code.grnet.gr Git - pithos-ms-client/blob - trunk/Pithos.Interfaces/PithosDateTimeConverter.cs

   1 using System;
   2 using System.Globalization;
   3 using Newtonsoft.Json;
   4 using Newtonsoft.Json.Converters;
   5 using Newtonsoft.Json.Utilities;
   6
   7 namespace Pithos.Interfaces
   8 {
   9     /// <summary>
  10     /// Converts a <see cref="DateTime"/> to and from a JavaScript date constructor (e.g. new Date(52231943)).
  11     /// </summary>
  12     public class PithosDateTimeConverter : DateTimeConverterBase
  13     {
  14         private DateTime _epoch = new DateTime(1970, 1, 1,0,0,0,DateTimeKind.Utc);
  15
  16         /// <summary>
  17         /// Writes the JSON representation of the object.
  18         /// </summary>
  19         /// <param name="writer">The <see cref="JsonWriter"/> to write to.</param>
  20         /// <param name="value">The value.</param>
  21         /// <param name="serializer">The calling serializer.</param>
  22         public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
  23         {
  24             double seconds;
  25
  26             if (value is DateTime)
  27             {
  28                 var dateTime = (DateTime)value;
  29                 var utcDateTime = dateTime.ToUniversalTime();
  30                 seconds = (utcDateTime - _epoch).TotalSeconds; ;
  31             }
  32             else if (value is DateTimeOffset)
  33             {
  34                 var dateTimeOffset = (DateTimeOffset)value;
  35                 var utcDateTimeOffset = dateTimeOffset.ToUniversalTime();
  36                 seconds= (utcDateTimeOffset.UtcDateTime - _epoch).TotalSeconds;
  37             }
  38             else
  39             {
  40                 throw new Exception("Expected date object value.");
  41             }
  42
  43             writer.WriteValue(seconds);
  44         }
  45
  46         /// <summary>
  47         /// Reads the JSON representation of the object.
  48         /// </summary>
  49         /// <param name="reader">The <see cref="JsonReader"/> to read from.</param>
  50         /// <param name="objectType">Type of the object.</param>
  51         /// <param name="existingValue">The existing property value of the JSON that is being converted.</param>
  52         /// <param name="serializer">The calling serializer.</param>
  53         /// <returns>The object value.</returns>
  54         public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
  55         {
  56             Type t = (IsNullableType(objectType))
  57                          ? Nullable.GetUnderlyingType(objectType)
  58                          : objectType;
  59
  60             if (reader.TokenType == JsonToken.Null)
  61             {
  62                 if (!IsNullableType(objectType))
  63                     throw new Exception(String.Format("Cannot convert null value to {0}.",objectType));
  64
  65                 return null;
  66             }
  67
  68             var seconds = double.Parse((string)reader.Value,CultureInfo.InvariantCulture);
  69
  70             DateTime d =  _epoch.AddSeconds(seconds);
  71
  72
  73             if (t == typeof(DateTimeOffset))
  74                 return new DateTimeOffset(d);
  75             return d;
  76         }
  77
  78         public static bool IsNullableType(Type t)
  79         {
  80             if (t== null)
  81                 throw new ArgumentNullException("t");
  82
  83             return (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(Nullable<>));
  84         }
  85     }
  86 }