Finishes functional design for unit 0 (back-end changes before front-end work)

2026-06-18 21:40:45 +02:00
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commit 53a307cdbd
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+# Tech Stack Decisions — Unit 0: Backend Prerequisites
+
+## Existing Stack (no changes)
+All existing technology choices are retained:
+- **.NET 10 / ASP.NET Core 10** — Web API framework
+- **Entity Framework Core 10** — ORM + migrations
+- **ASP.NET Core Identity** — User/role management, password hashing
+- **SQL Server** — Primary database
+
+---
+
+## New/Updated: Rate Limiting
+
+| Decision | Choice | Rationale |
+|----------|--------|-----------|
+| Rate limiter | ASP.NET Core built-in `RateLimiter` (Microsoft.AspNetCore.RateLimiting) | No extra NuGet package needed — available in .NET 7+; production-ready |
+| Login policy | Fixed window (5 req / 1 min / IP) | Predictable; blocks brute-force login attempts |
+| Refresh policy | Sliding window (20 req / 1 min / IP) | More lenient for token rotation; prevents abuse |
+| Configuration | `appsettings.json → RateLimiting` | Configurable without code recompile |
+
+---
+
+## New/Updated: CORS
+
+| Decision | Choice | Rationale |
+|----------|--------|-----------|
+| CORS implementation | ASP.NET Core built-in CORS middleware | No extra NuGet package; part of framework |
+| Origins configuration | `appsettings.json → Cors:AllowedOrigins[]` | Environment-specific; follows dotnet-appsettings pattern |
+| Credential support | `AllowCredentials()` | Required for httpOnly cookie to be sent cross-origin |
+| Methods | `AllowAnyMethod()` | Avoids future CORS issues when new endpoints are added |
+| Headers | `AllowAnyHeader()` | Standard approach; avoids pre-flight failures for custom headers |
+
+---
+
+## New/Updated: httpOnly Cookie
+
+| Decision | Choice | Rationale |
+|----------|--------|-----------|
+| Cookie implementation | ASP.NET Core `Response.Cookies.Append()` | Built-in, no extra library |
+| Token read | `Request.Cookies["refreshToken"]` | Standard ASP.NET Core cookie reading |
+| Secure flag | `request.IsHttps` | Adapts to environment; safe in production, usable in local HTTP dev |
+| SameSite | `Strict` | Maximum CSRF protection |
+
+---
+
+## New/Updated: Error Responses
+
+| Decision | Choice | Rationale |
+|----------|--------|-----------|
+| Error format | RFC 9457 ProblemDetails | .NET standard; consistent with ASP.NET Core defaults; interoperable |
+| Implementation | `Microsoft.AspNetCore.Mvc.ProblemDetails` (built-in) | No extra NuGet package needed |
+| Global handler | Existing `GlobalExceptionHandler` extended | Avoids duplication; centralises error formatting |
+
+---
+
+## appsettings.json Additions
+
+Following the dotnet-appsettings skill pattern:
+
+```json
+// appsettings.json (production defaults — no real values)
+{
+  "Cors": {
+    "AllowedOrigins": []
+  },
+  "RateLimiting": {
+    "Login": {
+      "PermitLimit": 5,
+      "WindowSeconds": 60
+    },
+    "Refresh": {
+      "PermitLimit": 20,
+      "WindowSeconds": 60
+    }
+  }
+}
+```
+
+```json
+// appsettings.Development.json (complete reference for developers)
+{
+  "Cors": {
+    "AllowedOrigins": ["http://localhost:5173"]
+  },
+  "RateLimiting": {
+    "Login": {
+      "PermitLimit": 5,
+      "WindowSeconds": 60
+    },
+    "Refresh": {
+      "PermitLimit": 20,
+      "WindowSeconds": 60
+    }
+  }
+}
+```
+
+```json
+// appsettings.local.json (developer override — gitignored)
+{
+  "Cors": {
+    "AllowedOrigins": ["http://localhost:5173"]
+  }
+}
+```