Issue #6856: Add a filter keyword argument to TarFile.add().

The filter argument must be a function that takes a TarInfo
object argument, changes it and returns it again. If the
function returns None the TarInfo object will be excluded
from the archive.
The exclude argument is deprecated from now on, because it
does something similar but is not as flexible.

1 files changed, 25 insertions, 2 deletions

diff --git a/Doc/library/tarfile.rst b/Doc/library/tarfile.rst
index 29968396e0..fa6cca7cc2 100644
--- a/Doc/library/tarfile.rst
+++ b/Doc/library/tarfile.rst
@@ -389,7 +389,7 @@ object, see :ref:`tarinfo-objects` for details.
       and :meth:`close`, and also supports iteration over its lines.
 
 
-.. method:: TarFile.add(name, arcname=None, recursive=True, exclude=None)
+.. method:: TarFile.add(name, arcname=None, recursive=True, exclude=None, filter=None)
 
    Add the file *name* to the archive. *name* may be any type of file (directory,
    fifo, symbolic link, etc.). If given, *arcname* specifies an alternative name
@@ -397,11 +397,22 @@ object, see :ref:`tarinfo-objects` for details.
    can be avoided by setting *recursive* to :const:`False`. If *exclude* is given
    it must be a function that takes one filename argument and returns a boolean
    value. Depending on this value the respective file is either excluded
-   (:const:`True`) or added (:const:`False`).
+   (:const:`True`) or added (:const:`False`). If *filter* is specified it must
+   be a function that takes a :class:`TarInfo` object argument and returns the
+   changed TarInfo object. If it instead returns :const:`None` the TarInfo
+   object will be excluded from the archive. See :ref:`tar-examples` for an
+   example.
 
    .. versionchanged:: 2.6
       Added the *exclude* parameter.
 
+   .. versionchanged:: 2.7
+      Added the *filter* parameter.
+
+   .. deprecated:: 2.7
+      The *exclude* parameter is deprecated, please use the *filter* parameter
+      instead.
+
 
 .. method:: TarFile.addfile(tarinfo, fileobj=None)
 
@@ -653,6 +664,18 @@ How to read a gzip compressed tar archive and display some member information::
            print "something else."
    tar.close()
 
+How to create an archive and reset the user information using the *filter*
+parameter in :meth:`TarFile.add`::
+
+    import tarfile
+    def reset(tarinfo):
+        tarinfo.uid = tarinfo.gid = 0
+        tarinfo.uname = tarinfo.gname = "root"
+        return tarinfo
+    tar = tarfile.open("sample.tar.gz", "w:gz")
+    tar.add("foo", filter=reset)
+    tar.close()
+
 
 .. _tar-formats: