Snootalogue/Data/SnootalogueContext.cs

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;
using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
using Microsoft.EntityFrameworkCore.ChangeTracking;
using Snootalogue.Models;
using System.Text.Json;
using System.Text.Json.Serialization;
using System.Collections.Generic;

namespace Snootalogue.Data {
	public class SnootalogueContext : DbContext {
		public DbSet<Snootalogue.Models.Document> Document { get; set; }

		public SnootalogueContext(
				DbContextOptions<SnootalogueContext> options)
				: base(options) {
		}

		protected override void OnModelCreating(ModelBuilder modelBuilder) {
			modelBuilder.Entity<Document>().Property(item => item.Authors).HasJsonConversion<List<string>>();
			modelBuilder.Entity<Document>().Property(item => item.Tags).HasJsonConversion<List<string>>();
		}
	}

	public static class JsonConversion {
		// big beebus thanks to https://stackoverflow.com/a/59185869
		public static PropertyBuilder<T> HasJsonConversion<T>(this PropertyBuilder<T> propertyBuilder) where T : class, new() {
			ValueConverter<T, string> converter = new ValueConverter<T, string>(
				value => JsonSerializer.Serialize(value, null),
				value => JsonSerializer.Deserialize<T>(value, null)
			);

			ValueComparer<T> comparer = new ValueComparer<T>(
				(l, r) => JsonSerializer.Serialize(l, null) == JsonSerializer.Serialize(r, null),
				value => value == null ? 0 : JsonSerializer.Serialize(value, null).GetHashCode(),
				value => JsonSerializer.Deserialize<T>(JsonSerializer.Serialize(value, null), null)
			);

			propertyBuilder.HasConversion(converter);
			propertyBuilder.Metadata.SetValueConverter(converter);
			propertyBuilder.Metadata.SetValueComparer(comparer);
			propertyBuilder.HasColumnType("jsonb");

			return propertyBuilder;
		}
	}
}