Which NSCharacterSet describes characters which are valid in a tel: URL?

Question

The NSURL initializer that takes a String is failable, and the documentation says:

If the URL string was malformed, returns nil.

Attempting to construct a URL with NSURL(string: "tel://+49 00 00 00 00 00") returns nil.

stringByAddingPercentEscapesUsingEncoding(_:) and friends are deprecated in iOS 9 in favour of stringByAddingPercentEncodingWithAllowedCharacters(_:) , which takes an NSCharacterSet . Which NSCharacterSet describes the characters which are valid in a tel: URL?

None of

• URLFragmentAllowedCharacterSet()
• URLHostAllowedCharacterSet()
• URLPasswordAllowedCharacterSet()
• URLPathAllowedCharacterSet()
• URLQueryAllowedCharacterSet()
• URLUserAllowedCharacterSet()

... seem to be relevant

Answer 1

You can NSDataDetector class to grep phone number from string. Next step in to remove all unnecessary characters from detected number and create NSURL.

  func getPhoneNumber(string: String) -> String? {
        if let detector = try? NSDataDetector(types: NSTextCheckingType.PhoneNumber.rawValue) {
            let matches = detector.matchesInString(string, options: [], range: NSMakeRange(0, string.characters.count))

            if let string = matches.flatMap({ return $0.phoneNumber}).first {
                let number = convertStringToNumber(string)
                return number
            }
        }


        return nil
    }

    func convertStringToNumber(var str: String) -> String {
        let set = NSMutableCharacterSet()
        set.formUnionWithCharacterSet(NSCharacterSet.whitespaceCharacterSet())
        set.formUnionWithCharacterSet(NSCharacterSet.symbolCharacterSet())
        set.formUnionWithCharacterSet(NSCharacterSet.punctuationCharacterSet())

        str = str.componentsSeparatedByCharactersInSet(set).reduce(String(), combine: +)

        return str
    }

Example:

 let possibleNumber = "+49 00 00 00 00 00"

 if let number = getPhoneNumber(possibleNumber), let url = NSURL(string: "tel://\(number)") {
     print(url.absoluteString)
 }