9 Creating a Web API for mobile and client applications using MVC

In the previous five chapters, you’ve worked through each layer of a server-side rendered ASP.NET Core application, using Razor Pages to render HTML to the browser. In this chapter you’ll see a different take on an ASP.NET Core application. Instead of using Razor Pages, we’ll explore Web APIs, which serve as the backend for client-side SPAs and mobile apps.

You can apply much of what you’ve already learned to Web APIs; they use the same MVC design pattern, and the concepts of routing, model binding, and validation all carry through. The differentiation from traditional web applications is primarily in the view part of MVC. Instead of returning HTML, they return data as JSON or XML, which client applications use to control their behavior or update the UI.

In this chapter you’ll learn how to define controllers and actions and see how similar they are to the Razor Pages and controllers you already know. You’ll learn how to create an API model to return data and HTTP status codes in response to a request, in a way that client apps can understand.

9.1 What is a Web API and when should you use one?

9.2 Creating your first Web API project

9.3 Applying the MVC design pattern to a Web API

9.4 Attribute routing: Linking action methods to URLs

9.4.1 Combining route attributes to keep your route templates DRY

9.4.2 Using token replacement to reduce duplication in attribute routing

9.4.3 Handling HTTP verbs with attribute routing

9.5 Using common conventions with the [ApiController] attribute

9.6 Generating a response from a model

9.6.1 Customizing the default formatters: Adding XML support

9.6.2 Choosing a response format with content negotiation

Summary