Turning off ASP.Net WebForms authentication for one sub-directory

Question

I have a large enterprise application containing both WebForms and MVC pages. It has existing authentication and authorisation settings that I don't want to change.

The WebForms authentication is configured in the web.config:

 <authentication mode="Forms">
  <forms blah... blah... blah />
 </authentication>

 <authorization>
  <deny users="?" />
 </authorization>

Fairly standard so far. I have a REST service that is part of this big application and I want to use HTTP authentication instead for this one service.

So, when a user attempts to get JSON data from the REST service it returns an HTTP 401 status and a WWW-Authenticate header. If they respond with a correctly formed HTTP Authorization response it lets them in.

The problem is that WebForms overrides this at a low level - if you return 401 (Unauthorised) it overrides that with a 302 (redirection to login page). That's fine in the browser but useless for a REST service.

I want to turn off the authentication setting in the web.config, overriding the 'rest' folder:

 <location path="rest">
  <system.web>
   <authentication mode="None" />
   <authorization><allow users="?" /></authorization>
  </system.web>
 </location>

The authorisation bit works fine, but the authentication line (<authentication mode="None" />) causes an exception:

It is an error to use a section registered as allowDefinition='MachineToApplication' beyond application level.

I'm configuring this at application level though - it's in the root web.config - and that error is for web.configs in sub-directories.

How do I override the authentication so that all of the rest of the site uses WebForms authentication and this one directory uses none?

This is similar to another question: 401 response code for json requests with ASP.NET MVC, but I'm not looking for the same solution - I don't want to just remove the WebForms authentication and add new custom code globally, there's far to much risk and work involved. I want to change just the one directory in configuration.

Update

I want to set up a single web application and in that I want all the WebForms pages and MVC views to use WebForms authentication. I want one directory to use basic HTTP authentication.

Note that I'm talking about authentication, not authorisation. I want REST calls to come with the username & password in an HTTP header, and I want WebForm & MVC pages to come with the authentication cookie from .Net - in either case authorisation is done against our DB.

I don't want to rewrite WebForms authentication and roll my own cookies - it seems ridiculous that is the only way to add an HTTP authorised REST service to an application.

I can't add an additional application or virtual directory - it's got to be as one application.

Answer 1

If "rest" is simply a folder in your root you are almost there: remove authentication line i.e.

<location path="rest">
  <system.web>
      <authorization>
        <allow users="*" />
      </authorization>
  </system.web>
 </location>

Alternatively you can add a web.config to your rest folder and just have this:

<system.web>
     <authorization>
          <allow users="*" />
     </authorization>
</system.web>

Check this one.