NAME
    Archive::Tar::Wrapper - API wrapper around the 'tar' utility

SYNOPSIS
        use Archive::Tar::Wrapper;

        my $arch = Archive::Tar::Wrapper->new();

        # Open a tarball, expand it into a temporary directory
        $arch->read("archive.tgz");

        # Iterate over all entries in the archive
        $arch->list_reset(); # Reset Iterator

        # Iterate through archive
        while(my $entry = $arch->list_next()) {
            my($tar_path, $phys_path) = @$entry;
            print "$tar_path\n";
        }

        # Get a huge list with all entries
        for my $entry (@{$arch->list_all()}) {
            my($tar_path, $real_path) = @$entry;
            print "Tarpath: $tar_path Tempfile: $real_path\n";
        }

        # Add a new entry
        $arch->add($logic_path, $file_or_stringref);

        # Remove an entry
        $arch->remove($logic_path);

        # Find the physical location of a temporary file
        my($tmp_path) = $arch->locate($tar_path);

        # Create a tarball
        $arch->write($tarfile, $compress);

DESCRIPTION
    Archive::Tar::Wrapper is an API wrapper around the "tar" command line
    program. It never stores anything in memory, but works on temporary
    directory structures on disk instead. It provides a mapping between the
    logical paths in the tarball and the 'real' files in the temporary
    directory on disk.

    It differs from Archive::Tar in two ways:

    *   Archive::Tar::Wrapper almost doesn't hold anything in memory (see
        "write" method), instead using disk as storage.

    *   Archive::Tar::Wrapper is 100% compliant with the platform's "tar"
        utility because it uses it internally.

METHODS
  new
        my $arch = Archive::Tar::Wrapper->new();

    Constructor for the "tar" wrapper class. Finds the "tar" executable by
    searching "PATH" and returning the first hit. In case you want to use a
    different tar executable, you can specify it as a parameter:

        my $arch = Archive::Tar::Wrapper->new(tar => '/path/to/tar');

    Since Archive::Tar::Wrapper creates temporary directories to store "tar"
    data, the location of the temporary directory can be specified:

        my $arch = Archive::Tar::Wrapper->new(tmpdir => '/path/to/tmpdir');

    Tremendous performance increases can be achieved if the temporary
    directory is located on a RAM disk. Check the "Using RAM Disks" in
    Archive::Tar::Wrapper section for details.

    Additional options can be passed to the "tar" command by using the
    "tar_read_options" and "tar_write_options" parameters. Example:

         my $arch = Archive::Tar::Wrapper->new(
                       tar_read_options => 'p'
                    );

    will use "tar xfp archive.tgz" to extract the tarball instead of just
    "tar xf archive.tgz". GNU tar supports even more options, these can be
    passed in via

         my $arch = Archive::Tar::Wrapper->new(
                        tar_gnu_read_options => ["--numeric-owner"],
                    );

    Similarly, "tar_gnu_write_options" can be used to provide additional
    options for GNU tar implementations. For example, the tar object

        my $tar = Archive::Tar::Wrapper->new(
                      tar_gnu_write_options => ["--exclude=foo"],
                  );

    will call the "tar" utility internally like

        tar cf tarfile --exclude=foo ...

    when the "write" method gets called.

    By default, the "list_*()" functions will return only file entries:
    directories will be suppressed. To have "list_*()" return directories as
    well, use

         my $arch = Archive::Tar::Wrapper->new(
                       dirs  => 1
                    );

    If more files are added to a tarball than the command line can handle,
    Archive::Tar::Wrapper will switch from using the command

        tar cfv tarfile file1 file2 file3 ...

    to

        tar cfv tarfile -T filelist

    where "filelist" is a file containing all file to be added. The default
    for this switch is 512, but it can be changed by setting the parameter
    "max_cmd_line_args":

         my $arch = Archive::Tar::Wrapper->new(
             max_cmd_line_args  => 1024
         );

    The allowable parameters are:

    *   "tar"

    *   "tmpdir"

    *   "tar_read_options"

    *   "tar_write_options"

    *   "tar_gnu_read_options"

    *   "tar_gnu_write_options"

    *   "max_cmd_line_args": defaults to 512

    *   "ramdisk"

    Returns a new instance of the class.

  read
        $arch->read("archive.tgz");

    read() opens the given tarball, expands it into a temporary directory
    and returns 1 on success or "undef" on failure. The temporary directory
    holding the tar data gets cleaned up when $arch goes out of scope.

    "read" handles both compressed and uncompressed files. To find out if a
    file is compressed or uncompressed, it tries to guess by extension, then
    by checking the first couple of bytes in the tar file.

    If only a limited number of files is needed from a tarball, they can be
    specified after the tarball name:

        $arch->read("archive.tgz", "path/file.dat", "path/sub/another.txt");

    The file names are passed unmodified to the "tar" command, make sure
    that the file paths match exactly what's in the tarball, otherwise
    read() will fail.

  list_reset
        $arch->list_reset()

    Resets the list iterator. To be used before the first call to
    list_next().

  tardir
        $arch->tardir();

    Return the directory the tarball was unpacked in. This is sometimes
    useful to play dirty tricks on Archive::Tar::Wrapper by
    mass-manipulating unpacked files before wrapping them back up into the
    tarball.

  is_compressed
    Returns a string to identify if the tarball is compressed or not.

    Expect as parameter a string with the path to the tarball.

    Returns:

    *   a "z" character if the file is compressed with "gzip".

    *   a "j" character if the file is compressed with "bzip2".

    *   a "" character if the file is not compressed at all.

  locate
        $arch->locate($logic_path);

    Finds the physical location of a file, specified by $logic_path, which
    is the virtual path of the file within the tarball. Returns a path to
    the temporary file Archive::Tar::Wrapper created to manipulate the
    tarball on disk.

  add
        $arch->add($logic_path, $file_or_stringref, [$options]);

    Add a new file to the tarball. $logic_path is the virtual path of the
    file within the tarball. $file_or_stringref is either a scalar, in which
    case it holds the physical path of a file on disk to be transferred
    (i.e. copied) to the tarball, or it is a reference to a scalar, in which
    case its content is interpreted to be the data of the file.

    If no additional parameters are given, permissions and user/group id
    settings of a file to be added are copied. If you want different
    settings, specify them in the options hash:

        $arch->add($logic_path, $stringref,
                   { perm => 0755, uid => 123, gid => 10 });

    If $file_or_stringref is a reference to a Unicode string, the "binmode"
    option has to be set to make sure the string gets written as proper
    UTF-8 into the tar file:

        $arch->add($logic_path, $stringref, { binmode => ":utf8" });

  perm_cp
    Copies the permissions from a file to another.

    Expects as parameters:

    1.  string of the path to the file which permissions will be copied
        from.

    2.  string of the path to the file which permissions will be copied to.

    Returns 1 if everything works as expected.

  perm_get
    Gets the permissions from a file.

    Expects as parameter the path to the source file.

    Returns an array reference with only the permissions values, as returned
    by "stat".

  perm_set
    Sets the permission on a file.

    Expects as parameters:

    1.  The path to the file where the permissions should be applied to.

    2.  An array reference with the permissions (see "perm_set")

    Returns 1 if everything goes fine.

    Ignore errors here, as we can't change uid/gid unless we're the
    superuser (see LIMITATIONS section).

  remove
        $arch->remove($logic_path);

    Removes a file from the tarball. $logic_path is the virtual path of the
    file within the tarball.

  list_all
        my $items = $arch->list_all();

    Returns a reference to a (possibly huge) array of items in the tar file.
    Each item is a reference to an array, containing two elements: the
    relative path of the item in the tar file and the physical path to the
    unpacked file or directory on disk.

    To iterate over the list, the following construct can be used:

        # Get a huge list with all entries
        for my $entry (@{$arch->list_all()}) {
            my($tar_path, $real_path) = @$entry;
            print "Tarpath: $tar_path Tempfile: $real_path\n";
        }

    If the list of items in the tar file is big, use list_reset() and
    list_next() instead of "list_all".

  list_next
        my ($tar_path, $phys_path, $type) = $arch->list_next();

    Returns the next item in the tar file. It returns a list of three
    scalars: the relative path of the item in the tar file, the physical
    path to the unpacked file or directory on disk, and the type of the
    entry (f=file, d=directory, l=symlink). Note that by default,
    Archive::Tar::Wrapper won't display directories, unless the "dirs"
    parameter is set when running the constructor.

  write
        $arch->write($tarfile, $compress);

    Write out the tarball by tarring up all temporary files and directories
    and store it in $tarfile on disk. If $compress holds a true value,
    compression is used.

  is_gnu
        $arch->is_gnu();

    Checks if the tar executable is a GNU tar by running 'tar --version' and
    parsing the output for "GNU".

    Returns true or false (in Perl terms).

  is_bsd
        $arch->is_bsd();

    Same as is_gnu(), but for BSD.

  ramdisk_mount
    Mounts a RAM disk.

    It executes the "mount" program under the hood to mount a RAM disk.

    Expects as parameter a hash with options to mount the RAM disk, like:

    *   "size"

    *   "type" (most probably "tmpfs")

    *   "tmpdir"

    Returns 1 if everything goes fine.

    Be sure to check the "Using RAM Disks" in Archive::Tar::Wrapper for full
    details on using RAM disks.

  ramdisk_unmount
    Unmounts the RAM disk already mounted with "ramdisk_mount".

    Don't expect parameters and returns 1 if everything goes fine.

    Be sure to check the "Using RAM Disks" in Archive::Tar::Wrapper for full
    details on using RAM disks.

Using RAM Disks
    On Linux, it's quite easy to create a RAM disk and achieve tremendous
    speedups while untarring or modifying a tarball. You can either create
    the RAM disk by hand by running

       # mkdir -p /mnt/myramdisk
       # mount -t tmpfs -o size=20m tmpfs /mnt/myramdisk

    and then feeding the RAM disk as a temporary directory to
    Archive::Tar::Wrapper, like

       my $tar = Archive::Tar::Wrapper->new( tmpdir => '/mnt/myramdisk' );

    or using Archive::Tar::Wrapper's built-in option "ramdisk":

       my $tar = Archive::Tar::Wrapper->new(
           ramdisk => {
               type => 'tmpfs',
               size => '20m',   # 20 MB
           },
       );

    Only drawback with the latter option is that creating the RAM disk needs
    to be performed as root, which often isn't desirable for security
    reasons. For this reason, Archive::Tar::Wrapper offers a utility
    functions that mounts the RAM disk and returns the temporary directory
    it's located in:

        # Create new ramdisk (as root):
        my $tmpdir = Archive::Tar::Wrapper->ramdisk_mount(
            type => 'tmpfs',
            size => '20m',   # 20 MB
        );

        # Delete a ramdisk (as root):
        Archive::Tar::Wrapper->ramdisk_unmount();

    Optionally, the ramdisk_mount() command accepts a "tmpdir" parameter
    pointing to a temporary directory for the RAM disk if you wish to set it
    yourself instead of letting Archive::Tar::Wrapper create it
    automatically.

KNOWN LIMITATIONS
    *   Currently, only "tar" programs supporting the "z" option (for
        compressing/decompressing) are supported. Future version will use
        "gzip" alternatively.

    *   Currently, you can't add empty directories to a tarball directly.
        You could add a temporary file within a directory, and then remove()
        the file.

    *   If you delete a file, the empty directories it was located in stay
        in the tarball. You could try to locate() them and delete them. This
        will be fixed, though.

    *   Filenames containing newlines are causing problems with the list
        iterators. To be fixed.

    *   If you ask Archive::Tar::Wrapper to add a file to a tarball, it
        copies it into a temporary directory and then calls the system tar
        to wrap up that directory into a tarball.

        This approach has limitations when it comes to file permissions: If
        the file to be added belongs to a different user/group,
        Archive::Tar::Wrapper will adjust the uid/gid/permissions of the
        target file in the temporary directory to reflect the original
        file's settings, to make sure the system tar will add it like that
        to the tarball, just like a regular tar run on the original file
        would. But this will fail of course if the original file's uid is
        different from the current user's, unless the script is running with
        superuser rights. The tar program by itself (without
        Archive::Tar::Wrapper) works differently: It'll just make a note of
        a file's uid/gid/permissions in the tarball (which it can do without
        superuser rights) and upon extraction, it'll adjust the permissions
        of newly generated files if the -p option is given (default for
        superuser).

BUGS
    Archive::Tar::Wrapper doesn't currently handle filenames with embedded
    newlines.

  Microsoft Windows support
    Support on Microsoft Windows is limited.

    Versions below Windows 10 will not be supported for desktops, and for
    servers only Windows 2012 and above.

    The GNU "tar.exe" program doesn't work properly with the current
    interface of Archive::Tar::Wrapper.

    You must use the "bsdtar.exe" and make sure it appears first in the
    "PATH" environment variable than the GNU tar (if it is installed). See
    <http://libarchive.org/> for details about how to download and install
    "bsdtar.exe", or go to <http://gnuwin32.sourceforge.net/packages.html>
    for a direct download. Be sure to look for the "bzip2" program package
    to install it as well.

    Windows 10 might come already with "bsdtar" program already installed.
    Please search for that on the appropriate page (Microsoft keeps changing
    the link to keep track of it here).

    Having spaces in the path string to the tar program might be an issue
    too. Although there is some effort in terms of workaround it, you best
    might avoid it completely by installing in a different path than
    "C:\Program Files". Installing both "bsdtar" and "bzip2" in
    "C:\GnuWin32" will probably be enough when running the installers.

SEE ALSO
    *   Linux Gazette article from Ben Okopnik, issue 87
        <https://linuxgazette.net/87/okopnik.html>.

BUGS
    Please report any bugs or feature requests on the bugtracker website
    <https://github.com/haarg/Archive-Tar-Wrapper/issues>

    When submitting a bug or request, please include a test-file or a patch
    to an existing test-file that illustrates the bug or desired feature.

AUTHORS
    *   Mike Schilli <cpan@perlmeister.com>

    *   Alceu Rodrigues de Freitas Junior <glasswalk3r@yahoo.com.br>

CONTRIBUTORS
    *   Chris Weyl <cweyl@alumni.drew.edu>

    *   David Cantrell <david@cantrell.org.uk>

    *   David Precious <davidp@preshweb.co.uk>

    *   Graham Knop <haarg@haarg.org>

    *   intrigeri <intrigeri@boum.org>

    *   Kent Fredric <kentfredric@gmail.com>

    *   Mark Gardner <mjg+github@phoenixtrap.com>

    *   Mike Schilli <github@perlmeister.com>

    *   Mohammad S Anwar <mohammad.anwar@yahoo.com>

    *   Paulo Custodio <pauloscustodio@gmail.com>

    *   Randy Stauner <randy@magnificent-tears.com>

    *   Sanko Robinson <sanko@cpan.org>

    *   Shoichi Kaji <skaji@cpan.org>

COPYRIGHT AND LICENSE
    This software is Copyright (c) 2024 by Mike Schilli.

    This is free software, licensed under:

      The GNU General Public License, Version 3, June 2007

