[Python-Dev] urllib.browse() issues
Eric S. Raymond
Thu, 6 Jul 2000 12:21:22 -0400
Having finally wrestled CVS into at least temporary submission,
I'm in the process of generating a patch to add a browser-launcher
function to the standard library. There are a couple of issues
connected to this.
One: location. I still think, after meditating on it, that urllib and
not os is the right place for this. Yes, it launches a process -- but
that's implementation. It's a way to fetch the contents of an URL. In
the potential *user's* view of the Python library, it belongs with other
ways to fetch URLs.
Two: cross-platform capability is a Good Thing. I rummaged around after a
half-forgotten bit of lore in my files and discovered an allegation
that under Windows,
os.system("start %s" % url)
is supposed to launch your default browser on the specified URL. Now
here's what I'd like to write:
_browsers = string.split(os.environ["BROWSER"], ":")
elif os.name == 'posix':
_browsers = ["mozilla %s &",
"netscape -remote 'openURL(%s)'",
"netscape %s &",
"lynx %s &",
"w3m %s &"]
elif os.name == 'nt':
_browsers = ["start %s"]
"""Launch a browser, in background, pointed at the given URL.
Accept either a string or a parsed URL tuple.
Interpret the BROWSER environment variable, if it exists,
as a colon-separated list of browser commands to try.
from urlparse import urlunparse
if type(url) == ():
url = urlunparse(url)
for browser in _browsers:
if os.system((browser % url)) == 0:
The missing piece of implementation is the function iscommand(). I know
how to write this under Unix:
return os.system('which 1>/dev/null 2>&1 ' + cmd) == 0
So my question is this: is there any analogous way to check for the existence
of a command under Windows? If so...
Three: I'd like to add a cross-platform iscommand() function to os.
<a href="http://www.tuxedo.org/~esr">Eric S. Raymond</a>
There's a truism that the road to Hell is often paved with good intentions.
The corollary is that evil is best known not by its motives but by its