iPhone Options for reading item from XML?

Question

I am accessing this data from a web server using NSURL, what I am trying to decide is should I read this as XML or should I just use NSScanner and rip out the [data] bit I need. I have looked around the web for examples of extracting fields from XML on the iPhone but it all seems a bit overkill for what I need. Can anyone make any suggestions or point me in the right direction. In an ideal world I would really like to just specify [data] and get a string back "2046 3433 5674 3422 4456 8990 1200 5284"

<!DOCTYPE tubinerotationdata>
<turbine version="1.0">
<status version="1.0" result="200">OK</status>
<data version="1.0">
    2046 3433 5674 3422 4456 8990 1200 5284
</data>
</turbine>

any comments / ideas are much appreciated.

gary

Answer 1

You should always parse XML with an XML parser. There are no guarantees on ordering and other things that will break your code eventually. Parsing with a real XML parser is the only way to be sure that your code won't break when the input changes.

Answer 2

For simple data tasks like this I use RegexKitLite which is a light-weight regex library for iPhone. A basic implementation might look like this (assuming the contents of your file are in NSString *XMLString)

NSString *regex = @"<data\\s+version=\"(\\d+\\.\\d+)\">([^<]+)<\\/data>";
NSArray *components = [XMLString arrayOfComponentsMatchingRegex:regex];
if (components.count == 3) {
  // [components objectAtIndex:0] contains the full match
  // [components objectAtIndex:1] contains the version number
  // [components objectAtIndex:2] contains the contents of the data tag
  //                              (including leading/trailing whitespace)
}

Answer 3

Personally, I would use NSXMLParser so that you have everything in place in case you want to extract more information from the XML file.