IO::Compress::Zip - Write zip files/buffers
use IO::Compress::Zip qw(zip $ZipError) ;
my $status = zip $input => $output [,OPTS]
or die "zip failed: $ZipError\n";
my $z = IO::Compress::Zip->new( $output [,OPTS] )
or die "zip failed: $ZipError\n";
$z->print($string);
$z->printf($format, $string);
$z->write($string);
$z->syswrite($string [, $length, $offset]);
$z->flush();
$z->tell();
$z->eof();
$z->seek($position, $whence);
$z->binmode();
$z->fileno();
$z->opened();
$z->autoflush();
$z->input_line_number();
$z->newStream( [OPTS] );
$z->deflateParams();
$z->close() ;
$ZipError ;
# IO::File mode
print $z $string;
printf $z $format, $string;
tell $z
eof $z
seek $z, $position, $whence
binmode $z
fileno $z
close $z ;This module provides a Perl interface that allows writing zip compressed data to files or buffer.
The primary purpose of this module is to provide streaming write access to zip files and buffers.
At present the following compression methods are supported by IO::Compress::Zip
To write Bzip2 content, the module IO::Uncompress::Bunzip2 must be installed.
To write LZMA content, the module IO::Uncompress::UnLzma must be installed.
To write Zstandard content, the module IO::Compress::Zstd must be installed.
To write Xz content, the module IO::Uncompress::UnXz must be installed.
For reading zip files/buffers, see the companion module IO::Uncompress::Unzip.
A top-level function, zip, is provided to carry out "one-shot" compression between buffers and/or files. For finer control over the compression process, see the "OO Interface" section.
use IO::Compress::Zip qw(zip $ZipError) ;
zip $input_filename_or_reference => $output_filename_or_reference [,OPTS]
or die "zip failed: $ZipError\n";The functional interface needs Perl5.005 or better.
zip expects at least two parameters, $input_filename_or_reference and $output_filename_or_reference and zero or more optional parameters (see "Optional Parameters")
$input_filename_or_reference parameterThe parameter, $input_filename_or_reference, is used to define the source of the uncompressed data.
It can take one of the following forms:
If the $input_filename_or_reference parameter is a simple scalar, it is assumed to be a filename. This file will be opened for reading and the input data will be read from it.
If the $input_filename_or_reference parameter is a filehandle, the input data will be read from it. The string '-' can be used as an alias for standard input.
If $input_filename_or_reference is a scalar reference, the input data will be read from $$input_filename_or_reference.
If $input_filename_or_reference is an array reference, each element in the array must be a filename.
The input data will be read from each file in turn.
The complete array will be walked to ensure that it only contains valid filenames before any data is compressed.
If $input_filename_or_reference is a string that is delimited by the characters "<" and ">" zip will assume that it is an input fileglob string. The input is the list of files that match the fileglob.
See File::GlobMapper for more details.
If the $input_filename_or_reference parameter is any other type, undef will be returned.
In addition, if $input_filename_or_reference is a simple filename, the default values for the Name, Time, TextFlag, ExtAttr, exUnixN and exTime options will be sourced from that file.
If you do not want to use these defaults they can be overridden by explicitly setting the Name, Time, TextFlag, ExtAttr, exUnixN and exTime options or by setting the Minimal parameter.
$output_filename_or_reference parameterThe parameter $output_filename_or_reference is used to control the destination of the compressed data. This parameter can take one of these forms.
If the $output_filename_or_reference parameter is a simple scalar, it is assumed to be a filename. This file will be opened for writing and the compressed data will be written to it.
If the $output_filename_or_reference parameter is a filehandle, the compressed data will be written to it. The string '-' can be used as an alias for standard output.
If $output_filename_or_reference is a scalar reference, the compressed data will be stored in $$output_filename_or_reference.
If $output_filename_or_reference is an array reference, the compressed data will be pushed onto the array.
If $output_filename_or_reference is a string that is delimited by the characters "<" and ">" zip will assume that it is an output fileglob string. The output is the list of files that match the fileglob.
When $output_filename_or_reference is an fileglob string, $input_filename_or_reference must also be a fileglob string. Anything else is an error.
See File::GlobMapper for more details.
If the $output_filename_or_reference parameter is any other type, undef will be returned.
When $input_filename_or_reference maps to multiple files/buffers and $output_filename_or_reference is a single file/buffer the input files/buffers will each be stored in $output_filename_or_reference as a distinct entry.
The optional parameters for the one-shot function zip are (for the most part) identical to those used with the OO interface defined in the "Constructor Options" section. The exceptions are listed below
AutoClose => 0|1This option applies to any input or output data streams to zip that are filehandles.
If AutoClose is specified, and the value is true, it will result in all input and/or output filehandles being closed once zip has completed.
This parameter defaults to 0.
BinModeIn => 0|1This option is now a no-op. All files will be read in binmode.
Append => 0|1The behaviour of this option is dependent on the type of output data stream.
A Buffer
If Append is enabled, all compressed data will be append to the end of the output buffer. Otherwise the output buffer will be cleared before any compressed data is written to it.
A Filename
If Append is enabled, the file will be opened in append mode. Otherwise the contents of the file, if any, will be truncated before any compressed data is written to it.
A Filehandle
If Append is enabled, the filehandle will be positioned to the end of the file via a call to seek before any compressed data is written to it. Otherwise the file pointer will not be moved.
When Append is specified, and set to true, it will append all compressed data to the output data stream.
So when the output is a filehandle it will carry out a seek to the eof before writing any compressed data. If the output is a filename, it will be opened for appending. If the output is a buffer, all compressed data will be appended to the existing buffer.
Conversely when Append is not specified, or it is present and is set to false, it will operate as follows.
When the output is a filename, it will truncate the contents of the file before writing any compressed data. If the output is a filehandle its position will not be changed. If the output is a buffer, it will be wiped before any compressed data is output.
Defaults to 0.
Here are a few example that show the capabilities of the module.
This very simple command line example demonstrates the streaming capabilities of the module. The code reads data from STDIN, compresses it, and writes the compressed data to STDOUT.
$ echo hello world | perl -MIO::Compress::Zip=zip -e 'zip \*STDIN => \*STDOUT' >output.zipThe special filename "-" can be used as a standin for both \*STDIN and \*STDOUT, so the above can be rewritten as
$ echo hello world | perl -MIO::Compress::Zip=zip -e 'zip "-" => "-"' >output.zipOne problem with creating a zip archive directly from STDIN can be demonstrated by looking at the contents of the zip file, output.zip, that we have just created.
$ unzip -l output.zip
Archive: output.zip
Length Date Time Name
--------- ---------- ----- ----
12 2019-08-16 22:21
--------- -------
12 1 fileThe archive member (filename) used is the empty string.
If that doesn't suit your needs, you can explicitly set the filename used in the zip archive by specifying the Name option, like so
echo hello world | perl -MIO::Compress::Zip=zip -e 'zip "-" => "-", Name => "hello.txt"' >output.zipNow the contents of the zip file looks like this
$ unzip -l output.zip
Archive: output.zip
Length Date Time Name
--------- ---------- ----- ----
12 2019-08-16 22:22 hello.txt
--------- -------
12 1 fileTo read the contents of the file file1.txt and write the compressed data to the file file1.txt.zip.
use strict ;
use warnings ;
use IO::Compress::Zip qw(zip $ZipError) ;
my $input = "file1.txt";
zip $input => "$input.zip"
or die "zip failed: $ZipError\n";To read from an existing Perl filehandle, $input, and write the compressed data to a buffer, $buffer.
use strict ;
use warnings ;
use IO::Compress::Zip qw(zip $ZipError) ;
use IO::File ;
my $input = IO::File->new( "<file1.txt" )
or die "Cannot open 'file1.txt': $!\n" ;
my $buffer ;
zip $input => \$buffer
or die "zip failed: $ZipError\n";To create a zip file, output.zip, that contains the compressed contents of the files alpha.txt and beta.txt
use strict ;
use warnings ;
use IO::Compress::Zip qw(zip $ZipError) ;
zip [ 'alpha.txt', 'beta.txt' ] => 'output.zip'
or die "zip failed: $ZipError\n";Alternatively, rather than having to explicitly name each of the files that you want to compress, you could use a fileglob to select all the txt files in the current directory, as follows
use strict ;
use warnings ;
use IO::Compress::Zip qw(zip $ZipError) ;
my @files = <*.txt>;
zip \@files => 'output.zip'
or die "zip failed: $ZipError\n";or more succinctly
zip [ <*.txt> ] => 'output.zip'
or die "zip failed: $ZipError\n";The format of the constructor for IO::Compress::Zip is shown below
my $z = IO::Compress::Zip->new( $output [,OPTS] )
or die "IO::Compress::Zip failed: $ZipError\n";It returns an IO::Compress::Zip object on success and undef on failure. The variable $ZipError will contain an error message on failure.
If you are running Perl 5.005 or better the object, $z, returned from IO::Compress::Zip can be used exactly like an IO::File filehandle. This means that all normal output file operations can be carried out with $z. For example, to write to a compressed file/buffer you can use either of these forms
$z->print("hello world\n");
print $z "hello world\n";The mandatory parameter $output is used to control the destination of the compressed data. This parameter can take one of these forms.
If the $output parameter is a simple scalar, it is assumed to be a filename. This file will be opened for writing and the compressed data will be written to it.
If the $output parameter is a filehandle, the compressed data will be written to it. The string '-' can be used as an alias for standard output.
If $output is a scalar reference, the compressed data will be stored in $$output.
If the $output parameter is any other type, IO::Compress::Zip::new will return undef.
OPTS is any combination of zero or more the following options:
AutoClose => 0|1This option is only valid when the $output parameter is a filehandle. If specified, and the value is true, it will result in the $output being closed once either the close method is called or the IO::Compress::Zip object is destroyed.
This parameter defaults to 0.
Append => 0|1Opens $output in append mode.
The behaviour of this option is dependent on the type of $output.
A Buffer
If $output is a buffer and Append is enabled, all compressed data will be append to the end of $output. Otherwise $output will be cleared before any data is written to it.
A Filename
If $output is a filename and Append is enabled, the file will be opened in append mode. Otherwise the contents of the file, if any, will be truncated before any compressed data is written to it.
A Filehandle
If $output is a filehandle, the file pointer will be positioned to the end of the file via a call to seek before any compressed data is written to it. Otherwise the file pointer will not be moved.
This parameter defaults to 0.
A quick bit of zip file terminology -- A zip archive consists of one or more archive members, where each member has an associated filename, known as the archive member name.
The options listed in this section control how the archive member name (or filename) is stored the zip archive.
Name => $stringThis option is used to explicitly set the archive member name in the zip archive to $string. Most of the time you don't need to make use of this option. By default when adding a filename to the zip archive, the archive member name will match the filename.
You should only need to use this option if you want the archive member name to be different from the uncompressed filename or when the input is a filehandle or a buffer.
The default behaviour for what archive member name is used when the Name option is not specified depends on the form of the $input parameter:
If the $input parameter is a filename, the value of $input will be used for the archive member name .
If the $input parameter is not a filename, the archive member name will be an empty string.
Note that both the CanonicalName and FilterName options can modify the value used for the archive member name.
Also note that you should set the Efs option to true if you are working with UTF8 filenames.
CanonicalName => 0|1This option controls whether the archive member name is normalized into Unix format before being written to the zip file.
It is recommended that you enable this option unless you really need to create a non-standard Zip file.
This is what APPNOTE.TXT has to say on what should be stored in the zip filename header field.
The name of the file, with optional relative path.
The path stored should not contain a drive or
device letter, or a leading slash. All slashes
should be forward slashes '/' as opposed to
backwards slashes '\' for compatibility with Amiga
and UNIX file systems etc.This option defaults to false.
FilterName => sub { ... }This option allow the archive member name to be modified before it is written to the zip file.
This option takes a parameter that must be a reference to a sub. On entry to the sub the $_ variable will contain the name to be filtered. If no filename is available $_ will contain an empty string.
The value of $_ when the sub returns will be used as the archive member name.
Note that if CanonicalName is enabled, a normalized filename will be passed to the sub.
If you use FilterName to modify the filename, it is your responsibility to keep the filename in Unix format.
Although this option can be used with the OO interface, it is of most use with the one-shot interface. For example, the code below shows how FilterName can be used to remove the path component from a series of filenames before they are stored in $zipfile.
sub compressTxtFiles
{
my $zipfile = shift ;
my $dir = shift ;
zip [ <$dir/*.txt> ] => $zipfile,
FilterName => sub { s[^$dir/][] } ;
}Efs => 0|1This option controls setting of the "Language Encoding Flag" (EFS) in the zip archive. When set, the filename and comment fields for the zip archive MUST be valid UTF-8.
If the string used for the filename and/or comment is not valid UTF-8 when this option is true, the script will die with a "wide character" error.
Note that this option only works with Perl 5.8.4 or better.
This option defaults to false.
Minimal => 1|0If specified, this option will disable the creation of all extra fields in the zip local and central headers. So the exTime, exUnix2, exUnixN, ExtraFieldLocal and ExtraFieldCentral options will be ignored.
This parameter defaults to 0.
Stream => 0|1This option controls whether the zip file/buffer output is created in streaming mode.
Note that when outputting to a file with streaming mode disabled (Stream is 0), the output file must be seekable.
The default is 1.
Zip64 => 0|1Create a Zip64 zip file/buffer. This option is used if you want to store files larger than 4 Gig or store more than 64K files in a single zip archive.
Zip64 will be automatically set, as needed, if working with the one-shot interface when the input is either a filename or a scalar reference.
If you intend to manipulate the Zip64 zip files created with this module using an external zip/unzip, make sure that it supports Zip64.
In particular, if you are using Info-Zip you need to have zip version 3.x or better to update a Zip64 archive and unzip version 6.x to read a zip64 archive.
The default is 0.
Defines the compression level used by zlib. The value should either be a number between 0 and 9 (0 means no compression and 9 is maximum compression), or one of the symbolic constants defined below.
Z_NO_COMPRESSION
Z_BEST_SPEED
Z_BEST_COMPRESSION
Z_DEFAULT_COMPRESSIONThe default is Z_DEFAULT_COMPRESSION.
Note, these constants are not imported by IO::Compress::Zip by default.
use IO::Compress::Zip qw(:strategy);
use IO::Compress::Zip qw(:constants);
use IO::Compress::Zip qw(:all);Defines the strategy used to tune the compression. Use one of the symbolic constants defined below.
Z_FILTERED
Z_HUFFMAN_ONLY
Z_RLE
Z_FIXED
Z_DEFAULT_STRATEGYThe default is Z_DEFAULT_STRATEGY.
BlockSize100K => numberSpecify the number of 100K blocks bzip2 uses during compression.
Valid values are from 1 to 9, where 9 is best compression.
This option is only valid if the Method is ZIP_CM_BZIP2. It is ignored otherwise.
The default is 1.
WorkFactor => numberSpecifies how much effort bzip2 should take before resorting to a slower fallback compression algorithm.
Valid values range from 0 to 250, where 0 means use the default value 30.
This option is only valid if the Method is ZIP_CM_BZIP2. It is ignored otherwise.
The default is 0.
Preset => numberUsed to choose the LZMA compression preset.
Valid values are 0-9 and LZMA_PRESET_DEFAULT.
0 is the fastest compression with the lowest memory usage and the lowest compression.
9 is the slowest compression with the highest memory usage but with the best compression.
This option is only valid if the Method is ZIP_CM_LZMA. It is ignored otherwise.
Defaults to LZMA_PRESET_DEFAULT (6).
Extreme => 0|1Makes LZMA compression a lot slower, but a small compression gain.
This option is only valid if the Method is ZIP_CM_LZMA. It is ignored otherwise.
Defaults to 0.
Time => $numberSets the last modified time field in the zip header to $number.
This field defaults to the time the IO::Compress::Zip object was created if this option is not specified and the $input parameter is not a filename.