ASP.NET Core – How to get request headers

There are two ways to get request headers: Use the Request.Headers dictionary. Use [FromHeader]. When a request comes in, the framework loads request headers into the Request.Headers dictionary. You can use this just like any other dictionary. Here’s an example of using TryGetValue() to check if a request header exists and get its value: Note: … Read more

ASP.NET Core – How to unit test a model validation attribute

You can directly unit test a model validation attribute by creating an instance of the attribute class, and then testing the two primary methods: IsValid() and FormatErrorMessage(). Here’s an example of unit testing a custom validation attribute: You can also test the built-in validation attributes (such as [Range], [RegularExpression], etc..), which is useful when you … Read more

ASP.NET Core – Create a custom model validation attribute

There are many built-in model validation attributes available – such as [Required] and [Range] – which you can use to handle most validation scenarios. When these aren’t sufficient, you can create a custom validation attribute with your own validation logic. I’ll show an example of how to do that. 1 – Subclass ValidationAttribute and implement … Read more

ASP.NET Core – API model validation attributes

It’s always a good idea to validate data coming into your web API. There are two steps you can do to guard against invalid data: Declare your model properties with the proper types. (ex: string, DateTime, int). Use model validation attributes. The main built-in ones are [Required], [Range], [StringLength], and [RegularExpression]. Here’s an example of … Read more