Synchronous category on AFNetworking

AFHTTPRequestOperation+MTSynchronousRequest.m

//
//  AFHTTPRequestOperation+MTSynchronousRequest.m
//  MTSyncAFNetworking
//
//  Created by Robert Thompson on 10/10/13.
//  Copyright (c) 2013 WillowTree Apps. All rights reserved.
//

#import "AFHTTPRequestOperation+MTSynchronousRequest.h"
@implementation AFHTTPRequestOperation (MTSynchronousRequest)
+ (id)sendSynchronousRequest:(NSURLRequest *)request withResponseSerializer:(AFHTTPResponseSerializer *)responseSerializer error:(NSError *__autoreleasing *)error
{
        AFHTTPRequestOperation* operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
        operation.responseSerializer = responseSerializer;
        operation.completionQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0);
        
        dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
        __block id response = nil;
        __block __autoreleasing NSError** blockError = error;
        [operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
                response = responseObject;
                dispatch_semaphore_signal(semaphore);
        } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
                if (blockError)
                {
                        *blockError = error;
                }
                dispatch_semaphore_signal(semaphore);
        }];
        
        [operation start];
        dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);
        
        return response;
}
@end