问如何在iPhone上验证url

EN

- (BOOL) validateUrl: (NSString *) candidate {
    NSString *urlRegEx =
    @"(http|https)://((\\w)*|([0-9]*)|([-|_])*)+([\\.|/]((\\w)*|([0-9]*)|([-|_])*))+";
    NSPredicate *urlTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", urlRegEx]; 
    return [urlTest evaluateWithObject:candidate];
}

 func isValidUrl(url: String) -> Bool {
        let urlRegEx = "^(https?://)?(www\\.)?([-a-z0-9]{1,63}\\.)*?[a-z0-9][-a-z0-9]{0,61}[a-z0-9]\\.[a-z]{2,6}(/[-\\w@\\+\\.~#\\?&/=%]*)?$"
        let urlTest = NSPredicate(format:"SELF MATCHES %@", urlRegEx)
        let result = urlTest.evaluate(with: url)
        return result
    }

NSURL *candidateURL = [NSURL URLWithString:candidate];
// WARNING > "test" is an URL according to RFCs, being just a path
// so you still should check scheme and all other NSURL attributes you need
if (candidateURL && candidateURL.scheme && candidateURL.host) {
  // candidate is a well-formed url with:
  //  - a scheme (like http://)
  //  - a host (like stackoverflow.com)
}

- (BOOL)isValidURL {
    NSUInteger length = [self length];
    // Empty strings should return NO
    if (length > 0) {
        NSError *error = nil;
        NSDataDetector *dataDetector = [NSDataDetector dataDetectorWithTypes:NSTextCheckingTypeLink error:&error];
        if (dataDetector && !error) {
            NSRange range = NSMakeRange(0, length);
            NSRange notFoundRange = (NSRange){NSNotFound, 0};
            NSRange linkRange = [dataDetector rangeOfFirstMatchInString:self options:0 range:range];
            if (!NSEqualRanges(notFoundRange, linkRange) && NSEqualRanges(range, linkRange)) {
                return YES;
            }
        }
        else {
            NSLog(@"Could not create link data detector: %@ %@", [error localizedDescription], [error userInfo]);
        }
    }
    return NO;
}