Asp.Net core get RouteData value from url

Question

I\'m wokring on a new Asp.Net core mvc app. I defined a route with a custom constraint, which sets current app culture from the url. I\'m trying to manage localization for m

Answer 1

There isn't an easy way to do this, and the ASP.Net team hasn't decided to implement this functionality yet. IRoutingFeature is only available after MVC has completed the request.

I was able to put together a solution that should work for you though. This will setup the routes you're passing into UseMvc() as well as all attribute routing in order to populate IRoutingFeature. After that is complete, you can access that class via httpContext.GetRouteValue("language");.

Startup.cs

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
    // setup routes
    app.UseGetRoutesMiddleware(GetRoutes);

    // add localization
    var requestLocalizationOptions = new RequestLocalizationOptions
    {
        DefaultRequestCulture = new RequestCulture("en-US")
    };
    requestLocalizationOptions.RequestCultureProviders.Clear();
    requestLocalizationOptions.RequestCultureProviders.Add(
        new MyCustomRequestCultureProvider()
    );
    app.UseRequestLocalization(requestLocalizationOptions);

    // add mvc
    app.UseMvc(GetRoutes);
}

Moved the routes to a delegate (for re-usability), same file/class:

private readonly Action GetRoutes =
    routes =>
    {
        routes.MapRoute(
            name: "custom",
            template: "{language=fr-FR}/{controller=Home}/{action=Index}/{id?}");

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

Add new middleware:

public static class GetRoutesMiddlewareExtensions
{
    public static IApplicationBuilder UseGetRoutesMiddleware(this IApplicationBuilder app, Action configureRoutes)
    {
        if (app == null)
        {
            throw new ArgumentNullException(nameof(app));
        }

        var routes = new RouteBuilder(app)
        {
            DefaultHandler = app.ApplicationServices.GetRequiredService(),
        };
        configureRoutes(routes);
        routes.Routes.Insert(0, AttributeRouting.CreateAttributeMegaRoute(app.ApplicationServices));
        var router = routes.Build();

        return app.UseMiddleware(router);
    }
}

public class GetRoutesMiddleware
{
    private readonly RequestDelegate next;
    private readonly IRouter _router;

    public GetRoutesMiddleware(RequestDelegate next, IRouter router)
    {
        this.next = next;
        _router = router;
    }

    public async Task Invoke(HttpContext httpContext)
    {
        var context = new RouteContext(httpContext);
        context.RouteData.Routers.Add(_router);

        await _router.RouteAsync(context);

        if (context.Handler != null)
        {
            httpContext.Features[typeof (IRoutingFeature)] = new RoutingFeature()
            {
                RouteData = context.RouteData,
            };
        }

        // proceed to next...
        await next(httpContext);
    }
}

You may have to define this class as well...

public class RoutingFeature : IRoutingFeature
{
    public RouteData RouteData { get; set; }
}