How to return NSData from NSURLSessionDataTask completion handler

Question

I am trying to make a simple class that I can use to call a post web service.

Everything is working perfectly except that I am not able to return the NSData

Answer 1

You should use a block method.

First define a block

typedef void (^OnComplete) (NSData *data);

Use the following method

+ (void)postCall:(NSDictionary *)parameters fromURL:(NSString *)url withBlock:(OnComplete)block; {

     NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
        NSURLSession *session = [NSURLSession sessionWithConfiguration:configuration];
        NSMutableArray *pairs = [[NSMutableArray alloc]init];
        for(NSString *key in parameters){
            [pairs addObject:[NSString stringWithFormat:@"%@=%@", key, parameters[key]]];
        }
        NSString *requestParameters = [pairs componentsJoinedByString:@"&"];
        NSURL *myURL = [NSURL URLWithString:url];
        NSMutableURLRequest *urlRequest = [NSMutableURLRequest requestWithURL:myURL];
        [urlRequest setHTTPMethod:@"POST"];
        [urlRequest setHTTPBody:[requestParameters dataUsingEncoding:NSUTF8StringEncoding]];
        NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:urlRequest completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
            block(data);
        }];
        [dataTask resume];
   }