使用 app.UseMvc() 或 app.UseEndpoints 在 asp.net core mvc 项目中设置路由有什么区别？

Question

I know that when migrating from asp.net 2.2 to 3 app.UseMvc() line in startup.cs file's configure method is replaced by app.UseRouting(); app.UseAuthorization(); app.UseEndpoints();.

Can anyone explain how app.UseEndpoints() and app.UseMvc() works internally ?

Answer 1

Under the asp.net core mvc 2.2 framework, to use traditional routing, you must configure the IRouteBuilder interface in the UseMVC middleware.

In the Configure method of the application Startup, the default routing settings are as follows:

app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller=Home}/{action=Index}/{id?}");
{

In the call to UseMvc, MapRoute is used to create a single route, also known as the default route. Most MVC applications use routing with templates. A convenient method for the default route can be used:

app.UseMvcWithDefaultRoute();

UseMvc and UseMvcWithDefaultRoute can add an instance of RouterMiddleware to the middleware pipeline. MVC does not directly interact with middleware, but uses routing to process requests. MVC connects to the route through an instance of MvcRouteHandler.

UseMvc does not directly define any routes. It adds placeholders {controller=Home}/{action=Index}/{id?} to the route collection of attribute routing. By overloading UseMvc(Action), users are allowed to add their own routes, and attribute routing is also supported.

UseEndpoints : Perform matching endpoints.

It separates routing matching and resolution functions from endpoint execution functions, and until now, these functions are bundled with MVC middleware.

First of all,you could have a look at their source code :

public static IApplicationBuilder UseEndpoints(this IApplicationBuilder builder, Action<IEndpointRouteBuilder> configure)
    {
        if (builder == null)
        {
            throw new ArgumentNullException(nameof(builder));
        }

        if (configure == null)
        {
            throw new ArgumentNullException(nameof(configure));
        }

        VerifyRoutingServicesAreRegistered(builder);

        VerifyEndpointRoutingMiddlewareIsRegistered(builder, out var endpointRouteBuilder);

        configure(endpointRouteBuilder);

        // Yes, this mutates an IOptions. We're registering data sources in a global collection which
        // can be used for discovery of endpoints or URL generation.
        //
        // Each middleware gets its own collection of data sources, and all of those data sources also
        // get added to a global collection.
        var routeOptions = builder.ApplicationServices.GetRequiredService<IOptions<RouteOptions>>();
        foreach (var dataSource in endpointRouteBuilder.DataSources)
        {
            routeOptions.Value.EndpointDataSources.Add(dataSource);
        }

        return builder.UseMiddleware<EndpointMiddleware>();
    }

ASP.NET Core 3 uses a refined endpoint routing which will generally give more control about routing within the application. Endpoint routing works in two separate steps:

In a first step, the requested route is matched agains the configured routes to figure out what route is being accessed.

In a final step, the determined route is being evaluated and the respective middleware, eg MVC, is called.

The two steps are set up by app.UseRouting() and app.UseEndpoints(). The former will register the middleware that runs the logic to determine the route. The latter will then execute that route.

Also, refer to:

https://asp.net-hacker.rocks/2019/08/12/aspnetcore30-look-into-startup.html https://aregcode.com/blog/2019/dotnetcore-understanding-aspnet-endpoint-routing/