RDns.cs

using System.Net;
using System.Threading.Tasks;
using Waher.Networking.DNS;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Exceptions;
using Waher.Script.Model;
using Waher.Script.Objects.VectorSpaces;
 
namespace Waher.Script.Networking.Functions
{
    public class RDns : FunctionOneScalarVariable
    {
        public RDns(ScriptNode IpAddress, int Start, int Length, Expression Expression)
            : base(IpAddress, Start, Length, Expression)
        {
        }
 
        public override string FunctionName => nameof(RDns);
 
        public override string[] DefaultArgumentNames => new string[] { "IpAddress" };
        
        public override bool IsAsynchronous => true;
 
        public override IElement EvaluateScalar(string Argument, Variables Variables)
        {
            return this.EvaluateScalarAsync(Argument, Variables).Result;
        }
 
        public override async Task<IElement> EvaluateScalarAsync(string Argument, Variables Variables)
        {
            if (IPAddress.TryParse(Argument, out IPAddress Address))
                return new ObjectVector(await DnsResolver.ReverseDns(Address));
            else
                throw new ScriptRuntimeException("Not an IP address.", this);
        }
 
        public override IElement EvaluateScalar(IElement Argument, Variables Variables)
        {
            return this.EvaluateScalarAsync(Argument, Variables).Result;
        }
 
        public override async Task<IElement> EvaluateScalarAsync(IElement Argument, Variables Variables)
        {
            if (Argument.AssociatedObjectValue is IPAddress IP ||
                IPAddress.TryParse(Argument.AssociatedObjectValue?.ToString() ?? string.Empty, out IP))
            {
                return new ObjectVector(await DnsResolver.ReverseDns(IP));
            }
            else
                throw new ScriptRuntimeException("Not an IP address.", this);
        }
    }
}