ASP.NET Core in Action, Third Edition

6 Mapping URLs to endpoints using routing

This chapter covers

• Mapping URLs to endpoint handlers
• Using constraints and default values to match URLs
• Generating URLs from route parameters

In chapter 5 you learned how to define minimal APIs, how to return responses, and how to work with filters and route groups. One crucial aspect of minimal APIs that we touched on only lightly is how ASP.NET Core selects a specific endpoint from all the handlers defined, based on the incoming request URL. This process, called routing, is the focus of this chapter.

This chapter begins by identifying the need for routing and why it’s useful. You’ll learn about the endpoint routing system introduced in ASP.NET Core 3.0 and why it was introduced, and explore the flexibility ...