ネットワークタイムスタンプを要求します。

#pragma mark --       

-(void)getInternetDateWithSuccess:(void(^)(NSTimeInterval timeInterval))success

                           failure:(void(^)(NSError *error))failure{
    
    //1.  URL
    
    NSString *urlString = @"http://m.baidu.com";
    
    urlString = [urlString stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]];
    
    //2.  request    
    
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
    
    [request setURL:[NSURL URLWithString: urlString]];
    
    [request setCachePolicy:NSURLRequestReloadIgnoringCacheData];
    
    [request setTimeoutInterval:5];
    
    [request setHTTPShouldHandleCookies:FALSE];
    
    [request setHTTPMethod:@"GET"];
    
    //3.  URLSession  
    
    NSURLSession *session = [NSURLSession sharedSession]; //4.         block
    
    NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
        
        if (error == nil && response != nil) {
            
            //                   “MMM”，    “MM”
            
            NSArray *monthEnglishArray = @[@"Jan",@"Feb",@"Mar",@"Apr",@"May",@"Jun",@"Jul",@"Aug",@"Sept",@"Sep",@"Oct",@"Nov",@"Dec"];
            
            NSArray *monthNumArray = @[@"01",@"02",@"03",@"04",@"05",@"06",@"07",@"08",@"09",@"09",@"10",@"11",@"12"];
            
            NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
            
            NSDictionary *allHeaderFields = [httpResponse allHeaderFields];
            
            NSString *dateStr = [allHeaderFields objectForKey:@"Date"];
            
            dateStr = [dateStr substringFromIndex:5];
            
            dateStr = [dateStr substringToIndex:[dateStr length]-4];
            
            dateStr = [dateStr stringByAppendingString:@" +0000"];
            
            //         ，        
            
            for (NSInteger i = 0 ; i < monthEnglishArray.count ; i++) {
                
                NSString *monthEngStr = monthEnglishArray[i];
                
                NSString *monthNumStr = monthNumArray[i];
                
                dateStr = [dateStr stringByReplacingOccurrencesOfString:monthEngStr withString:monthNumStr];
                
            }
            
            NSDateFormatter *dMatter = [[NSDateFormatter alloc] init];
            
            [dMatter setDateFormat:@"dd MM yyyy HH:mm:ss Z"];
            
            NSDate *netDate = [dMatter dateFromString:dateStr];
            
            NSTimeInterval timeInterval = [netDate timeIntervalSince1970];
            
            dispatch_async(dispatch_get_main_queue(), ^{
                
                success(timeInterval);
                
            });
            
        }else{
            
            dispatch_async(dispatch_get_main_queue(), ^{
                
                failure(error);
                
            });
            
        }
        
    }];
    
    //4、      
    
    [task resume];
    
}