JavaScriptSerializer not working with TimeSpan

[jakejscott]

Hi Guys,

Seems to serialise okay:
{"Ticks":12096000000000,"Days":14,"Hours":0,"Milliseconds":0,"Minutes":0,"Seconds":0,"TotalDays":14,"TotalHours":336,"TotalMilliseconds":1209600000,"TotalMinutes":20160,"TotalSeconds":1209600}

But when I deserialize I am getting an empty time span :(

public class NancyJsSerialiserTest
{
    [Fact] 
    public void Should_be_able_to_serialise_and_deserialise_timespan()
    {
        var serializer = new JavaScriptSerializer();
        var sb = new StringBuilder();
        var days = TimeSpan.FromDays(14);

        serializer.Serialize(days, sb);
        Console.WriteLine(sb.ToString());

        var actual = serializer.Deserialize<TimeSpan>(sb.ToString());

        actual.ShouldEqual(days);
    }
}

[grumpydev]

This is a limitation of the Microsoft one too (JSON doesn't really do times/dates), but we can "fix" it by registering a converter:

namespace JSONTestingAgain
{
    using System;
    using System.Collections.Generic;

    using Nancy.Json;

    public class TimeSpanJsonConverter : JavaScriptConverter
    {
        public override IEnumerable<Type> SupportedTypes
        {
            get
            {
                return new[] { typeof(TimeSpan) };
            }
        }

        public override object Deserialize(IDictionary<string, object> dictionary, Type type, JavaScriptSerializer serializer)
        {
            return new TimeSpan(
                this.GetValue(dictionary, "days"),
                this.GetValue(dictionary, "hours"),
                this.GetValue(dictionary, "minutes"),
                this.GetValue(dictionary, "seconds"),
                this.GetValue(dictionary, "milliseconds"));
        }

        public override IDictionary<string, object> Serialize(object obj, JavaScriptSerializer serializer)
        {
            var timeSpan = (TimeSpan)obj;

            var result = new Dictionary<string, object>
                {
                    { "days", timeSpan.Days },
                    { "hours", timeSpan.Hours },
                    { "minutes", timeSpan.Minutes },
                    { "seconds", timeSpan.Seconds },
                    { "milliseconds", timeSpan.Milliseconds }
                };

            return result;
        }

        private int GetValue(IDictionary<string, object> dictionary, string key)
        {
            const int DefaultValue = 0;

            object value;
            if (!dictionary.TryGetValue(key, out value))
            {
                return DefaultValue;
            }

            if (value is int)
            {
                return (int)value;
            }

            var valueString = value as string;
            if (valueString == null)
            {
                return DefaultValue;
            }

            int returnValue;
            return !int.TryParse(valueString, out returnValue) ? DefaultValue : returnValue;
        }
    }
}

Then:

serializer.RegisterConverters(new[] { new TimeSpanJsonConverter() });

It may be worth discovering / adding a static collection to allow users to add converters, and also ship some (like this one) in the box.

[grumpydev]

Restructured the JSON namespaces slightly so now the configuration is in the Json namespace (rather than responses) and now has an extra IList property for registering converters which is used in both JsonResponse and the JSON body deserializer.

[jakejscott]

Legend! Thanks :)

[grumpydev]

No worries .. it'll be in 0.8.1 this week.