[Tutor] (Self resolved) os.spawn behaviorism issue

Sat Dec 11 05:08:56 CET 2004

Further note: widen the window, this has long strings in it ... and is
PURELY for edification.

To work around a problem between my ISP and my router, I have to make my
router RELogin the PPPoE every time the wan ip changes. Which is not hard,
it's a http string in a browser to log in, followed by a pause and a second
http string to make the magic internet return, and my DDNS client is very
good at telling when the internet ceases to work. While I am a relative code
noob, this with a sleep.py was hacked out in 30 minutes (after some
testing).

But being a perfectionist, I wanted to do it entirely in python.

<psudocode>
import os,time
os.spawn(os.P_NOWAIT,browser,[logincommand])
time.sleep(20)
os.spawn(os.P_NOWAIT,browser,[relogcommand])
exit
</psudocode>

I have been hacking at getting os.spawnv to do what I want it to, with no
luck.

The 'want' is a simple one, open a browser (in this case IE) to a given URL.

Like;
YOUR PROMPT HERE> "C:/Program Files/Internet Explorer/Iexplore.exe"
http://www.yahoo.com
Which functions as expected.

Even os.system('"C:\Program Files\Internet Explorer\Iexplore.exe"
http://www.yahoo.com')
Works, but waits for the browser to close to return, and I need an immediate
return.

Here are some things I've tried ...

# Yields: Just Opens IE Successfully As expected!
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
[])
# os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet Explorer/Iexplore.exe',
[])

# Yields: Invalid Argument - forward slash, full command string
# os.spawnv(os.P_NOWAIT,'"C:/Program Files/Internet Explorer/Iexplore.exe"
www.yahoo.com',[])
# os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet Explorer/Iexplore.exe
http://www.yahoo.com',[])
# os.spawnv(os.P_NOWAIT,'"C:/Program Files/Internet Explorer/Iexplore.exe"
http://www.yahoo.com',[])
# os.spawnv(os.P_NOWAIT,'"C:/Program Files/Internet Explorer/Iexplore.exe"
http:////www.yahoo.com',[])
# os.spawnv(os.P_NOWAIT,r'C:/Program Files/Internet Explorer/Iexplore.exe
http://www.yahoo.com',[])
# os.spawnv(os.P_NOWAIT,r'"C:/Program Files/Internet Explorer/Iexplore.exe"
http://www.yahoo.com',[])

# Yields: No such file or directory
# os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet Explorer/Iexplore.exe
www.yahoo.com',[])

# Yields: Opens IE Successfully - Yet No ARG Passed to browser
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
['www.yahoo.com'])
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
["www.yahoo.com"])
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
['"www.yahoo.com"'])
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
[r'www.yahoo.com'])
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
[r"www.yahoo.com"])
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
[r'"www.yahoo.com"'])
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
['"http://www.yahoo.com"'])
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
["http://www.yahoo.com"])
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
['http://www.yahoo.com'])
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
['"http:////www.yahoo.com"'])
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
["http:////www.yahoo.com"])
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
['http:////www.yahoo.com'])
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
[r'"http://www.yahoo.com"'])
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
[r"http://www.yahoo.com"])
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
[r'http://www.yahoo.com'])
# os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet Explorer/Iexplore.exe',
['www.yahoo.com'])
# os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet Explorer/Iexplore.exe',
["www.yahoo.com"])
# os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet Explorer/Iexplore.exe',
['"www.yahoo.com"'])
# os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet Explorer/Iexplore.exe',
[r'www.yahoo.com'])
# os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet Explorer/Iexplore.exe',
[r"www.yahoo.com"])
# os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet Explorer/Iexplore.exe',
[r'"www.yahoo.com"'])
# os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet Explorer/Iexplore.exe',
['"http://www.yahoo.com"'])
# os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet Explorer/Iexplore.exe',
["http://www.yahoo.com"])
# os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet Explorer/Iexplore.exe',
['http://www.yahoo.com'])
# os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet Explorer/Iexplore.exe',
['"http:////www.yahoo.com"'])
# os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet Explorer/Iexplore.exe',
["http:////www.yahoo.com"])
# os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet Explorer/Iexplore.exe',
['http:////www.yahoo.com'])
# os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet Explorer/Iexplore.exe',
[r'"http://www.yahoo.com"'])
# os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet Explorer/Iexplore.exe',
[r"http://www.yahoo.com"])
# os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet Explorer/Iexplore.exe',
[r'http://www.yahoo.com'])

The issue seems to be passing the [argument] to the program .. Even example
source I've found on the net has
Sorry about the widthspam, any suggestions?

--

AND as I always search after I've completely written my message, I found a
tip from Richard Chamberlain in July of 2000
http://mail.python.org/pipermail/tutor/2000-July/001759.html. Says the
path/file has to be in the list.

# Yields Browser with
'http://files/Internet%20Explorer/Iexplore.exe%20www.yahoo.com' string in
it.
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
["C:/Program Files/Internet Explorer/Iexplore.exe", 'www.yahoo.com'])

# same as above, But WHY can't it take long file names?
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
[r"C:/Program Files/Internet Explorer/Iexplore.exe", 'www.yahoo.com'])

# Yields Browser with 'http://explorer/Iexplore.exe%20www.yahoo.com'
# os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
["C:/Progra~1/Internet Explorer/Iexplore.exe", 'www.yahoo.com'])

# Finally! Yields browser with www.yahoo.com in it, but took 8.3 format in
the list.
os.spawnv(os.P_NOWAIT,"C:/Program Files/Internet Explorer/Iexplore.exe",
["C:/Progra~1/Intern~1/Iexplore.exe", 'www.yahoo.com'])

Man was this the most unpythonesque oddity I've seen in python.

Why in the world doesn't the
http://www.python.org/doc/2.4/lib/os-process.html state that the program
name is required twice? Ok, the example DOES show it, but that is it ...
it's left unsaid. AND it functions with an empty list if there are no
arguments ...

# Interesting guess it's just a syntaxism of os.spawnv
os.spawnv(os.P_NOWAIT,'C:/Program Files/Internet
Explorer/Iexplore.exe',['foob',r'http://www.yahoo.com'])

--

To sum it up;
<psudocode>
import os,time
os.spawn(os.P_NOWAIT,browser,["ignorethis",logincommand])
time.sleep(20)
os.spawn(os.P_NOWAIT,browser,["ignorethis",relogcommand])
</psudocode>

--

OT: Fun with spellchecker in this message;
RELogin = Religion
PPPoE = Pope
IP = imp
psucodoce = pseudopodia
sleep.py = sloppy
os,time = costume

--

Programmer's mantra; Observe, Brainstorm, Prototype, Repeat

David Broadwell