Reliably detect Windows in Python

Question

I'm working on a couple of Linux tools and need to prevent installation on Windows, since it depends on FHS and is thus rendered useless on that platform. The platform.platform function comes close but only returns a string. Unfortunately I don't know what to search for in that string for it to yield a reliable result. Does anyone know what to search for or does anyone know of another function that I'm missing here?

Answer 1

Try this:

import platform

if platform.system() == "Darwin":
    # Don't have Windows handy, but I'd expect "Win32" or "Windows" for it

Edit: Just saw that you tried platform.platform()...platform.system() will work better for this case. Trust me, use it. Dark corners lie in platform detection.

distutils will do this too, if you ask it nicely.

You could always do something bad like os.path.exists() on a Windows file...but platform is as reliable as it gets in the Python standard library.

Edit 2: Another helpful answerer pointed out platform.system() is exactly equal to "Windows" on his Windows machine.

Answer 2

On my Windows box, platform.system() returns 'Windows'.

However, I'm not sure why you'd bother. If you want to limit the platform it runs on technologically, I'd use a white-list rather than a black-list.

In fact, I wouldn't do it technologically at all since perhaps the next release of Python may have Win32/Win64 instead of Windows (for black-listing) and *nix instead of Linux (for white-listing).

My advice is to simply state what the requirements are and, if the user chooses to ignore that, that's their problem. If they ring up saying they got an error message stating "Cannot find FHS" and they admit they're running on Windows, gently point out to them that it's not a supported configuration.

Maybe your customers are smart enough to get FHS running under Windows so that your code will work. They're unlikely to appreciate what they would then consider an arbitrary limitation of your software.

This is a problem faced by software developers every day. Even huge organizations can't support every single platform and configuration out there.

Answer 3

>>> import platform
>>> platform.system()
'Windows'

Answer 4

From help(platform)

system()
    Returns the system/OS name, e.g. 'Linux', 'Windows' or 'Java'.

    An empty string is returned if the value cannot be determined.