gdata

Upcoming talks on RDF, RDFa and XForms

Submitted by administrator on Thu, 05/01/2008 - 12:50.

May is going to be pretty busy with talks about XForms, RDF and RDFa coming up.

First up is my talk XForms, REST, XQuery...and skimming at XTech 2008. The talk embraces themes I've been pursuing for a couple of years now; that as we put more functionality into the client, and servers get 'cleverer', it becomes much easier to build sophisticated web applications. Of course server technologies are moving so fast now that this whole approach is making more and more sense, so I'm looking forward to taking in recent developments in my talk. For example, both Amazon and Google effectively have 'databases in the cloud' that can be used to store data and query it, via APIs, with literally no configuration.

A few weeks later I'm going to be giving a tutorial on RDF at SemTech. This is an interesting development for me, because RDF and the semantic web were always my first interests--before XForms and before XHTML 2. (As well as writing RDF parsers, and designing applications, I also contributed chapters on RDF and RDFS to a couple of books on metadata and XML.)

But one problem I always had when trying to build semantic-web applications was that defining the user interface was pretty hairy. This was partly because RDF Schema is tricky to process, but also because HTML was insufficiently powerful in its core feature-set, so the translation from RDF to HTML involved a lot of work.

The need for a user interface language that was much richer than HTML was therefore why I got involved in the XForms standard (and worked with a team of people to produce the first fully conforming XForms processor, formsPlayer). So although it may not seem directly connected to the semantic web, I believe that in the coming period XForms will start to become a key part of the semantic web's architecture.

Another problem I kept coming up against whilst developing for the semantic web was the difficulty in actually publishing metadata. In particular I always found it frustrating that there was a lot of really useful metadata just sitting in ordinary web pages, and no-one could get at it. Attempting to resolve this problem gave rise to RDFa, and I'm excited that the RDFa in XHTML working draft is extremely close to becoming a stable recommendation. And as interest in RDFa grows, I'm pleased to say that some of my other presentations in May will be 'tech talks' on RDFa at Yahoo!, eBay and Google. (I'm really excited that I might be getting to meet some of the guys behind Yahoo!'s SearchMonkey.)

My final talk of the month will be at the excitingly-named Kings of Code, and I'm looking forward to talking about XHTML, XHTML 2, HTML 5, XAML, and anything else I can think of in relation to web languages.

skimming at XML 2007 (and The Cloud's Silver Lining)

Submitted by administrator on Fri, 12/14/2007 - 16:51.

I've not yet had a chance to write up my experiences at XML 2007 in Boston last week, but an announcement today by Amazon prompts me to at least summarise one of the talks I did, called XForms, REST, XQuery...skimming. (Slides)

It's a theme I've touched on a little in this blog, and have spoken on before (at an XML UK meeting, last year, and at XTECH 2007, this year), and the idea goes something like this; building web applications by dynamically generating user interfaces that contain data, is awkward, and difficult to maintain. Web services (which includes REST and APP) removes some of the dependency on databases by hiding the data behind a simple abstraction layer--a kind of 'ODBC for the web'--and XQuery takes this further by giving us a standard language to get at the data.

But XForms is the icing on the cake, since it gives us a rich-client language that can be deployed like traditional web applications, yet is one that ensures a clean separation of the data and the user interface.

During the course of the presentation I showed how incredibly easy it is to create an application with XForms, since forms can be first created on the desktop--loading and saving their data from local XML files--before being deployed to any type of web server. By creating static forms that load their own data, rather than the more common model of dynamically generating static files that contain data, we end up with files that are completely agnostic about where they are delivered from. My demonstrations took them from the desktop, to a simple web server, to eXist (an XML database).

But these applications could even run in 'the cloud', with no web-server. That may sound odd, but I could store any of these XForms applications in SVN or Amazon's S3 and they would work as well as if they were in IIS or Apache. This is the ultimate in simple maintenance and future-proofing, since you are no longer reliant on any particular operating system or server-side language...the forms just 'are'.

GData

The final step of my presentation was to take this a little further and show an XForm that interacts with Google's GData; the form is simple, and accepts a longitude, latitude and comment which is then inserted as a row into a Google Spreadsheet, using Atom Publishing Protocol (APP). Another form is then used to retrieve the entire spreadsheet, and each row is used to create a pin on a map.

The great thing about this demonstration is that it shows that not only are our forms now agnostic about where they run--desktop, server-side, S3, etc.--but now the data becomes agnostic; we don't care how the data is stored, all we are concerned about is the protocol used to interact with it.

And crucailly, XForms' ability to get at this data shows that it really is the missing link when it comes to building a new kind of web application.

SimpleDB

But this generalisation about data just took another leap with the announcement today by Amazon of a closed beta called SimpleDB. This will allow programmers to store and query for data in a manner similar to the way that GData works.

By putting data into the cloud, and then using an easily deployed, declarative rich-client language like XForms, it is possible for the architecture of web applications to be altered in a quite fundamental way, in a direction that is completely different to what we're used to.

Skimming, and an Open Source project for a GData XForms client

Submitted by administrator on Tue, 05/01/2007 - 15:51.

For me, one of the most exciting developments on the web in recent years has been the growth in services that let you manage raw data. Many of the most useful such services originate when some web-based application--such as Google calendars or spreadsheets--exposes the underlying data. For example, with Google Spreadsheets, it's possible to use ATOM to query spreadsheets for certain values, or add rows and columns, making this a very powerful way of storing data 'in the cloud'. (See Web 2.0, Copernicus and Spartacus: Moving the centre of the web.)

We're building quite a few XForms applications that make full use of this power, and it's something I'll be talking about at XTech 2007, in my session XForms, REST, XQuery...and skimming. Since the approach we use could work on any XForms processor, talking to any ATOM-based server, we've decided to create an open source project to host the forms, and document their use. If this is an area of interest to you, check out the GData XForms client project on Google Code, and its discussion forum.