jellyfin-jellyfin-1/Jellyfin.Server.Implementations/Extensions/ServiceCollectionExtensions.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using Jellyfin.Server.Implementations.DatabaseConfiguration;
using MediaBrowser.Common.Configuration;
using MediaBrowser.Controller.Configuration;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using JellyfinDbProviderFactory = System.Func<System.IServiceProvider, Jellyfin.Server.Implementations.IJellyfinDatabaseProvider>;

namespace Jellyfin.Server.Implementations.Extensions;

/// <summary>
/// Extensions for the <see cref="IServiceCollection"/> interface.
/// </summary>
public static class ServiceCollectionExtensions
{
    private static IDictionary<string, JellyfinDbProviderFactory> GetSupportedDbProviders()
    {
        var items = new Dictionary<string, JellyfinDbProviderFactory>();
        foreach (var providerType in AppDomain
            .CurrentDomain
            .GetAssemblies()
            .SelectMany(f => f.GetTypes())
            .Where(e => e.IsClass && typeof(IJellyfinDatabaseProvider).IsAssignableFrom(e)))
        {
            var keyAttribute = providerType.GetCustomAttribute<JellyfinDatabaseProviderKeyAttribute>();
            if (keyAttribute is null || string.IsNullOrWhiteSpace(keyAttribute.DatabaseProviderKey))
            {
                continue;
            }

            var provider = providerType;
            items[keyAttribute.DatabaseProviderKey] = (services) => (IJellyfinDatabaseProvider)ActivatorUtilities.CreateInstance(services, providerType);
        }

        return items;
    }

    /// <summary>
    /// Adds the <see cref="IDbContextFactory{TContext}"/> interface to the service collection with second level caching enabled.
    /// </summary>
    /// <param name="serviceCollection">An instance of the <see cref="IServiceCollection"/> interface.</param>
    /// <param name="configurationManager">The server configuration manager.</param>
    /// <returns>The updated service collection.</returns>
    public static IServiceCollection AddJellyfinDbContext(this IServiceCollection serviceCollection, IServerConfigurationManager configurationManager)
    {
        var efCoreConfiguration = configurationManager.GetConfiguration<DatabaseConfigurationOptions>("database");
        var providers = GetSupportedDbProviders();
        JellyfinDbProviderFactory? providerFactory = null;

        if (efCoreConfiguration is null)
        {
            // when nothing is setup via new Database configuration, fallback to SqLite with default settings.
            efCoreConfiguration = new DatabaseConfigurationOptions()
            {
                DatabaseType = "SqLite",
            };
        }
        else if (!providers.TryGetValue(efCoreConfiguration.DatabaseType, out providerFactory!))
        {
            throw new InvalidOperationException($"Jellyfin cannot find the database provider of type '{efCoreConfiguration.DatabaseType}'. Supported types are {string.Join(", ", providers.Keys)}");
        }

        serviceCollection.AddSingleton<IJellyfinDatabaseProvider>(providerFactory!);

        serviceCollection.AddPooledDbContextFactory<JellyfinDbContext>((serviceProvider, opt) =>
        {
            var provider = serviceProvider.GetRequiredService<IJellyfinDatabaseProvider>();
            provider.Initialise(opt);
        });

        return serviceCollection;
    }
}