Wie mache ich eine asynchrone NSURLConnection innerhalb einer NSOperation?

Question

Ich möchte eine Asynchrous NSURLConnection innerhalb einer NSOperation auf einem Hintergrund-Thread tun.

(es ist, weil ich einige sehr teure Operationen an den Daten mache, wie sie zurückkommen, die als die Daten kommt und im Hintergrund durchgeführt werden soll)

Hier ist mein erster Versuch:

in meinem AppDelegate:

// create the opperation and add it to the queue: 
self.sharedOperationQueue = [[[NSOperationQueue alloc] init] autorelease]; 
LibXMLOperation *op = [[[LibXMLOperation alloc] init] autorelease]; 
[self.sharedOperationQueue addOperation:op]; 

Dies ist mein Betrieb:

@interface EbirdLibXMLOperation : NSOperation { 
@private 
    NSURLConnection *urlConnection; 
// Overall state of the parser, used to exit the run loop. 
BOOL done; 
// properties to maintain the NSOperation 
BOOL finished; 
BOOL executing; 
} 
- (void)downloadAndParse:(NSURL *)url; 
- (void)start; 
- (BOOL)isConcurrent; 
- (BOOL)isFinished; 
- (BOOL)isExecuting; 

@property BOOL done; 
@property (nonatomic, retain) NSURLConnection *ebirdConnection; 
// The autorelease pool property is assign because autorelease pools cannot be retained. 
@property (nonatomic, assign) NSAutoreleasePool *downloadAndParsePool; 

@end 


@implementation LibXMLOperation 
@synthesize urlConnection, done; 

- (void)start{ 
    if (![self isCancelled]) { 
    [self willChangeValueForKey:@"isExecuting"]; 
    executing = YES; 
    //set up the thread and kick it off... 
    [[NSURLCache sharedURLCache] removeAllCachedResponses]; 
    NSURL *url = [NSURL URLWithString:@"http://google.com"]; 
    [NSThread detachNewThreadSelector:@selector(downloadAndParse:) toTarget:self withObject:url]; 
    [self didChangeValueForKey:@"isExecuting"]; 
    } else { 
    // If it's already been cancelled, mark the operation as finished. 
    [self willChangeValueForKey:@"isFinished"]; 
    finished = YES; 
    [self didChangeValueForKey:@"isFinished"]; 
    } 
} 

- (BOOL)isConcurrent { 
    return YES; 
} 

- (BOOL)isExecuting { 
    return executing; 
} 

- (BOOL)isFinished { 
    return finished; 
} 


- (void)downloadAndParse:(NSURL *)url { 
    self.downloadAndParsePool = [[NSAutoreleasePool alloc] init]; 
    done = NO; 
    self.characterBuffer = [NSMutableData data]; 
    [[NSURLCache sharedURLCache] removeAllCachedResponses]; 
    NSURLRequest *theRequest = [NSURLRequest requestWithURL:url]; 
    urlConnection = [[NSURLConnection alloc] initWithRequest:theRequest delegate:self]; 
    if (urlConnection != nil) { 
    do { 
     [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]]; 
    } while (!done); 
    } 
    [self willChangeValueForKey:@"isFinished"]; 
    [self willChangeValueForKey:@"isExecuting"]; 
    finished = YES; 
    executing = NO; 
    // Clean up. 
    self.urlConnection = nil; 
    [downloadAndParsePool release]; 
    NSLog(@"download and parse cleaning up"); 
    self.downloadAndParsePool = nil; 
    [self didChangeValueForKey:@"isExecuting"]; 
    [self didChangeValueForKey:@"isFinished"]; 
} 


#pragma mark NSURLConnection Delegate methods 

// Disable caching so that each time we run this app we are starting with a clean slate. 

- (NSCachedURLResponse *)connection:(NSURLConnection *)connection willCacheResponse:(NSCachedURLResponse *)cachedResponse { 
    return nil; 
} 

// Forward errors to the delegate. 
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error { 
    done = YES; 
} 

// Called when a chunk of data has been downloaded. 
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data { 
    // Process the downloaded chunk of data. 
    NSLog(@"Did received %i bytes", [data length]); 
} 

- (void)connectionDidFinishLoading:(NSURLConnection *)connection { 
    // Set the condition which ends the run loop. 
    done = YES; 
}  

@end 

Wenn diese läuft, sehe ich die folgende Meldung im Log:

2009-08-20 15:18:48.858 App[1001:3e03]*** _NSAutoreleaseNoPool(): Object 0x1126a20 of class NSCFArray autoreleased with no pool in place - just leaking 
Stack: (0x305a2e6f 0x30504682 0x3057deba 0x305ced09 0x30577ddf 0x3056b43e 0x3050764a 0x58fc3 0x3050a79d 0x3050a338 0x94568155 0x94568012) 

Dieses Ereignis wird im allerletzten [self didChangeValueForKey: @ "isfinished"]; was mir nahelegt, dass ich die NSOperation falsch einrichte.

Alle Vorschläge sind willkommen, danke.

Answer 1

die Linien Verschieben:

[downloadAndParsePool release]; 
self.downloadAndParsePool = nil; 

bis zum Ende der -downloadAndParse: Methode.