Adding Autofac to .NET core 6.0 using the new single file template - autofac

Question

I am trying to add Autofac to a .Net 6.0 web API.
I'm using the latest ASP.NET Core Web API template that generates a single start-up Program.cs file.
Installed Autofac versions:
Autofac 6.3.0
Autofac.Extensions.DependancyInjection (7.2.0-preview.1)
Installed .Net 6.0 versions:
Microsoft.AspNetCore.App 6.0.0-rc.2.21480.10
Microsoft.NETCore.App 6.0.0-rc.2.21480.5
Microsoft.WindowsDesktop.App 6.0.0-rc.2.21501.6
Just in case of doubt, this is the entire content of the Program.cs file (yes, no namespaces or class definition. Only a Program.cs file and no StartUp class or Startup.cs file)
var builder = WebApplication.CreateBuilder(args);
// Add services to the container.
builder.Services.AddControllers();
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
var app = builder.Build();
// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
app.UseSwagger();
app.UseSwaggerUI();
}
app.UseHttpsRedirection();
app.UseAuthorization();
app.MapControllers();
app.Run()
I've tried looking through the latest Autofac documentation but the examples there, despite saying for .Net Core 3.x and later don't seem to fit with .Net 6.0 code. I can't figure out how to add Autofac into the middleware pipeline.
Any help is greatly appreciated.
Code snippet from Autofac website
public class Program
{
public static void Main(string[] args)
{
// ASP.NET Core 3.0+:
// The UseServiceProviderFactory call attaches the
// Autofac provider to the generic hosting mechanism.
var host = Host.CreateDefaultBuilder(args)
.UseServiceProviderFactory(new AutofacServiceProviderFactory())
.ConfigureWebHostDefaults(webHostBuilder => {
webHostBuilder
.UseContentRoot(Directory.GetCurrentDirectory())
.UseIISIntegration()
.UseStartup<Startup>();
})
.Build();
host.Run();
}
}
Autofac documention:
https://docs.autofac.org/en/latest/integration/aspnetcore.html#asp-net-core-3-0-and-generic-hosting

Answer 1

I found this.
https://learn.microsoft.com/en-us/aspnet/core/migration/50-to-60-samples?view=aspnetcore-5.0
var builder = WebApplication.CreateBuilder(args);
builder.Host.UseServiceProviderFactory(new AutofacServiceProviderFactory());
// Register services directly with Autofac here. Don't
// call builder.Populate(), that happens in AutofacServiceProviderFactory.
builder.Host.ConfigureContainer<ContainerBuilder>(builder => builder.RegisterModule(new MyApplicationModule()));
var app = builder.Build();

Answer 2

At "Program.cs"
You'll find
var builder = WebApplication.CreateBuilder(args);
Add below
builder.Host.UseServiceProviderFactory(new AutofacServiceProviderFactory())
.ConfigureContainer<ContainerBuilder>(builder =>
{
builder.RegisterModule(new AutofacBusinessModule());
});
Answer above, I've assumed that you had everything else set up.
I'm using Autofac and Autofact.Extras.DynamicProxy
Sharing below my AutofacBusinessModule just for clarification.
public class AutofacBusinessModule : Module
{
protected override void Load(ContainerBuilder builder)
{
builder.RegisterType<ProductManager>().As<IProductService>().SingleInstance();
builder.RegisterType<EfProductDal>().As<IProductDal>().SingleInstance();
}
}

Answer 3

I have attached examples of both manual declarations and Reflection API of how to add Autofac to .NET Core 6.0
Call UseServiceProviderFactory on the Host sub-property
Call ConfigureContainer on the Host sub-property
Declare your services and their lifetime
Example of a manual services declaration
var builder = WebApplication.CreateBuilder(args);
// Call UseServiceProviderFactory on the Host sub property
builder.Host.UseServiceProviderFactory(new AutofacServiceProviderFactory());
// Call ConfigureContainer on the Host sub property
builder.Host.ConfigureContainer<ContainerBuilder>(builder =>
{
// Declare your services with proper lifetime
builder.RegisterType<AppLogger>().As<IAppLogger>().SingleInstance();
builder.RegisterType<DataAccess>().As<IDataAccess>().InstancePerLifetimeScope();
});
Example of Assembly scanning "Reflection API"
var builder = WebApplication.CreateBuilder(args);
// Call UseServiceProviderFactory on the Host sub property
builder.Host.UseServiceProviderFactory(new AutofacServiceProviderFactory());
// Call ConfigureContainer on the Host sub property
builder.Host.ConfigureContainer<ContainerBuilder>(builder =>
{
builder.RegisterAssemblyTypes(Assembly.Load(nameof(DemoLibrary))).Where(t => t.Namespace?.Contains("Practicing.Services") == true)
.As(t => t.GetInterfaces().FirstOrDefault(i => i.Name == "I" + t.Name));
});