deleting from tarfile

[Uwe Mayer]

Hi,

is it possible to delete a file from a tar-archive using the tarfile module?

Thanks
Uwe

[Mark McEahern]

Re: deleting from tarfile

Uwe Mayer wrote:
[color=blue]
>Hi,
>
>is it possible to delete a file from a tar-archive using the tarfile module?
>
>Thanks
>Uwe
>
>[/color]
It doesn't appear so. A workaround, of course, is to create a new file
with the subset of files from the old file:

#!/usr/bin/env python

import tarfile
import os

def removeFile(file name, nameToDelete):
"""Remove nameToDelete from tarfile filename."""
prefix, ext = os.path.splitex t(filename)
newFilename = '%(prefix)s-modified%(ext)s ' % locals()
original = tarfile.open(fi lename)
modified = tarfile.open(ne wFilename, 'w')
for info in original.getmem bers():
if info.name == nameToDelete:
continue
extracted = original.extrac tfile(info)
if not extracted:
continue
modified.addfil e(info, extracted)
original.close( )
modified.close( )

// m

[Michael Hoffman]

Re: deleting from tarfile

Uwe Mayer wrote:[color=blue]
> is it possible to delete a file from a tar-archive using the tarfile module?[/color]

The tarlib.py in pyNMS claims to be able to do it. It doesn't use the
tarfile module, though.

http://cvs.sourceforge.net/viewcvs.py/pynms/pyNMS/lib/tarlib.py?rev=1.1.1.1&view=auto

--
Michael Hoffman

[Colin J. Williams]

The First International Conference on Open Source Systems - OSS 2005- Main

I haven't spotted a posting on c.l.p but someone here may be interested.

Colin W.

http://oss2005.case.unibz.it/

[Martin v. Löwis]

Re: deleting from tarfile

Mark McEahern wrote:[color=blue]
> It doesn't appear so. A workaround, of course, is to create a new file
> with the subset of files from the old file:[/color]

That is actually the *only* way to do that. tarfiles cannot be "sparse",
in the sense that parts of the file can be marked as deleted. So in
order to delete a file, you have to copy the entire tarfile, and skip
the file you want to delete - whether you do this yourself, or whether
tarfile.py does it for you.

Regards,
Martin

[Martin v. Löwis]

Re: deleting from tarfile

Mark McEahern wrote:[color=blue]
> It doesn't appear so. A workaround, of course, is to create a new file
> with the subset of files from the old file:[/color]

That is actually the *only* way to do that. tarfiles cannot be "sparse",
in the sense that parts of the file can be marked as deleted. So in
order to delete a file, you have to copy the entire tarfile, and skip
the file you want to delete - whether you do this yourself, or whether
tarfile.py does it for you.

Regards,
Martin