Custom VirtualPathProvider unable to serve URLs ending with a directory

As part of a CMS, I have created a custom VirtualPathProvider which is designed to serve a single file in place of an actual file structure. I have it set up such that if a file actually exists on the server, that file will be served. If the file does not exis开发者_开发知识库t, the virtual content stored for that address will be served instead. This is similar to the concept of serving a website from files stored in a database, though in this case the content is stored in XML files on the server.

This setup works perfectly when a request is made to a specific page. For example, if I ask for "www.mysite.com/foobar.aspx", the content that is stored for "foobar.aspx" will be served. Further, if I ask for "www.mysite.com/subdir/foobar.aspx", the appropriate content will also be served.

The problem is this: If I ask for something like "www.mysite.com/foobar", things begin to fall apart. If the directory exists on disk (and doesn't have a configured default page in IIS, such as index.aspx), I will get a "Directory Listing Denied" error. If the directory does not exist, I'll simply get a 404 - Resource Not Found.

I've tried several things, and so far nothing I've done has made a bit of difference. It seems as though IIS is simply noting the nonexistence of a directory (or default file in an existing directory) and serving up its own error code, without ever asking my application what to do with the request. If it ever did get to the application, I would be able to solve the problem, but as it stands, I'm quite lost. Does anyone know if there is some setting in IIS that is causing this?

I've looked for every resource I can find on the subject, and am coming up empty. I know this should be possible, because I have read tutorials on serving content from both databases and ZIP files. HELP!

p.s., I am running IIS6 and .NET 3.5

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IIS will only pass a request to the ASP.NET process if it is configured to do so for the particular extension. The default is aspx, ascx, etc. In other words, if you request a .html file, ASP.NET will never see that HTTP request. Likewise for empty extension.

To change this behavior, add a wildcard mapping to the ASP.NET process. Load IIS Manager, go to the Properties for your web site and look at the Home Directory tab. Click on "Configuration" and there you will see the extension-to-applicaiton mappings.