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STRATEGIC DEVELOPER: JON UDELL                  http://www.infoworld.com
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Thursday, November 11, 2004

THE STATE OF RICH WEB APPS

By Jon Udell

Posted November 05, 2004 3:00 PM Pacific Time

In my Oct. 22 column, I argued that Gmail's aggressive use of DHTML
qualifies it as a kind of RIA (rich Internet application). As e-mail
correspondents and bloggers pointed out, the technique has a fairly long
history. Many wonder why it remains on the fringe. The reason, I think,
is partly a weakness common to all RIA technologies. Whether it's based
on DHTML, Java, Flash, .Net, or just a standard GUI, an RIA has a
client/server architecture. Unlike a Web application that manages state
information almost entirely on the server, an RIA achieves a more
balanced distribution of that information between server and client. The
benefits that flow from this arrangement can include responsiveness,
context preservation, and offline capability.

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To achieve these benefits, though, we have to make some painful
trade-offs. First, there's no easy way to observe and measure the use of
your RIA. A developer once asked me, in a discussion of Flash as a front
end to Web services, "Where's the clickstream?" Great question. Web
server logs are important sources of interaction data, and Web analytics
tools know how to mine that data. But when interaction is localized to
the client, you're flying blind. You need to find another way to observe
and measure what users do.

This is a general issue that GUI software has never handled gracefully.
In my Sept. 17 column, I discussed the weak tradition of event logging
on the Windows desktop. It's a problem not only for security auditors
but also for developers who need to understand in detail how users
interact with their software. Failure scenarios can be maddeningly hard
to reproduce, as I'm reminded every time I try to pinpoint the glitch
that prevents my wife from printing address labels in Microsoft Word.

A related issue is integration. RIAs are protocol-driven. A programmer
who masters an application's protocols can extend it or combine it with
other applications. But there are no integration hooks available to the
user. In a Web application, those hooks are simply URLs. Consider what
happens when you include a MapQuest URL in an e-mail to someone. A piece
of state information -- namely, the state of the MapQuest viewer when
displaying a given location -- has been reduced to a token that one
person can hand to another. The same thing can usefully apply to the
state of a shopping cart or an airline reservation.

In a Java-based map viewer, a .Net-based shopping cart, or a Flash-based
airline reservation system, it's possible to expose these states to the
user so that they can be saved or exchanged. But this doesn't happen
automatically, as with standard Web-based software. Such uses must be
anticipated and explicitly prepared. Many, though, just can't be
foreseen. My best example here continues to be LibraryLookup, an ad-hoc
integration between book-buying sites and library catalogs. Because
these two classes of system are URL-driven, it took only a snippet of
JavaScript to automate the manual technique -- URL cut and paste -- that
was already available. Replace either system with an RIA, and this
integration opportunity goes up in smoke.

The idea that an application wears its state information on its sleeve,
readily available for users to bookmark, modify, and trade, is an
underappreciated strength of Web-based software. As the RIA bandwagon
picks up steam, let's honor that idea and find a way to move it forward.

Jon Udell is lead analyst at the InfoWorld Test Center.


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