newSessionDelegate.m

#import "SessionDelegate.h"
#import "SessionConfiguration.h"

@interface SessionConfiguration ()
+ (NSURLSessionConfiguration*)sessionConfig;
@end

@interface SessionDelegate ()
+ (SessionDelegate*)sharedSessionDelegate;
@property (nonatomic, strong) NSMutableDictionary *dForData;
@property (nonatomic, strong) NSOperationQueue *opQ;
@end

static NSURLSession *sharedSession;
static SessionDelegate *sessionDelegate;

@implementation SessionDelegate

#pragma mark - initialization

+ (void)initialize {
    sessionDelegate = [[SessionDelegate alloc] init];
    sharedSession = [NSURLSession sessionWithConfiguration:[SessionConfiguration sessionConfig]
                                                  delegate:sessionDelegate
                                             delegateQueue:[NSOperationQueue mainQueue]];
}

+ (SessionDelegate*)sharedSessionDelegate {
    return sessionDelegate;
}

#pragma mark - Initialization

- (id) init {
    if (self = [super init] ) {
        self.dForData = [NSMutableDictionary dictionary];
        if(!(IS_IOS_7)) {
            NSOperationQueue *myQueue = [[NSOperationQueue alloc] init];
            myQueue.name = @"APIQueue";
            myQueue.MaxConcurrentOperationCount = NSOperationQueueDefaultMaxConcurrentOperationCount;
            self.opQ = myQueue;
        }
    }
    return self;
}

#pragma mark - Requests

+ (void)invokeAPIRequest:(NSMutableURLRequest*)request completionHandler:(void (^)(NSData* data, NSError *error))completionHandler {
    if(IS_IOS_7) {
        NSURLSessionDataTask *task = [sharedSession dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
            completionHandler(data,error);
        }];
        [task resume];
    } else {
        [request setTimeoutInterval:API_RQST_TIME_OUT];
        [request setAllowsCellularAccess:YES];
        [request setCachePolicy:NSURLRequestReturnCacheDataElseLoad];
        [NSURLConnection sendAsynchronousRequest:request queue:sessionDelegate.opQ completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
            completionHandler(data,connectionError);
        }];
    }
}

#pragma mark - NSURLSessionTaskDelegate

- (void)URLSession:(NSURLSession *)session
              task:(NSURLSessionTask *)task
didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge
 completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential *credential))completionHandler {
//    NSURLSessionAuthChallengeDisposition disposition = NSURLSessionAuthChallengeUseCredential;
//    NSURLCredential *credential = [NSURLCredential credentialWithUser:CONSUMER_API_USERNAME password:CONSUMER_API_PASSWORD persistence:NSURLCredentialPersistenceNone];
//    completionHandler(disposition,credential);
}

#pragma mark - NSURLSessionDelegate

- (void)URLSession:(NSURLSession *)session didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential *credential))completionHandler {
//    NSURLSessionAuthChallengeDisposition disposition = NSURLSessionAuthChallengeUseCredential;
//    NSURLCredential *credential = [NSURLCredential credentialWithUser:CONSUMER_API_USERNAME password:CONSUMER_API_PASSWORD persistence:NSURLCredentialPersistenceNone];
//    completionHandler(disposition,credential);
}

- (void)URLSession:(NSURLSession *)session didBecomeInvalidWithError:(NSError *)error {
    STLog(@"Oh no ! Errors in handling APIs invoked in session - %@",[error description]);
}

@end