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This article mainly shows you "ASP.NET MVC5 request processing pipeline and life cycle example analysis", the content is simple and easy to understand, organized clearly, I hope to help you solve doubts, let Xiaobian lead you to study and learn about "ASP.NET MVC5 request processing pipeline and life cycle example analysis" this article bar.

request processing pipeline

A request pipeline is a combination of modules used to process HTTP requests. In ASP.NET, a request pipeline has two core components: IHttpModule and IHttpHandler. All HTTP requests go to IHttpHandler for final processing, while IHttpModule can preprocess requests before IHttpHandler processes HTTP requests or process HTTP requests again after IHttpHandler processes HTTP requests by subscribing to events in HttpApplication objects.

Before IIS7, such as IIS6 or IIS5, the request processing pipeline was divided into two parts: IIS request processing pipeline and ASP.NET pipeline. If the client requests static resources, only IIS pipeline will process the request, and ASP.NET pipeline will not process the request. Starting with IIS7, the two pipes merge into one, called an integrated pipe.

The figure above describes the processing of HTTP requests by the ASP.NET runtime without much detail.

HttpApplication and HttpModule

After the HTTP request is taken over by the ASP.NET runtime, HttpRuntime creates or fetches an HttpApplication object from the HttpApplication object pool using the HttpApplicationFactory (similar mechanisms in. NET include thread pools and string detention pools), and ASP.NET initializes the registered HttpModule according to the configuration file. HttpModule will subscribe to the events in HttpApplication to process the HTTP request when initialized.

In ASP.NET MVC5, the MvcApplication class is defined in the Global.asax file, inherited from the HttpApplication class:

public class MvcApplication : System.Web.HttpApplication{ protected void Application_Start() { AreaRegistration.RegisterAllAreas(); RouteTable.Routes.Add("xfhHandler", new Route( "{controller}/{action}", new RouteValueDictionary(new Dictionary() { ["controller"] = "home", ["action"] = "index" }), new XfhUrlRouteHandler()) ); //RouteConfig.RegisterRoutes(RouteTable.Routes); }}

The Application_Start() method is executed first, and some configurations are generally added to this method, such as route registration, global filter registration, etc.

Route

An HTTP request is processed through at least one HttpModule. UrlRoutingModule is a very important module, it is the core of the routing system. It is the responsibility of the routing system to retrieve the controller and action names and other request data from the request URL.

UrlRoutingModule matches the URL of the current request with the registered routing templates in RouteTable and returns the first route object matching the current request, and then obtains the routing data object RouteData according to the route object (in ASP.NET MVC, the routing data must contain the names of controller and action), and then RouteData obtains IRouteHandler. Finally, IRouteHandler obtains IHttpHandler.

HttpHandler

An HTTP request is ultimately processed in an HttpHandler, and an HTTP request can only be processed by an HttpHandler.

Controller

IHttpHandler processes the current request in the ProcessRequest method, where it gets the IControllerFactory from ControllerBuilder and then gets the Controller type by reflection.

Action

ControllerBase in ASP.NET MVC is the base class of all Controllers, and calls to Action are executed through the InvokeAction method of IActionInvoker in the Execute method of the type. Model binding and model validation operations are performed before the Action is executed.

Filters

There are five filters commonly used in ASP.NET MVC5: IAuthenticationFilter, IAuthorizationFilter, IActionFilter, IResultFilter, IExceptionFilter.

In ASP.NET MVC, all filters will eventually be encapsulated as Filter objects. In this object, the FilterScope type attribute Scope and the int type attribute Order are used to determine the order in which filters are executed. The specific rules are as follows:

The smaller the Order and FilterScope values, the higher the execution priority of the filter;

Order has a higher priority than FilterScope and is considered only if the Order attribute values are the same

//The smaller the value, the higher the execution priority public enum FilterScope{ Action= 30, Controller= 20, First= 0, Global= 10, Last= 100}ActionResult

After the Action is executed, an ActionResult type object will be returned as the result of processing the request. ASP.NET MVC will convert the return value that is not of ActionResult type to ActionResult type.

request life cycle

ASP.NET application life cycle starts with the browser sending a request to the Web server, the request arrives at the server and enters the processing pipeline until the browser receives the server response.

Finally, I attach a drawing of ASP.NET request pipeline drawn by foreigners. The picture is from ASP.NET MVC Interview Questions and Answers Book.

The above is "ASP.NET MVC5 Request Processing Pipeline and Life Cycle Sample Analysis" all the content of this article, thank you for reading! I believe that everyone has a certain understanding, hope to share the content to help everyone, if you still want to learn more knowledge, welcome to pay attention to the industry information channel!

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