Disable serialization for specific types

[EdwardCooke]

Discussed in https://github.com/aaubry/YamlDotNet/discussions/861

^{Originally posted by JamesTheButler October 30, 2023} Hi everyone!

I am serializing a class that contains a public Action field. Consider the following example:

record class Example
{
  public int Int { get; private set; }

  public Action? SomeAction;
};

public void Test()
{
  var serializer = new SerializerBuilder().Build();
  var output = serializer.Serialize(new DemoClass());
  // output:
  //  SomeAction: 
  //  Int: 0
}

SomeAction gets serialized to an empty string in yaml, which is a bit annoying but still okay. It get's fun if we actually subscribe to SomeAction when the serializer generates ~5.000 lines of yaml to describe the attached action.

Is it possible to not serialize members of a given type? I know about [YamlIgnore] but I would rather set up my serializer to ignore all members of the type Action (and possibly other types as well) in any of my serializable classes.

[EdwardCooke]

You can do this with a custom type inspector.

using YamlDotNet.Serialization;
using YamlDotNet.Serialization.TypeInspectors;

var data = new Receiver();

var serializer = new SerializerBuilder()
    .WithTypeInspector(inner=>new IgnoreTypeTypeInspector(inner), where=>where.OnBottom())
    .Build();
var yaml = serializer.Serialize(data);
Console.WriteLine(yaml);

public class IgnoreTypeTypeInspector : TypeInspectorSkeleton
{
    private readonly ITypeInspector innerTypeDescriptor;

    public IgnoreTypeTypeInspector(ITypeInspector innerTypeDescriptor)
    {
        this.innerTypeDescriptor = innerTypeDescriptor ?? throw new ArgumentNullException(nameof(innerTypeDescriptor));
    }

    public override IEnumerable<IPropertyDescriptor> GetProperties(Type type, object? container)
    {
        var properties = innerTypeDescriptor.GetProperties(type, container)
            .Where(p => p.Type != typeof(int));
        return properties;
    }
}

public class Receiver
{
    public string ReceiverType = Guid.NewGuid().ToString();
    public string ReceiverName = Guid.NewGuid().ToString();
    public int IgnoreMyIntType = 0;
}

Results in

ReceiverType: 24329920-d193-4e5b-b849-1b033e46c3a6
ReceiverName: f9e33caa-86e3-4c12-8931-ec303a74b59f