Support for Firestore Metadata fields (Id, CreateTimestamp, UpdateTimestamp, ReadTimestamp) in IFireStoreConverter<T>

Is your feature request related to a problem? Please describe. I’m using a custom converter to convert my type to/from a document (IDictionary<string,object>) to avoid decorating my types with attributes. (I want my types to be shared in other libraries where I can’t reference the Firestore lib.)

The custom converter works great, except I don’t think it exposes the 4 metadata properties you can get using attribute serialization:

• FirestoreDocumentId
• FirestoreDocumentCreateTimestamp
• FirestoreDocumentUpdateTimestamp
• FirestoreDocumentReadTimestamp

Describe the solution you’d like It would be awesome of these 4 properties could be passed through the IFirestoreConverter<T> class

Describe alternatives you’ve considered I don’t see any way to get these values using IFirestoreConverter<T> today.

Additional context I was exploring this scenario with the below types/converter:

using AutoMapper;
using Google.Cloud.Firestore;
using System;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    class Program
    {
        public static IMapper MapperInstance = new MapperConfiguration(cfg => { }).CreateMapper();

        static async Task Main(string[] args)
        {
            // Set GOOGLE_APPLICATION_CREDENTIALS env variable here

            FirestoreDbBuilder builder = new FirestoreDbBuilder();
            builder.ConverterRegistry = new ConverterRegistry();
            builder.ConverterRegistry.Add(new Converter());
            builder.ProjectId = "<project id>";

            FirestoreDb db = builder.Build();

            await db.Collection("Testing").AddAsync(new MyFireStoreType
            {
                Prop1 = "foo",
                Prop2 = 2
            });

            var result = await db.Collection("Testing").GetSnapshotAsync();

            MyFireStoreType deserializedType = result[0].ConvertTo<MyFireStoreType>();

            Console.WriteLine("Done");
        }
    }

    public sealed class MyFireStoreType : FireStoreBaseObject
    {
        public string Prop1 { get; set; }
        public int Prop2 { get; set; }
        public bool? Prop3 { get; set; }
    }

    public abstract class FireStoreBaseObject
    {
        public string FirestoreDocumentId { get; set; }

        public DateTimeOffset FirestoreDocumentCreateTimestamp { get; set; }

        public DateTimeOffset FirestoreDocumentUpdateTimestamp { get; set; }

        public DateTimeOffset FirestoreDocumentReadTimestamp { get; set; }
    }

    public class Converter : IFirestoreConverter<MyFireStoreType>
    {
        public MyFireStoreType FromFirestore(object value)
        {
            Dictionary<string, object> valueAsDict = (Dictionary<string, object>)value;
            // Issue - no Id, CreateTimestamp, UpdateTimestamp, ReadTimestamp values available in the above dictionary
            return Program.MapperInstance.Map<MyFireStoreType>(valueAsDict);
        }

        public object ToFirestore(MyFireStoreType value)
        {
            return Program.MapperInstance.Map<Dictionary<string, object>>(value);
        }
    }
}

[jskeet]

@ryandle: I released 2.3.0 yesterday - thanks for working so collaboratively on this.

[jskeet]

Okay, I’ve had an idea about how we should be able to make these available in an extensible, backwardly-compatible way. Basically you’d be able to configure additional properties that would be populated in the dictionary passed to FromFirestore. I’ll work on a PR today/tomorrow with that in…