Edit

Scripting Helper Objects

  • Article

WMI has several scripting helper objects that supply the conversions required by scripts.

WMI scripting helper objects include:

The helper objects break down composite data structures so that a script is not required to parse the structure to obtain any of the pieces. For example, the WMI DATETIME structure cannot be displayed directly, and is different from other Windows datetime data structures, such as VT_DATE.

SWbemDateTime

The SWbemDateTime object provides properties that parse out the day, month, year, time of day, and so on. It also provides conversion methods to convert the Windows Management Instrumentation (WMI) datetime to and from the VT_Date and FILETIME formats. For Internet Explorer (IE) security settings, the SWbemDateTime object is the only WMI scripting object that is marked safe for initialization and safe for scripting. For more information and examples of date and time conversions, see Dates and Times in the TechNet ScriptCenter Script Repository, and the article on TechNet ScriptCenter It's About Time (Oh, and About Dates, too).

SWbemObjectPath

The properties of SWbemObjectPath supply the absolute path of an object, but also break out the parts of the WMI path, such as server, namespace, class, or relative path. The object allows you to set the security of the path, obtain the key values of the objects representing the path, determine if an object is a singleton, and so on. For more information about working with WMI object paths, see Describing the Location of a WMI Object.

Win32_SecurityDescriptorHelper

The Win32_SecurityDescriptorHelper class converts the security descriptor of a securable object from one format to another.

Many objects, such as printers, WMI namespaces, registry keys, or DCOM applications, have security descriptors that control access to the object. You can use WMI to discover or change who has access to these objects by getting or setting the security descriptor associated with the object.

However, different methods may obtain security descriptors in a binary byte array, Security Descriptor Definition Language (SDDL) format, or as an instance of Win32_SecurityDescriptor. The binary byte array form of a security descriptor should not be manipulated except by the C++ methods designed for Security Descriptor Operations. Descriptors in SDDL are in strings, but are still awkward to manipulate. The easiest format to manipulate is Win32_SecurityDescriptor, because it contains embedded objects for trustee, ACE, and SID. For more information about the structure of security descriptors in WMI, see WMI Security Descriptor Objects. For more information about how to do conversions, see Changing Access Security on Securable Objects.

Scripting in WMI