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 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
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 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.
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.
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 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.
Liferay Portal has a section of the control panel called Plugins Installation, which you can find under the Server heading. This section not only allows you to see what plugins are installed in your portal, but also it enables you to run the search indexer on those portlets that support it and install new portlets.
Use the dockbar’s Go to menu to select Control Panel. Under the Server heading, select Plugins Installation. You should now see the page which allows you to configure and install portlets.
The default view of the Plugins Installation page shows which plugins are already installed on the system and whether or not they are active. The Portlet Plugins tab allows you reindex certain portlets to improve their searchability. The Theme and Layout Template Plugins tabs display which portal roles can access them.
If you would like to see what plugins are available, you can do so by clicking
the Install More
It’s easy to navigate from the initial page of the Plugin Installer to different pages 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.
After you click the Install More
Find the Web Form Portlet in the list by searching for it or browsing to it. Once you have found it, click on its name. Another page will be displayed which describes the portlet plugin in more detail. Below the description is an Install button. Click this button to install your plugin.
Once you click Install, your chosen plugin will automatically download and be installed on your instance of Liferay. If you have the Liferay console open, you can view the deployment as it happens. When it is finished, you should be able to go back to the Add Application window and add your new plugin to a page in your portal.
The same procedure is used for installing new Liferay themes, layout templates, hooks and web modules. Instead of the Portlet Plugins tab, you would use the appropriate tab for the type of plugin you wish to install to view the list of plugins of that type. For themes, convenient thumbnails (plus a larger version when you click on the details of a particular theme) are shown in the list.
After clicking on the Install button for a theme, the theme becomes available on the Look and Feel tab of any page.
Installing plugins manually is almost as easy as installing plugins via the Plugin Installer. 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 see any plugins displayed in the
Portlet Plugins or Theme Plugins tabs. Instead, you will need to click the
Upload File tab. This gives you a simple interface for uploading a
containing a plugin to your Liferay Portal.
Click the Browse button and navigate your file system to find the portlet or
.war you have downloaded. The other field on the page is optional: you
can specify your own context for deployment. If you leave this field blank, the
default context defined in the plugin (or the
.war file name itself) will be
That’s all the information the Plugin Installer needs in order to deploy your portlet, theme, layout template, hook or web module. Click the Install button and your plugin will be uploaded to the server and deployed. If it is a portlet, you should see it in the Add Content window. If it is a theme, it will be available on the Look and Feel tab in the page definition.
If you do not wish to use the Update Manager or Plugin Installer 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 section on your server in chapter 1. The first time Liferay is launched, it will create 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 will deploy it and make it available for use just as though you’d installed it via the Plugin Installer in the control panel. In fact, this is what the Plugin Installer is doing 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 portlet or theme 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-18.104.22.168.war Expanding: /Users/stephenkostas/java/liferay/bundles/liferay-portal-6.0.4/deploy/weather-portlet-22.214.171.124.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-126.96.36.199.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.
Sometimes plugins fail to install. There can be different reasons for installation failure based on several factors, including
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 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
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
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
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
WEB-INF/classes folder. Here you will find the
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
property would look like the following:
Remember, if you are on a Windows system, use forward slashes instead of back slashes, like so:
Save the file and then restart your container. Now plugins should install correctly.
Instead of changing the hot deploy destination directory in your
portal-ext.properties file, you can do it via the Plugin Installer. To change
the setting this way, navigate to the Plugins Installation page of the control
panel, click the Install More
The setting to change is the field labeled Destination Directory. Change this to the full path to your container’s auto deploy folder from the root of your file system. When you are finished, click the Save button at the bottom of the form. The setting will now take effect without your having to restart your container. Note the setting in the control panel overrides the setting in the properties file.
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
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.
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.
If you don’t have one already, create a
portal-ext.propertiesfile in the Liferay Home folder of your Liferay installation. Add the following directive to it:
Create a folder called
$LIFERAY_HOMEfolder. This is the folder where the Lucene index, Jackrabbit config and deploy folders are.
Make sure the
web.xmlfile inside the plugin you want to install has the following context parameter in it:
Liferay versions 5.2.2 and higher will automatically inject this into the
web.xml file on WebSphere containers.
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
.warfile into an autodeploy folder to have it actually deployed. Because WebSphere does not have an autodeploy feature, we need to separate these two steps.
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.dirin the first step, it will copy the resulting
$LIFERAY_HOME/websphere-deploy. You will see a copied successfully message in the log.
Use WebSphere’s tools to deploy the
.warfile. Make the context root for the
.warfile equal to the file name (i.e.,
/my-first-portlet). Once the
.warfile is deployed, save it to the master configuration.
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.
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
commands to then deploy plugins automatically.
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