Parsing an XML file with AFNetworking

Question

I am making a little weather app using the Yahoo api. This api gives me an XML file back. My problem is now how I can parse this file ? Here is my code that I have so far.

 AFXMLRequestOperation *operation = [AFXMLRequestOperation XMLParserRequestOperationWithRequest:request success:^(NSURLRequest *request, NSHTTPURLResponse *response, NSXMLParser *XMLParser) {
        NSLog(@"success");
        XMLParser.delegate = self;
        [XMLParser parse];
        NSLog(@"xmlParser is %@",XMLParser);
    } failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error, NSXMLParser *XMLParser) {
        NSLog(@"failure with error %@",error);
    }];

You can find the XML file over here.

Hope that anybody can help me

Answer 1

If you are looking to parse XMLs using NSXMLParser you'll need to have a class that implements the NSXMLParserDelegate. You can use your ViewController for this:

@interface ViewController : UIViewController <NSXMLParserDelegate>

Then using the SAX methods provided by this protocol you can parse this XML when you run [XMLParser parse]. Here is an example for your xml:

- (IBAction) makeRequest:(id)sender
{
    NSLog(@"Making request");
    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://weather.yahooapis.com/forecastrss?w=2442047&u=c"]];
    AFXMLRequestOperation *operation = [AFXMLRequestOperation XMLParserRequestOperationWithRequest:request success:^(NSURLRequest *request, NSHTTPURLResponse *response, NSXMLParser *XMLParser) {
        XMLParser.delegate = self;
        [XMLParser parse];
    } failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error, NSXMLParser *XMLParser) {
       NSLog(@"failure with error %@",error);
   }];
    [operation start];
}


#pragma mark - Parsing lifecycle

- (void)startTheParsingProcess:(NSData *)parserData
{
    NSXMLParser *parser = [[NSXMLParser alloc] initWithData:parserData]; //parserData passed to NSXMLParser delegate which starts the parsing process

    [parser setDelegate:self];
    [parser parse]; // starts the event-driven parsing operation.
}

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName attributes:(NSDictionary *)attributeDict
{
    if ([elementName isEqualToString:@"yweather:astronomy"])
    {
        NSLog(@"Sunrise: %@,  Sunset: %@", [attributeDict valueForKey:@"sunrise"], [attributeDict valueForKey:@"sunset"]);
    }

}

- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string{
    self.tmpInnerTagText = string; // Make a temp NSString to store the text in-between tags
}

- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName
{
    if ([elementName isEqualToString:@"title"])
    {
        NSLog(@"%@", self.tmpInnerTagText);
    }
    if ([elementName isEqualToString:@"description"])
    {
        NSLog(@"%@", self.tmpInnerTagText);
    }
}

- (void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError
{
    NSLog(@"Paser Error = %@", parseError);
    //TODO: Create Alert message error
}

Also to get AFNetworking to support the RSS xml you are using I had to add "application/rss+xml" to the acceptableContentTypes following the instructions from this site: http://www.suushmedia.com/simple-rss-reader-with-afnetworking/

Hope this helps

Answer 2

Better Solution: I found here

NSPropertyListFormat format;
NSArray *myObjects = [NSPropertyListSerialization propertyListWithData:responseObject options:NSPropertyListMutableContainers format:&format error:NULL];

    //If the root object of the plist is dictionary

NSDictionary *myObjects = [NSPropertyListSerialization propertyListWithData:responseObject options:NSPropertyListMutableContainers format:&format error:NULL];