TheTinyApplicationLayer

TheTinyApplicationLayer is a small ASP.NET Core + Blazor sample that shows how the Tiny suite fits together in a real application layer.

It is intentionally tiny: one user registration flow, one validation step, one command handler, one durable event, one worker, and one consumer side effect.

The goal is not to provide a production template. The goal is to make the boundaries easy to see.

Why This Sample Exists

The Tiny packages are small on purpose. Each one solves a narrow application-layer problem:

• TinyValidations answers: "Is this command valid before the use case runs?"
• TinyDispatcher answers: "How do I send this command or query to the right handler?"
• TinyEvents answers: "How do I publish an event without losing it if the process dies?"
• TinyEvents.Worker answers: "How do pending outbox events get processed later?"

This sample puts those pieces together in one ordinary ASP.NET Core app so you can see the full path from UI input to durable side effect.

The Story

The sample implements a single workflow: registering a user.

Blazor form
-> Minimal API endpoint
-> TinyDispatcher
-> TinyValidations middleware
-> RegisterUserHandler
-> EF Core saves the user
-> TinyEvents writes UserRegistered to the outbox
-> TinyEvents.Worker reads the outbox
-> CreateWelcomeEmailLog consumer runs
-> WelcomeEmailLogs records the side effect

The important idea is that the user and the event are saved durably before the asynchronous side effect runs. That makes the event processing visible, repeatable, and resilient.

What Uses What

Web project

TheTinyApplicationLayer.Web owns the HTTP and UI surface.

It contains:

• the Blazor form
• the Minimal API endpoints
• app startup
• TinyEvents worker registration
• validation problem-details middleware

It references:

• TinyDispatcher
• TinyValidations
• TinyEvents.Worker
• the Application project
• the Infrastructure project

Application project

TheTinyApplicationLayer.Application owns the application layer.

It contains:

• commands and queries
• handlers
• validation rules
• domain entities used by the sample
• event definitions
• event consumers
• the EF Core application DbContext

It references:

• TinyDispatcher
• TinyValidations
• TinyEvents
• TinyEvents.SqlServer.EntityFrameworkCore

Infrastructure project

TheTinyApplicationLayer.Infrastructure owns concrete persistence services.

It contains:

• SQL Server DbContext registration
• EF Core implementations for application interfaces

It references:

• Microsoft.EntityFrameworkCore.SqlServer
• TinyEvents.SqlServer.EntityFrameworkCore
• the Application project

Why Docker Compose Is Required

This sample uses SQL Server through Docker Compose because TinyEvents is an outbox-first library.

The interesting behavior only appears when events are stored durably and processed later by a worker. A real database lets the sample demonstrate:

• transaction boundaries
• outbox persistence
• worker claiming
• event processing
• consumer side effects

dotnet run alone is not enough. Start SQL Server first:

docker compose up -d

Run The App

The local connection string is in src/TheTinyApplicationLayer.Web/appsettings.json and points at SQL Server on port 14333.

dotnet restore
dotnet run --project src/TheTinyApplicationLayer.Web

In development, the sample uses EnsureCreatedAsync to create the schema. Production applications should use migrations. The EF Core model includes Users, WelcomeEmailLogs, and the TinyEvents outbox table through modelBuilder.UseTinyEventsOutbox().

What To Try

Open the app and submit the Register User form.

Before the worker processes the event:

• Users contains the registered user.
• TinyOutbox contains the serialized UserRegistered event.

After the worker processes the event:

• WelcomeEmailLogs contains the consumer side effect.
• The TinyEvents outbox row is marked processed according to TinyEvents behavior.

For this sample, the TinyEvents worker runs in the same ASP.NET Core host. In production, it could run in a separate worker process using the same database.

Good Places To Read First

Start here:

• src/TheTinyApplicationLayer.Web/Users/RegisterUserEndpoint.cs
• src/TheTinyApplicationLayer.Application/Users/RegisterUser/RegisterUser.cs
• src/TheTinyApplicationLayer.Application/Users/RegisterUser/RegisterUserValidation.cs
• src/TheTinyApplicationLayer.Application/Users/RegisterUser/RegisterUserHandler.cs
• src/TheTinyApplicationLayer.Application/Users/RegisterUser/UserRegistered.cs
• src/TheTinyApplicationLayer.Application/Users/RegisterUser/CreateWelcomeEmailLog.cs
• src/TheTinyApplicationLayer.Infrastructure/Persistence/ApplicationDbContext.cs
• src/TheTinyApplicationLayer.Web/Program.cs

Read more in TinySuite sample notes.

Package Versions

Verified against nuget.org on June 3, 2026:

• TinyValidations 1.0.0-rc.1
• TinyDispatcher 1.2.0-alpha.1
• TinyEvents 0.1.0-alpha.1
• TinyEvents.SqlServer.EntityFrameworkCore 0.1.0-alpha.1
• TinyEvents.Worker 0.1.0-alpha.1

TinyEvents is still alpha, so APIs may change before 1.0.

Tiny Suite Repositories

• TinyDispatcher — command and query dispatching for explicit use-case execution.
• TinyValidations — small source-generated validation for application commands.
• TinyEvents — durable domain and application events with outbox-first publishing.
• TheTinyApplicationLayer — this end-to-end sample showing the suite working together.