webbrowser.open (and two aliases):

1. document return value, which seems to be: True if a browser tab or window is opened, regardless of whether or not the url is found; False otherwise.

2. document that (on Windows, at least) the default browser only gets used if a non .htm(l) url starts with 'www' or 'http:'.

This is true because os.startfile(url) apparently only works if above is true, as required for the Start/Run box to recognize an entry as a url.

In particular, I have Firefox as default and 'www.google.com' and 'http://bugs.python.org' get opened in Firefox (new tab as requested). However, 'google.com' and 'bugs.python.org' open with IE after some delay. [Start/run either opens with Firefox or reports 'cannot find'.]
-----

In the longer run, what I would really like is for webbrowser to be better at using the default or finding executables.

I thought of adding 'http://' if not present but that would disable opening files in a file browser.

I suspect there is a registry entry but do not know what it is. That would also pick up new browswers like Chrome.

It seems to me that the current behavior is a 'limitation' in this code:

    # Detect some common Windows browsers, fallback to IE
    iexplore = os.path.join(os.environ.get("PROGRAMFILES", "C:\\Program Files"),
                            "Internet Explorer\\IEXPLORE.EXE")
    for browser in ("firefox", "firebird", "seamonkey", "mozilla",
                    "netscape", "opera", iexplore):
        if _iscommand(browser):
            register(browser, None, BackgroundBrowser(browser))

Firefox is not being recognized as a command because _iscommand('firefox') does not not see firefox.exe as an executable because it only checks _isexecutable() in the hodgepodge list of paths in PATH. At one time (but no longer), executables were ofter put in c:/windows, which by default is in PATH.

Since you hardcoded the default real path for iexplore (C:\\Program Files\\"Internet Explorer\\IEXPLORE.EXE"), you could do the same for other programs: 

firefox = os.path.join(os.environ.get("PROGRAMFILES", "C:\\Program Files"), "Mozilla Firefox\\firefox.exe")

> I thought of adding 'http://' if not present but that would disable opening files in a file browser.

I think that’s a Windows-specific behavior, not a promise of the *web*browser module.

On Wed, Jan 12, 2011 at 12:23:31AM +0000, Éric Araujo wrote:
> > I thought of adding 'http://' if not present but that would
> > disable opening files in a file browser.
> 
> I think that’s a Windows-specific behavior, not a promise of the
> *web*browser module.

If being lenient with URLs which do not start with http:// is the
idea, then webbrowser module can do explicitly add that. Having a
default protocol option in the open method and we can set it to
'http'.  Many WWW browsers do that.

But, I agree that it should not be related to Windows file-browser
behavior (for whatever it's behavior is).

Upon further experimentation, I realize that I can only open in Firefox because I have it set as my default browser. It would otherwise be inaccessible because it is not in the _browser registry. It also appears that I cannot intentionally use Internet Explorer because it also in not registered (except under the full path names used as a backup).

>>> webbrowser._browsers
{'windows-default': [<class 'webbrowser.WindowsDefault'>, None], 'c:\\program files\\internet explorer\\iexplore.exe': [None, <webbrowser.BackgroundBrowser object at 0x01000ED0>]}

If I understand the Windows code quoted before, the Class Names in the table would be different (BackgroundBrowser) on Windows if it did work.

Related issues
#8232 webbrowser.open incomplete on Windows
#8936 webbrowser regression on windows
#12237 Document how to open non-default webbrowser