How to get a name of default browser using python

Question

My script runs a command every X seconds.

If a command is like "start www" -> opens a website in a default browser I want to be able to close the browser before next time the command gets executed.

This short part of a script below:

if "start www" in command:
    time.sleep(interval - 1)
    os.system("Taskkill /IM chrome.exe /F")

I want to be able to support firefox, ie, chrome and opera, and only close the browser that opened by URL.

For that I need to know which process to kill.

How can I use python to identify my os`s default browser in windows?

Answer 1

The solution is going to differ from OS to OS. On Windows, the default browser (i.e. the default handler for the http protocol) can be read from the registry at:

HKEY_CURRENT_USER\Software\Classes\http\shell\open\command\(Default)

Python has a module for dealing with the Windows registry, so you should be able to do:

from _winreg import HKEY_CURRENT_USER, OpenKey, QueryValue
# In Py3, this module is called winreg without the underscore

with OpenKey(HKEY_CURRENT_USER,
             r"Software\Classes\http\shell\open\command") as key:
    cmd = QueryValue(key, None)

You'll get back a command line string that has a %1 token in it where the URL to be opened should be inserted.

You should probably be using the subprocess module to handle launching the browser; you can retain the browser's process object and kill that exact instance of the browser instead of blindly killing all processes having the same executable name. If I already have my default browser open, I'm going to be pretty cheesed if you just kill it without warning. Of course, some browsers don't support multiple instances; the second instance just passes the URL to the existing process, so you may not be able to kill it anyway.