DOTNET Core MVC（二）路由初探

搁置了几天，工作忙的一塌糊涂，今天终于抽空来继续看看MVC的知识。先来看看MVC的路由是如何处理的。以下为替代的路由：

app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllerRoute(
                    name: "default",
                    pattern: "{controller=Home}/{action=Index}/{id?}");
            });

通过Configure方法在运行时，以委托的形式注册。

UseEndpoints：将中间件添加到的IApplicationBuilder再调用该方法时，需要先调用UseRouting。

public static IApplicationBuilder UseRouting(this IApplicationBuilder builder)
{
    if (builder == null)
    {
        throw new ArgumentNullException(nameof(builder));
    }
    VerifyRoutingServicesAreRegistered(builder);//校验是否加载完成
    var endpointRouteBuilder = new DefaultEndpointRouteBuilder(builder);
    builder.Properties[EndpointRouteBuilder] = endpointRouteBuilder;
    return builder.UseMiddleware<EndpointRoutingMiddleware>(endpointRouteBuilder);
}

将Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware中间件添加到指定的IApplicationBuilder中。

private static void VerifyRoutingServicesAreRegistered(IApplicationBuilder app)
{
    // Verify if AddRouting was done before calling UseEndpointRouting/UseEndpoint
    // We use the RoutingMarkerService to make sure if all the services were added.
    if (app.ApplicationServices.GetService(typeof(RoutingMarkerService)) == null)
    {
        throw new InvalidOperationException(Resources.FormatUnableToFindServices(
            nameof(IServiceCollection),
            nameof(RoutingServiceCollectionExtensions.AddRouting),
            "ConfigureServices(...)"));
    }

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使用完善的终结点路由，通常可以对应用程序内部的路由提供更多控制。端点路由分为两个单独的步骤：

在第一步中，再次匹配所请求的路由和配置的路由，找出以访问正在的路由。在最后一步中，对确定的路由进行评估，并调用相应的中间件。

两个步骤独立，允许其他中间件在这些点之间起作用。允许中间件利用来自一个子的端点路由信息来处理授权，而不必执行实际的处理程序。

app.UseRouting（）将注册运行逻辑路由路由的中间件。

app.UseEndpoints（）将执行该路由。

MapControllerRoute：添加端点控制器操作的IEndpointRouteBuilder 并指定与路由给定name，pattern，  defaults，constraints，和dataTokens。

其他：

MapController将添加到属性路由的控制器支持。

MapController将添加到该属性路由的控制器支持。

MapControllerRoute 添加控制器的常规路由

原创。转载请注明出处。

啰嗦一堆，就说了两个方法，下一篇接着说路由的用法〜