When should I use XForms?

The question about how XForms should be sold to customers often comes up, and generally we reply "why would you?". As in any IT project you need to use the right tool for the job, so why would you try to sell XForms in and of itself? Sometimes XForms is the right thing, and sometimes not, but either way--we say to those who ask--it's a tool in your armoury (if you want to use it), not your customers'.

If you have a system that uses web services a lot (for example), then a rich client that can handle XForms will be ideal--that's where most of our use cases are coming from for formsPlayer deployment. I've mentioned before a system that we've built for a customer that involves using the OpenWFE workflow engine and the eXist XML database, and we've written practically no code on the server! All we've done is used a few workflow templates, and the REST/XQuery interface to eXist, and everything else is achieved via the XForms themselves. Maintaining such a system is not only very straightforward, but is easy to move to other platforms, as well as swap components in and out (since the interfaces--such as XQuery--are all standard). This is all at the heart of the skimming approach we've been talking about.

But unfortunately, at the other end of the spectrum, if you have a system that uses a server-side scripting language, with direct queries on a database to populate list-boxes (that whole nineties thing!) then you might not find XForms that useful. You'll have a maintenance nightmare with such an application, either way. For XForms to be of benefit in this scenario it would have to dramatically improve the user experience, rather than only being 'as good' as what you have already.

I'm not differentiating here between using client and server technologies, but rather between the use of high-level constructs versus painstakingly creating pages with server-side script. So in the approach I'm suggesting, you will also get productivity improvements if you can use a pipeline-based system like Orbeon, since it too uses 'big constructs', even though it delivers HTML to the user.

At least in the short term, the main benefits of XForms will generally accrue to the developers and not to the users, and will be of most use to those who have a service oriented architecture, rather than an old-fashioned web-site. So trying to 'sell XForms' is probably not only a waste of time, but actually unnecessary--if it fits your system, use it.