Dns.cs

using System;
using System.Threading.Tasks;
using Waher.Networking.DNS;
using Waher.Networking.DNS.Enumerations;
using Waher.Networking.DNS.ResourceRecords;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Exceptions;
using Waher.Script.Model;
using Waher.Script.Objects;
using Waher.Script.Objects.VectorSpaces;
 
namespace Waher.Script.Networking.Functions
{
    public class Dns : FunctionMultiVariate
    {
        public Dns(ScriptNode Name, int Start, int Length, Expression Expression)
            : base(new ScriptNode[] { Name }, argumentTypes1Scalar, Start, Length, Expression)
        {
        }
 
        public Dns(ScriptNode Name, ScriptNode Type, int Start, int Length, Expression Expression)
            : base(new ScriptNode[] { Name, Type }, argumentTypes2Scalar, Start, Length, Expression)
        {
        }
 
        public Dns(ScriptNode Name, ScriptNode Type, ScriptNode Class, int Start, int Length, Expression Expression)
            : base(new ScriptNode[] { Name, Type, Class }, argumentTypes3Scalar, Start, Length, Expression)
        {
        }
 
        public override string FunctionName => nameof(Dns);
 
        public override string[] DefaultArgumentNames => new string[] { "Name", "QTYPE", "QCLASS" };
 
        public override bool IsAsynchronous => true;
 
        public override IElement Evaluate(IElement[] Arguments, Variables Variables)
        {
            return this.EvaluateAsync(Arguments, Variables).Result;
        }
 
        public override async Task<IElement> EvaluateAsync(IElement[] Arguments, Variables Variables)
        {
            string Name = Arguments[0].AssociatedObjectValue?.ToString() ?? string.Empty;
            int c = Arguments.Length;
            QTYPE TYPE = c < 2 ? QTYPE.A : this.ToEnum<QTYPE>(Arguments[1]);
            QCLASS CLASS = c < 3 ? QCLASS.IN : this.ToEnum<QCLASS>(Arguments[2]);
 
            ResourceRecord[] Records = await DnsResolver.Resolve(Name, TYPE, CLASS);
 
            if (Records.Length == 0)
                throw new ScriptRuntimeException("Unable to resolve name.", this);
            else if (Records.Length == 1)
                return new ObjectValue(Records[0]);
            else
                return new ObjectVector(Records);
        }
    }
}