Domain-based routing in ASP.NET Core 2.0

Question

I have an ASP.NET Core 2.0 app hosted on an Azure App Service.

This application is bound to domainA.com. I have one route in my app—for example, d

Answer 1

For .net Core MVC, you can create a new IRouteConstraint and a RouteAttribute

=> IRouteConstraint.cs

using System;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;

namespace Microsoft.AspNetCore.Routing
{
    public class ConstraintHost : IRouteConstraint
    {

        public string _value { get; private set; }
        public ConstraintHost(string value)
        {
            _value = value;
        }

        public bool Match(HttpContext httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection)
        {
            string hostURL = httpContext.Request.Host.ToString();
            if (hostURL == _value)
            {
                return true;
            }
            //}
            return false;
            //return hostURL.IndexOf(_value, StringComparison.OrdinalIgnoreCase) >= 0;
        }

        public bool Match(HttpContext httpContext, IRouter route, string routeKey, RouteValueDictionary values, RouteDirection routeDirection)
        {
            throw new NotImplementedException();
        }
    }
    public class ConstraintHostRouteAttribute : RouteAttribute
    {
        public ConstraintHostRouteAttribute(string template, string sitePermitted)
            : base(template)
        {
            SitePermitted = sitePermitted;
        }

        public RouteValueDictionary Constraints
        {
            get
            {
                var constraints = new RouteValueDictionary();
                constraints.Add("host", new ConstraintHost(SitePermitted));
                return constraints;
            }
        }

        public string SitePermitted
        {
            get;
            private set;
        }
    }
} 

And in your Controller can use it like that:

    [ConstraintHostRoute("myroute1/xxx", "domaina.com")]
    [ConstraintHostRoute("myroute2/yyy", "domainb.com")]
    public async Task MyController()
    {
      return View();
    }