What are asp.net mvc filters?

[Cai]

Hi, I would like to ask you an important problem to ask about this subject, what are asp.net mvc filters Please help me, thank you very much for answering me as soon as possible.

[Lucian]

ASP.NET MVC supports the following types of action filters:

Authorization filters. These implement IAuthorizationFilter and make security decisions about whether to execute an action method, such as performing authentication or validating properties of the request. The AuthorizeAttribute class and the RequireHttpsAttribute class are examples of an authorization filter. Authorization filters run before any other filter.

Action filters. These implement IActionFilter and wrap the action method execution. The IActionFilter interface declares two methods: OnActionExecuting and OnActionExecuted. OnActionExecuting runs before the action method. OnActionExecuted runs after the action method and can perform additional processing, such as providing extra data to the action method, inspecting the return value, or canceling execution of the action method.

Result filters. These implement IResultFilter and wrap execution of the ActionResult object. IResultFilter declares two methods: OnResultExecuting and OnResultExecuted. OnResultExecuting runs before the ActionResult object is executed. OnResultExecuted runs after the result and can perform additional processing of the result, such as modifying the HTTP response. The OutputCacheAttribute class is one example of a result filter.

Exception filters. These implement IExceptionFilter and execute if there is an unhandled exception thrown during the execution of the ASP.NET MVC pipeline. Exception filters can be used for tasks such as logging or displaying an error page. The HandleErrorAttribute class is one example of an exception filter.