CustomEncode.cs

using System.Collections.Generic;
using System.Text;
using Waher.Content;
using Waher.Content.Binary;
using Waher.Runtime.IO;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Exceptions;
using Waher.Script.Model;
using Waher.Script.Objects;
 
namespace Waher.Script.Content.Functions.Encoding
{
    public class CustomEncode : FunctionTwoVariables
    {
        public CustomEncode(ScriptNode Binary, ScriptNode ContentType, int Start, int Length, Expression Expression)
            : base(Binary, ContentType, Start, Length, Expression)
        {
        }
 
        public override string FunctionName => nameof(CustomEncode);
 
        public override string[] DefaultArgumentNames => new string[] { "Binary", "ContentType" };
 
        public override IElement Evaluate(IElement Argument1, IElement Argument2, Variables Variables)
        {
            object Obj = Argument1.AssociatedObjectValue;
            string ContentType = ToString(Argument2) ?? string.Empty;
 
            if (!(Obj is byte[] Bin))
            {
                if (Obj is string s)
                {
                    KeyValuePair<string, string>[] Fields = CommonTypes.ParseFieldValues(ContentType.Trim());
                    string Charset = null;
 
                    foreach (KeyValuePair<string, string> P in Fields)
                    {
                        if (string.Compare(P.Key, "charset", true) == 0)
                        {
                            Charset = P.Value;
                            break;
                        }
                    }
 
                    if (Charset is null)
                    {
                        Bin = Strings.Utf8WithBom.GetBytes(s);
                        ContentType += "; charset=utf-8";
                    }
                    else
                    {
                        System.Text.Encoding Encondig = System.Text.Encoding.GetEncoding(Charset);
                        Bin = Encondig.GetBytes(s);
                    }
                }
                else
                    throw new ScriptRuntimeException("Expected binary or string content.", this);
            }
 
            return new ObjectValue(new CustomEncoding(ContentType, Bin));
        }
 
    }
}