Web 2.0 still in beta
Filed under: breve template xml xhtmlMy work on Breve has revealed more dark corners of the web than I thought I ever wanted to know.
Breve is, at its heart, an XML-generation engine. The fact that it can output HTML and that doing so is its primary purpose is almost incidental, really. What this means is that Breve happily outputs things like <div /> which is logically sound, but technically incorrect.
Now, in a previous, happier life I was blissfully unaware that not all elements can be self-closing in XHTML, especially since such tags will even validate in the W3C's own validator. I ran across the issue when Breve output something similar to the following:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0
Strict//EN" "DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
</head>
<body>
<div />
<div>test</div>
<div />
</body>
</html>
Now on the surface, this looks fine. However, this is how Firefox rendered it:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0
Strict//EN" "DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
</head>
<body>
<div>
<div>test</div>
<div></div>
</div>
</body>
</html>
I spent about an hour trying to figure out what I was doing wrong, changing doctypes, adding meta tags, etc. As it turns out, I was missing a key element: the HTTP header "text/xml". Now, I didn't think I was missing it, since I'd tried setting that via a meta tag to no avail. Luckily someone on #firefox pointed me to this bug report.
The short story is that there is no practical way to specify that an XML document is, in fact, XML from within the document itself. You must configure the web server to output the proper headers.
The longer story is that I modified Breve to only output self-closing tags for a small subset of XHTML and all is well (except for my faith in people who write RFC's).
