How do I restrict access to pdf files on my server?

Question

I am using ASP.Net MVC. I have restricted access to the web site using ASP Forms authentication. However, the web pages contain links to pdf files on the server which I also want protected.

For example, the user can browse to foo.com and foo.com/account/logon. Once they logon they can access foo.com/category/bar which presents the view in bar.aspx. On that view is a link to foo.com/files/theta.pdf which loads up in the browser just fine. However, I don’t want foo.com/files/theta.pdf accessible from the browser unless the user has authenticated.

How do I prevent a user from accessing foo.com/files/theta.pdf directly from their browser without first authenticating at foo.com/account/logon?

Answer 1

Pass the request through a controller, and return a FileResult. You can apply whatever security you want to the controller method, either by using the Authorize attribute, or by checking permissions inside the controller method.

There is an example of such code at this question, which illustrates how to return an image file. Just return your pdf instead of the image file, and use application/pdf as the MIME type.

Answer 2

If you want to restrict all access to the /files directory you could simply use a location element in your web.config to restrict access.

E.g.

<location path="~/files">
  <system.web>
    <authorization>
      <deny users="?" />
    </authorization>
  </system.web>
</location>

I should add that I agree with Robert and Rob for advanced security, but if you just want a simple solution this should do the trick. :-)

HTHs,
Charles