I am attempting to convert this sample RouteBase implementation to work with MVC 6. I have worked out most of it by following the example in the Routing project, but I am getting tripped up on how to return the asynchronous Task from the method. I really don't care if it actually is asynchronous (cheers to anyone who can provide that answer), for now I just want to get it functioning.
I have the outgoing routes functioning (meaning ActionLink works fine when I put in the route values). The problem is with the RouteAsync method.
public Task RouteAsync(RouteContext context)
{
var requestPath = context.HttpContext.Request.Path.Value;
if (!string.IsNullOrEmpty(requestPath) && requestPath[0] == '/')
{
// Trim the leading slash
requestPath = requestPath.Substring(1);
}
// Get the page that matches.
var page = GetPageList()
.Where(x => x.VirtualPath.Equals(requestPath))
.FirstOrDefault();
// If we got back a null value set, that means the URI did not match
if (page != null)
{
var routeData = new RouteData();
// This doesn't work
//var routeData = new RouteData(context.RouteData);
// This doesn't work
//routeData.Routers.Add(this);
// This doesn't work
//routeData.Routers.Add(new MvcRouteHandler());
// TODO: You might want to use the page object (from the database) to
// get both the controller and action, and possibly even an area.
// Alternatively, you could create a route for each table and hard-code
// this information.
routeData.Values["controller"] = "CustomPage";
routeData.Values["action"] = "Details";
// This will be the primary key of the database row.
// It might be an integer or a GUID.
routeData.Values["id"] = page.Id;
context.RouteData = routeData;
// When there is a match, the code executes to here
context.IsHandled = true;
// This test works
//await context.HttpContext.Response.WriteAsync("Hello there");
// This doesn't work
//return Task.FromResult(routeData);
// This doesn't work
//return Task.FromResult(context);
}
// This satisfies the return statement, but
// I'm not sure it is the right thing to return.
return Task.FromResult(0);
}
The entire method runs all the way through to the end when there is a match. But when it is done executing, it doesn't call the Details method of the CustomPage controller, as it should. I just get a blank white page in the browser.
I added the WriteAsync line as was done in this post and it writes Hello there to the blank page, but I can't understand why MVC isn't calling my controller (in previous versions this worked without a hitch). Unfortunately, that post covered every part of routing except for how to implement an IRouter or INamedRouter.
How can I make the RouteAsync method function?
Entire CustomRoute Implementation
using Microsoft.AspNet.Routing;
using Microsoft.Framework.Caching.Memory;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
public class PageInfo
{
// VirtualPath should not have a leading slash
// example: events/conventions/mycon
public string VirtualPath { get; set; }
public int Id { get; set; }
}
public interface ICustomRoute : IRouter
{ }
public class CustomRoute : ICustomRoute
{
private readonly IMemoryCache cache;
private object synclock = new object();
public CustomRoute(IMemoryCache cache)
{
this.cache = cache;
}
public Task RouteAsync(RouteContext context)
{
var requestPath = context.HttpContext.Request.Path.Value;
if (!string.IsNullOrEmpty(requestPath) && requestPath[0] == '/')
{
// Trim the leading slash
requestPath = requestPath.Substring(1);
}
// Get the page that matches.
var page = GetPageList()
.Where(x => x.VirtualPath.Equals(requestPath))
.FirstOrDefault();
// If we got back a null value set, that means the URI did not match
if (page != null)
{
var routeData = new RouteData();
// TODO: You might want to use the page object (from the database) to
// get both the controller and action, and possibly even an area.
// Alternatively, you could create a route for each table and hard-code
// this information.
routeData.Values["controller"] = "CustomPage";
routeData.Values["action"] = "Details";
// This will be the primary key of the database row.
// It might be an integer or a GUID.
routeData.Values["id"] = page.Id;
context.RouteData = routeData;
context.IsHandled = true;
}
return Task.FromResult(0);
}
public VirtualPathData GetVirtualPath(VirtualPathContext context)
{
VirtualPathData result = null;
PageInfo page = null;
// Get all of the pages from the cache.
var pages = GetPageList();
if (TryFindMatch(pages, context.Values, out page))
{
result = new VirtualPathData(this, page.VirtualPath);
context.IsBound = true;
}
return result;
}
private bool TryFindMatch(IEnumerable<PageInfo> pages, IDictionary<string, object> values, out PageInfo page)
{
page = null;
int id;
object idObj;
object controller;
object action;
if (!values.TryGetValue("id", out idObj))
{
return false;
}
id = Convert.ToInt32(idObj);
values.TryGetValue("controller", out controller);
values.TryGetValue("action", out action);
// The logic here should be the inverse of the logic in
// GetRouteData(). So, we match the same controller, action, and id.
// If we had additional route values there, we would take them all
// into consideration during this step.
if (action.Equals("Details") && controller.Equals("CustomPage"))
{
page = pages
.Where(x => x.Id.Equals(id))
.FirstOrDefault();
if (page != null)
{
return true;
}
}
return false;
}
private IEnumerable<PageInfo> GetPageList()
{
string key = "__CustomPageList";
IEnumerable<PageInfo> pages;
// Only allow one thread to poplate the data
if (!this.cache.TryGetValue(key, out pages))
{
lock (synclock)
{
if (!this.cache.TryGetValue(key, out pages))
{
// TODO: Retrieve the list of PageInfo objects from the database here.
pages = new List<PageInfo>()
{
new PageInfo() { Id = 1, VirtualPath = "somecategory/somesubcategory/content1" },
new PageInfo() { Id = 2, VirtualPath = "somecategory/somesubcategory/content2" },
new PageInfo() { Id = 3, VirtualPath = "somecategory/somesubcategory/content3" }
};
this.cache.Set(key, pages,
new MemoryCacheEntryOptions()
{
Priority = CacheItemPriority.NeverRemove,
AbsoluteExpirationRelativeToNow = TimeSpan.FromMinutes(15)
});
}
}
}
return pages;
}
}
CustomRoute DI Registration
services.AddTransient<ICustomRoute, CustomRoute>();
MVC Route Configuration
// Add MVC to the request pipeline.
app.UseMvc(routes =>
{
routes.Routes.Add(routes.ServiceProvider.GetService<ICustomRoute>());
routes.MapRoute(
name: "default",
template: "{controller=Home}/{action=Index}/{id?}");
// Uncomment the following line to add a route for porting Web API 2 controllers.
// routes.MapWebApiRoute("DefaultApi", "api/{controller}/{id?}");
});
In case it matters I am using Beta 5, DNX 4.5.1 and DNX Core 5.
Solution
I created a generic solution that can be used for a simple primary key to URL 2-way mapping in this answer based on the information I learned here. The controller, action, data provider, and datatype of the primary key can be specified when wiring it into MVC 6 routing.
See Question&Answers more detail:
os 
