Using ASP.NET routing to serve static files

asp.neturl-routing

Can ASP.Net routing (not MVC) be used to serve static files?

Say I want to route

http://domain.tld/static/picture.jpg

to

http://domain.tld/a/b/c/picture.jpg

and I want to do it dynamically in the sense that the rewritten URL is computed on the fly. I cannot set up a static route once and for all.

Anyway, I can create a route like this:

routes.Add(
  "StaticRoute", new Route("static/{file}", new FileRouteHandler())
);

In the FileRouteHandler.ProcessRequest method I can rewrite the path from /static/picture.jpg to /a/b/c/picture.jpg. I then want to create a handler for static files. ASP.NET uses the StaticFileHandler for this purpose. Unfortunately, this class is internal. I have tried to create the handler using reflection and it actually works:

Assembly assembly = Assembly.GetAssembly(typeof(IHttpHandler));
Type staticFileHandlerType = assembly.GetType("System.Web.StaticFileHandler");
ConstructorInfo constructorInfo = staticFileHandlerType.GetConstructor(BindingFlags.NonPublic | BindingFlags.Instance, null, Type.EmptyTypes, null);
return (IHttpHandler) constructorInfo.Invoke(null);

But using internal types doesn't seem to be the proper solution. Another option is to implement my own StaticFileHandler, but doing so properly (supporting HTTP stuff like ranges and etags) is non-trivial.

How should I approach routing of static files in ASP.NET?

Best Solution

Why not use IIS to do this? You could just create redirect rule to point any requests from the first route to the second one before the request even gets to your application. Because of this, it would be a quicker method for redirecting requests.

Assuming you have IIS7+, you do something like...

<rule name="Redirect Static Images" stopProcessing="true">
  <match url="^static/?(.*)$" />
  <action type="Redirect" url="/a/b/c/{R:1}" redirectType="Permanent" />
</rule>

Or, if you don't need to redirect, as suggested by @ni5ni6:

<rule name="Rewrite Static Images" stopProcessing="true">
  <match url="^static/?(.*)$" />
  <action type="Rewrite" url="/a/b/c/{R:1}" />
</rule>

Edit 2015-06-17 for @RyanDawkins:

And if you're wondering where the rewrite rule goes, here is a map of its location in the web.config file.

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <system.webServer>
    <rewrite>
      <rules>
        <!-- rules go below -->
        <rule name="Redirect Static Images" stopProcessing="true">
          <match url="^static/?(.*)$" />
          <action type="Redirect" url="/a/b/c/{R:1}" redirectType="Permanent" />
        </rule>
      </rules>
    </rewrite>
  </system.webServer>
</configuration>
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