gistfile1.txt

MyCompany.MyProduct.Api/
├── Features/                                        # Vertical slices grouped by business capability (preferred over Layers)
│   ├── Billing/                                     # Business feature area: billing transactions, adjustments, etc.
│   │   ├── CreateBillingTransaction/                # Single use case slice (Command)
│   │   │   ├── CreateBillingTransactionCommand.cs   # MediatR request (input for the use case)
│   │   │   ├── CreateBillingTransactionValidator.cs # FluentValidation/input validation for command
│   │   │   ├── CreateBillingTransactionHandler.cs   # Use case logic; calls repo/db abstractions, maps result
│   │   │   ├── CreateBillingTransactionRequest.cs   # API request model (controller-facing model) if separate from command
│   │   │   ├── CreateBillingTransactionResponse.cs  # API response model / DTO for endpoint response
│   │   │   └── Sql/                                 # SQL for this use case if feature-specific
│   │   │       ├── InsertBillingTransaction.sql
│   │   │       └── CheckDuplicateByHash.sql
│   │   ├── GetBillingTransactionById/               # Single use case slice (Query)
│   │   │   ├── GetBillingTransactionByIdQuery.cs
│   │   │   ├── GetBillingTransactionByIdHandler.cs
│   │   │   ├── GetBillingTransactionByIdResponse.cs
│   │   │   └── Sql/
│   │   │       └── SelectBillingTransactionById.sql
│   │   ├── SearchBillingTransactions/               # List/search query use case
│   │   └── Common/                                  # Billing-specific shared types (enums, mappers, constants)
│   │
│   ├── Returns/                                     # Another feature area
│   │   ├── CreateReturn/
│   │   ├── GetReturn/
│   │   └── Common/
│   │
│   ├── Discounts/                                   # Another feature area
│   │   ├── CreateDiscount/
│   │   ├── ListDiscounts/
│   │   └── Common/
│   │
│   ├── Integrations/                                # Integration-related features (enrollment, pulls, hashes, dedupe)
│   │   ├── EnrollAgent/
│   │   ├── SubmitRawPayload/
│   │   ├── ReprocessBatch/
│   │   ├── GetPullStatus/
│   │   └── Common/
│   │
│   └── Health/                                      # App-specific health/status endpoints (if business-related)
│       └── GetSystemStatus/
│
├── Controllers/                                     # Thin MVC controllers (API Controllers, not minimal APIs)
│   ├── BillingController.cs                         # Route + HTTP concerns only; delegates to MediatR
│   ├── ReturnsController.cs
│   ├── DiscountsController.cs
│   ├── IntegrationsController.cs
│   └── HealthController.cs
│
├── Infrastructure/                                  # Technical implementations (db, auth, files, messaging, etc.)
│   ├── Persistence/                                 # Data access and DB concerns
│   │   ├── Connections/
│   │   │   ├── IDbConnectionFactory.cs              # Factory abstraction for opening DB connections
│   │   │   └── SqlConnectionFactory.cs              # Dapper/SQL Server implementation
│   │   ├── Dapper/                                  # Dapper helpers and conventions
│   │   │   ├── SqlRunner.cs                         # Wrapper for Query/Execute patterns, logging, retries (optional)
│   │   │   ├── SqlParameterBuilder.cs               # Optional helper for parameter consistency
│   │   │   └── TypeHandlers/                        # Dapper custom type handlers (DateOnly, enums, JSON, etc.)
│   │   ├── Repositories/                            # Shared repositories only (avoid generic repo overuse)
│   │   │   ├── IBillingReadRepository.cs
│   │   │   ├── BillingReadRepository.cs
│   │   │   └── ...
│   │   ├── Sql/                                     # Shared SQL scripts used across features (optional)
│   │   └── Migrations/                              # SQL migrations (if not in separate migrator project)
│   │
│   ├── Authentication/                              # JWT, Cognito/Entra, policies, auth handlers
│   │   ├── Jwt/
│   │   ├── Policies/
│   │   └── ApiKey/                                  # If used for agent enrollment/bootstrap only
│   │
│   ├── Observability/                               # Logging, tracing, metrics enrichers
│   │   ├── LoggingScopes/
│   │   ├── Telemetry/
│   │   └── Correlation/
│   │
│   ├── Messaging/                                   # Queue/event bus implementations if applicable
│   ├── Files/                                       # File storage, blob clients, etc.
│   └── Time/                                        # System clock implementation (ITimeProvider)
│
├── Application/                                     # Cross-feature app-layer concerns (still thin in vertical slice)
│   ├── Behaviors/                                   # MediatR pipeline behaviors (cross-cutting)
│   │   ├── ValidationBehavior.cs                    # Runs validators before handlers
│   │   ├── LoggingBehavior.cs                       # Request/response logging
│   │   ├── PerformanceBehavior.cs                   # Timing/metrics
│   │   ├── TransactionBehavior.cs                   # DB transaction boundary (when needed)
│   │   ├── IdempotencyBehavior.cs                   # Request dedupe / replay safety (great for ingestion)
│   │   └── ExceptionHandlingBehavior.cs             # Maps/normalizes exceptions
│   │
│   ├── Abstractions/                                # Interfaces shared across features (e.g., IHashService, ICurrentUser)
│   ├── Common/                                      # Result<T>, error models, paging, sort, filters, etc.
│   ├── Mapping/                                     # Shared mapping profiles/extensions (if not feature-local)
│   └── Validation/                                  # Shared validation helpers/rules
│
├── Domain/                                          # Domain entities/value objects/business rules (if your app benefits from it)
│   ├── Entities/                                    # Rich entities (only if you truly have domain behavior)
│   ├── ValueObjects/                                # Money, TransactionHash, DateRange, etc.
│   ├── Enums/                                       # Domain enums (PaymentType, AdjustmentType, etc.)
│   ├── Events/                                      # Domain events (optional)
│   └── Services/                                    # Domain services (pure business logic, no infrastructure)
│
├── Endpoints/                                       # Optional: endpoint metadata conventions, route constants
│   └── RouteNames.cs
│
├── Middleware/                                      # ASP.NET middleware (exception handling, correlation, etc.)
│   ├── ExceptionHandlingMiddleware.cs
│   ├── CorrelationIdMiddleware.cs
│   └── RequestBodyBufferingMiddleware.cs            # If needed for canonical hashing/idempotency
│
├── Filters/                                         # MVC filters (if using controller filters instead of middleware)
│   ├── ValidateModelFilter.cs
│   └── ApiExceptionFilter.cs
│
├── Authorization/                                   # Policy names, requirement handlers (if not under Infrastructure/Auth)
│   ├── Policies.cs
│   ├── Requirements/
│   └── Handlers/
│
├── Configuration/                                   # Options classes and DI setup by concern
│   ├── DependencyInjection/
│   │   ├── ApiServiceCollectionExtensions.cs        # High-level registration entry point
│   │   ├── MediatRServiceCollectionExtensions.cs
│   │   ├── DapperServiceCollectionExtensions.cs
│   │   ├── AuthenticationServiceCollectionExtensions.cs
│   │   └── SwaggerServiceCollectionExtensions.cs
│   ├── Options/
│   │   ├── DatabaseOptions.cs
│   │   ├── AuthOptions.cs
│   │   └── ...
│   └── StartupValidation/                           # Validates options/config at startup
│
├── Contracts/                                       # API-wide request/response models (only truly shared ones)
│   ├── Errors/
│   │   ├── ProblemDetailsExtensions.cs
│   │   └── ApiErrorResponse.cs
│   ├── Pagination/
│   └── Common/
│
├── OpenApi/                                         # Swagger examples, operation filters, schema filters
│   ├── Examples/
│   ├── OperationFilters/
│   └── SchemaFilters/
│
├── Properties/                                      # launchSettings.json etc.
├── appsettings.json                                 # Base config
├── appsettings.Development.json                     # Dev config
├── Program.cs                                       # Composition root (DI, middleware, MVC, auth, swagger)
└── GlobalUsings.cs                                  # Global using directives (optional)