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IIS Samples - ISAPI DumpVars

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This sample demonstrates how to access IIS server variables from an ISAPI extension. Server variables provide such information as header values, the application's physical path, authentication information, client information, and so on.

warning Warning Header values should never be used to make important decisions in your code because header values can be fabricated by a malicious user.

important Important These samples are provided for educational purposes only. They are not intended to be used in a production environment, have not been tested in a production environment, and Microsoft does not provide technical support for them.

Sample Overview
Requirements
Location of the Source Code
Build and Install the Sample
Run the Sample
Sample Output
Helpdesk

Sample Overview

DumpVars.dll uses the ISAPI extension GetServerVariable callback function to display a list of a few select IIS server variables (supported on IIS versions 4.0 through 6.0). A complete list of server variables can be found in the IIS Software Developer Kit (SDK) under Server Variables.

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Requirements

This sample requires the installation of the following software to function properly:

  • Windows XP Professional with IIS 5.1 installed or Windows .NET Server with IIS 6.0 installed.
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Location of the Source Code

IIS samples are included in the IIS Software Developer Kit (SDK). You can download the IIS SDK from Platform SDK Update. You can view the SDK at MSDN Online. In the table of contents at MSDN Online, click Web Development, Server Technologies, Internet Information Services (IIS), SDK Documentation, Internet Information Services, Samples.

The following source code files are required for this sample:

File Description
DumpVars.sln DumpVars Visual Studio .NET solution file, required to build this sample in Visual Studio .NET.
DumpVars.vcproj DumpVars Visual Studio .NET C Project file, required to build this sample in Visual Studio .NET.
DumpVars.dsp, DumpVars.dsw DumpVars Visual Studio 6.0 project files, required to build this sample in Visual Studio Version 6.
DumpVars.cpp DumpVars source module containing the code that implements the sample.
DumpVars.def DumpVars.dll definition containing code for creating the sample.
MAKEFILE DumpVars makefile for command line compilation
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Build and Install the Sample

To build this sample using the Visual C++ IDE, the following steps must be performed:

  1. Open the solution (VS.NET) or desktop (VS6) file to open the project.
  2. Click Build to create the DLL.

To build and run this sample without using the Visual C++ IDE, the following steps must be performed:

  1. Type NMAKE All from the command line. For example, if your sample files are located in a folder called C:\MySamples, type the following at the command line: 
    cd /d c:\MySamples
NMAKE All

To install this sample, the following steps must be performed:

  1. Copy the DumpVars.dll to a physical folder on your computer. For example, create a folder called C:\Samples and copy the DumpVars.dll to that folder.
  2. Create a virtual directory that maps to the physical folder containing your files. To create a virtual directory, open the Internet Information Services (IIS) Manager by clicking Start, Run, type inetmgr in the text box and click OK. Right-click the Web site where you want to create a virtual directory, click New, and click Virtual Directory. In the Alias text box, type the name you want for your virtual directory, for example, DumpVars. In the Directory text box, type the path to the folder that contains your files.
  3. Configure strong security on your new virtual directory. Right-click the virtual directory name, click Properties, and click the Directory Security tab. Press F1 for tips on securing your virtual directory.
  4. Use Windows Explorer to set restricted access control on the sample .dll file in its physical folder. For more information, click Start, Help and Support, and search for Access Control.
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Run the Sample

In order to run this sample, follow the instructions listed below:

  1. Browse to your sample Web files in Internet Explorer (IE). For example, if your files are in a virtual directory called DumpVars, type https://localhost/DumpVars/DumpVars.dll in the Address bar of IE.
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Sample Output

After performing step 1 from Run the Sample, you should see a list of server variables starting with the following output.

  Server Variable Dump

  --------------------------------------------------------------------------------
  APPL_MD_PATH: /LM/W3SVC/1/ROOT
  APPL_PHYSICAL_PATH: d:\inetpub\wwwroot\
  AUTH_PASSWORD: 
  AUTH_TYPE:
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Help Desk

If here you do not find answers to your questions, visit the Microsoft Help and Support Web site.

Problem Possible Solution
When building the dll, C++ returns a permissions error. Once you have called the dll from your web page, your system considers it a loaded dll. You must unload it to build it again, either by unloading the ASP application or deleting the dll from system32\dllcache.
When browsing to the dll, IE gives you a permissions error. The folder and virtual directory must have Execute permissions set on them.
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