E-MailOPEN SOURCE PORTALS
by Brian J. Dooley
Enterprise portals are becoming an increasingly important tool in the integration of data access and applications, in providing a platform for convergence of numerous different services, and in supporting and enabling collaboration. The portal market now includes an array of players, ranging from massive development frameworks such as IBM WebSphere to simplified portals for smaller businesses and peripheral operations as well as portals dedicated to specific functions. While IBM, Microsoft, and BEA have achieved some degree of dominance at the high end, much of the portal space remains up for grabs. This is significant in that corporations will most likely adopt and possibly integrate a number of different portal infrastructures; this is being simplified by the Java Specification Request (JSR) 168 and Web Services Remote Portlets (WSRP) standards.
Open source portals represent an interesting alternative to commercial portals and compose an important percentage of recent deployments. Their appearance and success derive from the new standards that allow them to interoperate with commercial portal systems and take advantage of portlets being developed for major portals. If they fit requirements, open source portals can provide considerable cost savings and maximum flexibility in implementation. They are not for everyone, however; and they require careful evaluation of both existing IT skills and infrastructure requirements. Otherwise, the result could be expensive and fraught with problems.
Open source portals are generally based on Java technology and are heavily standards driven. They take advantage of the JSR 168 and WSRP portlet standards, which define portlets and how they are integrated into a portal system. Open source licensing means that source code for these implementations is available for free and, importantly, can be freely modified provided that modifications are shared. Many open source products can also be purchased in binary form, but purchasing price is minimal. The cost lies in consultation and support, which, for infrastructure-level systems such as portals, can be formidable. But support requirements are heavily dependent on an organization's existing skill levels.
Pushed forward by the growing needs for integration and collaboration, by the need for even cash-strapped organizations to integrate applications and support collaboration, and, importantly, by standards, open source portals now exist in abundance at every level of complexity and to suit a variety of special purposes. Although a number have been built specifically for the enterprise, it is fair to say that most were created to support nonprofit organizations and academia and to provide collaboration and single-point access for open source software development projects.
The use of portals in developing open source software projects is of special interest, because these projects often involve hundreds of programmers and vast amounts of content. They absolutely demand high levels of collaboration. Portals that can prove themselves in this environment should easily meet the more modest needs of most enterprises, though connection with back-office applications remains an issue.
STANDARDS
Standardization is critical to the future growth of both commercial and open source portals. Portals have developed an infrastructure that generally provides a portal server, which offers services to clients (generally browsers); a portlet container that interfaces between portlets and the server; and the portlets themselves, which provide the connection to specific applications and services.
At present, the most important standards in this environment are JSR 168 and WSRP, which define how services are connected. Figure 1 displays the basic portal infrastructure.
Figure 1 -- Basic portal infrastructure. |
JSR 168 is a standard specifying a set of APIs for portlets and provides standardizations that enable interoperability among portlets and portals. Any JSR 168 portlet developed for one portal server should be able to run on another portal server.
Created by OASIS, WSRP is a standard that defines the interface and semantics for a Web services standard to connect plug-and-play of portlets with portals and other "aggregating Web applications." It permits content to be hosted in its native environment, and it is specifically useful in connecting portlets between different portals. It differs from JSR 168 in that a portlet server is not necessary to serve WSRP-compliant content; it can be provided as any Web service would be.
JSR 168 and WSRP operate at different levels. JSR 168 specifies how a portlet attaches and interacts with a portlet container, while WSRP specifies how to access portlets across portals. The development of these standards has provided a degree of interoperability among portal systems that support them, enabling the creation of an environment that unifies portal infrastructure. Within this environment, open source portals are likely to provide the greatest benefit, handling tasks outside the reach of commercial portal systems and linking them to a unified portal environment.
THE PROS AND CONS
The chief advantages of open source portals are the following:
-
Trialability. Since they cost
nothing to obtain, it is possible to experiment
with many alternatives without incurring any costs
other than time spent in the trial period.
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Low acquisition cost. As open
source products, acquisition costs are
minimal.
-
No proprietary lock-in. There's no
requirement to use a single portal infrastructure
system or OS; integration isn't limited to specific
applications.
-
Standard support. Open source
portals are likely to be standards driven.
-
Active support community. These
products are hot, and the major open source portals
have developed active discussion communities that
debate and respond to questions on implementation,
security, extension, and integration.
However, open source portals also raise a number of significant concerns:
-
No one has ultimate
responsibility. There's no one to blame if
the project goes wrong, and it's unlikely that
there will be a vendor to clean up the mess.
-
Support costs can be high. Some of
these products require substantially more coding
and configuration than commercial products. Changes
must be documented and maintained through the
lifecycle of the product, which can result in high
costs.
-
Lack of immediate solutions. While
portlets providing an interface to common
applications may be available, locating,
connecting, and testing portals to get it right is
likely to be a laborious prospect. There is no
out-of-the-box solution.
-
Lack of good documentation.
Documentation in open source projects is often low
grade or lacking, which can make configuration
difficult.
-
Uncertainty regarding future
development. There are no guarantees that
the project under open source development will
continue. This is offset, however, by strong
standards support.
EXAMPLES
There are numerous open source portals, and it is impossible to adequately survey the market due to the nature of open source. Important open source portal projects include the following:
- Jetspeed
- Liferay
- Red Hat Portal Server
- GridSphere
There are many others, but these products have achieved significant followings and provide a representative sample.
Jetspeed. Now in version 2, Jetspeed is from the Apache Software Foundation, which provides the open source Apache Web Server. Jetspeed is a customizable portal based on Java and XML. Jetspeed-2 offers a number of architectural enhancements over Jetspeed-1. Providing additional support for Jetspeed is CHEF, the CompreHensive collaborativE Framework, a J2EE-based application server that incorporates Jetspeed and collaborative tools.
Liferay Portal Enterprise. Liferay is designed as a customizable portal to deploy JSR 168 Java portlets. It contains a variety of portlets for mail, document library, calendar, and message boards. It was developed for a church group, which has enhanced its collaboration focus, but internal biblical links and other church-related features may put off commercial users.
Red Hat Portal Server. Red Hat's contribution, this open source portal supports multiple languages in its user interface and a variety of document standards including WAP, XHTML, and VoiceXML. It is significant given Red Hat's dominance in the Linux space.
GridSphere. GridSphere is a JSR 168 API-compliant portal system that offers near-complete compatibility with IBM WebSphere. It is one of the more complex open source portal offerings. Features include high-level model creation, built-in support for role-based access control, and localization support for a number of different languages.
Other open source portals include eXo, oPortal, jPortal, OpenPortal, basicPortal CMS, Stringbeans, JBoss Nukes, Gluecode Portal Foundation Server, uPortal, Jahia (collaborative source rather than open source), and Cocoon portal framework.
CONCLUSION
As enterprise portals have grown in importance, the alternatives for implementations have proliferated. Alongside the commercial options, many open source portals have been developed that offer a wide range of complexity levels and suitability for different purposes. Open source portals provide a viable alternative to commercial products, but they must be evaluated and implemented with care.
Key issues include existing staff's IT skills, fit with existing infrastructure and applications, and the size and complexity of the implementation project in comparison with the requirements for a commercial project. It is important to consider the total cost, including development, customization, and ongoing maintenance.
Open source portals are not for everyone. They do need to be considered, however, if only to provide a basis against which commercial portal applications can be evaluated.