StreamSplit

gistfile1.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json;
using NUnit.Framework;

[TestFixture]
public class Class1
{

    [Test]
    public void Foo()
    {
        File.Delete("target.json");

        var source = File.OpenRead("file.json");
        var target = File.Create("target.json");

        var splitStream = new SplitStream(source, target);
        var streamReader = new JsonTextReader(new StreamReader(splitStream));

        var jsonSerializer = JsonSerializer.Create();
        var product = jsonSerializer.Deserialize<Product>(streamReader);

        Debug.WriteLine(product);

    }
}


public class SplitStream:Stream
{
    Stream source;
    Stream targetToDuplicate;

    public SplitStream(Stream source, Stream targetToDuplicate)
    {
        this.source = source;
        this.targetToDuplicate = targetToDuplicate;
    }

    public override void Flush()
    {
        source.Flush();
        targetToDuplicate.Flush();
    }

    public override long Seek(long offset, SeekOrigin origin)
    {
        throw new NotImplementedException();
    }

    public override void SetLength(long value)
    {
        throw new NotImplementedException();
    }

    public override int Read(byte[] buffer, int offset, int count)
    {
        var read = source.Read(buffer, offset, count);
        targetToDuplicate.Write(buffer, offset, read);
        return read;
    }

    public override void Write(byte[] buffer, int offset, int count)
    {
        throw new NotSupportedException();
    }

    public override bool CanRead
    {
        get { return true; }
    }

    public override bool CanSeek
    {
        get { return false; }
    }

    public override bool CanWrite
    {
        get { return false; }
    }

    public override long Length
    {
        get { throw new NotSupportedException(); }
    }

    public override long Position
    {
        get { throw new NotSupportedException(); }
        set { throw new NotSupportedException(); }
    }
}
public class Product
{
    public string Name { get; set; }
    public DateTime Expiry { get; set; }
    public string[] Sizes { get; set; }
}