Domain based routing with ASP.NET Web API

Imagine you are building an API which is “multi-tenant”: the domain name defines the tenant or customer name and should be passed as a route value to your API. An example would be http://customer1.mydomain.com/api/v1/users/1. Customer 2 can use the same API, using http://customer2.mydomain.com/api/v1/users/1. How would you solve routing based on a (sub)domain in your ASP.NET Web API projects?

Almost 2 years ago (wow, time flies), I’ve written a blog post on ASP.NET MVC Domain Routing. Unfortunately, that solution does not work out-of-the-box with ASP.NET Web API. The good news is: it almost works out of the box. The only thing required is adding one simple class:


Code highlighting produced by Actipro CodeHighlighter (freeware)
http://www.CodeHighlighter.com/
—> 1 public class HttpDomainRoute
 2     : DomainRoute
 3 {
 4     public HttpDomainRoute(string domain, string url, RouteValueDictionary defaults)
 5         : base(domain, url, defaults, HttpControllerRouteHandler.Instance)
 6     {
 7     }
 8 
 9     public HttpDomainRoute(string domain, string url, object defaults)
10         : base(domain, url, new RouteValueDictionary(defaults), HttpControllerRouteHandler.Instance)
11     {
12     }
13 }

Using this class, you can now define subdomain routes for your ASP.NET Web API as follows:


Code highlighting produced by Actipro CodeHighlighter (freeware)
http://www.CodeHighlighter.com/
—> 1 RouteTable.Routes.Add(new HttpDomainRoute(
 2     “{controller}.mydomain.com”, // without tenant
 3     “api/v1/{action}/{id}”,
 4      new { id = RouteParameter.Optional }
 5 ));
 6 
 7 RouteTable.Routes.Add(new HttpDomainRoute(
 8     “{tenant}.{controller}.mydomain.com”, // with tenant
 9     “api/v1/{action}/{id}”,
10      new { id = RouteParameter.Optional }
11 ));

And consuming them in your API controller is as easy as:


Code highlighting produced by Actipro CodeHighlighter (freeware)
http://www.CodeHighlighter.com/
—> 1 public class UsersController
 2     : ApiController
 3 {
 4     public string Get()
 5     {
 6         var routeData = this.Request.GetRouteData().Values;
 7         if (routeData.ContainsKey(“tenant”))
 8         {
 9             return “UsersController, called by tenant ” + routeData[“tenant”];
10         }
11         return “UsersController”;
12     }
13 }

Here’s a download for you if you want to make use of (sub)domain routes. Enjoy!

WebApiSubdomainRouting.zip (496.64 kb)