jellyfin/Emby.Server.Implementations/Connect/Validator.cs

using System.Text.RegularExpressions;

namespace Emby.Server.Implementations.Connect
{
    public static class Validator
    {
        static readonly Regex ValidEmailRegex = CreateValidEmailRegex();

        /// <summary>
        /// Taken from http://haacked.com/archive/2007/08/21/i-knew-how-to-validate-an-email-address-until-i.aspx
        /// </summary>
        /// <returns></returns>
        private static Regex CreateValidEmailRegex()
        {
            const string validEmailPattern = @"^(?!\.)(""([^""\r\\]|\\[""\r\\])*""|"
                                             + @"([-a-z0-9!#$%&'*+/=?^_`{|}~]|(?<!\.)\.)*)(?<!\.)"
                                             + @"@[a-z0-9][\w\.-]*[a-z0-9]\.[a-z][a-z\.]*[a-z]$";

            return new Regex(validEmailPattern, RegexOptions.IgnoreCase);
        }

        internal static bool EmailIsValid(string emailAddress)
        {
            bool isValid = ValidEmailRegex.IsMatch(emailAddress);

            return isValid;
        }
    }
}