Combining Ajax and Web Services can lead to simpler, more maintainable programs. They're a natural fit: browser-based Ajax apps can consume web services from within your enterprise or from across the world.

But this new architecture has its challenges. How much logic gets shoved into the client? How do you aggregate data from multiple domains? Does a web service always mean XML? And how secure will all this be?

Mark Pruett will illustrate the Ajax/Web Service data pipeline: as data flows from the disk it's tranformed multiple times before reaching the user's screen. With Ajax you can now choose where these transformations take place. But what are the trade-offs of that choice?

You'll see how open source tools let you build both REST (Representational State Transfer) and SOAP web services.

You'll see how to put a REST front end on a SOAP web service (and why that might be a good idea).

You'll learn how to avoid Ajax's cross-domain limitations by configuring the Apache web server to build proxies using ProxyPass or mod_rewrite. And you'll see how to build intelligent proxies using Perl.

You'll come away from this session with an understanding of all the technical issues you'll face when building web applications with these two technologies.