I always try to keep my models seperate from the implementation or configuration. EF Core 2.1 added great support for custom type converters with HasConversion. MongoDB also has a support for custom type conversion, though it is not quite as well documented.
The basic premise revolves around implementing IBsonSerializer<TType>. Let's suppose I have a Bitrate struct I want to convert to a long. Bitrate has a BitsPerSecond property which is the underlying long value. My BitrateSerializer will look something like this:
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public class BitrateSerializer : IBsonSerializer<Bitrate> { public Type ValueType => typeof(Bitrate); public void Serialize(BsonSerializationContext context, BsonSerializationArgs args, Bitrate value) { BsonSerializer.Serialize(context.Writer, value.BitsPerSecond); } Bitrate IBsonSerializer<Bitrate>.Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args) { return new Bitrate(BsonSerializer.Deserialize<long>(context.Reader)); } public object Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args) { // You can reuse Deserialize method, but ensure you don't end up in an infinte loop. return new Bitrate(BsonSerializer.Deserialize<long>(context.Reader)); } public void Serialize(BsonSerializationContext context, BsonSerializationArgs args, object value) { Serialize(context, args, (Bitrate)value); } } |
This being Mongo driver, it is not so easy to add unit tests. I'll cover this another time.