Advanced C# Backend Workshop (Copilot-focused)

This workshop is an advanced, multi-hour exercise for experienced C# developers. The objective is to build a production-quality backend API using modern .NET techniques while leveraging GitHub Copilot as a development assistant. The materials in this folder are intentionally challenging and open-ended to encourage exploration, design trade-offs, and advanced problem solving.

Estimated time: 4-8 hours (depending on experience and depth of optional extensions)

What's included

• Step-by-step instruction files in the c#/content folder: 0-get-started.md, 1-create-model-data.md, 2-create-api.md, 3-create-integration-verification.md (integration is optional/minimal), 4-advanced-backend-exercises.md (for extra challenges)
• Hints and Copilot-friendly prompts embedded in each step
• Checkpoints and evaluation criteria for mentors

Goals

• Design a robust domain model and persistence layer using EF Core or other data-access patterns, including DDD aggregates and domain events
• Create a secure, well-tested ASP.NET Core Web API with async patterns, DI, middleware, and resilience patterns (circuit breakers, retries)
• Implement advanced features: background processing, idempotency, CQRS, event sourcing, API versioning, distributed caching, and telemetry
• Explore microservices concepts: service boundaries, message queues, and observability
• Use GitHub Copilot intentionally: craft prompts, iterate on generated code, and critically review its suggestions

How to use this folder

1. Read 0-get-started.md to set up the environment and use the recommended starter scaffold for efficient sessions or create everything from scratch if you are an experienced user.
2. Work through 1-create-model-data.md and 2-create-api.md for the core backend work.
3. Optionally complete 3-create-integration-verification.md if you want to test and integrate the API.
4. Tackle 4-advanced-backend-exercises.md for deeper challenges.

Copilot guidance

• Use the provided example prompts in each step. Start with small prompts (function-level) and progress to higher-level design prompts (architecture, tests).
• Treat Copilot as a pair programmer: accept small suggestions, but run tests and statically review generated code. Add unit tests and integration tests that validate behavior.
• Context Awareness: Copilot works best when related files are open. Keep your Flight entity open in a tab when writing your FlightRepository to help Copilot infer properties.

Assessment / Checkpoints

• Checkpoint 1 (1-2 hours): Domain model and migrations exist; basic CRUD endpoints implemented and tested.
• Checkpoint 2 (3-5 hours): Add advanced features (background worker, caching, idempotency, CQRS, event sourcing) and secure the API (JWT or API keys).
• Final (4-8 hours): End-to-end tests, documentation, perf checks, telemetry, and retrospective: record what Copilot helped with and what required manual changes. Include a "Vulnerability Check": Ask Copilot to review its own code for security flaws (e.g., Prompt: "Review this controller method for security vulnerabilities and suggest fixes.").