How to deserialize java duration in c#?

Question

Assuming that I got a duration from Java: "PT-328H-46M-43.2082074S". How to deserialize it to NodaTime Duration in system.text.json?

Answer 1

That's the format that Noda Time usually uses for periods rather than durations. Unfortunately the presence of multiple signs within the value means you can't parse it using DurationPattern - but PeriodPattern.NormalizingIso appears to work okay:

using NodaTime.Text;

var pattern = PeriodPattern.NormalizingIso;
var result = pattern.Parse("PT-328H-46M-43.2082074S");
var period = result.Value;
var duration = period.ToDuration();

Console.WriteLine(duration);

To use that within System.Text.Json, you'd need to specify the right period pattern... and then potentially sort of "trampoline" from the period to the duration. Here's a complete example:

Program.cs:

using NodaTime;
using NodaTime.Serialization.SystemTextJson;
using NodaTime.Text;
using System.Text.Json;

string json = """
{
  "name": "Jon",
  "duration": "PT-328H-46M-43.2082074S"
}
""";

var settings = new NodaJsonSettings
{
    PeriodConverter = new NodaPatternConverter<Period>(PeriodPattern.NormalizingIso)
};
var options = new JsonSerializerOptions().ConfigureForNodaTime(settings);

var model = JsonSerializer.Deserialize<Model>(json, options);
Console.WriteLine(model.Duration);

Model.cs:

using NodaTime;
using System.Text.Json.Serialization;

public class Model
{
    [JsonPropertyName("name")]
    public string Name { get; set; }

    [Obsolete]
    [JsonPropertyName("duration")]
    public Period Period
    {
        // TODO: A getter, if you want to be able to serialize back.
        // That's a little more work as there isn't a Duration.ToPeriod conversion.
        set => Duration = value.ToDuration();
    }

    [JsonIgnore]
    public Duration Duration { get; set; }
}