Improving the resilience of the API

The previous sections show a possible implementation of ItemController class and how to test it using the tools provided by ASP.NET Core. In this section, we will learn how to improve the resilience of our service by performing some restriction checks on the information exposed by the ItemController. Additionally, we will look at how to present validation errors and how to paginate returned data. This section will apply the concepts explained in the previous chapters to the web service project.

Existence check

Let's start by implementing the action filter that performs an existence check on the requested data. The filter will be used by the action methods that get or edit a single...