private string NormalizeForDns()

in client/Apache.ShenYu.Client/Registers/ShenyuConsulRegister.cs [119:150]

• 30 lines of code
• 9 McCabe index (conditional complexity)

        private string NormalizeForDns(string s)
        {
            if (string.ReferenceEquals(s, null) || !char.IsLetter(s[0]) || !char.IsLetterOrDigit(s[s.Length - 1]))
            {
                throw new System.ArgumentException("Consul service ids must not be empty, must start "
                    + "with a letter, end with a letter or digit, "
                    + "and have as interior characters only letters, "
                    + "digits, and hyphen: " + s);
            }

            StringBuilder normalized = new StringBuilder();
            char? prev = null;
            foreach (char curr in s.ToCharArray())
            {
                char? toAppend = null;
                if (char.IsLetterOrDigit(curr))
                {
                    toAppend = curr;
                }
                else if (prev == null || !(prev == SEPARATOR))
                {
                    toAppend = SEPARATOR;
                }
                if (toAppend != null)
                {
                    normalized.Append(toAppend);
                    prev = toAppend;
                }
            }

            return normalized.ToString();
        }