NSURLSession, NSURLSessionConfiguration, NSURLSessionDelegate, NSURLSessionDataTask, AFNetworking, AFHTTPRequestOperation, Core-Class

SessionDelegate.m

#define IS_IOS_7    ([[[[UIDevice currentDevice] systemVersion] componentsSeparatedByString:@"."][0] intValue] >= 7)
#define API_RQST_TIME_OUT                       30
// part of header file --------------------------------------------------------
#import <Foundation/Foundation.h>

@protocol API_Handler <NSObject>
@required
- (void)didSuccess:(NSData*)data;
- (void)didFail:(NSError*)error;
@end

@interface SessionDelegate : NSObject <NSURLSessionDataDelegate, NSURLSessionDelegate, NSURLSessionTaskDelegate>

+ (id)getDataWithRequest:(NSMutableURLRequest*)request andHandler:(id <API_Handler>)handler;

@end

@interface SessionConfiguration : NSObject

@end

// ----------------------------------------------------------------------------------------------------------------

// part of implementation file --------------------------------------------------------
#import "SessionDelegate.h"

static NSURLSessionConfiguration *sharedSessionConfig;

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

@implementation SessionConfiguration

+ (void)initialize {
    sharedSessionConfig = [NSURLSessionConfiguration defaultSessionConfiguration];
    sharedSessionConfig.timeoutIntervalForRequest = API_RQST_TIME_OUT;
    sharedSessionConfig.allowsCellularAccess = YES;
    sharedSessionConfig.requestCachePolicy = NSURLRequestReloadIgnoringCacheData;
}

+ (NSURLSessionConfiguration*)sessionConfig {
    return sharedSessionConfig;
}

@end

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

@interface SessionDelegate ()
+ (SessionDelegate*)sharedSessionDelegate;
@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 - Requests

+ (id)getDataWithRequest:(NSMutableURLRequest*)request andHandler:(id <API_Handler>)handler {
    __block id handler_for_block = handler;
    if(IS_IOS_7) {
        NSURLSessionDataTask *task = [sharedSession dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
            if(!error) {
                [handler_for_block didSuccess:data];
            } else {
                [handler_for_block didFail:error];
            }
        }];
        [task resume];
        return task;
    } else {
        [request setTimeoutInterval:API_RQST_TIME_OUT];
        [request setAllowsCellularAccess:YES];
        [request setCachePolicy:NSURLRequestReloadIgnoringCacheData];
        NSURLCredential *cred = [NSURLCredential credentialWithUser:<#username#> password:<#password#> persistence:NSURLCredentialPersistenceForSession];
        AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
        [operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
            [handler_for_block didSuccess:[operation responseData]];
        } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
            [handler_for_block didFail:error];
        }];
        operation.credential = cred;
        [operation start];
        return operation;
    }
}

- (void)URLSession:(NSURLSession *)session
              task:(NSURLSessionTask *)task
didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge
 completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential *credential))completionHandler {
    NSURLSessionAuthChallengeDisposition disposition = NSURLSessionAuthChallengeUseCredential;
    NSURLCredential *credential = [NSURLCredential credentialWithUser:<#username#> password:<#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:<#username#> password:<#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
// ----------------------------------------------------------------------------------------------------------------