A small collection of type converter that are used to map types in and out of DynamoDB items.

README.md

.Net TypeConverters for DynamoDB

Here's a small collection of type converter that are used to map types in and out of DynamoDB items. Each is used on the item class, e.g:

  [DynamoDBTable("UserInvites")]
  public class UserInviteItem
  {
    [DynamoDBHashKey]
    [DynamoDBProperty(typeof(GuidTypeConverter))]
    public Guid ID { get; set; }
    [DynamoDBProperty]
    public string Email { get; set; }
    [DynamoDBProperty]
    public string Code { get; set; }
    [DynamoDBProperty]
    public Guid OrganisationID { get; set; }
    [DynamoDBProperty]
    public string Message { get; set; }
    [DynamoDBProperty]
    public string Role { get; set; }
    [DynamoDBProperty(typeof(DateTimeOffsetTypeConverter))]
    public DateTimeOffset Sent { get; set; }
    [DynamoDBProperty(typeof(NullableDateTimeOffsetTypeConverter))]
    public DateTimeOffset? Accepted { get; set; }

  }

DateTimeOffsetTypeConverter.cs

using Amazon.DynamoDBv2.DataModel;
using Amazon.DynamoDBv2.DocumentModel;
using System;

namespace barXui.Models.Data.Dynamo
{
  public class DateTimeOffsetTypeConverter : IPropertyConverter
  {
    public object FromEntry(DynamoDBEntry entry)
    {
      Primitive primitive = entry as Primitive;
      if (primitive == null || !(primitive.Value is String) || string.IsNullOrEmpty((string)primitive.Value))
        throw new ArgumentOutOfRangeException();

      return DateTimeOffset.Parse(primitive.Value.ToString());
    }

    public DynamoDBEntry ToEntry(object value)
    {
      try
      {
        return new Primitive
        {
          Value = ((DateTimeOffset)value).ToString("o")
        };
      }
      catch
      {
        return new Primitive
        {
          Value = (new DateTimeOffset()).ToString("o")
        };
      }
    }
  }
}

GuidTypeConverter.cs

using Amazon.DynamoDBv2.DataModel;
using Amazon.DynamoDBv2.DocumentModel;
using System;

namespace barXui.Models.Data.Dynamo
{
  public class GuidTypeConverter : IPropertyConverter
  {
    public object FromEntry(DynamoDBEntry entry)
    {
      Primitive primitive = entry as Primitive;
      if (primitive == null || !(primitive.Value is String) || string.IsNullOrEmpty((string)primitive.Value))
        throw new ArgumentOutOfRangeException();

      return Guid.Parse(primitive.Value.ToString());
    }

    public DynamoDBEntry ToEntry(object value)
    {
      try
      {
        return new Primitive
        {
          Value = ((Guid)value).ToString()
        };
      }
      catch
      {
        return new Primitive
        {
          Value = Guid.Empty.ToString()
        };
      }
    }
  }
}

IntTypeConverter.cs

using Amazon.DynamoDBv2.DataModel;
using Amazon.DynamoDBv2.DocumentModel;
using System;

namespace barXui.Models.Data.Dynamo
{
  /// <summary>
  /// Partition keys must be string
  /// </summary>
  public class IntTypeConverter : IPropertyConverter
  {
    public object FromEntry(DynamoDBEntry entry)
    {
      Primitive primitive = entry as Primitive;
      if (primitive == null || !(primitive.Value is String) || string.IsNullOrEmpty((string)primitive.Value))
        throw new ArgumentOutOfRangeException();

      return Convert.ToInt32(primitive.Value.ToString());
    }

    public DynamoDBEntry ToEntry(object value)
    {
      try
      {
        return new Primitive
        {
          Value = ((int)value).ToString()
        };
      }
      catch
      {
        return new Primitive
        {
          Value = "0"
        };
      }
    }
  }
}

NullableDateTimeOffsetTypeConverter.cs

using Amazon.DynamoDBv2.DataModel;
using Amazon.DynamoDBv2.DocumentModel;
using System;

namespace barXui.Models.Data.Dynamo
{
  public class NullableDateTimeOffsetTypeConverter : IPropertyConverter
  {
    public object FromEntry(DynamoDBEntry entry)
    {
      Primitive primitive = entry as Primitive;
      if (primitive == null || !(primitive.Value is String) || string.IsNullOrEmpty((string)primitive.Value))
        throw new ArgumentOutOfRangeException();

      return primitive.Value == null ? null : DateTimeOffset.Parse(primitive.Value.ToString());
    }

    public DynamoDBEntry ToEntry(object value)
    {
      try
      {
        return new Primitive
        {
          Value = ((DateTimeOffset)value).ToString("o")
        };
      }
      catch
      {
        return new Primitive
        {
          Value = null
        };
      }
    }
  }
}