Use libphonenumber to validate mobile phone number without knowing the country

Question

I have a list (string) of phone numbers from any country.

for example:

var items = new List<string> { "[phone]", "009891234599882", "[phone]", "00336615551212"};

at first, I think that every country code length is exactly two number, for example(33: France, 39: Italy, 98: Iran , ...).

using libphonenumber library, you must be pass the regCode for parsing. and because of (in my scenario) I get the list of string(mobile number), then I must be separate country code from number.

       foreach (var item in items)
        {
            int countryCode = 0;
            var number = "";

            if (item.StartsWith("+"))
            {
                countryCode = int.Parse(item.Substring(1, 2));
                number = item.Substring(3);
            }
            else if (item.StartsWith("00"))
            {
                countryCode = int.Parse(item.Substring(2, 2));
                number = item.Substring(4);
            }
           var regCode = phoneUtil.GetRegionCodeForCountryCode(countryCode);

            var numberWithRegCode = phoneUtil.Parse(number, regCode);

            if (!phoneUtil.IsValidNumber(numberWithRegCode)) continue;
            //else ...
        }  

this code fine worked just for country codes that their length is two numbers!

but after a little time , I knew that some country code length is one number( for example, US: 1) and even three number!.

now, is exists any way using libphonenumber library (or other solutions) to solve this issue?

thanks a lot

Sportscast

This is off topic since you are requesting off-site resources. In addition, there may be limited amounts of rationale behind always validating phone number formats. If a user doesn't want to provide a real phone number, they'll just make one up. – Tildie

The first part of your question is trivial to prove incorrect - most countries use 3 digit dialing codes, some use 4, 5 even 6: en.wikipedia.org/wiki/List_of_country_calling_codes – Tucker

Their github page links to this website as a demo libphonenumber.appspot.com and their demo says to use "ISO 3166-1 two-letter country code" and links here: iso.org/iso/english_country_names_and_code_elements. So maybe try using those 2 character alpha codes instead of the 1-3 digit numeric codes. E.g., try using US for united states instead of 840. – Levitate

Answer 1

The libphonenumber library can find country codes by itself as long as the number starts with a +. So, just replace double zeros at the beginning of a number with a plus. And then let the library decide whether the number is valid on its own.

libphonenumber will on its own know which is the country code following the plus sign (it internally has a list of all the codes) and then apply the rules according to the correct country to decide whether the number is valid.

bool IsValidNumber(string aNumber)
{
    bool result = false;

    aNumber = aNumber.Trim();

    if (aNumber.StartsWith("00"))
    {
        // Replace 00 at beginning with +
        aNumber = "+" + aNumber.Remove(0, 2);
    }

    try
    {
        result = PhoneNumberUtil.Instance.Parse(aNumber, "").IsValidNumber;
    }
    catch
    {
        // Exception means is no valid number
    }

    return result; 
}

Hirudin

how to check only mobile numbers? – Avunculate

@Avunculate #31761165 – Hirudin

Answer 2

You can use date ftom this package https://www.npmjs.com/package/dialcodes

Ranch