Just like siblings have common features inherited from their parents, applications that ship with Liferay also share common features. These include look and feel, communication, scoping, sharing, permissions, archive configurations, and exporting/importing portlet data. So before we get into the nitty gritty of the applications themselves, it’s best to cover these common features first, starting with the look and feel configuration options.
An administrator can access the look and feel configuration menu of any Liferay portlet by clicking on the wrench icon at the top right corner of the portlet and selecting Look and Feel. The location of the wrench icon and other portlet icons (minimixe, maximize, and remove) may vary, depending on your theme. Liferay portlets’ look and feel dialog boxes contain seven tabs:
- Portlet Configuration
- Text Styles
- Background Styles
- Border Styles
- Margin and Padding
- Advanced Styling
- WAP Styling
After making customizations on any tab, remember to click the Save button to apply your changes. To see the effect of your changes, you may have to refresh the page. If you don’t like the effect of your changes, click the Reset button to discard them.
On the Portlet Configuration tab, you can check the Use Custom Title box to rename your portlet’s title. The value you enter in the Portlet Title box will be displayed at the top of the portlet window on the page. You can also select a language from the Portlet Title dropdown menu. If you’ve provided a language key translation for the language you select, the your portlet’s title will be displayed in the selected language.
If you select a page in the Link Portlet URLs to Page dropdown menu, all portlet URLs will point to the page you selected. The current page is the default. Note that you can use the Asset Publisher’s View in a Specific Portlet feature and web content articles’ Display Page attribute to achieve a more elegant solution for displaying the full view of web content articles on specific pages. Please see the Display Page section of chapter 5 for details.
You can also choose whether or not to display borders around your portlet. By default, borders are displayed. Be careful about turning portlet borders off; some themes assume that portlet borders are turned on and may not display correctly with them turned off.
The Text Styles tab allows you to configure format of the text that appears in the portlet. The fonts you can choose from include Arial, Georgia, Times New Roman, Tahoma, Trebuchet MS, and Verdana. Arial is the default. You can set the text to bold, italics, or both. You can set the font size anywhere from 0.1 em to 12 em, with 0.1 em increments. 1 em is the default. You can set the text color to any six digit hex color code. If you’d like help choosing a color, click on the pencil icon to open the color palette. You can set the text alignment to left, center, right, or justified. (Justified text is both left and right aligned.) You can set an underline, overline, or strikethrough as the text decoration. The default text decoration is none.
You can set the word spacing anywhere from -1 em to 0.95 em, with 0.5 em increments. 0 em is the default. You can set the line height anywhere from 0 em to 12 em, with 0.1 em increments. 0 em is the default. Finally, you can set the letter spacing anywhere from -10 px to 50 px, with 1 px increments. 0 px is the default.
The Background Styles tab allows you to specify the portlet’s background color. You can enter any six digit hex color code or you click on the pencil icon to use the color palette.
On the Border Styles tab, you can configure your portlet’s border width, border style, and border color. For each of these attributes, leave the Same for All box checked to apply the same settings to top, right, bottom, and left borders.
For border width, you can specify any % value, em value, or px value. For border style, you can select dashed, double, dotted, groove, hidden, inset, outset, ridge, or solid. For border color, you can enter any six digit hex color code, just like for the text color and background color. You can also use the color palette.
The Margin and Padding tab allows you to specify margin and padding lengths for the edges of your portlet. Just like for border styles, leave the Same for All box checked to apply the same settings to each side (top, right, bottom, and left) of the portlet.
For both padding and margin, you can specify any % value, em value, or px value.
The Advanced Styling tab displays current information about your portlet, including your portlet’s Liferay ID and CSS classes.
On this tab, you can also enter custom CSS class names for your portlet and custom CSS code. Clicking the Add a CSS rule for just this portlet or Add a CSS rule for all portlets like this one links adds the CSS code shells into your custom CSS text box. If you check the Update my styles as I type box, your CSS code will be dynamically applied to your portlet so you can see the effects of your edits.
The WAP Styling tab allows you to specify a custom portlet title that will be displayed when mobile devices using the Wireless Application Protocol make page requests. You can also set the initial window state to normal or minimized. Normal is the default.
Next, let’s discuss exporting and importing portlet data.
Some Liferay portlets allow you to export or import portlet data. These include
many of Liferay’s collaborative applications, such as the Blogs, Wiki, and
Message Boards portlets. To export or import portlet data, right-click on the
wrench icon of your portlet and select Export/Import. Exporting portlet data
.lar file that you can save and import into another portlet
applicaton of the same type. To import portlet data, you must select a
file. Be careful not to confuse portlet-specific
.lar files with
.lar files. See the Backing up and Restoring Pages section of
chapter 2 for a discussion of exporting and importing data across an entire
Each portlet has different configuration options. Checking the Setup box selects the portlet’s saved configuration for export. Checking the User Preferences box selects saved portlet configurations of specific users. The Data box is the most important one–check this to select your portlet’s data (like blog entries, message board posts, or wiki articles, for example) for export. When you check the Data box, more options appear, allowing you to choose specific kinds of metadata to include and to select a data range. Check the Permissions box if you’d like to export your the permissions defined for your portlet. When you check this box, a subbox called Permissions Assigned to Roles appears. If you wish, you can export your portlet’s permissions but not the permissions assigned to roles. Finally, you can check the Categories box to include categories for export. When selected, all categories referenced by portlet data will be exported or imported, keeping their hierarchy.
When you import portlet data, only the data types you select will be
overwritten. If you’d like to import portlet data, you have to select a
file. You can import any items that were included when your
.lar file was
created. Note that user preferences can only be successfully imported when the
user UUIDs match. Additionally, you can import any archived setups into your
portlet, if any. Archived setups provide a means to save multiple portlet
configurations and to switch between them. We discuss archived setups below. If
you check the Delete portlet data before importing box, all data created by
the portlets will be deleted just before the import process. Be careful, some
portlets on others pages may be referencing this data.
Next, let’s discuss the concept of a portlet’s scope.
As we learned earlier, roles can be scoped by the portal, by a site, or by an organization. A role only takes effect within its scope. For example, a Message Boards Administrator role with complete access to the Message Boards portlet has different permissions based on the role’s scope. If it’s a portal role, members have permission to administer message boards across the entire portal. If it’s a site role, members only have permission to administer message boards within the site where they’ve been assigned the role. For organizations with sites, site roles are automatically assigned to organization members based on the organization roles they have. So for an organization-scoped Message Boards administrator role, members only have permission to administer message boards within the site of the organization that assigned the role to them.
We also use the word scope to refer to the data set of a portlet. By default, when a portlet is added to a page in a site, it is scoped for that site. This means that its data belongs to that site. If the portlet is added to a page in a different site, it employs a completely different data set. This enables you to place a Message Boards portlet in one site with one set of categories and threads, and place another Message Boards portlet in different site with a different set of categories and threads.
Scoping by site means that you can only have one Message Boards portlet per site. If you add one Message Boards portlet to a page in a site and add another Message Boards portlet to a different page in the same site, the second Message Boards portlet contains exactly the same data as the first. This is because, by default, the Message Boards portlet is scoped by site. Most of Liferay’s other portlets also default to being scoped by site.
To avoid this limitation, many Liferay portlets can be scoped by page. In this case, the data sets of page-scoped portlets serve a single page, not an entire site. If you set the scope of a portlet to page instead of site, you can add any number of these portlets to different pages, and then they have different sets of data. This allows you to have more than one message board per site if you wish. Most portlets, however, default to the “native” configuration, and have their scopes set to the site where they are placed.
Unless otherwise noted, all the portlets in this chapter support scoping by portal (global), site (default), or page (select layout → current page). This grants you some flexibility in how you want to set up your portal. You can configure the scope of a portlet with just a few simple steps.
Click the Menu icon in the portlet window (the wrench).
Select the Scope tab.
Use the drop-down menu to set the scope.
That’s all it takes to change the scope for a particular portlet instance. By setting the scope to Current Page, you can add as many of these portlets to a site as you want, provided they are all added to separate pages.
Another useful feature of Liferay’s portlets is Archived Setups.
Once you’ve configured a portlet, Archived Setups enables you to save those settings in an “archive”. If someone goes in and changes the settings of a particular portlet, it then becomes easy to revert those changes back to the original, archived configuration.
To create an archived setup, click the Configuration option from the menu in the portlet’s title bar. If the current settings of the portlet you’re configuring are the ones you want to archive, click the Archive/Restore Setup link. If not, change and save the settings until you have the portlet configured the way you want it, and then click the Archive/Restore Setup link.
There is only one field to fill out. Enter a name for your archive and click Save. You should now see your archive in the list. If you ever need to revert the portlet to these archived settings, you can click Actions → Restore next to the archived setup you want to restore.
Unless otherwise noted, all of the portlets in this chapter support this feature. This is particularly useful for portlets that have a lot of configuration options, such as the Message Boards portlet.
Next, we’ll see how permissions apply to Liferay portlets in general.
All of Liferay’s portlets support Liferay’s robust, fine-grained permissions system. Some higher level permissions can be configured in the permissions tab of the portlet configuration dialog box. You can grant roles permission to add the portlet to a page, configure the portlet, or view the portlet. To set these permissions, go to the Configuration menu and click on Permissions. This shows you a table of roles defined in the portal. Use the check boxes to grant certain permissions to different roles. Click Submit after you have made your selections.
Beyond this, specific permissions are generally defined for specific applications. For example, the message boards portlet contains a Ban User permission. This makes no sense in the context of another portlet, say, the blogs portlet. We’ll go over permissions for specific applications in the sections for those applications. For now, let’s move on to sharing applications.
Liferay implements several communication mechanisms across portlets including those specified by the JSR-286 standard: public render parameters and events. Public render parameters are easy to use and can be quite powerful. Some Liferay portlets provide a configuration UI to help you get the most out of this communication mechanism. To access this UI, open your portlet’s configuration window by clicking on the wrench icon and selecting Configuration. Then click on the Communication tab.
The screenshot above is for the Wiki portlet, which has six public render parameters: categoryId, nodeId, nodeName, resetCur, tag, title. For each of these parameters, you can configure the portlet to ignore the values coming from other portlets to read the value from another parameter.
Why might it be useful to ignore the values for certain parameters that come from other portlets? Consider a common use case for the Wiki portlet. The Wiki portlet is often used along with the Tags Navigation portlet so that when a user clicks on a tag of the latter, the Wiki portlet shows a list of pages with that tag. In some cases, an administrator may want the Wiki portlet to always show the front page independently of any tag navigation done through other portlets. This can be achieved by checking the Ignore checkbox so that the values of the parameter coming from those other portlets are ignored.
Reading the value of a parameter from another portlet is an advanced but very powerful option that allows portlets to communicate with each other even if their developers didn’t intend them to. For example, imagine that the Wiki portlet is being used to publish information about certain countries. Imagine further that there’s another portlet that allows browsing countries for administrative reasons. The second portlet has a public render parameter called country with the name of the country. We’d like the Wiki to show the information from the country that’s selected in the administration portlet. This can be achieved by setting the value of the title parameter of the Wiki portlet to be read from the country parameter of the administration portlet. Cool, isn’t it?
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.
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 subtabs under sharing: Any Web Site, Facebook, Google Gadget, Netvibes, and Friends.
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.
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 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 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.
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.
Now that we’ve seen all the common options available in Liferay’s portlet applications, we can move on to specific applications, starting with blogs.