Where the conversion code should be placed

[kzhui125]

Hello, I meet a issue similar to the following code: the controller get a body(string), the conversion from body to domain object(dto object) is very complicated. And both Application layer and Infrastructure layer(repository) reply on the conversion.

I don't know where to put the conversion code.

Need help, thanks!

Domain:

// Domain Layer
public record DataObject(int Id, int I1, double D1, string S1, string S2, string S3, string S4, string S5);

public interface IDataReposity
{
    public void SaveData(DataObject dataObject);
    public DataObject GetDataById(int id);
}

Application Layer:

// Application Layer
public record DataDto(int Id, int I1, double D1, string S1, string S2, string S3, string S4, string S5);

public record DataVm(string Body);

public record GetDataQuery : IRequest<DataVm>
{
    public int Id { get; init; }
}

public class GetDataQueryHandler : IRequestHandler<GetDataQuery, DataVm>
{
    private readonly IDataReposity _dataReposity;
    public GetDataQueryHandler(IDataReposity dataReposity)
    {
        _dataReposity = dataReposity;
    }

    public Task<DataVm> Handle(GetDataQuery request, CancellationToken cancellationToken)
    {
        DataObject d =  _dataReposity.GetDataById(request.Id);
        DataDto dto = new(d.Id, d.I1, d.D1, d.S1, d.S2, d.S3, d.S4, d.S5);

        // convert dto to body: Where the conversion code should be placed?
        string body = "converted"; //
        DataVm vm = new(body);
        return Task.FromResult(vm);
    }
}

public record AddDataCommand : IRequest
{
    public string Body { get; init; } = "";
}

public class AddDataCommandHandler : IRequestHandler<AddDataCommand>
{
    private readonly IDataReposity _dataReposity;
    public AddDataCommandHandler(IDataReposity dataReposity)
    {
        _dataReposity = dataReposity;
    }

    public Task<Unit> Handle(AddDataCommand request, CancellationToken cancellationToken)
    {
        string body = request.Body;
        // convert body to DataObject: Where the conversion code should be placed?
        DataObject dataObject = new(1, 1, 1, "", "", "", "", "");
        return Task.FromResult(Unit.Value);
    }
}

// Infrastructure layer
public class DataReposity : IDataReposity
{
    private string GetBodyFromDatabase(int id)
    {
        // get str body from databse
        string body = "";
        return body;
    }

    private void SaveBodyToDatabase(int id, string body)
    {
        // save str body from databse
        return;
    }

    public DataObject GetDataById(int id)
    {
        string body = GetBodyFromDatabase(id);
        // convert body to DataObject: Where the conversion code should be placed?
        DataObject dataObject = new(1, 1, 1, "", "", "", "", "");
        return dataObject;
    }

    public void SaveData(DataObject dataObject)
    {
        int id = dataObject.Id;
        // convert DataObject to body : Where the conversion code should be placed?
        string body = "";
        SaveBodyToDatabase(id, body);
    }
}