CountryWeatherAPI

A RESTful API built with .NET Core 7 and PostgreSQL, following Clean Architecture with separate Domain, Application and Infrastructure layers. It manages countries, the representative responsible for each country, and current weather data pulled from OpenWeatherMap.

Core features

• Country and representative management. EF Core configuration enforces that each country has exactly one representative.
• Coordinate ranges. Countries are stored with latitude/longitude ranges (e.g. 36–42°N, 26–45°E) validated by custom attributes on create and update.
• Representative validation. A composite unique key on name, surname and birth date, plus phone number validation with LibPhoneNumber.

Weather integration

• Async OpenWeatherMap client with Polly retry policies for fault tolerance.
• Background scheduler (IHostedService) that refreshes weather data for all countries automatically.
• ETag-based versioning so repeated update requests are idempotent.

Performance

• Batched EF Core operations with AddRangeAsync and ExecuteUpdate, halving bulk update latency.
• Parallel async processing with Parallel.ForEachAsync and throttled concurrency, reaching 300+ weather updates per minute.
• Spatial indexing with a PostgreSQL GiST index on latitude and longitude for fast coordinate lookups.

Data integrity

• Unique indexes prevent duplicate coordinates.
• SERIALIZABLE transactions keep concurrent writes consistent.
• CQRS separates the read and write models for weather queries.

Tooling

Swagger/OpenAPI documentation generated from XML comments, and a Docker Compose setup for running PostgreSQL locally.