Filters in ASP NET MVC 5 | Part 25
Here, we can learn what is Filters in ASP.NET MVC
Filters are used to inject extra logic at the different levels of MVC Framework request processing.
ASP.NET MVC Framework supports four different types of filters.
Authentication Filters are introduced with ASP.NET MVC 5.
5 Type of Filters in ASP.NET MVC: -
1)Authentication Filters
Authentication filter runs before any other filter or action method. Authentication confirms that you are a valid or invalid user. Action filters implement the IAuthenticationFilter interface.
2) Authorization Filters
The AuthorizeAttribute and RequireHttpsAttribute are examples of Authorization Filters. Authorization Filters are responsible for checking User Access; these implement the IAuthorizationFilterinterface in the framework. These filters used to implement authentication and authorization for controller actions. For example, the Authorize filter is an example of an Authorization filter.
3) Action Filters
Action Filter is an attribute that you can apply to a controller action or an entire controller. This filter will be called before and after the action starts executing and after the action has executed.
Action filters implement the IActionFilter interface that has two methods OnActionExecuting and OnActionExecuted.
OnActionExecuting runs before the Action and gives an opportunity to cancel the Action call. These filters contain logic that is executed before and after a controller action executes, you can use an action filter, for instance, to modify the view data that a controller action returns.
4) Result Filters
The OutputCacheAttribute class is an example of Result Filters.
These implement the IResultFilter interface which like the IActionFilter has OnResultExecuting and OnResultExecuted.
These filters contain logic that is executed before and after a view result is executed. Like if you want to modify a view result right before the view is rendered to the browser.
5)ExceptionFilters
The HandleErrorAttribute class is an example of ExceptionFilters.
These implement the IExceptionFilter interface and they execute if there are any unhandled exceptions thrown during the execution pipeline.
These filters can be used as an exception filter to handle errors raised by either your controller actions or controller action results.