Ytukyg

I am trying to wire up a background thread that will update the database once an hour from Active Directory. I am not sure how to pass the current

    public void ConfigureServices(IServiceCollection services)

        {

            services.Configure<CookiePolicyOptions>(options =>

            {

                // This lambda determines whether user consent for non-essential cookies is needed for a given request.

                options.CheckConsentNeeded = context => false;

                options.MinimumSameSitePolicy = SameSiteMode.None;

            });



            // Add framework services.

            services.AddDbContext<ApplicationDbContext>(options =>

                options.UseSqlServer(Configuration.GetConnectionString("Connection")));



            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1).AddSessionStateTempDataProvider();

            services.AddSession();

            services.AddHttpContextAccessor();



            services.AddSingleton(Configuration);

            services.AddScoped<IAppDbRepository, AppDbRepository>();

            services.AddScoped<IActiveDirectoryUtility, ActiveDirectoryUtility>();

            services.AddScoped<IActiveDirectoryManager, ActiveDirectoryManager>();



            services.AddHostedService<LdapManager>();

            services.AddScoped<ILdapManager, LdapManager>();



        }



In the LdapManager class I would like to call the UpdateUsers method every hour:



    public class LdapManager : ILdapManager, IHostedService

    {

        private IConfiguration _configuration = null;

        private Logging _logger;

        private List<string> ldapConnectorForDirectoryEntries = new List<string>();



        public LdapManager(IConfiguration configuration)

        {

            _configuration = configuration;



            UpdateUsers();

            SyncActiveDirectoryUsers();

        }





    public void SyncActiveDirectoryUsers()

        {

            try

            {

                using (var waitHandle = new AutoResetEvent(false))

                {

                    ThreadPool.RegisterWaitForSingleObject(waitHandle, (state, timeout) => { UpdateUsers(); }, null, TimeSpan.FromHours(1), false);

                }

            }

            catch

            {

                throw;

            }

        }

    }

The UpdateUsers() method should be able to call the applicationDBContext.SaveChanges() method.

How can I ensure that the LDAP manger class can use the Application DB context?

You probably want class LdapManager : BackgroundService, ILdapManager

BackgroundService is .NET Core 2.1, there is a code sample available for core 2.0

Inject IServiceScopeFactory and override Task ExecuteAsync( ), run a while loop there.

while(!stoppingToken.IsCancellationRequested)

{

    using (var scope = _serviceScopeFactory.CreateScope())

    {

        var context = scope.ServiceProvider.GetRequiredService<ApplicationDbContext>();

        ...; // do your stuff

    }

    await Task.Delay(myConfig.BackgroundDelay, stoppingToken);

}

And here is a good read about this on MSDN, including the code sample for 2.0

For accessing ApplicationDbContext from HostedService.

• 
  

  DbHostedService

  
  
  

  public class DbHostedService : IHostedService
  
   {
  
  private readonly ILogger _logger;
  
  
  
  public DbHostedService(IServiceProvider services,
  
      ILogger<DbHostedService> logger)
  
  {
  
      Services = services;
  
      _logger = logger;
  
  }
  
  
  
  public IServiceProvider Services { get; }
  
  
  
  public Task StartAsync(CancellationToken cancellationToken)
  
  {
  
      _logger.LogInformation(
  
          "Consume Scoped Service Hosted Service is starting.");
  
  
  
      DoWork();
  
  
  
      return Task.CompletedTask;
  
  }
  
  
  
  private void DoWork()
  
  {
  
      _logger.LogInformation(
  
          "Consume Scoped Service Hosted Service is working.");
  
  
  
      using (var scope = Services.CreateScope())
  
      {
  
          var context =
  
              scope.ServiceProvider
  
                  .GetRequiredService<ApplicationDbContext>();
  
  
  
          var user = context.Users.LastOrDefault();
  
  
  
          _logger.LogInformation(user?.UserName);
  
      }
  
  }
  
  
  
  public Task StopAsync(CancellationToken cancellationToken)
  
  {
  
      _logger.LogInformation(
  
          "Consume Scoped Service Hosted Service is stopping.");
  
  
  
      return Task.CompletedTask;
  
  }
  
  }
  
  

  
  


• 
  

  Register DbHostedService

  
  
  

  services.AddHostedService<DbHostedService>();