Create Injectable and static serialisers

[StuartFerguson]

public interface ISerializer
{
    string Serialize<T>(T obj);
    T Deserialize<T>(string json);
}

public class SystemTextJsonSerializer : ISerializer
{
    private readonly JsonSerializerOptions _options;

    public SystemTextJsonSerializer(JsonSerializerOptions options)
    {
        _options = options;
    }

    public string Serialize<T>(T obj)
    {
        return JsonSerializer.Serialize(obj, _options);
    }

    public T Deserialize<T>(string json)
    {
        return JsonSerializer.Deserialize<T>(json, _options)!;
    }
}

public class NewtonsoftJsonSerializer : ISerializer
{
    private readonly JsonSerializerSettings _settings;

    public NewtonsoftJsonSerializer(JsonSerializerSettings settings)
    {
        _settings = settings;
    }

    public string Serialize<T>(T obj)
    {
        return JsonConvert.SerializeObject(obj, _settings);
    }

    public T Deserialize<T>(string json)
    {
        return JsonConvert.DeserializeObject<T>(json, _settings)!;
    }
}

DI registration

builder.Services.AddSingleton<ISerializer>(sp =>
{
    var options = new JsonSerializerOptions
    {
        PropertyNamingPolicy = JsonNamingPolicy.SnakeCaseLower
    };

    return new SystemTextJsonSerializer(options);
});

builder.Services.AddControllers()
    .AddJsonOptions(options =>
    {
        options.JsonSerializerOptions.PropertyNamingPolicy =
            JsonNamingPolicy.CamelCase;
    });

Or add a static wrapper like we do with Logger

Serialiser.Initialise(new SystemTextJsonSerializer());