public static bool TryParse(string host, out IPHost hostObj)
{
if (string.IsNullOrWhiteSpace(host))
{
hostObj = IPHost.None;
return(false);
}
// See if it's an IPv6 with port address e.g. [::1] or [::1]:120.
int i = host.IndexOf(']', StringComparison.Ordinal);
if (i != -1)
{
return(TryParse(host.Remove(i - 1).TrimStart(' ', '['), out hostObj));
}
if (IPNetAddress.TryParse(host, out var netAddress))
{
// Host name is an ip address, so fake resolve.
hostObj = new IPHost(host, netAddress.Address);
return(true);
}
// Is it a host, IPv4/6 with/out port?
string[] hosts = host.Split(':');
if (hosts.Length <= 2)
{
// This is either a hostname: port, or an IP4:port.
host = hosts[0];
if (string.Equals("localhost", host, StringComparison.OrdinalIgnoreCase))
{
hostObj = new IPHost(host);
return(true);
}
if (IPAddress.TryParse(host, out var netIP))
{
// Host name is an ip address, so fake resolve.
hostObj = new IPHost(host, netIP);
return(true);
}
}
else
{
// Invalid host name, as it cannot contain :
hostObj = new IPHost(string.Empty, IPAddress.None);
return(false);
}
// Use regular expression as CheckHostName isn't RFC5892 compliant.
// Modified from gSkinner's expression at https://stackoverflow.com/questions/11809631/fully-qualified-domain-name-validation
string pattern = @"(?im)^(?!:\/\/)(?=.{1,255}$)((.{1,63}\.){0,127}(?![0-9]*$)[a-z0-9-]+\.?)$";
if (Regex.IsMatch(host, pattern))
{
hostObj = new IPHost(host);
return(true);
}
hostObj = IPHost.None;
return(false);
}
public static bool TryParse(string host, out IPHost hostObj)
{
if (!string.IsNullOrEmpty(host))
{
// See if it's an IPv6 with port address e.g. [::1]:120.
int i = host.IndexOf("]:", StringComparison.OrdinalIgnoreCase);
if (i != -1)
{
return(TryParse(host.Remove(i - 1).TrimStart(' ', '['), out hostObj));
}
else
{
// See if it's an IPv6 in [] with no port.
i = host.IndexOf(']', StringComparison.OrdinalIgnoreCase);
if (i != -1)
{
return(TryParse(host.Remove(i - 1).TrimStart(' ', '['), out hostObj));
}
// Is it a host or IPv4 with port?
string[] hosts = host.Split(':');
if (hosts.Length > 2)
{
hostObj = new IPHost(string.Empty, IPAddress.None);
return(false);
}
// Remove port from IPv4 if it exists.
host = hosts[0];
if (string.Equals("localhost", host, StringComparison.OrdinalIgnoreCase))
{
hostObj = new IPHost(host, new IPAddress(Ipv4Loopback));
return(true);
}
if (IPNetAddress.TryParse(host, out IPNetAddress netIP))
{
// Host name is an ip address, so fake resolve.
hostObj = new IPHost(host, netIP.Address);
return(true);
}
}
// Only thing left is to see if it's a host string.
if (!string.IsNullOrEmpty(host))
{
// Use regular expression as CheckHostName isn't RFC5892 compliant.
// Modified from gSkinner's expression at https://stackoverflow.com/questions/11809631/fully-qualified-domain-name-validation
Regex re = new Regex(@"^(?!:\/\/)(?=.{1,255}$)((.{1,63}\.){0,127}(?![0-9]*$)[a-z0-9-]+\.?)$", RegexOptions.IgnoreCase | RegexOptions.Multiline);
if (re.Match(host).Success)
{
hostObj = new IPHost(host);
return(true);
}
}
}
hostObj = IPHost.None;
return(false);
}