Feel My Pain: NSXMLParser Problems Upgrading to the iPhone 3.0 SDK


I set out a couple of weeks ago to port the Killer Deals
application from the iPhone 2.2.1 SDK to 3.0. “No problem”, I thought; the
application doesn’t veer far from the standard APIs and controls, and it is a
relatively straightforward application, implementation-wise.

As I was making my updates (some minor method and property
name changes here and there), I stumbled upon a show stopper: The NSXMLParser
was no longer parsing my XML data. After scratching my head for a few hours, I
finally figured out the problem.

It seems Apple has removed support for Windows-1252
character encoding in the latest iteration of the NSXMLParser. I used this
encoding to prevent the appearance of those funny characters you occasionally
see on a web page. Those funny characters are caused by a character-encoding
mismatch between a text renderer and the document. Some Microsoft tools use the
Windows-1252 character encoding for documents by default. Unfortunately, some
of the Killer Deals data is only available in this encoding.

While the previous version would give a NSXMLParserUnknownEncodingError and continue to parse, the new version simply stops parsing after the
error (although strangely, the
parserDidStartDocument() method is still called after
the error).

this point, I was going to force the encoding to UTF-8 on the server, and put a
hack in the code to convert the ‘invalid’ characters to the proper UTF-8
equivalents. That ended up in an invalid character error via the parser.

seems Apple has degraded the parser and offers less tolerance for ‘unsupported’
formats. Does this have anything to do with bad blood between Apple and
Microsoft? Hmmm…

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