Customized Authentication Filters in ASP.MVC5

As we studied in last article, Filters are used to inject logic at the different levels of request processing. Below is the filters execution sequence:

Authentication Filters ==>  Authorization filter ==> Action filter ==> Result filter ==> Exceptionfilter

The authentication filter executes before any other filter

The authorization filter executes after Authentication filter and action method, or before any other filter

The action filter executes before and after any action method

The result filter executes before and after the execution of any action result

The exception filter executes only if any action methods, filters, or results throws an exception

Create a new class

Implement IAuthenticationFilter Interface

Derive it from ActionFilterAttribute

Override the OnAuthentication method to run logic before the action methodg

OnAuthentication Method

The program invokes Authentication Filters by calling this method. This method creates the AuthenticationContext. AuthenticationContext has information about performing authentication. We can use this information to make authentication decisions based on the current context.

OnAuthenticationChallenge Method

This method executes after the OnAuthentication method. We can use the OnAuthenticationChallenge method to perform additional tasks on request. This method creates an AuthenticationChallengeContext the same way as OnAuthentication.