Configuring Internet Information Services (part 4)

Working with Virtual Directories

A common requirement within Web sites is to include content from folders that are located outside of the Web site’s primary folder structure. For example, multiple Web sites that share the same set of images might need to access a pointer to a single path from which they can all access files. Virtual directories are designed to provide this capability. Virtual directories can be created at either the level of a Web site or within a specific Web application. They include an alias name (which will be used in the requesting URL) and point to a physical file system location path.

Creating a Virtual Directory

The process of creating a virtual directory is similar to that of creating a Web application. In IIS Manager, right-click the appropriate parent Web site or Web application and then select Add Virtual Directory. You will be able to provide an alias for the virtual directory (such as Images), along with security credentials and the physical path to the virtual directory. When a request is received for this alias, IIS will look in the appropriate file system location automatically for the requested content.

Comparing Virtual Directories and Web Applications

Although the settings for a virtual directory are similar to those of a Web application, there are some differences in their usage. Web Applications are generally designed to support executable Web code such as applications built using ASP.NET. They run within an isolated process space, using WAS. The reliance on WAS also enables Web applications to respond using protocols other than HTTP and HTTPS (assuming that other protocols have been installed and configured on the local server).

Virtual directories, on the other hand, are primarily used to point to static content that is stored in an alternate file system location. Both Web applications and virtual directories form a portion of the complete URL that is used to access a Web site. They can also both be nested to provide access to multiple levels of site content. The more appropriate choice will be based on the requirements of the Web application that you plan to support.

Using Command-Line Management

Performing simple administrator tasks on a few IIS servers is a relatively simple process, using the IIS Manager console. However, when you want to commit the same changes on many different servers, or you want to automate the configuration process by using scripting, command-line utilities can make these tasks more efficient. IIS includes an executable command, AppCmd.exe, which provides a simple way for systems administrators to perform common operational tasks. The actual parameters are designed to map to the structure of IIS Web sites, Web applications, and virtual directories.

The AppCmd.exe file is located within the %SystemRoot%\System32\Inetsrv folder. You can get initial help for the utility by running the command with the -/? switch. (See Figure 18.) You can use the same switch to get additional details about other commands. The general syntax for the command is:

AppCmd.exe Command Object "ObjectName" /parameter:value

Figure 18. Viewing help for the AppCmd.exe utility

Understanding Command Options

AppCmd has been designed to use a simple set of six commands for performing tasks on objects. The list of commands includes:

• List Returns information about the specified object.

• Add Creates a new object of the type that is specified. Details can be added, using parameters and values.

• Delete Deletes the specified object (such as a Web site or Web application).

• Set Changes settings for the object, as specified by the parameters and values.

• Start / Stop Available for objects that support these actions (such as a Web site).

If you want to perform multiple operations (either from a script file or from the command line), you will need to call AppCmd.exe for each operation. This helps keep the syntax of the statements simple and easy to read.

Understanding Objects

In a standard AppCmd statement, you will need to provide an object type and the name of the object that you plan to use. The types of objects supported by AppCmd.exe include the following:

• App (Web Application)

• AppPool (Application Pool)

• Backup (Server configuration backups)

• Config (Server configuration information)

• Module

• Request

• Site (Web Site)

• Trace

• VDir (Virtual Directory)

• WP (Worker Process)

You can get more information about the parameters and values that apply to an object by typing -? after the command.

Appcmd site -?

Examples of Commands

The process of listing, creating, and managing IIS configuration settings by using AppCmd is generally fairly simple. Table 1 provides some examples of common commands and their purpose.

AppCmd add vdir /app.name:"Default Web Site/"
				/path:/Images /physicalPath:"C:\Inetpub\wwwroot\images"

Using Windows PowerShell

In addition to using the AppCmd utility, Web server administrators can use the command shell and scripting language, Microsoft Windows PowerShell. Windows Server 2008 includes Windows PowerShell as a feature, but it is not enabled by default. To enable Windows PowerShell, open Server Manager, right-click Features, and select Add Feature. Select the Windows PowerShell option, and then click Next to finish installing it. Once it has been installed, you can launch it from within the Windows PowerShell 1.0 program group in the Start menu. Windows PowerShell enables you to write and create powerful scripts for performing many common administration operations.

Automation Using .NET Framework

Many Web developers already have a significant amount of knowledge about working with the .NET Framework. Therefore, it can be helpful for them to manage IIS by using standard .NET code. IIS 7.0 provides two .NET namespaces that can be used to manage IIS configuration settings programmatically. They are:

• Microsoft.Web.Administration This namespace provides objects and methods that are useful for managing and changing Web server settings. It is focused primarily on performing configuration changes for an IIS Web server.

• Microsoft.Web.Management Although the default IIS Manager user interface has been designed to provide simple access to the majority of commonly used functionality, some environments might want to create their own management extensions for performing specific tasks. The Microsoft.Web.Management namespace includes objects and methods that enable developers to extend the user interface functionality of IIS management tools. These additions can then be configured to run in a standalone environment, or they can be integrated with the built-in IIS Manager utility for easy access.

Understanding how to write applications by using the .NET Framework is beyond the scope of Exam 70-643, but it can be helpful to know that these options are available for automating configuration and management tasks. Additional information about the namespaces mentioned here and others can be found at http://msdn2.microsoft.com/en-us/library/aa388745.aspx.