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:

• Calendar with recurring event support.
• Custom Table Builder for user-defined data structures.

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Table of Contents

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

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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

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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
└─────────────────────────────────────────────┘

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Tech Stack

Category	Technology
Runtime	.NET 10 / ASP.NET Core
ORM	Entity Framework Core 9
Database	MariaDB 10.11
Object Mapping	Mapster
Containerization	Docker / Docker Compose
Testing	xUnit, Moq, FluentAssertions
Documentation	Swagger / OpenAPI
CI/CD	GitHub Actions

---

Project Structure

Multitool.sln
│
├── src/
│   ├── Multitool.Api/                  # Entry point, controllers, middleware
│   │   ├── Controllers/
│   │   │   ├── CalendarController.cs
│   │   │   └── CustomTableController.cs
│   │   ├── Exceptions/
│   │   │   └── GlobalExceptionHandler.cs
│   │   └── Extensions/
│   │       └── MigrationExtensions.cs
│   │
│   ├── Multitool.Application/          # Services, DTOs, mappings
│   │   ├── Interfaces/
│   │   ├── Mappings/
│   │   │   └── MappingConfig.cs
│   │   ├── Models/
│   │   └── Services/
│   │       ├── CalendarService.cs
│   │       └── CustomTableService.cs
│   │
│   ├── Multitool.Domain/               # Core entities and contracts
│   │   ├── Entities/
│   │   │   ├── Calendar/
│   │   │   └── CustomTable/
│   │   ├── Enums/
│   │   ├── Exceptions/
│   │   └── Interfaces/
│   │
│   └── Multitool.Infrastructure/       # EF Core, repositories, API clients
│       ├── ApiClients/
│       │   └── CalendarApiClient.cs
│       ├── Data/
│       │   ├── AppDbContext.cs
│       │   └── Migrations/
│       └── Repositories/
│           ├── CalendarRepository.cs
│           └── CustomTableRepository.cs
│
└── tests/
    ├── Multitool.Api.Tests/            # Controller unit tests
    ├── Multitool.Application.Tests/    # Service unit tests
    └── Multitool.Tests.Shared/         # Shared test fixtures and data

---

API Reference

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

Calendar – /api/calendar

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

Custom Tables – /api/customtable

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

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Environment Variables

Copy the example file and fill in your values:

Variable	Description
DB_HOST	Database host (use db for Docker Compose)
DB_PORT	Database port (default: 3306)
DB_ROOT_PASSWORD	MariaDB root password
DB_NAME	Database name
DB_USER	Database user
DB_PASSWORD	Database password
API_PORT	Port the API is exposed on
ASPNETCORE_ENVIRONMENT	Development or Production

Test coverage:

Project	Scope
Multitool.Api.Tests	Controller tests — verifies HTTP responses and service delegation
Multitool.Application.Tests	Service tests — verifies business logic and repository interactions
Multitool.Tests.Shared	Shared test fixtures and seed data

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

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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