Retry-After iOS workaround

retry-after.m

        id retryAfterValue = [[(NSHTTPURLResponse *)response allHeaderFields] valueForKey:@"Retry-After"];
        if (retryAfterValue != nil){
            NSMutableDictionary *editedHeaders = [NSMutableDictionary dictionaryWithDictionary:[(NSHTTPURLResponse *)response allHeaderFields]];
            // Max-age should be calculated based on the retry-after value, which can be an integer or a string date
            NSString *maxAgeString = [NSString stringWithFormat:@"max-age=%@" , retryAfterValue];
            [editedHeaders setValue:maxAgeString forKey:@"Cache-Control"];
            // Retry-after header must be removed
            [editedHeaders setValue:nil forKey:@"Retry-After"];
            NSHTTPURLResponse   *editedResponse = [[NSHTTPURLResponse alloc] initWithURL:[response URL] statusCode:[(NSHTTPURLResponse *)response statusCode] HTTPVersion:(NSString *)kCFHTTPVersion1_1 headerFields:[editedHeaders copy]];
            NSCachedURLResponse *cachedResponse = [[NSCachedURLResponse alloc] initWithResponse:editedResponse data:data];
            [[NSURLCache sharedURLCache] storeCachedResponse:cachedResponse forRequest:[self request]];
        }