CocoaDev

The Omni Group has a small library that can be downloaded that includes calls for the Expat XML library.

The simplest way of working with this framework is to use this nice encapsulated call:

#import <OmniBase/OmniBase.h> #import <OmniExpat/OmniExpat.h>

NSString *xmlFile = [NSString stringWithContentsOfFile:[NSString stringWithCString:argv[1]]]; NSDictionary *propertyList = [xmlFile propertyListFromXMLFormat];

This code returns the elements in a dictionary. This is quick and simple use of the Expat library. I used the code from this framework to get up to speed a bit quicker on some Objective-C stuff. The other reason I started with this framework was that many things I do (or want to do) revolve around XML, include data validation, object building, etc. Because I use the builder pattern a lot with my XML, I did not want to use the dictionary and went to the base. This code is the manual way of parsing XML files.

// XmlHandler.h #import <Foundation/Foundation.h> #import <OmniFoundation/OmniFoundation.h> #import <OmniExpat/OmniExpat.h> #import <OmniExpat/xmlparse.h>

@interface XmlHandler : NSObject { }

• (void)parseXml: (NSString*)content;

@end

// XmlHandler.m #import “XmlHandler.h”

void handleStartElement(void *userData, const char *name, const char *‘attributes); void handleEndElement(void *userData, const char *name); void handleCharacters(void *userData, const char *data, int len);

@implementation XmlHandler

• (void)parseXml: (NSString*)content { XML_Parser parser = XML_ParserCreate(“UTF-8”); XML_SetElementHandler(parser, handleStartElement, handleEndElement); XML_SetCharacterDataHandler(parser, handleCharacters);

  if (XML_Parse(parser, [content UTF8String], [content length], YES ) == 0) { int errorCode = XML_GetErrorCode(parser); int lineNumber = XML_GetCurrentLineNumber(parser); const char* errorDescription = XML_ErrorString(errorCode); NSLog(@”Parse Failure, code: %d, line: %d, description: %s”, errorCode, lineNumber, errorDescription);

    XML_ParserFree(parser);   }
  

  XML_ParserFree(parser); }

void handleStartElement(void userData, const char *name, const char *‘attributes) { NSString elementName = [NSString stringWithUTF8String:name]; NSLog(@”Start> %@”,elementName);

 if (*attributes) 
 {
     char *'attributeNameIndex;
     
     /* Step to next key/value pair */
     for (attributeNameIndex = attributes; *attributeNameIndex != NULL; attributeNameIndex += 2 )        
     {
         NSString *attributeName = [NSString stringWithCString:*attributeNameIndex];
         NSString *attributeValue = [NSString stringWithCString:*(attributeNameIndex + 1)];
         
         NSLog(@"Attribute> %@=%@",attributeName,attributeValue);
     }
 }  }

void handleEndElement(void userData, const char *name) { NSString elementName = [NSString stringWithUTF8String:name]; }

void handleCharacters(void *userData, const char *data, int len) { NSData *utf8Data = [NSData dataWithBytes:data length:len]; NSString *dataString = [NSString alloc] initWithData:utf8Data encoding:NSUTF8StringEncoding] autorelease];

 NSLog(@"CData=%@",dataString);  }

@end

Here is some simple calling code.

 XmlHandler* handler = [[XmlHandler alloc]init];
 [handler parseXml:@"<Root>aaa</Root>"];
 [handler release];

There are other features, but this meets most needs. – [[BryanZarnett

I would recommend Apple’s XML Services before OmniExpat. Seems just as simple, but more powerful – TheoHultberg/Iconara