R – URL Rewriting with UrlRewriter.Net, ASP.NET MVC Routing or What Do You Recommend

This is the best article I found about this topic: IIS URL Rewriting and ASP.NET routing by Ruslan Yakushev.

IIS URL Rewriting

When a client makes a request to the Web server for a particular URL, the URL-rewriting component analyzes the requested URL and changes it to a different other URL on the same server. The URL-rewriting component runs very early in the request processing pipeline, so is able to modify the requested URL before the Web server makes a decision about which handler to use for processing the request.

ASP.NET Routing

ASP.NET routing is implemented as a managed-code module that plugs into the IIS request processing pipeline at the Resolve Cache stage (PostResolveRequestCache event) and at the Map Handler stage (PostMapRequestHandler). ASP.NET routing is configured to run for all requests made to the Web application.

Differences between URL rewriting and ASP.NET routing:

1. URL rewriting is used to manipulate URL paths before the request is handled by the Web server. The URL-rewriting module does not know anything about what handler will eventually process the rewritten URL. In addition, the actual request handler might not know that the URL has been rewritten.
2. ASP.NET routing is used to dispatch a request to a handler based on the requested URL path. As opposed to URL rewriting, the routing component knows about handlers and selects the handler that should generate a response for the requested URL. You can think of ASP.NET routing as an advanced handler-mapping mechanism.

In addition to these conceptual differences, there are some functional differences between IIS URL rewriting and ASP.NET routing:

1. The IIS URL-rewrite module can be used with any type of Web application, which includes ASP.NET, PHP, ASP, and static files. ASP.NET routing can be used only with .NET Framework-based Web applications.
2. The IIS URL-rewrite module works the same way regardless of whether integrated or classic IIS pipeline mode is used for the application pool. For ASP.NET routing, it is preferable to use integrated pipeline mode. ASP.NET routing can work in classic mode, but in that case the application URLs must include file extensions or the application must be configured to use "*" handler mapping in IIS.
3. The URL-rewrite module can make rewriting decisions based on domain names, HTTP headers, and server variables. By default, ASP.NET routing works only with URL paths and with the HTTP-Method header.
4. In addition to rewriting, the URL-rewrite module can perform HTTP redirection, issue custom status codes, and abort requests. ASP.NET routing does not perform those tasks.
5. The URL-rewrite module is not extensible in its current version. ASP.NET routing is fully extensible and customizable.

A simple example of how to use routing in ASP.NET

1. Create Empty Web Application
2. Add first form - Default.aspx
3. Add second form - Second.aspx
4. Add third form - Third.aspx

5. Add to default.aspx 3 buttons -

   protected void Button1_Click(object sender, EventArgs e)
   {
       Response.Redirect("Second.aspx");
   }
   
   protected void Button2_Click(object sender, EventArgs e)
   {
       Response.Redirect("Third.aspx?Name=Pants");
   }
   
   protected void Button3_Click(object sender, EventArgs e)
   {
       Response.Redirect("Third.aspx?Name=Shoes");
   }
   

6. Read query string on third page

   protected void Page_Load(object sender, EventArgs e)
   {
       Response.Write(Request.QueryString["Name"]);
   }
   

Now if you run the program, you will be able to navigate to second and third form. This is how it used to be. Let's add routing.

7. Add new item - Global.aspx using System.Web.Routing;

   protected void Application_Start(object sender, EventArgs e)
   {
       RegisterRoutes(RouteTable.Routes);
   }
   void RegisterRoutes(RouteCollection routes)
   {
       routes.MapPageRoute(
           "HomeRoute",
           "Home",
           "~/Default.aspx"
       );
       routes.MapPageRoute(
           "SecondRoute",
           "Second",
           "~/Second.aspx"
       );
       routes.MapPageRoute(
           "ThirdRoute",
           "Third/{Name}",
           "~/Third.aspx"
       );
   }
   

8. In default.aspx modify protected void Button1_Click(object sender, EventArgs e) { // Response.Redirect("Second.aspx"); Response.Redirect(GetRouteUrl("SecondRoute", null)); }

   protected void Button2_Click(object sender, EventArgs e)
   {
       //Response.Redirect("Third.aspx?Name=Pants");
      Response.Redirect(GetRouteUrl("ThirdRoute", new {Name = "Pants"}));
   }
   
   protected void Button3_Click(object sender, EventArgs e)
   {
      // Response.Redirect("Third.aspx?Name=Shoes");
       Response.Redirect(GetRouteUrl("ThirdRoute", new { Name = "Shoes" }));
   }
   

9. Modify page load in third.aspx

   protected void Page_Load(object sender, EventArgs e)
   {
       //Response.Write(Request.QueryString["Name"]);
       Response.Write(RouteData.Values["Name"]);
   }
   

Run the program, Please note that url looks much cleaner - there are not file extensions in it (Second.aspx becomes just Second)

10. To pass more then one argument

    • add new button to default.aspx with the following code:

      protected void Button4_Click(object sender, EventArgs e)
      {
          Response.Redirect(GetRouteUrl("FourthRoute", new { Name = "Shoes" , Gender = "Male"}));
      }
      

    • add the following code to global.asax

          routes.MapPageRoute(
            "FourthRoute",
            "Fourth/{Name}-{Gender}",
            "~/Fourth.aspx"
        );
      

    • create Fourth.aspx page with the following page load:

      protected void Page_Load(object sender, EventArgs e)
      {
      Response.Write("Name is: " + RouteData.Values["Name"] + " and Gender is " + RouteData.Values["Gender"]);
      }