this can usually be done in one step, because Liferay can make the modifications and then copy the resulting .war file into an autodeploy folder to have it actually deployed. Because WebSphere does not have an autodeploy feature, we need to separate these two steps.

  5. Deploy your .war file using Liferay’s Plugin Installer or by copying it into $LIFERAY_HOME/deploy. Liferay will make its modifications, and because we changed the auto.deploy.dest.dir in the first step, it will copy the resulting .war file into $LIFERAY_HOME/websphere-deploy. You will see a copied successfully message in the log.

  6. Use WebSphere’s tools to deploy the .war file. Make the context root for the .war file equal to the file name (i.e., /my-first-portlet). Once the .war file is deployed, save it to the master configuration.

  7. Go back to the Applications → Enterprise Applications screen in the WebSphere Admin Console. You will see your portlet is deployed but not yet started. Start it.

  8. Liferay will immediately recognize the portlet has been deployed and register it. The portlet will be automatically started and registered upon subsequent restarts of WebSphere.

Experienced WebSphere system administrators can further automate this by writing a script which watches the websphere-deploy directory and uses wsadmin commands to then deploy plugins automatically.

Changing the Configuration Options in Multiple Places

Sometimes, especially during development when several people have administrative access to the server at the same time, the auto deploy folder location may inadvertently be customized in both the portal-ext.properties file and in the Control Panel. If this happens, the value in the Control Panel takes precedence over the value in the properties file. If you go into the Control Panel and change the value to the correct setting, plugin deployment will start working again.

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