NSURLConnection delegate methods on background thread

Question

EDIT2 - Rewrote the question

I want to do some web service communication in the background. I am using Sudzc as the handler of HTTPRequests and it works like this:

SudzcWS *service = [[SudzcWS alloc] init];
[service sendOrders:self withXML:@"my xml here" action:@selector(handleOrderSending:)];
[service release];

It sends some XML to the webservice, and the response (in this one, a Boolean) is handled in the selector specified:

- (void)handleOrderSending:(id)value
{ 
//some controls  
    if ([value boolValue] == YES)
    {
        //my stuff
    }
}

When I tried to use Grand Central Dispatch on my sendOrders:withXML:action: method, I noticed that the selector is not called. And I believe the reason for that is that NSURLConnection delegate messages are sent to the thread of which the connection is created But the thread does not live that long, it ends when the method finishes, killing any messages to the delegate.

Regards

EDIT1 [request send] method:

- (void) send {
//dispatch_async(backgroundQueue, ^(void){
    // If we don't have a handler, create a default one
    if(handler == nil) {
        handler = [[SoapHandler alloc] init];
    }

    // Make sure the network is available
    if([SoapReachability connectedToNetwork] == NO) {
        NSError* error = [NSError errorWithDomain:@"SudzC" code:400 userInfo:[NSDictionary dictionaryWithObject:@"The network is not available" forKey:NSLocalizedDescriptionKey]];
        [self handleError: error];
    }

    // Make sure we can reach the host
    if([SoapReachability hostAvailable:url.host] == NO) {
        NSError* error = [NSError errorWithDomain:@"SudzC" code:410 userInfo:[NSDictionary dictionaryWithObject:@"The host is not available" forKey:NSLocalizedDescriptionKey]];
        [self handleError: error];
    }

    // Output the URL if logging is enabled
    if(logging) {
        NSLog(@"Loading: %@", url.absoluteString);
    }

    // Create the request
    NSMutableURLRequest* request = [NSMutableURLRequest requestWithURL: url];
    if(soapAction != nil) {
        [request addValue: soapAction forHTTPHeaderField: @"SOAPAction"];
    }
    if(postData != nil) {
        [request setHTTPMethod: @"POST"];
        [request addValue: @"text/xml; charset=utf-8" forHTTPHeaderField: @"Content-Type"];
        [request setHTTPBody: [postData dataUsingEncoding: NSUTF8StringEncoding]];

        if(self.logging) {
            NSLog(@"%@", postData);
        }
    }


    //dispatch_async(dispatch_get_main_queue(), ^(void){
        // Create the connection
        conn = [[NSURLConnection alloc] initWithRequest: request delegate: self];
        if(conn) {
                                        NSLog(@" POST DATA %@", receivedData);
            receivedData = [[NSMutableData data] retain];
                        NSLog(@" POST DATA %@", receivedData);
        } else {
            // We will want to call the onerror method selector here...
            if(self.handler != nil) {
                NSError* error = [NSError errorWithDomain:@"SoapRequest" code:404 userInfo: [NSDictionary dictionaryWithObjectsAndKeys: @"Could not create connection", NSLocalizedDescriptionKey,nil]];
                [self handleError: error];
            }
        }
    //});


    //finished = NO;

    //    while(!finished) {
    //        
    //        [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
    //        
    //    }

//});
}

The parts that are commented out are the various things I tried. The last part worked but I'M not sure if that's a good way. In the NURLConnection delegate method of the class, here is what happens:

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
NSError* error;
if(self.logging == YES) {
    NSString* response = [[NSString alloc] initWithData: self.receivedData     encoding: NSUTF8StringEncoding];
    NSLog(@"%@", response);
    [response release];
}

CXMLDocument* doc = [[CXMLDocument alloc] initWithData: self.receivedData options: 0 error: &error];
if(doc == nil) {
    [self handleError:error];
    return;
}

id output = nil;
SoapFault* fault = [SoapFault faultWithXMLDocument: doc];

if([fault hasFault]) {
    if(self.action == nil) {
        [self handleFault: fault];
    } else {
        if(self.handler != nil && [self.handler respondsToSelector: self.action]) {

                [self.handler performSelector: self.action withObject: fault];


        } else {
            NSLog(@"SOAP Fault: %@", fault);
        }
    }
} else {
    CXMLNode* element = [[Soap getNode: [doc rootElement] withName: @"Body"] childAtIndex:0];
    if(deserializeTo == nil) {
        output = [Soap deserialize:element];
    } else {
        if([deserializeTo respondsToSelector: @selector(initWithNode:)]) {
            element = [element childAtIndex:0];
            output = [deserializeTo initWithNode: element];
        } else {
            NSString* value = [[[element childAtIndex:0] childAtIndex:0] stringValue];
            output = [Soap convert: value toType: deserializeTo];
        }
    }

    if(self.action == nil) { self.action = @selector(onload:); }
    if(self.handler != nil && [self.handler respondsToSelector: self.action]) {


            [self.handler performSelector: self.action withObject: output];


    } else if(self.defaultHandler != nil && [self.defaultHandler respondsToSelector:@selector(onload:)]) {
        [self.defaultHandler onload:output];
    }
}

[self.handler release];
[doc release];
[conn release];
conn = nil;
[self.receivedData release];
}

The delegate is unable to send messages because the thread it is dies when -(void)send finishes.

Answer 1

I've had help from both these links SO NURLConnection question and the original one.

It does not seem risky for my code and I will use it at my own risk. Thanks.

Any recommendations are still welcome of course.

Additional thanks to Pingbat for taking the time to try and help.