The web was once thought of as a number of islands of applications in a vast universe of “cyberspace.” Many web sites attempted to make their island the biggest. Some succeeded to a large extent and some failed. More recently, the concept of the web as an application itself has taken hold, and so widgets have become very popular nowadays. This concept is part of the “Web 2.0” concept and is very much enabled by widgets. What is a widget? A widget is a small piece of code which provides a piece of functionality, can be included on any web site, but does not necessarily have to be hosted by that web site. If you have ever embedded a YouTube video on your own web site so that users could watch a video without actually having to visit http://youtube.com, then you’ve already used a widget.
Liferay supports serving its portlets as widgets. You can embed a particular instance of a portlet running on your site into another site, such as Facebook. This opens up a whole new avenue of exposure to your web site that you would not have had otherwise. In fact, this is how all those Facebook games work.
Figure 4.11: The Sharing tab of the Portlet Configuration Dialog Box allows you to share your portlet in a variety of ways.
To share one of your portlets as a widget, open the Configuration dialog box from the portlet’s title bar and select the Sharing tab. There are five sub-tabs under sharing: Any Web Site, Facebook, OpenSocial Gadget, Netvibes, and Friends.
Any Web Site
Copy and paste the provided snippet of JavaScript code into the web site to which you want to add the portlet as a widget. That’s all you need to do. When a user loads the page on the other web site, the code will pull the relevant portlet from your site and display it.
You can add any Liferay portlet as an application on Facebook. To do this, you must first get a developer key. A link for doing this is provided to you in the Facebook tab. You’ll have to create the application on Facebook and get the key and canvas page URL from Facebook. Once you’ve done this, you can copy and paste their values into the Facebook tab. Your portlet will now be available on Facebook as a Facebook application.
Figure 4.12: Liferay's Forums on Facebook is an example of sharing the Message Boards portlet.
Incidentally, this makes Liferay a fantastic platform upon which to build applications for Facebook. See the Liferay Developer’s Guide or Liferay in Action for more details.
OpenSocial Gadget
OpenSocial comprises a container and a set of APIs for social networking and other web applications. iGoogle is a service provided by Google that lets users create a customizable page and add Gadgets to that page. Liferay can serve up portlets to be used as Open Social Gadgets on iGoogle or other OpenSocial-compatible pages.
To serve a Liferay portlet on iGoogle, check the box labeled Allow users to add [portlet-name] to iGoogle. Then copy and paste the URL provided into Google’s Add a feed or gadget feature on the iGoogle configuration page. Your Liferay portal instance will serve that portlet directly onto your iGoogle page. The URL provided is unique to the specific instance of the portlet, so you could serve multiple instances of the same portlet as different Google Gadgets.
You could use this feature to allow users to view what’s happening on your portal at a glance, using asset publishers or custom RSS feeds. You could also use Liferay’s API to build your own portlet and provide the URL for users to place on their iGoogle pages.
Netvibes
Netvibes offers a similar service to iGoogle–users can log in, create their own personal portal, called a dashboard, and add customizable widgets to the dashboard that they create. To set up Netvibes support for a particular portlet, check the Allow users to add [portlet-name] to Netvibes pages box. You can then use the provided URL to create a custom Netvibes widget based on the instance of the portlet that you’re using.
Friends
The final sub-tab of the Sharing tab is called Friends. This tab has a single check box that allows you to give your friends permission to add the application as a widget to another web site. This could be particularly useful for your blog or calendar if you wish to share them.
Next, let’s explore what the Recycle Bin does for your Liferay applications.