Intermediaries and Transcoding
The IBM WebSphere Transcoding Publisher combines two powerful technologies: intermediaries and transcoding. The result is an extensible framework for adding value to web content, including specific abilities to transform text and images.
In a typical web environment, information is simply sent from a server to a browser for display and interaction. However, there are many ways that adding an intermediary between the browser and the server can improve the system. For example, an intermediary can keep track of the information the user has viewed to make it easier to find information again. Or an intermediary may enhance the information the user sees by adding annotations and personalization beyond what the server was designed to do. Intermediaries turn the network into a "smart pipe", enabling applications that can enhance information on the web.
Researchers at IBM Almaden have developed a framework for building and running intermediaries of all sorts. The Web Intermediaries (WBI) framework provides programmers with tools for designing and building complex intermediary applications for the web. For more information, the recent IBM Systems Journal article on intermediaries, including their application to transcoding.
One key intermediary application is the transformation of information from one form to another, a process called transcoding. Transcoding is already commonly used in many applications to change data formats, for example to convert a document from one word processor to another. The need for transcoding is growing tremendously, as information on the web becomes more important and new ways are provided for people to access it. For example, many web pages contain large color images that cannot be viewed on palmtop computers, and XML data on the web often needs to be transformed into other forms of XML or possibly into HTML before it can be viewed. Business-to-business communication often requires information to be transcoded from the formats and structures specific to one company to formats and structures understood by business partners, suppliers, and customers. Transcoders are specialized programs for transforming information into different forms. For more examples and for additional information on transcoding, see Internet Transcoding for Universal Access.
Transcoders can be used in many different ways. Servers can transcode information before sending it to the client. Applications can access networked transcoding services to take care of their information transformation needs. Or transcoders can be implemented as intermediaries, transforming information as it flows from the server to the browser or from server to server.
IBM WebSphere Transcoding Publisher can be deployed as a network intermediary. The extensible WBI intermediary backbone is combined with transcoding applications to produce a web proxy that can be used to transform images and text according to user, network, and device preferences. The WBI technology can host a number of different transcoding applications that can modify requests on the way to the web server or responses on the way back to the client. For each transaction, WBI selects and sequences the correct set of transcoders to produce the desired result for the specific request.
For more information on the WBI technology and its applications, see the WBI home page. The WBI Development Kit for Java is available for download and includes documentation and sample code for programmers to develop a many web intermediary applications. Moreover, these plugin applications can be registered with the IBM WebSphere Transcoding Publisher, along with the standard text and image transcoding plugins that come with this beta.