---

What you will explore

This sample hosts a small library event model and its read-side artifacts through ASP.NET Core dependency injection.

HTTP request
    │
    ▼
minimal endpoint ──► Chronicle event log ──► processing ──► materialized view

It adds reducers, projections, reactors, MongoDB-backed views, and focused HTTP endpoints to the smaller Chronicle Backend starting point.

Run it

Prerequisites

• .NET 10 SDK
• Docker or another compatible container runtime
• curl

Start from the sample directory:

cd Chronicle/Quickstart/AspNetCore
docker compose -f ../docker-compose.yml up -d

Start the API:

dotnet run

The application listens on http://localhost:5000.

Build it

dotnet build AspNetCore.csproj --configuration Debug

This focused host currently has no dedicated test project.

Send a couple of events

Record a reservation:

curl --request POST http://localhost:5000/api/books/reserve

Record a borrowing event with explicit sample identifiers:

curl --request POST \
  http://localhost:5000/api/books/11111111-1111-1111-1111-111111111111/borrow/22222222-2222-2222-2222-222222222222

Then open Chronicle Workbench at http://localhost:8080 and select the Quickstart event store to inspect the events and processing state.

Code tour

Area	Location
Chronicle host setup	Program.cs
HTTP endpoints	../Common.AspNetCore/Api.cs
Dependency registration	../Common.AspNetCore/CommonServices.cs
MongoDB registration	../Common.AspNetCore/MongoDBServices.cs
Shared events and read-side artifacts	../Common

The key host setup is deliberately short:

var builder = WebApplication.CreateBuilder(args)
    .AddCratisChronicle(options => options.EventStore = "Quickstart");

var app = builder.Build();
app.UseCratisChronicle();

Try changing it

1. Add a GET endpoint that answers a specific library question.
2. Add validation before recording a borrowing event.
3. Introduce one new event and follow its processing in Workbench.
4. Compare the processing setup with the focused Chronicle Processing sample.

Stop the infrastructure

docker compose -f ../docker-compose.yml down