XML is not being parsed correctly (NSData)

[idny99]

Hello,

I am trying to get xml from an .NET web service which I will then parse through an instance of NSXML.

If you wish to test the web service output (xml) please use http://www.osqar.co.uk/OsqarWCF/fran...reForID?id=396

Below is my URL request to my web service. NSLog shows the xml was read successfully. This is shown in the line NSLog(@"Response: %@",responseString);. This string is then given to the XMLParser.

// viewController.m
-(IBAction)getQuestionnaire
{
    // Obtain questionnaire ID from input textfield
    NSString *qid = questionnaireId.text;
    
    // Begin creating URL string and contact web service
    dataWebService = [NSMutableData data];
    NSString *combinedRequest = [NSString stringWithFormat:@"http://www.osqar.co.uk/OsqarWCF/frank.svc/getQuestionnaireForID?id=%@", qid];
    NSURL * myURL = [NSURL URLWithString:combinedRequest];
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL: myURL];
    NSURLConnection *myConnection = [NSURLConnection connectionWithRequest:request delegate:self];
    [myConnection start];  
    
    outputLabel.text = qid;
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response 
{
    [dataWebService setLength:0];
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data 
{
    [dataWebService appendData:data];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection 
{
    NSString *responseString = [[NSString alloc] initWithData:dataWebService encoding:NSUTF8StringEncoding];
    NSLog(@"Response: %@",responseString);
    // NSLog show that XML was successfully read and it displayed in debug output
    XMLParser *parseQuestionnaire = [[XMLParser alloc] init];
    Questionnaire *myQuestionnaire = [parseQuestionnaire parseXML:responseString];	
}

Now when I try and parse the XML from the viewController to the XMLParser class the data appears to get scrambled. (See XMLParser.m below). The first NSLog statement "Incoming xml ------>" shown in the debug output that the xml is correct. However after the NSData command the NSLog statement outputs like this.

after NSData ----->: <3c517565 7374696f 6e6e6169 7265584d 4c20786d 6c6e733d 22687474 703a2f2f 73636865 6d61732e 64617461 636f6e74 72616374 2e6f7267

After this the XML parser appears to do nothing.
Code for XML Parse below:

#import "XMLParser.h"
#import "Questionnaire.h"

@implementation XMLParser

-(Questionnaire *)parseXML:(NSString *)xml
{
    userRet = [[Questionnaire alloc] init];
    NSLog(@"incoming xml ----->: %@",xml);
	NSData *data = [xml dataUsingEncoding:NSUTF8StringEncoding];
    NSLog(@"after NSData ----->: %@",data);
    // data appears to be in hexidecimal
    BOOL success;
    questionnaireParser = [[NSXMLParser alloc] initWithData:data];
    [questionnaireParser setDelegate:self];
    [questionnaireParser setShouldResolveExternalEntities:YES];
    success = [questionnaireParser parse];
    return userRet;
}

- (void) parser: (NSXMLParser *) parser didStartElement: (NSString *) elementName
   namespaceURI: (NSString *) namespaceURI
  qualifiedName: (NSString *) qName
     attributes: (NSDictionary *) attributeDict
{
	if ([elementName isEqualToString:@"QuestionnaireName"]) 
    {
        NSString *name = [attributeDict objectForKey:@"QuestionnaireName"];
        NSLog(@"QuestionnaireNameBefore: %@", name);
     }
}

If I let the code continue then the NSLog statement above (@"QuestionnaireNameBefore: %@, name) returns (null). From this I assume the XML parse cannot read the data being input because of the hexidecimal form it appears in.
How can I parse this XML correctly? How can I get name element to be identified? What is causing the NSData command to scramble the XML?

I hope this made sense. Thanks in advance.

[timle8n1]

Originally Posted by idny99

after NSData ----->: <3c517565 7374696f 6e6e6169 7265584d 4c20786d 6c6e733d 22687474 703a2f2f 73636865 6d61732e 64617461 636f6e74 72616374 2e6f7267

How would you expect NSData to appear?

Originally Posted by idny99

If I let the code continue then the NSLog statement above (@"QuestionnaireNameBefore: %@, name) returns (null). From this I assume the XML parse cannot read the data being input because of the hexidecimal form it appears in.

I think you assume wrong the fact that your log statement appears tells you that the NSXMLParser found an element named QuestionnaireName.

The problem is QuestionnaireName is not an attribute within QuestionnaireName. An attribute takes the form

<Element Attribute="foo">ElementData</Element>

To use NSXMLParser to capture the ElementData you need to create something to accumulate the data when didStartElement: is called, implement foundCharacters: to append to that something, and implement didEndElement: to know you call all the characters in the ElementData.

See here - Parsing XML Files - Xcode Tutorials