HS256.cs

using System;
using Waher.Script;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Exceptions;
using Waher.Script.Model;
using Waher.Script.Objects;
 
namespace Waher.Security.JWS.Functions
{
    public class HS256 : FunctionMultiVariate
    {
        public HS256(int Start, int Length, Expression Expression)
            : base(new ScriptNode[0], argumentTypes0, Start, Length, Expression)
        {
        }
 
        public HS256(ScriptNode Secret, int Start, int Length, Expression Expression)
            : base(new ScriptNode[] { Secret }, argumentTypes1Scalar, Start, Length, Expression)
        {
        }
 
        public override string FunctionName => nameof(HS256);
 
        public override string[] DefaultArgumentNames => new string[] { "Secret" };
 
        public override IElement Evaluate(IElement[] Arguments, Variables Variables)
        {
            if (Arguments.Length == 0)
                return new ObjectValue(new HmacSha256());
 
            object Obj = Arguments[0].AssociatedObjectValue;
 
            if (Obj is byte[] Bin)
                return new ObjectValue(new HmacSha256(Bin));
            else if (Obj is string s)
                return new ObjectValue(new HmacSha256(Convert.FromBase64String(s)));
            else
                throw new ScriptRuntimeException("Expected secret to be a binary array, or a base64-encoded string.", this);
        }
    }
}