A portal is a web application that commonly provides personalization, single sign on, content aggregation from different sources, and hosts the presentation layer of information systems. Aggregation is the act of integrating content from different sources within a web page.
Portal functionality can be divided into three main parts:- Portlet container: A portlet container is very similar to a servlet container, in that every portlet is deployed inside a portlet container that controls the life cycle of the portlet and provides it with necessary resources and information about its environment. A portlet container is responsible for initializing and destroying portlets and also for passing user requests to it and collecting responses.
- Content aggregator: As defined in the Portlet Specification, one of the main jobs of a portal is to aggregate content generated by various portlet applications.
- Common services:One of the main strengths of a portal server is the set of common services that it provides. Services are not part of the portlet specification, but commercial portal implementations provide a rich set of common services to distinguish themselves from their competitors. A few common services that you can hope to find in most implementations are:
- Single sign on:Allows you to get access to all other applications once you log into the portal server, meaning you don’t have to log into every application separately. For example, once I log in to my intranet site, I should get access to my mail application, IM messaging application, and other intranet applications, without having to log into each of these applications separately.A portal server will provide you with a secured credentials store. What you do is to go to the mail application and specify your user name and password once. This information will be stored in the credentials store in encrypted form. From the next time onwards, when you log into your intranet site, the portal server will read your credentials from the store and log into your mail server on your behalf. The same goes for other applications.
- Personalization:The basic implementation of personalization service allows a user to customize her page in two ways. First, the user can decide what colors she wants for title bars and what icons she wants for controls. Second, the user can decide which portlets she wants on her page. For example, if I’m a big sports fan, I will probably replace the stock and news update portlets with a portlet that lets me track my favorite team.There are also a few advanced commercial implementations of personalization services that allow you to decide which applications should be displayed to user based on criteria such as his income or interests. In this case, you can create some business rules like “Show the premium products portlet to any user with X amount of income” and “Show the discount deals portlet to users with Y amount of income.”
