Question

In an iPhone app I am developing, there is a setting in which you can enter a URL, because of form & function this URL needs to be validated online as well as offline.

So far I haven’t been able to find any method to validate the url, so the question is;

How do I validate an URL input on the iPhone (Objective-C) online as well as offline?

Answer 1

Thanks to this post, you can avoid using RegexKit.
Here is my solution (works for iphone development with iOS > 3.0) :

- (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];
}

If you want to check in Swift my solution given below:

 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
    }