iPhone parse xhtml + css - iphone

Question

I have a complex long XHTML file, which contains CSS. Searching on google and on this site, I've found some libraries that can be useful on XHTML parsing:
NSXMLParser
TBXML
And some others
However, I'm wondering if there is any library for iPhone that can convert a xhtml + css document to a NSAttributedString (only the text, of course).
I have been thinking on that problem, and I have had some ideas, but I think it won't be very efficient. My main idea is formed by this steps:
Detect on the XTHML file all tags with an id or class attribute and get the range of the string where they have effect (I cannot achieve this).
Save all the CSS attributes on a NSDictionary, with more NSDictionary objects inside. Something like this:
mainDict {
object: dictionary {
object: #"#00ff00"
key: #"color"
object: #"1em"
key: #"font-size"
}
key: #"a id"
object: anotherDictionary {
...
}
key: #"another id"
}
Convert these CSS attributes dictionary on the NSAttributedStringattributes dictionary.
I know that this is complex, and I don't need you to provide the code (of course, if you provide it, it would be great), I only want the link to a library or, if it doesn't exist, some advice for create a parser myself.
Of course, if you need some more information, ask by comments.
Thanks you!!

Answer 1

It depends on your needs if this will do what you want, but DTCoreText has an HTML -> NSAttributedString converter. It's very specific for what DTCoreText wants to / needs to do, but it might at least point you in the right direction.

Answer 2

My way to parse an HTML string into NSAttributedString is to recursively append parsed node (and its childNodes) into an NSMutableAttributedString.
I am not ready to publish my full code anywhere yet. But hopefully this can give you some hints...
NSString+HTML.h
/* - toHTMLElements
* parse the string itself into a dictionary collection of htmlelements for following keys
* : #"attributedString" // html main body
* : #"insets" // images and/or videos with range info
* : #"as" // href with range info
*
*/
- (NSMutableDictionary*) toHTMLElements;
NSString+HTML.m
- (NSMutableDictionary*) toHTMLElements {
// …
// handle escape encoding here
// assume that NSString* htmlString is the processed string;
// …
NSMutableDictionary * htmlElements = [[NSMutableDictionary dictionary] retain];
NSMutableAttributedString * attributedString = [[[NSMutableAttributedString alloc] init] autorelease];
NSMutableArray * insets = [NSMutableArray array];
NSMutableArray * as = [NSMutableArray array];
[htmlElements setObject:attributedString forKey:HTML_ATTRIBUTEDSTRING];
[htmlElements setObject:insets forKey:HTML_INSETS];
[htmlElements setObject:as forKey:HTML_AS];
// parse the HTML with an XML parser
// CXXML is a variance of TBXML (http://www.tbxml.co.uk/ ) which can handle the inline tags such as <span>
// code not available to public yet, so write your own inline-tag-enabled HTML/XML parser.
CXXML * xml = [CXXML tbxmlWithXMLString:htmlString];
TBXMLElement * root = xml.rootXMLElement;
TBXMLElement * next = root->firstChild;
while (next != nil) {
//
// do something here for special treatments if needed
//
NSString * tagName = [CXXML elementName:next];
[self appendXMLElement:next withAttributes:[HTMLElementAttributes defaultAttributesFor:tagName] toHTMLElements:htmlElements];
next = next->nextSibling;
}
return [htmlElements autorelease];
}
- (void) appendXMLElement:(TBXMLElement*)aElement withAttributes:(NSDictionary*)parentAttributes toHTMLElements:(NSMutableDictionary*) htmlElements {
// do your parse of aElement and its attribute values,
// assume NSString * tagAttrString is the parsed html attribute string (either from "style" attribute or css file) for this tag like : width:200px; color:#123456;
// let an external HTMLElementAttributes class to handle the attribute updates from the parent node's attributes
NSDictionary * tagAttr = [HTMLElementAttributes updateAttributes: parentAttributes withCSSAttributes:tagAttrString];
// create your NSAttributedString styled by tagAttr
// create insets such as images / videos or hyper links objects
// then update the htmlElements for storage
// once this tag is handled, recursively visit and process the current tag's children
TBXMLElement * nextChild = aElement->firstChild;
while (nextChild != nil) {
[self appendXMLElement:nextChild withAttributes:tagAttr toHTMLElements:htmlElements];
nextChild = nextChild->nextSibling;
}
}