NSXMLParser + CoreData Sample

ItemParser.h

#import <Foundation/Foundation.h>
#import "Item.h" // Core Data MO


// Synchronous parser ! Will lock thread !

@interface ItemParser : NSObject <NSXMLParserDelegate>

@property (nonatomic, retain) NSManagedObjectContext *managedObjectContext; // MOC for newly created MO
@property (nonatomic, retain) Item *currentItem;
@property (nonatomic, retain) NSMutableString *currentString;

- (id)initWithContext:(NSManagedObjectContext *)managedObjContext;
- (BOOL)parseXMLFileAtURL:(NSURL *)URL parseError:(NSError **)error;

// Used to delete existing items in DB
- (void)deleteExistingItems;

@end

ItemParser.m

#import "ItemParser.h"

@implementation ItemParser
@synthesize managedObjectContext, currentItem, currentString;

- (id)initWithContext:(NSManagedObjectContext *)moc
{
    self = [super init];
    if (self) {
        self.managedObjectContext = moc;
        [self deleteExistingItems];
    }
    return self;
}

- (void)dealloc
{
	self.managedObjectContext = nil;
    self.currentItem = nil;
    self.currentString = nil;
	[super dealloc];
}
- (NSEntityDescription *)entityDescription
{
    return [NSEntityDescription entityForName:@"Item" inManagedObjectContext:self.managedObjectContext];
}

#pragma mark - Parser methods

- (void)deleteExistingItems
{
    NSEntityDescription *entity = [self entityDescription];
    
	NSFetchRequest *fr = [[NSFetchRequest alloc] init];
    [fr setEntity:entity];
    
    NSError *error = nil;
    
    NSArray *results = [self.managedObjectContext executeFetchRequest:fr error:&error];
    if (error) {
        NSLog(@"Error removing items: %@", [error localizedDescription]);
    }
    
    for (NSManagedObject *object in results) {
        [self.managedObjectContext deleteObject:object];
    }
    
	// Update the data model effectivly removing the objects we removed above.
	if (![self.managedObjectContext save:&error]) {
		// Handle the error.
		NSLog(@"%@", [error domain]);
	}
}

- (BOOL)parseXMLFileAtURL:(NSURL *)URL parseError:(NSError **)error
{
	BOOL result = YES;
	
    NSXMLParser *parser = [[NSXMLParser alloc] initWithContentsOfURL:URL];

    // Set self as the delegate of the parser so that it will receive the parser delegate methods callbacks.
    parser.delegate = self;
    
    
    // Depending on the XML document you're parsing, you may want to enable these features of NSXMLParser.
    parser.shouldProcessNamespaces = NO;
    parser.shouldReportNamespacePrefixes = NO;
    parser.shouldResolveExternalEntities = NO;
    
    [parser parse];
    
    NSError *parseError = [parser parserError];
    if (parseError && error) {
        *error = parseError;
		result = NO;
    }
    
    [parser release];
	
	return result;
}

#pragma mark - NSXMLParser delegates

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
{
    
    if (qName) {
        elementName = qName;
    }

    if ([elementName isEqualToString:@"item"]) {
        self.currentItem = (Item *)[NSEntityDescription insertNewObjectForEntityForName:@"Item" inManagedObjectContext:self.managedObjectContext];

        // Set attributes
        self.currentItem.attribute = [attributeDict objectForKey:@"attribute"];
        
    } // else if.....
    

}

- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName
{    
    if (qName) {
        elementName = qName;
    }
    
	// If we're at the end of a additive. Save changes to object model
	if ([elementName isEqualToString:@"item"]) {
		
        NSError *error;
        
        // Store what we imported already
        if (![self.managedObjectContext save:&error]) {
            NSLog(@"%@", [error domain]);
		}
    } 
    /*
    else if ([elementName isEqualToString:@"title"]) {
        NSString *string = [self.currentString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
        self.item.title = string;
    }
    */
    
    self.currentString = [NSMutableString string];
    
}


- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string
{
    [self.currentString appendString:string];
}

@end