ContactsApp

John Vishnefske

Example full stack .NET application. Console client (targeting .NET 8.0) consuming an ASP.NET Core gRPC API with a SQL backend. The API is designed to run on Linux.

Milestones

• • Database Setup: The ContactsApi now uses SQLite. The database file (contacts.db) will be automatically created and initialized with necessary tables (Contacts, Prefixes, Suffixes) and initial lookup data when the API starts for the first time. No manual setup is required.
• • API Configuration: The ContactsApi's database connection string is now configured in appsettings.json under the ConnectionStrings:DefaultConnection key. The Utilities class is now a service that reads this configuration. Ensure the gRPC endpoint is correctly exposed (e.g., https://localhost:7001).
• • Client Configuration: The Client console application's gRPC endpoint address is now configurable via Client/App.config under the GrpcApiAddress key.
• • Clean Build: Achieve a build with zero errors and zero warnings across all projects.
• • Error Handling & Logging: Enhanced error handling and structured logging have been implemented:
  • API: ContactsGrpcService and LookupsGrpcService now include try-catch blocks to handle exceptions from the Utilities layer, logging errors and returning appropriate RpcException statuses (e.g., StatusCode.Internal, StatusCode.NotFound). Utilities also logs its operations.
  • Client: Client/Program.cs now includes try-catch blocks around gRPC calls to catch RpcException and display user-friendly error messages.
  • Logging Configuration: ContactsApi/Program.cs is configured for console and debug logging.
• • User Interface: The current client is a console application. If a graphical user interface (GUI) is desired, a new client project would need to be developed using a cross-platform UI framework (e.g., Avalonia UI, .NET MAUI). (Out of Scope for this request)
• • Testing:
  • • Unit Testing: Unit tests are implemented for ContactsApi's persistence layer (UtilitiesTests.cs) and gRPC services (ContactsGrpcServiceTests.cs, LookupsGrpcServiceTests.cs). These tests mock dependencies and use TestServerCallContext for isolated testing of service logic. IConfiguration mocking has been made robust using ConfigurationBuilder.AddInMemoryCollection().
  • • Integration Testing: A new ContactsApi.Tests/IntegrationTests.cs class has been added. It uses Microsoft.AspNetCore.Mvc.Testing to host the ContactsApi in an in-memory test server and Grpc.Net.ClientFactory to create gRPC clients, allowing for end-to-end testing of the API.
• • Deployment: Add basic instructions for deploying the ContactsApi to a Linux environment (e.g., Docker, Kestrel behind Nginx) and the Client console application. (Documentation Task)
• Best Practices for Simplicity:
  • • Asynchronous Programming: Ensure all I/O-bound and long-running operations are truly asynchronous to avoid blocking calls and simplify concurrent execution flow.
  • • Minimize Exceptions for Control Flow: Exceptions are used only for truly exceptional conditions (e.g., missing configuration, unexpected database errors), not for normal program flow (e.g., GetContact returns null or throws RpcException.NotFound).
  • • Offload Long-Running Tasks: This is not directly applicable to the current simple CRUD operations, as they are primarily I/O-bound and handled asynchronously.
  • • Correct Context and Service Lifetime Management: HttpContext is no longer relevant in the gRPC context. Utilities is registered as a singleton, ensuring a single instance manages database connections efficiently.
  • • Efficient Data Retrieval: Retrieve only the necessary data from the database to simplify data models and reduce processing overhead. (General guideline, no specific code changes planned unless clear inefficiency is found).