R – Calling WMPLib.mediaCollection methods from ASP.NET on IIS return empty lists

impersonationwmplib

I am trying to access a Windows Media Player library from ASP.NET.

The following code:

WMPLib.WindowsMediaPlayer mplayer = new WMPLib.WindowsMediaPlayer();

WMPLib.IWMPStringCollection list = mplayer.mediaCollection.getAttributeStringCollection("artist", "audio");

Returns an non-empty list when run using the VS2005 development web server but an empty list when using IIS.

Setting impersonation with:

System.Security.Principal.WindowsImpersonationContext impersonationContext = ((System.Security.Principal.WindowsIdentity)User.Identity).Impersonate();

Doesn't help. It seems that WMPLib still doesn't thinks its running as a user who has a library.

Is there a way to get around this?

Best Answer

Have you tried configuration via web.config in ASP.NET? When you're running in the VS2005 debugger, you're (probably) running code as yourself, but when under IIS you'll be running it as IUSR_machinename or another low-permission system account.

Try adding something like this to your web.config file:

<system.web>
<identity impersonate="true" userName="MYDOMAIN\myuser" password="p@ssw0rd" />
</system.web>

No idea whether this works with Media Player specifically, but it works for other identity/security related problems like this.

Related Solutions

C# – Impersonation in ASP.NET MVC

Impersonation allows machine to machine impersonation, so the client browser and the server are on the same page when it comes to the impersonation. When you then attempt to access the network share, the computer doesn't trust the impersonated credentials.

You need to enable delegation for the IIS machine in Active Directory. Go to Active Directory Users and Computers, find the computer, click properties, and 'Trust computer for delegation'. (You might need to restart IIS for this to work, I don't remember).

There is way more theory than this that I don't fully understand, but this should work. Whether it is right or not someone else could comment on!

Also, the reason it works on your development machine is that the development server runs as the developer, not (Local)\Network Service.

A decent link:

http://msdn.microsoft.com/en-us/library/cc949004.aspx

What is the difference between impersonation and delegation?

Impersonation flows the original caller’s identity to back-end resources on the same computer. Delegation flows the original caller’s identity to back-end resources on computers other than the computer running the service.

For example, if a service is running within IIS without impersonation, the service will access resources using the ASP.NET account in IIS 5.0, or the Network Service account in IIS 6.0. With impersonation, if the client is connecting using the original caller’s account, the service will access resources such as a SQL Server database on the same machine using the original caller’s account instead of the system ASP.NET account. Delegation is similar except that the SQL Server database could be on a different machine that is remote to the service.

ASP.NET impersonation problem (part 2)

I'm not sure if you've found an answer, but if anyone is having problems with it you will need the following in your web.config file

<authentication mode="Windows"/>
<identity impersonate="true"/>

And in IIS you will need Asp.net Impersonation enabled as well as Windows Authentication enabled, the others should be disabled. And in Windows Authentication, go to Advanced Settings and UNCHECK the Enable Kernel-mode authentication. That should do it. Your site should now be set for Local Intranet apps and using any of the following will work

System.Security.Principal.WindowsIdentity.GetCurrent().Username()
HttpContext.Current.User.Identity.Name
System.Threading.Thread.CurrentPrincipal.Identity.Name

But using Environment.Username will only return the server name, hopefully this helps anyone struggling with this

Best Answer

Related Solutions

C# – Impersonation in ASP.NET MVC

ASP.NET impersonation problem (part 2)

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