Trying to Use Strophe with Prototype, Dojo, and YUI

January 11, 2010

I use jQuery quite a bit in my own JavaScript development, and I think it works quite well with Strophe.js. However, not everyone uses jQuery, so I want to write a series of tutorials on how to use the other popular JavaScript libraries with Strophe. Unfortunately, I am running into issues with stanza manipulation, and I need your help.

My goal is to show the three or four most common pieces of each library that make writing XMPP applications easier. In my own code, and in the applications in Professional XMPP Programming, I use features like DOM manipulation to work with XMPP stanzas and custom events to make separating code easier.

In jQuery, these normally take the form of $(document).bind() and $(document).trigger() for events and $(stanza).find() or $(stanza).children() for stanza manipulation. It turns out to be pretty easy stuff.

Unfortunately, I can’t seem to get stanza manipulation working in any other library. Below are the problems I’ve run into, and I’m hoping that someone more familiar with these libraries can offer some assistance.

YUI

The more I read about YUI, the more I like it. It seems quite well designed, and I’m seriously considering using it in some real projects. However, it doesn’t seem to be able to deal with XMPP stanzas at all.

You can convert an XMPP stanza, which is an XML DOM element, to a YUI Node object with Y.one(stanza). This works great, and you can easily access attributes with functions like Y.one(stanza).getAttribute('from') or Y.one(stanza).get('tagName'). Unfortunately, finding arbitrary child elements doesn’t work. Y.one(stanza).all('item') returns an empty NodeList object, even when the stanza has several <item> children.

Similarly, using Y.Selector.query() also fails to find the elements.

Both of these functions work great on the HTML DOM elements I’ve tried, so I suspect this is an issue with XML DOM elements.

Dojo

I’ve been meaning to check out Dojo for quite a while, and I was pretty excited to put it to use on XMPP. After all, it has some XMPP support built in. It also has an implementation of Twisted-style deferreds which make asynchronous programming awesome.

Unfortunately, Dojo also seems unable to work with XMPP stanzas. dojo.query('item', stanza) returns an empty array.

Prototype

I’ve used Prototype on projects in the past and was quite happy with it. I figured this task would be a piece of cake since it’s one of the older libraries.

Just like YUI and Dojo, though, it can’t seem to manipulate XMPP stanzas. stanza.select() doesn’t work because Prototype doesn’t seem to extend XML DOM element objects. Selector.findChildElements(stanza, ['item']) fails with $(root).identify is not a function, which I assume is also an XML DOM problem.

If you can help figure out how to use these libraries to access and manipulate XMPP stanzas, or just let me know if it’s really not possible, it would be much appreciated.