This article has cheat sheets for retrieving various bits of ASP.NET runtime information. For each bit of info, there is:

  • A code snippet for retrieving it in a page, with a link to MSDN
  • Description, sometimes explanation
  • The value for the live ASP.NET app backing this site The values are static right now. They were obtained from a request to http://minuteman.duartes.org/gustavo/articles/Asp.net-Runtime-Cheat-Sheet-HttpRequest-HttpRuntime.aspx?param1=foo&param2=bar

The code for the ASP.NET user control that generates the cheat sheets is in AspNetRuntimeDiagnostics.ascx.

HttpRequest information

HttpRequest.LogonUserIdentity and Process

When troubleshooting ASP.NET problems you often ask two questions: which process is the code running in?; and which Windows user is it running as? The default setups are thus:

Windows + IIS Worker Process ASP.NET threads
Vista + IIS 7.0 w3wp.exe running as NETWORK SERVICE, one per application pool IUSR, well-known account with SID S-1-5-17, see this post
Windows 2003 + IIS 6.0 w3wp.exe running as NETWORK SERVICE, one per application pool IUSR_MACHINE_NAME, per-machine anonymous IIS user
Windows 2000/XP + IIS 5.0 aspnet_wp.exe, one for all ASP.NET applications ASPNET, per-machine ASP.NET worker account

These defaults however are subject to many factors, so often you need to find the answers yourself. The cheat sheet below shows you the relevant classes and properties to use. ProcessMonitor is a great tool for troubleshooting Windows runtime problems, especially permission and access denied issues. If you wish to read up on security and .NET, see Keith Brown's superb online book, The .NET Developer's Guide to Windows Security.

HttpRequest.LogonUserIdentity And Process
C# Page snippet + description Value

Process.GetCurrentProcess().MainModule.FileName

GetCurrentProcess() has security demands and may not be available in certain situations. One work-around is to use Environment.GetCommandLineArgs()[0] to at least get the file name		 c:\windows\system32\inetsrv\w3wp.exe

Process.GetCurrentProcess().Id

The Windows process ID for the process running your code. This is the process you attach to for debugging, watch for perf monitoring, and kill to restart your app 'cold'.		 3008

Process.GetCurrentProcess().MainModule.FileVersionInfo

 File: c:\windows\system32\inetsrv\w3wp.exe
File version: 6.0.3790.3959 (srv03_sp2_rtm.070216-1710)
FileDescription: IIS Worker Process
Product: Internet Information Services

Process.GetCurrentProcess().StartTime

 12/24/2008 3:09:55 AM

this.Request.LogonUserIdentity.AuthenticationType

this.Request.LogonUserIdentity.Groups

These are the Windows groups which contain the user running your ASP.NET code.		 MINUTEMAN\None
Everyone
BUILTIN\Guests
BUILTIN\Users
NT AUTHORITY\NETWORK
NT AUTHORITY\Authenticated Users
NT AUTHORITY\This Organization
NT AUTHORITY\NTLM Authentication

this.Request.LogonUserIdentity.Name

This is the Windows user running your ASP.NET code. This user should be granted the permissions needed by your application.		 MINUTEMAN\IUSR_MINUTEMAN

this.Request.LogonUserIdentity.ImpersonationLevel

This is 'Impersonation' if the thread running your code is impersonating a Windows user, otherwise it's 'None'. In IIS 6 and 7, this is normally 'Impersonation' because the ASP.NET threads run under a different user than the IIS worker process.		 Impersonation

this.Request.LogonUserIdentity.IsAnonymous

 False

this.Request.LogonUserIdentity.IsSystem

True if your code is running as Local System. This should never be the case.		 False

this.Request.LogonUserIdentity.User.Value

The SID for the account.		 S-1-5-21-433945606-595587905-2999028010-1013

Paths

Path names in ASP.NET may be confusing, but the concepts are simple:

  • Physical paths refer to the server's filesystem (e.g., c:\inetpub\wwwroot\index.aspx).
  • Virtual paths refer to HTTP paths, the stuff in the browser address bar. They come in two types: absolute and relative.
  • Absolute virtual paths are exactly what you see in the browser, starting with the / after the host name (e.g., /gustavo/articles).
  • Relative (or app-relative) virtual paths start with ~/. The ~/ is magic and always represents the root virtual path of your application. So for an IIS application deployed at /bunny/love/ ASP.NET transforms ~/ into /bunny/love/. If the app is deployed to the IIS root (/), then ~/ simply becomes /.

There are two useful ASP.NET tools to manipulate paths. The HttpServerUtility.MapPath method converts a virtual path to a physical path. The VirtualPathUtility class has several methods for manipulating virtual paths.

HttpRequest and Page Paths
C# Page snippet + description Value

this.Request.ApplicationPath

Gets the IIS root virtual path for your ASP.net application. ASP.NET transforms ~/ into this value when making an absolute virtual path.		 /

this.Request.AppRelativeCurrentExecutionFilePath

Returns the app-relative virtual path for the HttpHandler currently executing, normally your page. Equivalent to this.Page.AppRelativeVirtualPath		 ~/gustavo/articles/Asp.net-Runtime-Cheat-Sheet-HttpRequest-HttpRuntime.aspx

this.Request.CurrentExecutionFilePath

Returns the absolute virtual path for the HttpHandler currently executing, normally your page.		 /gustavo/articles/Asp.net-Runtime-Cheat-Sheet-HttpRequest-HttpRuntime.aspx

this.Request.PhysicalApplicationPath

The root of your application in the server's file system.		 c:\inetpub\wwwroot\Duartes\

this.Request.PhysicalPath

The file system location for the HttpHandler currently executing, normally your page.		 c:\inetpub\wwwroot\Duartes\gustavo\articles\Asp.net-Runtime-Cheat-Sheet-HttpRequest-HttpRuntime.aspx

this.Page.TemplateSourceDirectory

 /gustavo/articles

Click here for an example where the ApplicationPath is not /.

Request.Url

C# Page snippet + description Value

this.Request.Url.AbsolutePath

 /gustavo/articles/Asp.net-Runtime-Cheat-Sheet-HttpRequest-HttpRuntime.aspx

this.Request.Url.AbsoluteUri

 http://minuteman.duartes.org/gustavo/articles/Asp.net-Runtime-Cheat-Sheet-HttpRequest-HttpRuntime.aspx?param1=foo&param2=bar

this.Request.Url.Authority

 minuteman.duartes.org

this.Request.Url.DnsSafeHost

 minuteman.duartes.org

this.Request.Url.Fragment

this.Request.Url.Host

 minuteman.duartes.org

this.Request.Url.HostNameType

 Dns

this.Request.Url.LocalPath

 /gustavo/articles/Asp.net-Runtime-Cheat-Sheet-HttpRequest-HttpRuntime.aspx

this.Request.Url.OriginalString

 http://minuteman.duartes.org:80/gustavo/articles/Asp.net-Runtime-Cheat-Sheet-HttpRequest-HttpRuntime.aspx?param1=foo&param2=bar

this.Request.Url.PathAndQuery

 /gustavo/articles/Asp.net-Runtime-Cheat-Sheet-HttpRequest-HttpRuntime.aspx?param1=foo&param2=bar

this.Request.Url.Port

 80

this.Request.Url.Query

 ?param1=foo&param2=bar

this.Request.Url.Scheme

 http

this.Request.Url.Segments

 [0]: /
[1]: gustavo/
[2]: articles/
[3]: Asp.net-Runtime-Cheat-Sheet-HttpRequest-HttpRuntime.aspx

this.Request.Url.UserInfo

Information from the HTTP request headers

C# Page snippet + description Value

this.Request.AnonymousID

Used with ASP.NET anonymous profiles.		 null

this.Request.ContentLength

Length in bytes for the BODY in the client's request. For a GET request, this is normally zero as there is no body. For a POST request it depends on how much data is sent to the server.		 0

this.Request.TotalBytes

This is usually equal to ContentLength, but it could be slightly different depending on how the client encoded its HTTP request.		 0

this.Request.UrlReferrer

The URL that sent the user your way. Bless them.		 null

this.Request.UserAgent

The client's browser.		 Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.0.5) Gecko/2008120122 Firefox/3.0.5

this.Request.UserHostAddress

 10.1.10.150

this.Request.UserHostName

 10.1.10.150

this.Request.UserLanguages

User-configured language preferences sent by the browser. You might tune your content based on this.		 [0]: en-us
[1]: en;q=0.5

Environment

C# Page snippet + description Value

Environment.OSVersion

 Microsoft Windows NT 5.2.3790 Service Pack 2

Environment.WorkingSet

Amount of physical memory used by the ASP.net worker process		 149577728

Thread.CurrentThread.CurrentCulture

Used by string formatting and other culture-sensitive methods.		 en-US

Thread.CurrentThread.CurrentUICulture

Used by the ResourceManager to load culture-specific resources like strings and images .		 en-US

Environment.UserDomainName

 NT AUTHORITY

Environment.UserName

Do not trust this value. Stick to HttpRequest.LogonUserIdentity		 NETWORK SERVICE

Environment.Version

.NET Framework version. This returns '2.0' even for assemblies compiled as .NET 3.5.		 2.0.50727.1433

HttpContext

C# Page snippet + description Value

HttpContext.Current.SkipAuthorization

 False

HttpContext.Current.User.Identity.AuthenticationType

HttpContext.Current.User.Identity.IsAuthenticated

 False

HttpContext.Current.User.Identity.Name

HttpContext.Current.Timestamp

 12/24/2008 3:57:45 AM

HttpRuntime and AppDomain

Your ASP.NET code runs inside a .NET AppDomain, which in turn runs inside a Windows process. The IIS version and configurations determine where your AppDomain will run. IIS 6 and 7 by default run AppDomains in a Worker Process called w3wp.exe. There is one worker process for each IIS application pool. Inside the Worker Process, there is one AppDomain for each application in the pool. Here are some useful tidbits on the current AppDomain and process:

C# Page snippet + description Value

AppDomain.CurrentDomain.SetupInformation.ConfigurationFile

Configuration file for the current AppDomain. For ASP.net this is the web.config file.		 c:\inetpub\wwwroot\Duartes\web.config

HttpRuntime.AppDomainAppId

The /LM/W3SVC part is fixed for a given IIS instance. The following number is the Site ID within IIS. The last piece is the IIS root virtual path for the application (or 'ROOT' for /).		 /LM/W3SVC/1/ROOT

HttpRuntime.AppDomainAppPath

The filesystem folder containing your application. Equivalent to AppDomain.CurrentDomain.BaseDirectory		 c:\inetpub\wwwroot\Duartes\

HttpRuntime.AppDomainAppVirtualPath

 /

HttpRuntime.AppDomainId

Equivalent to AppDomain.CurrentDomain.FriendlyName		 /LM/W3SVC/1/ROOT-1-128745617956562500

HttpRuntime.AspClientScriptPhysicalPath

 C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\asp.netclientfiles

HttpRuntime.AspClientScriptVirtualPath

 /aspnet_client/system_web/2_0_50727

HttpRuntime.AspInstallDirectory

 C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\

HttpRuntime.BinDirectory

Equivalent to AppDomain.CurrentDomain.RelativeSearchPath		 c:\inetpub\wwwroot\Duartes\bin\

HttpRuntime.ClrInstallDirectory

 C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\

HttpRuntime.CodegenDir

This is where ASP.NET stores generated source files for your pages, controls, etc. Watch this folder to see what a processed page becomes. Pages are compiled to DLLs which are also stored here. Equivalent to AppDomain.CurrentDomain.DynamicDirectory		 C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\1943e657\37080f43

HttpRuntime.MachineConfigurationDirectory

 C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Config

Loaded Assemblies

.NET code is packaged into .NET assemblies. It is often important to know which assemblies are loaded into your ASP.NET AppDomain because many problems boil down to missing or incorrect assemblies. The method AppDomain.CurrentDomain.GetAssemblies returns a list of assemblies loaded in your AppDomain (it requires full trust). Here's the output for the current domain:

Count of loaded assemblies: 27

Assemblies

C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\mscorlib.dll

mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089

C:\WINDOWS\assembly\GAC_32\System.Web\2.0.0.0__b03f5f7f11d50a3a\System.Web.dll

System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a

C:\WINDOWS\assembly\GAC_MSIL\System\2.0.0.0__b77a5c561934e089\System.dll

System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089

C:\WINDOWS\assembly\GAC_MSIL\System.Configuration\2.0.0.0__b03f5f7f11d50a3a\System.Configuration.dll

System.Configuration, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a

C:\WINDOWS\assembly\GAC_MSIL\System.Xml\2.0.0.0__b77a5c561934e089\System.Xml.dll

System.Xml, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089

C:\WINDOWS\assembly\GAC_MSIL\Microsoft.JScript\8.0.0.0__b03f5f7f11d50a3a\Microsoft.JScript.dll

Microsoft.JScript, Version=8.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a

C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\1943e657\37080f43\App_global.asax.2xsiz5uk.dll

App_global.asax.2xsiz5uk, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null

C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\1943e657\37080f43\assembly\dl3\b59cf41d\50132709_c073c801\WebSite.DLL

WebSite, Version=0.1.802.2002, Culture=neutral, PublicKeyToken=null

C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\1943e657\37080f43\assembly\dl3\e477bdd8\14e5df28_726cc801\Common.Helpers.DLL

Common.Helpers, Version=0.1.0.0, Culture=neutral, PublicKeyToken=null

C:\WINDOWS\assembly\GAC_MSIL\System.Web.Mobile\2.0.0.0__b03f5f7f11d50a3a\System.Web.Mobile.dll

System.Web.Mobile, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a

C:\WINDOWS\assembly\GAC_MSIL\System.ServiceModel\3.0.0.0__b77a5c561934e089\System.ServiceModel.dll

System.ServiceModel, Version=3.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089

C:\WINDOWS\assembly\GAC_MSIL\System.Web.Extensions\3.5.0.0__31bf3856ad364e35\System.Web.Extensions.dll

System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35

C:\WINDOWS\assembly\GAC_MSIL\System.Core\3.5.0.0__b77a5c561934e089\System.Core.dll

System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089

C:\WINDOWS\assembly\GAC_32\System.Data\2.0.0.0__b77a5c561934e089\System.Data.dll

System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089

C:\WINDOWS\assembly\GAC_32\System.Transactions\2.0.0.0__b77a5c561934e089\System.Transactions.dll

System.Transactions, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089

C:\WINDOWS\assembly\GAC_32\System.EnterpriseServices\2.0.0.0__b03f5f7f11d50a3a\System.EnterpriseServices.dll

System.EnterpriseServices, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a

C:\WINDOWS\assembly\GAC_MSIL\SMDiagnostics\3.0.0.0__b77a5c561934e089\SMDiagnostics.dll

SMDiagnostics, Version=3.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089

C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\1943e657\37080f43\App_Web_ghr_5vya.dll

App_Web_ghr_5vya, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null

C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\1943e657\37080f43\App_Web_z-opz3of.dll

App_Web_z-opz3of, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null

C:\WINDOWS\assembly\GAC_MSIL\System.Web.RegularExpressions\2.0.0.0__b03f5f7f11d50a3a\System.Web.RegularExpressions.dll

System.Web.RegularExpressions, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a

C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\1943e657\37080f43\App_Web_jzwzgh0y.dll

App_Web_jzwzgh0y, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null

C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\1943e657\37080f43\App_Web_goxujwqv.dll

App_Web_goxujwqv, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null

C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\1943e657\37080f43\assembly\dl3\c0be40b0\30f22d7a_a06bc801\Iris.DLL

Iris, Version=0.1.712.1401, Culture=neutral, PublicKeyToken=null

C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\1943e657\37080f43\App_Web_l1fsy2rr.dll

App_Web_l1fsy2rr, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null

C:\WINDOWS\assembly\GAC_MSIL\System.Drawing\2.0.0.0__b03f5f7f11d50a3a\System.Drawing.dll

System.Drawing, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a

C:\WINDOWS\assembly\GAC_MSIL\System.Data.Linq\3.5.0.0__b77a5c561934e089\System.Data.Linq.dll

System.Data.Linq, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089

C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\1943e657\37080f43\assembly\dl3\740e21a0\8a54307a_a06bc801\Newtonsoft.Json.DLL

Newtonsoft.Json, Version=1.3.0.0, Culture=neutral, PublicKeyToken=null