to extract a part of the URl after XML parsing? - iphone

Question

I am trying to parse an XML file in which an element named "description" is as given below:
<description>
<![CDATA[
<a href='http://www.okmagazine.com/posts/view/13756/'>
<img src='http://www.okmagazine.com/img/photos/thumbs/27044' />
</a>
<br />
Ashlee and Pete take their tiny tot to FAO Schwarz in NYC for some new toys.
<p> <strong>Pete Wentz</strong> and <strong>Ashlee Simpson Wentz</strong> made the new parent pilgrimage to New York’s FAO Schwarz today, where 6-month old <strong>Bronx Mowgli </strong>was the...]]>
</description>
What I want is to get the link in the tag <img src='http://www.okmagazine.com/img/photos/thumbs/27044'> using which I can display an image in my image view... How can I separate this string from the contents of description tag?
A part of code when parsing is as given below
- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string{
//NSLog(#"found characters: %#", string);
// save the characters for the current item...
if ([currentElement isEqualToString:#"title"]) {
[currentTitle appendString:string];
} else if ([currentElement isEqualToString:#"link"]) {
[currentLink appendString:string];
} else if ([currentElement isEqualToString:#"description"]) {
[currentSummary appendString:string];
} else if ([currentElement isEqualToString:#"pubDate"]) {
[currentDate appendString:string];
}
}
Please help
regards
Arun

Answer 1

I've never used that exact framework, but what you have to keep in mind is that while it will notify you when it finds the CDATA, anything inside is just plain-text to the parser. So it looks like you want to implement foundCDATA. You'll get passed a NSData block, and from there you have to parse the contents. Now, you can use another parser to do that, but it's probably faster just to do manual substring.

Answer 2

Have you thought about using regexp?

Answer 3

NSString *str = #"<![CDATA[<a href='http://www.okmagazine.com/posts/view/13756/'><img src='http://www.okmagazine.com/img/photos/thumbs/27044' /></a><br />Ashlee and Pete take their tiny tot to FAO Schwarz in NYC for some new toys. <p> <strong>Pete Wentz</strong> and <strong>Ashlee Simpson Wentz</strong> made the new parent pilgrimage to New York’s FAO Schwarz today, where 6-month old <strong>Bronx Mowgli </strong>was the...]]>";
NSRange range = [str rangeOfString: #"<img src='"];
str = [str substringFromIndex: range.location + range.length];
range = [str rangeOfString: #"'"];
str =[str substringToIndex: range.location];
CFShow(str);

Answer 4

Attributes are passed in to the didStartElement delegate method of the parser as a dictionary of strings keyed by attribute name. Thus, you can extract the urls you want from the attributes using NSDictionary's objectForKey: with the attribute name as the key. i.e.:
- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
{
if([elementName compare: #"img"] == NSOrderedSame) // check for <img ...> element
{
NSString* url = [attributeDictionary objectForKey:#"src"];
// url now contains the url you require from the HTML