How to deserialize a unix timestamp (μs) to a DateTime from JSON?

Question

JSON

{    "title":"Mozilla Firefox",    "id":24,    "parent":2,    "dateAdded":1356753810000000,    "lastModified":1356753810000000,    "type":"text/x-moz-place-container",    "children":[] } 

C#

class Bookmark {     public string title;     public string id;     [JsonProperty(ItemConverterType = typeof(JavaScriptDateTimeConverter))]     public DateTime dateAdded;     [JsonProperty(ItemConverterType = typeof(JavaScriptDateTimeConverter))]     public DateTime lastModified;     public string type;     public string root;     public long parent;     public List<Bookmark> children; }  private static void Main(string[] args) {     var json = File.ReadAllText(@"T:/bookmarks-2013-11-13.json");     var bookmarks = JsonConvert.DeserializeObject<Bookmark>(json); } 

I get an exception when I try running this,

Additional information: Error reading date. Unexpected token: Integer. Path 'dateAdded'

I thought by using the JavaScriptDateTimeConverter, JSON.NET could figure out how to deserialize those unix timestamps (ms μs since epoch). What's the easiest way to do this?

Having trouble finding documentation on the converters... it probably wouldn't be too hard to write one myself if necessary.

Edit: Those are actually microseconds, not milliseconds.

Answer 1

I cleaned up Cris's solution a tad and implemented WriteJson:

class Bookmark {     public string title;     public long id;     [JsonConverter(typeof(MicrosecondEpochConverter))]     public DateTime dateAdded;     [JsonConverter(typeof(MicrosecondEpochConverter))]     public DateTime lastModified;     public string type;     public string root;     public long parent;     public List<Bookmark> children;     public string uri;      public override string ToString()     {         return string.Format("{0} - {1}", title, uri);     } }  public class MicrosecondEpochConverter : DateTimeConverterBase {     private static readonly DateTime _epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);      public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)     {         writer.WriteRawValue(((DateTime)value - _epoch).TotalMilliseconds + "000");     }      public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)     {         if (reader.Value == null) { return null; }         return _epoch.AddMilliseconds((long)reader.Value / 1000d);     } }  internal class Program {      private static void Main(string[] args)     {         var jsonString = File.ReadAllText(@"T:/bookmarks-2013-11-13.json");         var rootMark = JsonConvert.DeserializeObject<Bookmark>(jsonString);         var ret = JsonConvert.SerializeObject(rootMark);     } } 

Answer 2

There's a built-in way to convert from unix timestamp to DateTime without having to write your own class:

[JsonConverter(typeof(UnixDateTimeConverter))] public DateTime lastModified; 

https://www.newtonsoft.com/json/help/html/T_Newtonsoft_Json_Converters_UnixDateTimeConverter.htm

The annotation in Cris' answer is not correct, as JavaScriptDateTimeConverter is for Date(52231943) format rather than the Unix timestamp from the OP.

I realize this question is a few years old now so it's highly likely this class has been added since this question has been asked, but this may help anyone who comes across the same issue.