[Python-ideas] Symlink chain resolver module

[Giampaolo Rodola']

On 4 Dic, 20:06, "Guido van Rossum" <gu... at python.org> wrote:
> Isn't this pretty close to os.path.realpath()?
>
> On Dec 4, 2007 10:46 AM, Giampaolo Rodola' <gne... at gmail.com> wrote:
>
>
>
>
>
> > Hi there,
> > I thought it would have been good sharing this code I used in a
> > project of mine.
> > I thought it could eventually look good incorporated in Python stdlib
> > through os or os.path modules.
> > Otherwise I'm merely offering it as a community service to anyone who
> > might be interested.
>
> > -- Giampaolo
>
> > #!/usr/bin/env python
> > # linkchainresolver.py
>
> > import os, sys, errno
>
> > def resolvelinkchain(path):
> >     """Resolve a chain of symbolic links by returning the absolute
> > path
> >     name of the final target.
>
> >     Raise os.error exception in case of circular link.
> >     Do not raise exception if the symlink is broken (pointing to a
> >     non-existent path).
> >     Return a normalized absolutized version of the pathname if it is
> >     not a symbolic link.
>
> >     Examples:
>
> >     >>> resolvelinkchain('validlink')
> >     /abstarget
> >     >>> resolvelinkchain('brokenlink') # resolved anyway
> >     /abstarget
> >     >>> resolvelinkchain('circularlink')
> >     Traceback (most recent call last):
> >       File "<stdin>", line 1, in <module>
> >       File "module.py", line 19, in resolvelinkchain
> >         os.stat(path)
> >     OSError: [Errno 40] Too many levels of symbolic links: '3'
>
> >     """
> >     try:
> >         os.stat(path)
> >     except os.error, err:
> >         # do not raise exception in case of broken symlink;
> >         # we want to know the final target anyway
> >         if err.errno == errno.ENOENT:
> >             pass
> >         else:
> >             raise
> >     if not os.path.isabs(path):
> >         basedir = os.path.dirname(os.path.abspath(path))
> >     else:
> >         basedir = os.path.dirname(path)
> >     p = path
> >     while os.path.islink(p):
> >         p = os.readlink(p)
> >         if not os.path.isabs(p):
> >             p = os.path.join(basedir, p)
> >             basedir = os.path.dirname(p)
> >     return os.path.join(basedir, p)
> > _______________________________________________
> > Python-ideas mailing list
> > Python-id... at python.org
> >http://mail.python.org/mailman/listinfo/python-ideas
>
> --
> --Guido van Rossum (home page:http://www.python.org/~guido/)
> _______________________________________________
> Python-ideas mailing list
> Python-id... at python.orghttp://mail.python.org/mailman/listinfo/python-ideas- Nascondi testo tra virgolette -
>
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Are you trying to tell me that I've lost the whole evening when such a
thing was already available in os.path? :-)
Wait a moment. I'm going to check what os.path.realpath() does.