The Failure Path

How you handle failures deeply affects the readability and maintainability of your architectural layers.

1. Exceptions for Exceptional Cases

In standard .NET, we throw exceptions (e.g., NotFoundException). In the Presentation layer, we use a **Global Exception Handler** to catch these and map them to HTTP 404/400. This is easy, but it makes the 'Failure Path' invisible in the method signature.

2. The Result Pattern

Instead of throwing, methods return a Result<T> object that contains either the Value or an Error. This makes the possibility of failure explicit. var result = await service.DoWork(); if (result.IsFailure) return BadRequest(result.Error);. This is common in functional programming and leads to code that is much easier to reason about and test.

3. Architect Insight

Q: "Which one is better for Clean Architecture?"

Architect Answer: "Use the **Result Pattern** for business logic failures (e.g., 'Insufficient Funds'). This is a 'Domain' result. Use **Exceptions** only for truly unexpected technical failures (e.g., 'Database is Down'). This separation tells the reader exactly which errors are 'Business as usual' and which are 'Critical failures'."