NBMsgPack032: Converters should override GetJsonSchema

Custom converters (classes that derive from MessagePackConverter<T>) should override the GetJsonSchema method to document the schema of the msgpack they emit.

Learn more about custom converters.

Example violations

The following class converts MyType into a single integer. It fails to document this, however.

public class MyTypeConverter : MessagePackConverter<MyType>
{
    public override MyType Read(ref MessagePackReader reader, SerializationContext context)
    {
        int a = reader.ReadInt32();
        return new MyType(a);
    }

    public override void Write(ref MessagePackWriter writer, in MyType value, SerializationContext context)
    {
        writer.Write(value.A);
    }
}

Resolution

Override the GetJsonSchema method to document that the object is serialized as an integer.

public class MyTypeConverter : MessagePackConverter<MyType>
{
    public override MyType Read(ref MessagePackReader reader, SerializationContext context)
    {
        int a = reader.ReadInt32();
        return new MyType(a);
    }

    public override void Write(ref MessagePackWriter writer, in MyType value, SerializationContext context)
    {
        writer.Write(value.A);
    }

    public override JsonObject GetJsonSchema(JsonSchemaContext context, ITypeShape typeShape)
    {
        return new JsonObject
        {
             ["type"] = "integer",
        };
    }
}

Learn more about JSON Schema and review the docs for the GetJsonSchema method for details.