Automatic URL Parameter Encoding Failing

Question

Background

In HomeController.cs I have:

[HttpGet]
public GetPerson(string name)
{
 return View(new PersonModel { ... });
}

In Global.asax.cs I have:

public static void RegisterRoutes(RouteCollection routes)
{
 routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
 routes.MapRoute(
 "Word", "person/{name}",
 new { controller = "Home", action = "GetPerson" });
 routes.MapRoute(
 "Default", "{controller}/{action}",
 new { controller = "Home", action = "Index" });
}

In SomePage.cshtml I have, effectively, this:

@{ var name = "Winston S. Churchill"; }
<a href="@Url.Action("GetPerson", "Home", new { name })">@name</a>

Problem

If I click the link for Winston S. Churchill, I am routed to the URL http://localhost/person/Winston%20S.%20Churchill, which yields the standard 404 page:

HTTP Error 404.0 - Not Found

The resource you are looking for has been removed, had its name changed, or is temporarily unavailable.

This only happens if the name variable contains a . (period). All my code works perfectly fine when the name is, for example, Winston Churchill.

How can I make ASP.NET MVC 3 percent-encode the . (period) in the URL?

Or, how can I make the routing work without . (period) being percent-encoded?

Unacceptable Workaround (if presented without justification)

If I change the route to the following, everything works.

routes.MapRoute(
 "Word", "person",
 new { controller = "Home", action = "GetPerson" });

However, the URL becomes http://localhost/person?name=Winston%20S.%20Churchill, which isn't what I want. I want the name in the path part of the URL, not the query.

Answer 1

Routes which contain a period and unknown extension are interpreted by IIS as static files and not sent through the .NET pipeline. For example, the URL you cite is interpreted as a static file with a %20Churchill extension.

You can force ASP.NET to handle all requests by adding this to web.config:

<system.webServer>
 <modules runAllManagedModulesForAllRequests="true" />
</system.webServer>

You'll also need this, to handle name values that end with a period (as opposed to just containing one):

<system.web>
 <httpRuntime relaxedUrlToFileSystemMapping="true" />
</system.web>

All /person/{name} URLs will then be picked up by your ASP.NET code.

If you would rather not use this setting, the easiest workaround would be to use a custom encoding:

name.Replace(".","--")

• Timothy Shields: Are there any safety issues with this that could be unexpected?
• Timothy Shields: Also, while this works for Winston S. Churchill (I just tried it), it fails for Albert Gore Jr. (note period at end).
• James: No safety issues, but it means that ASP.NET will try to process all requests so files that actually are static (images, CSS, etc.) will take a tiny bit longer to load. In practice, you are unlikely to notice a difference. To fix the issue with the terminating period, try adding <httpRuntime relaxedUrlToFileSystemMapping="true" /> to <system.web>.
• Andy T: The issue with runAllManagedModulesForAllRequests is not really a security one, but with performance since all requests will be handled by managed modules even request for static files.
• Timothy Shields: Excellent. My site has very little static content (shortcut icon is it so far). The two changes you outlined worked great. I'm going to edit your answer to highlight the relaxedUrlToFileSystemMapping setting.