UdemyCourse — Core Package Suite

A production-ready collection of 25 reusable .NET 9.0 NuGet packages providing the foundational building blocks for enterprise-grade microservice applications. This monorepo covers everything from CQRS and clean architecture abstractions to security, messaging, observability, and resilience.

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Packages Overview

Foundation

Package	Version	Description
Core.Domain	3.0.2	Base domain primitives — Entity, AggregateRoot, Value Object
Core.Abstractions	3.1.9	Interfaces for CQRS, repositories, events, and messaging
Core.Cqrs	3.0.2	MediatR-based CQRS dispatcher implementation
Core.Application	3.0.4	MediatR pipeline behaviors (validation, authorization)
Core.Extensions	3.0.7	Utility extension methods for auth, HTTP, and common types
Core.WebApi	3.0.3	Web API helpers, response wrappers, and controller extensions
Core.CrossCuttingConcerns.Exceptions	3.0.1	Global exception handling with RFC 7807 Problem Details

Persistence

Package	Version	Description
Core.Persistence	3.0.9	Generic repositories for EF Core, MongoDB, and Redis

Security

Package	Version	Description
Core.Security.Domain	3.0.1	Security entities (User, Token, OTP) and enums
Core.Security.Hashing	3.0.0	BCrypt password hashing
Core.Security.Encryption	3.0.0	AES / RSA encryption utilities
Core.Security.Jwt	3.0.0	JWT access & refresh token generation and validation
Core.Security.Extensions	3.0.0	DI registration extensions for the security stack
Core.Security.EmailAuthenticator	3.0.0	Email-based two-factor authentication (OTP codes)
Core.Security.Redis	3.0.2	Redis-backed token revocation and session management

Messaging & Events

Package	Version	Description
Core.Messaging	3.0.4	Outbox pattern core — publisher, background processor, serialization
Core.Messaging.Postgres	3.0.3	PostgreSQL implementation of the outbox store
Core.Messaging.Transport.RabbitMq	3.0.5	RabbitMQ producer/consumer with Polly retry
Core.Events	3.0.3	In-process domain event dispatching via MediatR

Infrastructure

Package	Version	Description
Core.Mailing	3.0.2	Email delivery via MailKit / SMTP
Core.Scheduling.Hangfire	3.0.2	Background job scheduling with Hangfire
Core.Monitoring	3.0.0	Health checks UI and Prometheus metrics exporter
Core.Tracing	3.0.1	OpenTelemetry distributed tracing for HTTP, MediatR, and RabbitMQ
Core.Resiliency	3.0.0	Polly-based retry, circuit-breaker, and timeout policies
Core.ElasticSearch	3.0.1	Elasticsearch CRUD and search helpers via NEST

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Architecture

┌──────────────────────────────────────────────────────────────────┐
│                        Your Application                          │
├────────────────┬────────────────────────┬────────────────────────┤
│  Presentation  │      Application       │       Domain           │
│  Core.WebApi   │  Core.Application      │  Core.Domain           │
│                │  Core.Cqrs             │  Core.Abstractions     │
├────────────────┴────────────────────────┴────────────────────────┤
│                       Infrastructure                             │
│  Core.Persistence  │ Core.Messaging  │ Core.Security.*          │
│  Core.Mailing      │ Core.Events     │ Core.ElasticSearch        │
│  Core.Tracing      │ Core.Monitoring │ Core.Resiliency           │
│  Core.Scheduling.Hangfire                                        │
└──────────────────────────────────────────────────────────────────┘

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Technology Stack

Category	Technology
Runtime	.NET 9.0
ORM	Entity Framework Core 9.0
Databases	PostgreSQL, SQL Server, MongoDB, Redis
Search	Elasticsearch (NEST 7)
Messaging	RabbitMQ 7
Scheduling	Hangfire 1.8
Observability	OpenTelemetry 1.15, Prometheus, Health Checks UI
Security	JWT, BCrypt, AES/RSA
Validation	FluentValidation 12
Resilience	Polly 8.6
Email	MailKit 4.15
Mediator	MediatR 12.5

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Getting Started

Prerequisites

• .NET 9.0 SDK
• Visual Studio 2022 v17+ or JetBrains Rider

Build All Packages

dotnet build UdemyCourse-CorePackage.sln --configuration Release

Built .nupkg files are placed in the Packages/ directory at the repository root.

Use a Local Package Source

dotnet nuget add source ./Packages --name CorePackages

Then reference packages in your project:

<PackageReference Include="Core.Persistence" Version="3.0.9" />

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Package Dependency Graph

Core.Domain
  └── Core.Security.Domain
        └── Core.Security.Hashing
        └── Core.Security.Encryption
              └── Core.Security.Jwt
        └── Core.Security.Redis

Core.Domain
  └── Core.Abstractions
        └── Core.Cqrs
        └── Core.Persistence
        └── Core.Messaging
              └── Core.Messaging.Postgres
              └── Core.Messaging.Transport.RabbitMq
        └── Core.Events
        └── Core.Extensions
              └── Core.WebApi
              └── Core.Application

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Contributing

1. Fork the repository and create a feature branch.
2. Follow existing conventions — each package is a self-contained class library.
3. Bump the <Version> in the .csproj using semantic versioning.
4. Open a pull request with a clear description of the change.

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License

This project is created for educational purposes as part of the Udemy course curriculum.