In a post called Who knows an XML document from a hole in the ground? Aristotle Pagaltzis wrote about problems with the namespace handling in aggregators that claim to support Atom 1.0. He concludes that NetNewsWire is a “working aggregator” and later in a follow-up that NetNewsWire is “conformant”. Unfortunately, it is not that simple.
The XHTML
elements appear unprefixed in the
test cases that were used to draw the conclusion. Therefore, the test cases do not reveal
whether an aggregator is able to properly handle XHTML elements with
a namespace prefix. After all, both reserializing the content in a
namespace-unaware way and grabbing the raw markup from underneath the
XML parser would appear to work when the unprefixed markup
was pasted in a text/html template.
Earlier this week I upgraded fiMUG’s Atom feed to Atom 1.0. I took the minimal steps that were necessary in order to make the code produce Atom 1.0 instead of 0.3. The feed binds the XHTML namespace to a prefix. All the XHTML elements have colonified names.
I loaded the new feed into NetNewsWire Lite 2.0.1. Like previously with prefixed element names in Atom 0.3 in NetNewsWire Lite, the text was visible but the links did not show up as links nor did paragraph breaks appear.
So what's going on here? It appears that NetNewsWire sticks the
XHTML content in a text/html template without removing
the namespace prefixes. There are two problems here:
text/htmlThe first is an obvious flaw. The latter is short-sighted
considering that WebKit
is expected to support embedded SVG on the XML side in the future
and Web
Applications 1.0 will allow XHTML constructs that will be
incompatible with text/html parsers.
Update: There is a modified version of Aristotle’s test case with the XHTML namespace bound to a prefix. Here’s another test case that also has some FooML markup which should not be treated as XHTML.