| Archive::Tar - module for manipulations of tar archives |
Archive::Tar - module for manipulations of tar archives
use Archive::Tar;
my $tar = Archive::Tar->new;
$tar->read('origin.tgz',1);
$tar->extract();
$tar->add_files('file/foo.pl', 'docs/README');
$tar->add_data('file/baz.txt', 'This is the contents now');
$tar->rename('oldname', 'new/file/name');
$tar->write('files.tar');
Archive::Tar provides an object oriented mechanism for handling tar files. It provides class methods for quick and easy files handling while also allowing for the creation of tar file objects for custom manipulation. If you have the IO::Zlib module installed, Archive::Tar will also support compressed or gzipped tar files.
An object of class Archive::Tar represents a .tar(.gz) archive full of files and things.
Returns a new Tar object. If given any arguments, new() calls the
read() method automatically, passing on the arguments provided to
the read() method.
If new() is invoked with arguments and the read() method fails
for any reason, new() returns undef.
Read the given tar file into memory. The first argument can either be the name of a file or a reference to an already open filehandle (or an IO::Zlib object if it's compressed) The second argument indicates whether the file referenced by the first argument is compressed.
The read will replace any previous content in $tar!
The second argument may be considered optional if IO::Zlib is installed, since it will transparently Do The Right Thing. Archive::Tar will warn if you try to pass a compressed file if IO::Zlib is not available and simply return.
Note that you can currently not pass a gzip compressed
filehandle, which is not opened with IO::Zlib, nor a string
containing the full archive information (either compressed or
uncompressed). These are worth while features, but not currently
implemented. See the TODO section.
The third argument can be a hash reference with options. Note that all options are case-sensitive.
limit files. This is useful if you have
very big archives, and are only interested in the first few files.
extract_archive function.
Note however that entries will not be read into memory, but written
straight to disk.
All files are stored internally as Archive::Tar::File objects.
Please consult the the Archive::Tar::File manpage documentation for details.
Returns the number of files read in scalar context, and a list of
Archive::Tar::File objects in list context.
Check if the archive contains a certain file. It will return true if the file is in the archive, false otherwise.
Note however, that this function does an exact match using eq
on the full path. So it cannot compensate for case-insensitive file-
systems or compare 2 paths to see if they would point to the same
underlying file.
Write files whose names are equivalent to any of the names in
@filenames to disk, creating subdirectories as necessary. This
might not work too well under VMS.
Under MacPerl, the file's modification time will be converted to the
MacOS zero of time, and appropriate conversions will be done to the
path. However, the length of each element of the path is not
inspected to see whether it's longer than MacOS currently allows (32
characters).
If extract is called without a list of file names, the entire
contents of the archive are extracted.
Returns a list of filenames extracted.
Write an entry, whose name is equivalent to the file name provided to disk. Optionally takes a second parameter, which is the full native path (including filename) the entry will be written to.
For example:
$tar->extract_file( 'name/in/archive', 'name/i/want/to/give/it' );
$tar->extract_file( $at_file_object, 'name/i/want/to/give/it' );
Returns true on success, false on failure.
Returns a list of the names of all the files in the archive.
If list_files() is passed an array reference as its first argument
it returns a list of hash references containing the requested
properties of each file. The following list of properties is
supported: name, size, mtime (last modified date), mode, uid, gid,
linkname, uname, gname, devmajor, devminor, prefix.
Passing an array reference containing only one element, 'name', is
special cased to return a list of names rather than a list of hash
references, making it equivalent to calling list_files without
arguments.
Returns the Archive::Tar::File objects matching the filenames
provided. If no filename list was passed, all Archive::Tar::File
objects in the current Tar object are returned.
Please refer to the Archive::Tar::File documentation on how to
handle these objects.
Return the content of the named file.
Make the string $content be the content for the file named $file.
Rename the file of the in-memory archive to $new_name.
Note that you must specify a Unix path for $new_name, since per tar standard, all files in the archive must be Unix paths.
Returns true on success and false on failure.
Removes any entries with names matching any of the given filenames
from the in-memory archive. Returns a list of Archive::Tar::File
objects that remain.
clear clears the current in-memory archive. This effectively gives
you a 'blank' object, ready to be filled again. Note that clear
only has effect on the object, not the underlying tarfile.
Write the in-memory archive to disk. The first argument can either
be the name of a file or a reference to an already open filehandle (a
GLOB reference). If the second argument is true, the module will use
IO::Zlib to write the file in a compressed format. If IO::Zlib is
not available, the write method will fail and return.
Note that when you pass in a filehandle, the compression argument
is ignored, as all files are printed verbatim to your filehandle.
If you wish to enable compression with filehandles, use an
IO::Zlib filehandle instead.
Specific levels of compression can be chosen by passing the values 2 through 9 as the second parameter.
The third argument is an optional prefix. All files will be tucked away in the directory you specify as prefix. So if you have files 'a' and 'b' in your archive, and you specify 'foo' as prefix, they will be written to the archive as 'foo/a' and 'foo/b'.
If no arguments are given, write returns the entire formatted
archive as a string, which could be useful if you'd like to stuff the
archive into a socket or a pipe to gzip or something.
Takes a list of filenames and adds them to the in-memory archive.
The path to the file is automatically converted to a Unix like equivalent for use in the archive, and, if on MacOS, the file's modification time is converted from the MacOS epoch to the Unix epoch. So tar archives created on MacOS with Archive::Tar can be read both with tar on Unix and applications like suntar or Stuffit Expander on MacOS.
Be aware that the file's type/creator and resource fork will be lost, which is usually what you want in cross-platform archives.
Returns a list of Archive::Tar::File objects that were just added.
Takes a filename, a scalar full of data and optionally a reference to a hash with specific options.
Will add a file to the in-memory archive, with name $filename and
content $data. Specific properties can be set using $opthashref.
The following list of properties is supported: name, size, mtime
(last modified date), mode, uid, gid, linkname, uname, gname,
devmajor, devminor, prefix, type. (On MacOS, the file's path and
modification times are converted to Unix equivalents.)
Valid values for the file type are the following constants defined in Archive::Tar::Constants:
Returns the Archive::Tar::File object that was just added, or
undef on failure.
Returns the current errorstring (usually, the last error reported).
If a true value was specified, it will give the Carp::longmess
equivalent of the error, in effect giving you a stacktrace.
For backwards compatibility, this error is also available as
$Archive::Tar::error although it is much recommended you use the
method call instead.
Archive::Tar needs to know the current directory, and it will run
Cwd::cwd() every time it extracts a relative entry from the
tarfile and saves it in the file system. (As of version 1.30, however,
Archive::Tar will use the speed optimization described below
automatically, so it's only relevant if you're using extract_file()).
Since Archive::Tar doesn't change the current directory internally
while it is extracting the items in a tarball, all calls to Cwd::cwd()
can be avoided if we can guarantee that the current directory doesn't
get changed externally.
To use this performance boost, set the current directory via
use Cwd;
$tar->setcwd( cwd() );
once before calling a function like extract_file and
Archive::Tar will use the current directory setting from then on
and won't call Cwd::cwd() internally.
To switch back to the default behaviour, use
$tar->setcwd( undef );
and Archive::Tar will call Cwd::cwd() internally again.
If you're using Archive::Tar's exract() method, setcwd() will
be called for you.
Returns true if we currently have IO::String support loaded.
Either IO::String or perlio support is needed to support writing
stringified archives. Currently, perlio is the preferred method, if
available.
See the GLOBAL VARIABLES section to see how to change this preference.
Returns true if we currently have perlio support loaded.
This requires perl-5.8 or higher, compiled with perlio
Either IO::String or perlio support is needed to support writing
stringified archives. Currently, perlio is the preferred method, if
available.
See the GLOBAL VARIABLES section to see how to change this preference.
Creates a tar file from the list of files provided. The first argument can either be the name of the tar file to create or a reference to an open file handle (e.g. a GLOB reference).
The second argument specifies the level of compression to be used, if any. Compression of tar files requires the installation of the IO::Zlib module. Specific levels of compression may be requested by passing a value between 2 and 9 as the second argument. Any other value evaluating as true will result in the default compression level being used.
Note that when you pass in a filehandle, the compression argument
is ignored, as all files are printed verbatim to your filehandle.
If you wish to enable compression with filehandles, use an
IO::Zlib filehandle instead.
The remaining arguments list the files to be included in the tar file. These files must all exist. Any files which don't exist or can't be read are silently ignored.
If the archive creation fails for any reason, create_archive will
return false. Please use the error method to find the cause of the
failure.
Note that this method does not write on the fly as it were; it
still reads all the files into memory before writing out the archive.
Consult the FAQ below if this is a problem.
Returns a list of the names of all the files in the archive. The first argument can either be the name of the tar file to list or a reference to an open file handle (e.g. a GLOB reference).
If list_archive() is passed an array reference as its third
argument it returns a list of hash references containing the requested
properties of each file. The following list of properties is
supported: full_path, name, size, mtime (last modified date), mode,
uid, gid, linkname, uname, gname, devmajor, devminor, prefix.
See Archive::Tar::File for details about supported properties.
Passing an array reference containing only one element, 'name', is special cased to return a list of names rather than a list of hash references.
Extracts the contents of the tar file. The first argument can either be the name of the tar file to create or a reference to an open file handle (e.g. a GLOB reference). All relative paths in the tar file will be created underneath the current working directory.
extract_archive will return a list of files it extracted.
If the archive extraction fails for any reason, extract_archive
will return false. Please use the error method to find the cause
of the failure.
A simple checking routine, which will return true if Archive::Tar
is able to uncompress compressed archives on the fly with IO::Zlib,
or false if IO::Zlib is not installed.
You can use this as a shortcut to determine whether Archive::Tar
will do what you think before passing compressed archives to its
read method.
Set this variable to 1 to make Archive::Tar effectively make a
copy of the file when extracting. Default is 0, which
means the symlink stays intact. Of course, you will have to pack the
file linked to as well.
This option is checked when you write out the tarfile using write
or create_archive.
This works just like /bin/tar's -h option.
By default, Archive::Tar will try to chown your files if it is
able to. In some cases, this may not be desired. In that case, set
this variable to 0 to disable chown-ing, even if it were
possible.
The default is 1.
By default, Archive::Tar will try to chmod your files to
whatever mode was specified for the particular file in the archive.
In some cases, this may not be desired. In that case, set this
variable to 0 to disable chmod-ing.
The default is 1.
By default, Archive::Tar will try to put paths that are over
100 characters in the prefix field of your tar header, as
defined per POSIX-standard. However, some (older) tar programs
do not implement this spec. To retain compatibility with these older
or non-POSIX compliant versions, you can set the $DO_NOT_USE_PREFIX
variable to a true value, and Archive::Tar will use an alternate
way of dealing with paths over 100 characters by using the
GNU Extended Header feature.
Note that clients who do not support the GNU Extended Header
feature will not be able to read these archives. Such clients include
tars on Solaris, Irix and AIX.
The default is 0.
Set this variable to 1 to always get the Carp::longmess output
of the warnings, instead of the regular carp. This is the same
message you would get by doing:
$tar->error(1);
Defaults to 0.
Set this variable to 0 if you do not want any warnings printed.
Personally I recommend against doing this, but people asked for the
option. Also, be advised that this is of course not threadsafe.
Defaults to 1.
Holds the last reported error. Kept for historical reasons, but its
use is very much discouraged. Use the error() method instead:
warn $tar->error unless $tar->extract;
This variable indicates whether Archive::Tar should allow
files to be extracted outside their current working directory.
Allowing this could have security implications, as a malicious tar archive could alter or replace any file the extracting user has permissions to. Therefor, the default is to not allow insecure extractions.
If you trust the archive, or have other reasons to allow the
archive to write files outside your current working directory,
set this variable to true.
Note that this is a backwards incompatible change from version
1.36 and before.
This variable holds a boolean indicating if we currently have
perlio support loaded. This will be enabled for any perl
greater than 5.8 compiled with perlio.
If you feel strongly about disabling it, set this variable to
false. Note that you will then need IO::String installed
to support writing stringified archives.
Don't change this variable unless you really know what you're doing.
This variable holds a boolean indicating if we currently have
IO::String support loaded. This will be enabled for any perl
that has a loadable IO::String module.
If you feel strongly about disabling it, set this variable to
false. Note that you will then need perlio support from
your perl to be able to write stringified archives.
Don't change this variable unless you really know what you're doing.
/bin/tar
However, it's very portable. If speed is an issue, consider using
/bin/tar instead.
Compress::Zlib and therefore
IO::Zlib doesn't support seek on their filehandles, there is little
choice but to read the archive into memory.
This is ok if you want to do in-memory manipulation of the archive.
If you just want to extract, use the extract_archive class method
instead. It will optimize and write to disk immediately.
/bin/tar instead.
Unix has a few filetypes that aren't supported on other platforms,
like Win32. If we encounter a hardlink or symlink we'll just
try to make a copy of the original file, rather than throwing an error.
This does require you to read the entire archive in to memory first, since otherwise we wouldn't know what data to fill the copy with. (This means that you cannot use the class methods on archives that have incompatible filetypes and still expect things to work).
For other filetypes, like chardevs and blockdevs we'll warn that
the extraction of this particular item didn't work.
Archive::Tar is in a completely POSIX-compatible
mode, which uses the POSIX-specification of tar to store files.
For paths greather than 100 characters, this is done using the
POSIX header prefix. Non-POSIX-compatible clients may not support
this part of the specification, and may only support the GNU Extended
Header functionality. To facilitate those clients, you can set the
$Archive::Tar::DO_NOT_USE_PREFIX variable to true. See the
GLOBAL VARIABLES section for details on this variable.
Note that GNU tar earlier than version 1.14 does not cope well with
the POSIX header prefix. If you use such a version, consider setting
the $Archive::Tar::DO_NOT_USE_PREFIX variable to true.
You can do this by filtering a list of Archive::Tar::File objects
based on your criteria. For example, to extract only files that have
the string foo in their title, you would use:
$tar->extract(
grep { $_->full_path =~ /foo/ } $tar->get_files
);
This way, you can filter on any attribute of the files in the archive.
Consult the Archive::Tar::File documentation on how to use these
objects.
Archive::Tar module can optionally use Compress::Zlib (via
the IO::Zlib module) to access tar files that have been compressed
with gzip. Unfortunately tar files compressed with the Unix compress
utility cannot be read by Compress::Zlib and so cannot be directly
accesses by Archive::Tar.
If the uncompress or gunzip programs are available, you can use
one of these workarounds to read .tar.Z files from Archive::Tar
Firstly with uncompress
use Archive::Tar;
open F, "uncompress -c $filename |";
my $tar = Archive::Tar->new(*F);
...
and this with gunzip
use Archive::Tar;
open F, "gunzip -c $filename |";
my $tar = Archive::Tar->new(*F);
...
Similarly, if the compress program is available, you can use this to
write a .tar.Z file
use Archive::Tar;
use IO::File;
my $fh = new IO::File "| compress -c >$filename";
my $tar = Archive::Tar->new();
...
$tar->write($fh);
$fh->close ;
Archive::Tar uses byte semantics for any files it reads from or writes
to disk. This is not a problem if you only deal with files and never
look at their content or work solely with byte strings. But if you use
Unicode strings with character semantics, some additional steps need
to be taken.
For example, if you add a Unicode string like
# Problem
$tar->add_data('file.txt', "Euro: \x{20AC}");
then there will be a problem later when the tarfile gets written out
to disk via $tar-write()>:
Wide character in print at .../Archive/Tar.pm line 1014.
The data was added as a Unicode string and when writing it out to disk,
the :utf8 line discipline wasn't set by Archive::Tar, so Perl
tried to convert the string to ISO-8859 and failed. The written file
now contains garbage.
For this reason, Unicode strings need to be converted to UTF-8-encoded
bytestrings before they are handed off to add_data():
use Encode;
my $data = "Accented character: \x{20AC}";
$data = encode('utf8', $data);
$tar->add_data('file.txt', $data);
A opposite problem occurs if you extract a UTF8-encoded file from a
tarball. Using get_content() on the Archive::Tar::File object
will return its content as a bytestring, not as a Unicode string.
If you want it to be a Unicode string (because you want character semantics with operations like regular expression matching), you need to decode the UTF8-encoded content and have Perl convert it into a Unicode string:
use Encode;
my $data = $tar->get_content();
# Make it a Unicode string
$data = decode('utf8', $data);
There is no easy way to provide this functionality in Archive::Tar,
because a tarball can contain many files, and each of which could be
encoded in a different way.
http://www.gnu.org/software/tar/manual/tar.html
http://www.opengroup.org/onlinepubs/007904975/utilities/pax.html
http://www.delorie.com/gnu/docs/tar/tar_114.htmlhttp://www.gnu.org/software/tar/manual/html_node/Formats.html
http://gd.tuwien.ac.at/utils/archivers/star/README.otherbugs
This module by Jos Boumans <kane@cpan.org>.
Please reports bugs to <bug-archive-tar@rt.cpan.org>.
Thanks to Sean Burke, Chris Nandor, Chip Salzenberg, Tim Heaney and especially Andrew Savige for their help and suggestions.
This module is copyright (c) 2002 - 2007 Jos Boumans <kane@cpan.org>. All rights reserved.
This library is free software; you may redistribute and/or modify it under the same terms as Perl itself.
| Archive::Tar - module for manipulations of tar archives |