AFNetworking and NSURLConnection on main thread - ios

Question

EDIT: The highlighted row in the screenshot is what I have a problem with, why is NSURLConnection running on [NSThread main] when I'm not calling it, AFNetworking is.
I'm using AFNetworking for my project, but when running Time Profiler in Instruments I'm seeing a lot of activity on the main thread for NSURLConnection, I have a feeling this is not what I want.
My method is
- (void)parseArticles {
NSMutableArray *itemsToParse = [[FMDBDataAccess sharedDatabase] getItemsToParse];
NSMutableArray *operations = [[NSMutableArray alloc] init];
for (Post *p in itemsToParse) {
NSMutableString *strURL = [NSMutableString new];
[strURL appendString:#"http://xxxxxxxxxxxxxxxxxxxxxx.php?url="];
[strURL appendString:[p href]];
NSURL *url = [NSURL URLWithString:strURL];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
[[ParserClient sharedInstance] registerHTTPOperationClass:[AFHTTPRequestOperation class]];
[operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
dispatch_async(loginParseQueue, ^{
Parser *parse = [[Parser alloc] init];
[parse parseLink:responseObject rowID:[p rowID]];
});
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(#"%#",error);
}];
[operations addObject:operation];
}
NSOperationQueue *operationQueue = [[NSOperationQueue alloc] init];
[operationQueue setMaxConcurrentOperationCount:3];
[operationQueue addOperations:operations waitUntilFinished:NO];
}
Why would AFNetworking be using the main thread? and how do I fix it.

Answer 1

AFNetworking is running on a child thread not in main thread, but every thread has a main method, which is on the image you post. This is not the main thread.Now tell me What do you want to fix?

Answer 2

It's because AFNetworking uses "successCallbackQueue" to route the completion block :
AFHTTPRequestOperation.m :
self.completionBlock = ^{
if (self.error) {
if (failure) {
dispatch_async(self.failureCallbackQueue ?: dispatch_get_main_queue(), ^{
failure(self, self.error);
});
}
} else {
if (success) {
dispatch_async(self.successCallbackQueue ?: dispatch_get_main_queue(), ^{
success(self, self.responseData);
});
}
}
};
You can simply assign a different thread to success and failure completion blocks :
dispatch_queue_t backgroundQueue = dispatch_queue_create("com.name.bgqueue", NULL);
AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
operation.successCallbackQueue = backgroundQueue;
operation.failureCallbackQueue = backgroundQueue;

Answer 3

EDIT:
Here is some code to run operations in a background thread. Use of any function called from the UI thread will run on on the UI thread. You can use a technique similar to the one specified below to run your operation on a background thread, and then dispatch the result back to the UI thread for later use.
Here is the technique I used, you may replace my sendSynchronousRequest call with your AFHTTPRequestOperation :
Specify a special type (a block) so you can pass blocks of code around.
typedef void (^NetworkingBlock)(NSString* stringOut);
Then, you need to dispatch to a background thread, so as not to freeze your UI thread.
Here's a function to call stuff in a background thread, and then wait for a response, and then call a block when done without using the UI thread to do it:
- (void) sendString:(NSString*)stringIn url:(NSString*)url method:(NSString*)method completion:(NetworkingBlock)completion {
//build up a request.
NSMutableURLRequest* request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:url]];
NSData *postData = [stringIn dataUsingEncoding:NSUTF8StringEncoding];
[request setHTTPMethod:method];
[request setValue:[NSString stringWithFormat:#"%d", postData.length] forHTTPHeaderField:#"Content-Length"];
[request setValue:#"application/json" forHTTPHeaderField:#"Content-Type"]; //or whatever
[request setHTTPBody:postData];
//dispatch a block to a background thread using GCD (grand central dispatch)
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
NSURLResponse *response;
NSError* error;
//request is sent synchronously here, but doesn't block UI thread because it is dispatched to another thread.
NSData* responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
//call complete, so now handle the completion block.
if (completion) {
//dispatch back to the UI thread again
dispatch_async(dispatch_get_main_queue(), ^{
if (responseData == nil) {
//no response data, so pass nil to the stringOut so you know there was an error.
completion(nil);
} else {
//response received, get the content.
NSString *content = [[NSString alloc] initWithBytes:[responseData bytes] length:responseData.length encoding:NSUTF8StringEncoding];
NSLog(#"String received: %#", content);
//call your completion handler with the result of your call.
completion(content);
}
});
}
});
}
Use it like this:
- (void) myFunction {
[self sendString:#"some text in the body" url:#"http://website.com" method:#"POST" completion:^(NSString *stringOut) {
//stringOut is the text i got back
}];
}