What's the perfect (OS independent) way of storing filepaths ?

[Stef Mientki]

hello,

I (again) wonder what's the perfect way to store, OS-independent,
filepaths ?
I can think of something like:
- use a relative path if drive is identical to the application (I'm
still a Windows guy)
- use some kind of OS-dependent translation table if on another drive
- use ? if on a network drive

I'm interested what you all use for this kind of problem.
And I wonder why there isn't a standard solution / library in Python
available.

thanks,
Stef Mientki

[drobinow]

On Oct 19, 8:35*am, Stef Mientki <stef.mien...@g mail.comwrote:

I (again) wonder what's the perfect way to store, OS-independent,
filepaths ?

I don't think there is any such thing. What problem are you trying to
solve?

[Steven D'Aprano]

On Sun, 19 Oct 2008 14:35:01 +0200, Stef Mientki wrote:

hello,

I (again) wonder what's the perfect way to store, OS-independent,
filepaths ?

"Perfect"? I can't imagine any scheme which will work on every imaginable
OS, past present and future.

However, in practice I think there are two common forms still in use:
Posix paths, and Windows paths. I believe that OS/2 can deal with Windows
pathnames, and Mac OS X uses Posix paths (I think...). If you have to
support Classic Mac OS or other non-Posix systems, then your life will
become interesting and complicated.

And let's not even consider Unicode issues...

You might find this page useful:
http://en.wikipedia.org/wiki/Path_(computing)

Note that raw strings are for regular expressions, not Windows paths. Raw
strings can't end in a backslash, so you can't do this:

r'C:\My Documents\'

Instead, you can avoid having to escape backslashes by taking advantage
of the fact that Windows will accept forward slashes as well as
backslashes as path separators, and write 'C:/My Documents/' instead.

I assume you're familiar with the path-manipulation utilities in os.path?

>>import os
os.path.split drive('C://My Documents/My File.txt')

('C:\\\\', 'My Documents\\My File.txt')

I had to fake the above output because I'm not running Windows, so excuse
me if I got it wrong.

But honestly, I think your biggest problem isn't finding a platform-
independent way of storing paths, but simply translating between each
OS's conventions on where files should be stored.

In Linux, config files should go into:

~/.<appname>/ or /etc/<appname>/

In Windows (which versions?) then should go into the Documents And
Settings folder, where ever that is.

There's no single string which can represent both of these conventions!

--
Steven

[Duncan Booth]

Steven D'Aprano <st***@REMOVE-THIS-cybersource.com .auwrote:

In Linux, config files should go into:

~/.<appname>/ or /etc/<appname>/

In Windows (which versions?) then should go into the Documents And
Settings folder, where ever that is.

There's no single string which can represent both of these conventions!

The first of those should do nicely for both Linux and Windows:

>>os.path.normp ath(os.path.exp anduser('~/.appname'))

'C:\\Documents and Settings\\Dunca n\\.appname'

[Duncan Booth]

Steven D'Aprano <st***@REMOVE-THIS-cybersource.com .auwrote:

>>>import os
os.path.spli tdrive('C://My Documents/My File.txt')

('C:\\\\', 'My Documents\\My File.txt')

I had to fake the above output because I'm not running Windows, so
excuse me if I got it wrong.

Not that it matters, but:

>>os.path.split drive('C://My Documents/My File.txt')

('C:', '//My Documents/My File.txt')

[Grant Edwards]

On 2008-10-19, Stef Mientki <st**********@g mail.comwrote:

I (again) wonder what's the perfect way to store, OS-independent,
filepaths ?

The question appears to me to be meaningless. File paths are
not OS independant, so an OS-independant way to store them
doesn't seem to be a useful thing to talk about.

--
Grant

[Eric Wertman]

>I (again) wonder what's the perfect way to store, OS-independent,

>filepaths ?

I'm in agreement that perfect probably isn't applicable. If I were
doing this myself, I might store the information in a tuple:

base = 'some root structure ('/' or 'C')
path = ['some','set','o f','path','name s']
filename = 'somefile.ext'

pathdata = (root,path,file name)

and write a couple of simple functions to reconstruct them based on the os.

[Stef Mientki]

Eric Wertman wrote:

>>I (again) wonder what's the perfect way to store, OS-independent,
filepaths ?

I'm in agreement that perfect probably isn't applicable. If I were
doing this myself, I might store the information in a tuple:

base = 'some root structure ('/' or 'C')
path = ['some','set','o f','path','name s']
filename = 'somefile.ext'

pathdata = (root,path,file name)

and write a couple of simple functions to reconstruct them based on the os.

Eric, I like your idea.
It looks like a workable technique,
the user should initial define the roots once and everything works.
It should even work for network drives and websites.

Duncan, in windows it's begin to become less common to store settings in
Docs&Settings,
because these directories are destroyed by roaming profiles (a big
reason why I can't run Picassa ;-(
It's more common to follow the portable apps approach, store them in the
application directory.

Drobinow, I want to distribute an application with a large number of
docs and examples.
Now for this application I can put everything in subpaths of the
main-application,
but you triggered me to put a warning in my code if I go outside the
application path.
Another application I've in mind, is a data manager (now written in Delpi),
in which I organize all my information: docs, websites, measurement data
etc.

Others, thank you for the ideas, you learende me some new os.path functions.

cheers,
Stef

--
http://mail.python.org/mailman/listinfo/python-list

[Aaron Brady]

Duncan Booth wrote:

Steven D'Aprano <st***@REMOVE-THIS-cybersource.com .auwrote:

>In Linux, config files should go into:

~/.<appname>/ or /etc/<appname>/

In Windows (which versions?) then should go into the Documents And
Settings folder, where ever that is.

There's no single string which can represent both of these conventions!

The first of those should do nicely for both Linux and Windows:

>>>os.path.norm path(os.path.ex panduser('~/.appname'))

'C:\\Documents and Settings\\Dunca n\\.appname'

A tuple of path elements, I would think.

>>a= ( 'c:', 'windows', 'system' )
a= ( '~', 'usr', 'bin' )
a= ( '..', 'src' )

You'll want a subclass too, which has a file for the last name, instead
of just folders.

>>a= ( 'c:', 'python', 'python.exe' )

If '..' and '~' aren't universally, recognized, you'll want special
flags.

>>DirUp= type( 'DirUp', (object,), { '__repr__': ( lambda self: 'DirUp' ) } )()
a= ( DirUp, 'src' )
a

(DirUp, 'src')

As for rendering them, 'win', 'unix', and 'mac' could be methods.

[Steven D'Aprano]

On Sun, 19 Oct 2008 15:40:32 +0000, Duncan Booth wrote:

Steven D'Aprano <st***@REMOVE-THIS-cybersource.com .auwrote:

>In Linux, config files should go into:

~/.<appname>/ or /etc/<appname>/

In Windows (which versions?) then should go into the Documents And
Settings folder, where ever that is.

There's no single string which can represent both of these conventions!

The first of those should do nicely for both Linux and Windows:

>>>os.path.norm path(os.path.ex panduser('~/.appname'))

'C:\\Documents and Settings\\Dunca n\\.appname'

Except Windows users will be wondering why they have a directory starting
with '.' in their home directory. Dot to make files hidden is not AFAIK
supported by Windows.

--
Steven