Generic host and Program.cs — Modern .NET — Hosting, Configuration, DI & Deployment

3. Generic host and Program.cs

Basic★ Must knowLesson 3 of 9

csharp

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddControllers();
builder.Services.AddDbContext<AppDbContext>(o => o.UseSqlServer(builder.Configuration.GetConnectionString("Db")));
builder.Services.AddHostedService<OutboxPublisher>();      // background worker

var app = builder.Build();
if (app.Environment.IsDevelopment()) app.MapOpenApi();
app.UseHttpsRedirection();
app.UseAuthentication();
app.UseAuthorization();
app.MapControllers();
app.Run();

Non-web apps (worker services, console tools) use Host.CreateApplicationBuilder(args) and get the same configuration/DI/logging.

csharp

public class OutboxPublisher(ILogger<OutboxPublisher> log, IServiceScopeFactory scopes) : BackgroundService
{
    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        using var timer = new PeriodicTimer(TimeSpan.FromSeconds(10));
        while (await timer.WaitForNextTickAsync(stoppingToken))
        {
            using var scope = scopes.CreateScope();
            var db = scope.ServiceProvider.GetRequiredService<AppDbContext>();
            // publish pending messages...
        }
    }
}