AuthenticationContextFactory.cs

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using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging;
using System;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Tgstation.Server.Host.Database;
using Tgstation.Server.Host.Models;

namespace Tgstation.Server.Host.Security
{
    sealed class AuthenticationContextFactory : IAuthenticationContextFactory, IDisposable
    {
        public IAuthenticationContext CurrentAuthenticationContext { get; private set; }

        readonly IDatabaseContext databaseContext;

        readonly IIdentityCache identityCache;

        readonly ILogger<AuthenticationContextFactory> logger;

        public AuthenticationContextFactory(
            IDatabaseContext databaseContext,
            IIdentityCache identityCache,
            ILogger<AuthenticationContextFactory> logger)
        {
            this.databaseContext = databaseContext ?? throw new ArgumentNullException(nameof(databaseContext));
            this.identityCache = identityCache ?? throw new ArgumentNullException(nameof(identityCache));
            this.logger = logger ?? throw new ArgumentNullException(nameof(logger));
        }

        public void Dispose() => CurrentAuthenticationContext?.Dispose();

        public async Task CreateAuthenticationContext(long userId, long? instanceId, DateTimeOffset validAfter, CancellationToken cancellationToken)
        {
            if (CurrentAuthenticationContext != null)
                throw new InvalidOperationException("Authentication context has already been loaded");

            var user = await databaseContext
                .Users
                .AsQueryable()
                .Where(x => x.Id == userId)
                .Include(x => x.CreatedBy)
                .FirstOrDefaultAsync(cancellationToken)
                .ConfigureAwait(false);
            if (user == default)
            {
                logger.LogWarning("Unable to find user with ID {0}!", userId);
                CurrentAuthenticationContext = new AuthenticationContext();
                return;
            }

            ISystemIdentity systemIdentity;
            if (user.SystemIdentifier != null)
                systemIdentity = identityCache.LoadCachedIdentity(user);
            else
            {
                if (user.LastPasswordUpdate.HasValue && user.LastPasswordUpdate > validAfter)
                {
                    logger.LogDebug("Rejecting token for user {0} created before last password update: {1}", userId, user.LastPasswordUpdate.Value);
                    CurrentAuthenticationContext = new AuthenticationContext();
                    return;
                }

                systemIdentity = null;
            }

            try
            {
                InstanceUser instanceUser = null;
                if (instanceId.HasValue)
                {
                    instanceUser = await databaseContext.InstanceUsers
                        .AsQueryable()
                        .Where(x => x.UserId == userId && x.InstanceId == instanceId && x.Instance.Online.Value)
                        .Include(x => x.Instance)
                        .FirstOrDefaultAsync(cancellationToken)
                        .ConfigureAwait(false);

                    if (instanceUser == null)
                        logger.LogDebug("User {0} does not have permissions on instance {1}!", userId, instanceId.Value);
                }

                CurrentAuthenticationContext = new AuthenticationContext(systemIdentity, user, instanceUser);
            }
            catch
            {
                systemIdentity?.Dispose();
                throw;
            }
        }
    }
}