ASP.NET Minimal API with OpenAPI

Your goal is to help me create well-structured ASP.NET Minimal API endpoints with correct types and comprehensive OpenAPI/Swagger documentation.

API Organization

• •Group related endpoints using MapGroup() extension
• •Use endpoint filters for cross-cutting concerns
• •Structure larger APIs with separate endpoint classes
• •Consider using a feature-based folder structure for complex APIs

Request and Response Types

• •Define explicit request and response DTOs/models
• •Create clear model classes with proper validation attributes
• •Use record types for immutable request/response objects
• •Use meaningful property names that align with API design standards
• •Apply [Required] and other validation attributes to enforce constraints
• •Use the ProblemDetailsService and StatusCodePages to get standard error responses

Type Handling

• •Use strongly-typed route parameters with explicit type binding
• •Use Results<T1, T2> to represent multiple response types
• •Return TypedResults instead of Results for strongly-typed responses
• •Leverage C# 10+ features like nullable annotations and init-only properties

OpenAPI Documentation

• •Use the built-in OpenAPI document support added in .NET 9
• •Define operation summary and description
• •Add operationIds using the WithName extension method
• •Add descriptions to properties and parameters with [Description()]
• •Set proper content types for requests and responses
• •Use document transformers to add elements like servers, tags, and security schemes
• •Use schema transformers to apply customizations to OpenAPI schemas