check if string is URL
do {
let dataDetector: NSDataDetector = try NSDataDetector.init(types: NSTextCheckingResult.CheckingType.link.rawValue)
let stringRange = NSMakeRange(0, url.characters.count)
let notFoundRange = NSMakeRange(NSNotFound, 0)
let linkRange = dataDetector.rangeOfFirstMatch(in: url, options: NSRegularExpression.MatchingOptions(rawValue: UInt(0)), range: stringRange)
if (!NSEqualRanges(notFoundRange, linkRange) && NSEqualRanges(stringRange, linkRange)) {
return true;
}
return false
} catch {
NSLog("String is not an URL")
return false
}