Multitool API

A RESTful Web API built with .NET 10 and ASP.NET Core, serving as the backend for the Multitool Frontend (repository will be published soon). The application follows a Clean Architecture pattern and currently provides the following features:

• Authentication & Security with JWT-based protection and rate limiting.
• Calendar with recurring event support.
• Custom Table Builder for user-defined data structures.
• Todo List for task management.

---

Table of Contents

• Features
• Architecture
• Tech Stack
• Project Structure
• API Reference
• Environment Variables
• Test coverage
• CI/CD

---

Features

Calendar

• Create, read, update and delete calendar events
• Support for recurring events via iCalendar RRULE strings (daily, weekly, monthly, yearly)
• Date-range-based event retrieval with optional category filtering
• Full-text event search across title and notes
• German public holidays fetched from a third-party API (api-feiertage.de)
• Category management with custom colors

Custom Table Builder

• Dynamically create tables with user-defined columns
• Five supported column types: String, Int, Decimal, Date, Bool
• Add, remove and reorder columns and rows at runtime
• Inline cell editing with automatic type coercion and validation
• Persistent row and column ordering

Todo List

• Create, read, update, and delete task items
• Toggle task completion status
• Request validation for task creation and updates

Authentication & Security

• JWT-based authorization protecting core API endpoints
• Secure user registration validated by an administrative key (X-Admin-Key header)
• Rate limiting configured on the login endpoint to prevent brute force attempts
• Secure password hashing using BCrypt

Background Jobs

• Scheduled database cleanup of past calendar events using a customizable cron expression

---

Architecture

The solution follows a Clean Architecture approach with a strict separation of concerns across four layers:

┌─────────────────────────────────────────────┐
│               Multitool.Api                 │  Controllers, Exception Handling, DI Setup
├─────────────────────────────────────────────┤
│           Multitool.Application             │  Business Logic, Services, DTOs, Mappings
├─────────────────────────────────────────────┤
│             Multitool.Domain                │  Entities, Interfaces, Enums, Exceptions
├─────────────────────────────────────────────┤
│          Multitool.Infrastructure           │  EF Core, Repositories, External API Clients, Auth
└─────────────────────────────────────────────┘

---

Tech Stack

Category	Technology
Runtime	.NET 10 / ASP.NET Core
ORM	Entity Framework Core 10
Database	PostgreSQL
Object Mapping	Mapster
Containerization	Docker
Testing	xUnit, Moq, FluentAssertions, SQLite (in-memory)
Documentation	Swagger / OpenAPI
CI/CD	GitHub Actions
Cryptography & Auth	BCrypt.Net-Next, JWT (JSON Web Tokens)
Scheduling	Cronos

---

Project Structure

The following project structure illustrates the Clean Architecture layout and the separation of concerns across API, Application, Domain, and Infrastructure layers.

Multitool.sln
│
├── src/
│   ├── Multitool.Api/                  # Entry point, controllers, middleware, background jobs
│   │   ├── BackgroundJobs/
│   │   ├── Configuration/
│   │   ├── Controllers/
│   │   ├── Exceptions/
│   │   │   └── GlobalExceptionHandler.cs
│   │   └── Extensions/
│   │
│   ├── Multitool.Application/          # Services, DTOs, mappings
│   │   ├── Interfaces/
│   │   ├── Mappings/
│   │   │   └── MappingConfig.cs
│   │   ├── Models/
│   │   └── Services/
│   │
│   ├── Multitool.Domain/               # Core entities and contracts
│   │   ├── Entities/
│   │   ├── Enums/
│   │   ├── Exceptions/
│   │   └── Interfaces/
│   │
│   └── Multitool.Infrastructure/       # EF Core, repositories, API clients, authentication helpers
│       ├── ApiClients/
│       ├── Authentification/
│       ├── Data/
│       │   ├── Migrations/
│       │   ├── AppDbContext.cs
│       └── Repositories/
│
└── tests/
    ├── Multitool.Api.Tests/            # Controller unit tests
    ├── Multitool.Application.Tests/    # Service unit tests
    ├── Multitool.Infrastructure.Tests/ # Repository and infrastructure unit tests
    └── Multitool.Tests.Shared/         # Shared test fixtures and test data

---

API Reference

All endpoints are also available via Swagger UI at /swagger when running in development mode.

Authentication – /api/auth

Method	Endpoint	Description
POST	/register	Registers a new user. Requires the X-Admin-Key header.
POST	/login	Authenticates a user and returns a JWT session token. Rate-limited by IP.

Calendar – /api/calendar

Method	Endpoint	Description
GET	/events	Get events by date range; optionally filter by category IDs. Requires JWT.
GET	/events/search	Full-text search across event title and note. Requires JWT.
POST	/events	Create a new calendar event. Requires JWT.
PUT	/events	Update an existing calendar event. Requires JWT.
DELETE	/events/{id}	Delete a calendar event by ID. Requires JWT.
GET	/holidays/{year}	Get Bavarian public holidays for a given year.

Category – /api/category

Method	Endpoint	Description
GET	/categories	Get all available event categories. Requires JWT.

Custom Tables – /api/customtable

Method	Endpoint	Description
GET	/tables	Get a list of all tables. Requires JWT.
GET	/tables/{id}	Get a full table with columns and rows. Requires JWT.
POST	/tables	Create a new table with an initial column. Requires JWT.
PUT	/tables/{id}	Rename a table. Requires JWT.
DELETE	/tables/{id}	Delete a table and all its data. Requires JWT.
POST	/tables/{tableId}/columns	Add a new default column to a table. Requires JWT.
PUT	/columns/{id}	Update column name, type and order. Requires JWT.
PUT	/columns/order	Reorder multiple columns in bulk. Requires JWT.
DELETE	/tables/{tableId}/columns/{columnId}	Delete a column. Requires JWT.
POST	/tables/{tableId}/rows	Add a new empty row. Requires JWT.
PUT	/rows/order	Reorder multiple rows in bulk. Requires JWT.
DELETE	/tables/{tableId}/rows	Delete multiple rows by ID. Requires JWT.
PUT	/rows/{rowId}/cells/{columnId}	Create or update a single cell value. Requires JWT.

Todo List – /api/todo

Method	Endpoint	Description
GET	/	Get all todo items. Requires JWT.
POST	/	Create a new todo item. Requires JWT.
PUT	/{id}	Update an existing todo item's details. Requires JWT.
PATCH	/{id}/toggle	Toggle completion status of a todo item. Requires JWT.
DELETE	/{id}	Delete a todo item by ID. Requires JWT.

Status – /api/status

Method	Endpoint	Description
GET	/live	Liveness check endpoint. Allows anonymous access.

---

Environment Variables

Configure the following environment variables or configuration keys in your appsettings.json / container environment:

Variable	Description
DB_CONNECTION_STRING	Connection string to the PostgreSQL database
Jwt__Key	Secret key used to sign JWT session tokens (required)
Jwt__Issuer	Issuer of the JWT session tokens (default: MultitoolApi)
Jwt__Audience	Audience of the JWT session tokens (default: MultitoolFrontend)
AdminKey	Key checked on user registration via X-Admin-Key header
APPLY_MIGRATIONS	Set to true to run migrations on startup in development environment
ASPNETCORE_ENVIRONMENT	Runtime environment, e.g. Development or Production
CronJobs__CleanUpPastEvents	Cron expression for background cleanup of calendar events (default: 0 0 1 * *)
CronJobs__CleanUpPastEventsMonths	Months of past calendar events to retain during cleanup (default: 3)

---

Test coverage:

Project	Scope
Multitool.Api.Tests	Controller tests — verifies HTTP responses, routing, and service delegation
Multitool.Application.Tests	Service tests — verifies business logic and repository interactions
Multitool.Infrastructure.Tests	Repository and utility tests — verifies database operations using SQLite in-memory, and checks helper logic like JWT generation
Multitool.Tests.Shared	Shared test fixtures, mock setups, and test seed data

Tests are written with xUnit, assertions use FluentAssertions, and dependencies are mocked with Moq.

---

CI/CD

A GitHub Actions workflow runs on every push and pull request to main and dev:

1. Restores NuGet dependencies
2. Builds the solution in Release configuration
3. Runs the API controller tests
4. Runs the application service tests
5. Runs the infrastructure repository tests