About WinSys

The Windows API offers the would-be system administrator a plethora of low-level tools to secure files, log changes, investigate problems and do whatever else might be needed to a Windows system. The pywin32 extensions for Windows offer an enormous amount of that functionality to the Python user. And the builtin ctypes library allows you to fill in the gaps.

But it’s all quite low-level and the examples are mostly in C. And all you want to do is take ownership of a bunch of files, move them to an archive area and compress them there. And you want to do that for the home folder of every user who’s left the company. And you want to do that every Sunday morning.

Enter WinSys: the Python Windows Administrator’s Toolkit. A collection of modules with a consistent approach, wrapping the Windows API calls already exposed by pywin32, adding some with ctypes, and giving them all a pythonic feel. There’s nothing here you couldn’t do yourself with 10 minutes and a copy of the pywin32 and SDK docs. But it’s all here already, and with a more Pythonish feel about it.

Design Principles

The following principles have directed the design of the modules and packages wherever possible:

  • Make ad-hoc use possible and easy (and even attractive)
  • Provide sensible defaults for the common cases, always allowing for more complex scenarios
  • Put all constants into one place, grouping them according to their API usage
  • Use the pywin32 functionality where available, supplementing it with ctypes where needed
  • Assume a recent version of Python (2.5 at least)
  • Make good use of context managers (with-statements)
  • Have each object able to dump its contents and that of its children cleanly
  • Maintain an object approach, but provide convenient module-level functions
  • Have useful factory functions for classes, robustly accepting string or object parameters

Common Features

Most of the objects in winsys subclass the core._WinSysObject class which offers sensible defaults and defines common functionality such as a dump function. In addition, the following features are common to many of the modules:

Pythonic Naming

This is mildly contentious, but the same naming convention has been used throughout, following the lowercase_with_underscores convention widely adopted in the Python community. The most widespread exception to this is in the constants module, where Windows constants retain their UPPERCASE_WITH_UNDERSCORES names.

Module-level Functions

While a lot of use has been made of Python classes to wrap the function-driven Windows API, a lot of the functionality has been exposed as module-level convenience functions. So, for example, in the fs module, the fs.File class offers a fs.File.copy() method, but the same functionality is exposed at the module level as fs.copy(). That way, you don’t have to instantiate one or more objects simply for the purpose of a single operation.

Factory Functions

Most of the classes have a corresponding factory function (usually with the same name in lower case) which tries to be more accepting in what its parameters are and to convert them to what’s needed by the class’s own __init__ method. So, for example, the Principal class whose initialiser expects a PySID structure has a corresponding principal() function which will take a Sid or a user or group name or None or an existing Principal object.


Each object derived from core._WinSysObject has a dump method which is intended to display its internal structures, possibly recursively where some of the structures are themselves WinSys objects. This is intended more for ad-hoc use in the interpreter where it’s convenient to see, eg, the security structure which has been loaded from a file.

Iterators & Generators

Where possible and meaningful, lazy iterators have been used, often implemented by generators. This started in the fs module where thousands of files were being queried for information, but the approach has generally been adopted across the package.

Context Managers

Where it makes sense, context managers have been used, either by means of the contextlib contextmanager decorator or by defining an object as its own context manager by means of __enter__ and __exit__ methods. Examples of context-managed objects include the ipc.Mailslot and security.Security objects. Examples of decorated functions include the security.change_privileges() and security.impersonate() functions.


Obviously, there’s loads to do. The Windows API is vast; even the amount of it exposed by pywin32 far exceeds my immediate needs and the time at my disposal. The implementation of this package has been driven largely by the very specific needs of our Windows sysadmins in their day-to-day work. My intention is to carry on wrapping Windows functionality in a similar way, but if anyone has particular needs, or can provide functionality to add in, let’s hear about it.