CryptoInfoTracker

CryptoInfoTracker is a fullstack software solution developed as part of a technical assessment for Hahn Software. The project integrates a well-structured backend built in .NET 9 using Minimal APIs with a modern Vue.js + TypeScript frontend, incorporating Hangfire for background job processing. It leverages Clean Architecture, Domain-Driven Design (DDD), and SOLID principles.

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🌍 Purpose

The application’s core purpose is to:

• Fetch live cryptocurrency data from the public Coinlore API
• Store and update this data periodically using a background job
• Expose the data via a clean REST API
• Display it in a responsive, filterable frontend table

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📦 How to Run the Project Locally

Requirements

• .NET 9 SDK
• SQL Server (I used SQLServer on Docker)
• Node.js
• (Optional) EF Core CLI: dotnet tool install --global dotnet-ef

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✅ 1. Web API (Hahn.WebApi)

This is the minimal API exposing /cryptos.

cd HahnSoftwareTest\src\Hahn.WebApi

# Restore and build
dotnet build

# Apply DB migrations (migration assembly is Hahn.WebApi)
dotnet ef database update

# Run the WebAPI
dotnet run

✅ 2. Worker Service (Hahn.WorkerService)

cd HahnSoftwareTest\src\Hahn.WorkerService

dotnet run

✅ 3. Frontend

cd HahnSoftwareTest\frontend
npm install
npm run dev

📂 Project Structure

HahnSoftwareTest/
├── src/                         # Backend source folder
│   ├── Hahn.Application         # Use cases, interfaces, UpsertCryptoService (CoinLore api access)
│   ├── Hahn.Domain              # Core domain entities, models, enums, repository interface
│   ├── Hahn.Infrastructure      # Data access with EF Core, AppDbContext
│   ├── Hahn.Jobs                # Hangfire job logic (CryptoUpsertJob)
│   ├── Hahn.WorkerService       # Host for background job scheduler
│   └── Hahn.WebApi              # Minimal API that exposes crypto data
└── frontend/                    # Vue 3 + TypeScript frontend

✨ Key Backend Features

🛠️ Worker Service with Hangfire

• The Hahn.WorkerService hosts a background job using Hangfire.
• Job scheduled via RecurringJob.AddOrUpdate to run every hour.
• The CryptoUpsertJob calls the UpsertCryptoService, which:
  • Sends a GET request to Coinlore API
  • Deserializes the response into domain models
  • Maps to internal CryptoCurrency entity
  • Upserts the data using a repository pattern and EF Core
• Dependencies registered via AddWorkerServices()

💡 Web API with Clean Architecture

• API hosted in Hahn.WebApi using .NET Minimal APIs
• Main endpoint: GET /cryptos
• Supports sorting by:
  • Name
  • Symbol
  • Price
  • 24h change
  • Market cap
• Sorting is dynamic via enums: EnumSortBy and EnumSortDirection
• Query parameters wrapped in CryptoQueryParams
• Business logic lives in Hahn.Application

📁 Infrastructure Layer

• Implements:
  • HTTP calls to Coinlore API
  • Data mapping and transformation
  • EF Core DbContext with SQL Server provider
• UpsertAsync() method handles full transformation of Coinlore data into domain entities

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💻 Frontend – Vue 3 + TypeScript

• SPA built with Vue 3 + TypeScript + Vite
• Styling via Tailwind CSS and Flowbite UI

Core Features:

• Filter cryptos by name or symbol
• Sort by top gainers, losers, market cap
• Pagination support
• Main component: App.vue
• Custom composable: useCryptos.ts handles:
  • API data fetching
  • Filtering, sorting, pagination logic
  • Uses fetch or axios for API communication

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🔗 Tech Stack Summary

📁 Backend:

• .NET 8
• Entity Framework Core
• SQL Server
• Hangfire
• Clean Architecture + DDD + SOLID

🔮 Frontend:

• Vue 3
• TypeScript
• Tailwind CSS
• Flowbite UI
• Vite

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⚖️ How the App Works (Flow Summary)

1. Hangfire job runs every hour
2. Calls Coinlore API
3. Upserts crypto data into SQL Server database
4. Web API exposes /cryptos endpoint
5. Frontend fetches from API
6. Displays data in styled table with filtering, sorting, and pagination