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IOS8 NSXMLParser Error

I crashed in NSXMLParser

* Application termination due to the uncaught exception "NSInternalInconsistencyException", reason: "NSXMLParser does not support parsing."

Here is my code

NSString *wrappedSnippet = [NSString stringWithFormat:@"<html>%@</html>", self.snippet]; NSXMLParser *parser = [[NSXMLParser alloc] initWithData:[wrappedSnippet dataUsingEncoding:NSUTF8StringEncoding]]; [parser setDelegate:self]; [parser parse];

the application crashes on the last line.

Note that everything works great on iOS7!

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5 answers

iOS8 throws an exception that previous versions caught and processed in the background.
see the manual. As with ios 5, NSXMLParser is thread safe, but not reentrant! make sure you are not calling a session from your NSXMLParser delegate. "I" in your case.

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 dispatch_queue_t reentrantAvoidanceQueue = dispatch_queue_create("reentrantAvoidanceQueue", DISPATCH_QUEUE_SERIAL); dispatch_async(reentrantAvoidanceQueue, ^{ NSXMLParser* parser = [[NSXMLParser alloc] initWithData:xml]; [parser setDelegate:self]; if (![parser parse]) { NSLog(@"There was an error=%@ parsing the xml. with data %@", [parser parserError], [[NSString alloc] initWithData:xml encoding: NSASCIIStringEncoding]); } [parser release]; }); dispatch_sync(reentrantAvoidanceQueue, ^{ });

Replace your code with the lines above, hope this helps you!

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I solved the problem by sending a parser in the background!

NSXMLParser is now thread safe. However, it is not reentrant for this flow; Do not call -parse on NSXMLParser from within the delegate callback of another NSXMLParser.

 - (void)parseWithCompletion:(ParserHandler)handler { dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0ul); dispatch_async(queue, ^{ self.handler = handler; [self parse]; }); } - (void)parserDidEndDocument:(NSXMLParser *)parser { dispatch_async(dispatch_get_main_queue(), ^{ if (self.handler) { self.handler(YES, self.dictionary, nil); self.handler = nil; } }); }
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In this problem, this means that you can re-call the [NSXMLParser parse] function in everything that it has. Sometimes you can call [parser parse] in parserDidEndDocument:
But he will notify you that this is a repeated mistake!

So the solution is that you can [parser-parser] in another queue,
for example, you can do this by calling dispatch_async (dispatch_get_main_queue (), ^ {do in block});

or you need to set up call flow,
make sure you don’t call the parser function on the delegate.

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I had the same problem and I wrote a subclass based on NSXMLParser that handles the case:

  class SynchronizedXMLParser: NSXMLParser { // shared queue private static let _serialQueue: NSOperationQueue = { let queue = NSOperationQueue() queue.qualityOfService = NSQualityOfService.UserInitiated // making it serial on purpose in order to avoid // the "reentrant parsing" issue queue.maxConcurrentOperationCount = 1 return queue }() // instance level convenience accessor private var _serialQueue: NSOperationQueue { get { return self.dynamicType._serialQueue } } private weak var _associatedParsingTask: NSBlockOperation? deinit { _associatedParsingTask?.cancel() } //MARK: - Overridden required override init(data: NSData) { super.init(data: data) } // still unsafe to call within the delegate callbacks override func parse() -> Bool { var parsingResult = false if (_associatedParsingTask == nil) { let parsingTask = NSBlockOperation(block: {() -> Void in parsingResult = super.parse() }) _associatedParsingTask = parsingTask // making it synchronous in order to return the result // of the super parse call _serialQueue.addOperations([parsingTask], waitUntilFinished: true) } return parsingResult } override func abortParsing() { if let parsingTask = _associatedParsingTask { parsingTask.cancel() _associatedParsingTask = nil } super.abortParsing() } // MARK: - Introduced // safe to use everywhere as it doesn't force the calling thread to wait until this me thod returns func parse(completion completion:(Bool) -> Void) -> Void { var parsingResult = false if (_associatedParsingTask == nil) { let parsingTask = NSBlockOperation(block: {() -> Void in parsingResult = super.parse() }) parsingTask.completionBlock = { () -> Void in completion(parsingResult) } _associatedParsingTask = parsingTask // making it synchronous in order to return the result // of the super parse call _serialQueue.addOperation(parsingTask) } } }

PS The idea pretty much matches what @CrimeZone suggested.

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Source: https://habr.com/ru/post/1200589/

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