IO::Compress::Zip
IO::Compress::Zip(3) User Contributed Perl Documentation IO::Compress::Zip(3)
NAME
IO::Compress::Zip - Write zip files/buffers
SYNOPSIS
use IO::Compress::Zip qw(zip $ZipError) ;
my $status = zip $input => $output [,OPTS]
or die "zip failed: $ZipError\n";
my $z = new IO::Compress::Zip $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 ;
DESCRIPTION
This module provides a Perl interface that allows writing zip com-
pressed data to files or buffer.
The primary purpose of this module is to provide streaming write
access to zip files and buffers. It is not a general-purpose file
archiver. If that is what you want, check out "Archive::Zip".
At present three compression methods are supported by IO::Com-
press::Zip, namely Store (no compression at all), Deflate and Bzip2.
Note that to create Bzip2 content, the module "IO::Compress::Bzip2"
must be installed.
For reading zip files/buffers, see the companion module IO::Uncom-
press::Unzip.
Functional Interface
A top-level function, "zip", is provided to carry out "one-shot" com-
pression 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 => $output [,OPTS]
or die "zip failed: $ZipError\n";
The functional interface needs Perl5.005 or better.
zip $input => $output [, OPTS]
"zip" expects at least two parameters, $input and $output.
The $input parameter
The parameter, $input, is used to define the source of the uncom-
pressed data.
It can take one of the following forms:
A filename
If the $input 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.
A filehandle
If the $input parameter is a filehandle, the input data will be
read from it. The string ’-’ can be used as an alias for stan-
dard input.
A scalar reference
If $input is a scalar reference, the input data will be read from
$$input.
An array reference
If $input is an array reference, each element in the array must
be a filename.
The input data will be read from each file in turn.
The complete array will be walked to ensure that it only contains
valid filenames before any data is compressed.
An Input FileGlob string
If $input is a string that is delimited by the characters "<" and
">" "zip" will assume that it is an input fileglob string. The
input is the list of files that match the fileglob.
If the fileglob does not match any files ...
See File::GlobMapper for more details.
If the $input parameter is any other type, "undef" will be returned.
In addition, if $input is a simple filename, the default values for
the "Name", "Time", "ExtAttr" and "exTime" options will be sourced
from that file.
If you do not want to use these defaults they can be overridden by
explicitly setting the "Name", "Time", "ExtAttr" and "exTime" options
or by setting the "Minimal" parameter.
The $output parameter
The parameter $output is used to control the destination of the com-
pressed data. This parameter can take one of these forms.
A filename
If the $output parameter is a simple scalar, it is assumed to be
a filename. This file will be opened for writing and the
compressed data will be written to it.
A filehandle
If the $output parameter is a filehandle, the compressed data
will be written to it. The string ’-’ can be used as an alias
for standard output.
A scalar reference
If $output is a scalar reference, the compressed data will be
stored in $$output.
An Array Reference
If $output is an array reference, the compressed data will be
pushed onto the array.
An Output FileGlob
If $output 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 is an fileglob string, $input must also be a file-
glob string. Anything else is an error.
If the $output parameter is any other type, "undef" will be returned.
Notes
When $input maps to multiple files/buffers and $output is a single
file/buffer the input files/buffers will each be stored in $output as
a distinct entry.
Optional Parameters
Unless specified below, the optional parameters for "zip", "OPTS", are
the same as those used with the OO interface defined in the "Construc-
tor Options" section below.
"AutoClose => 0│1"
This 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│1"
When reading from a file or filehandle, set "binmode" before
reading.
Defaults to 0.
"Append => 0│1"
TODO
Examples
To 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 = new IO::File "<file1.txt"
or die "Cannot open ’file1.txt’: $!\n" ;
my $buffer ;
zip $input => \$buffer
or die "zip failed: $ZipError\n";
To compress all files in the directory "/my/home" that match "*.txt"
and store the compressed data in the same directory
use strict ;
use warnings ;
use IO::Compress::Zip qw(zip $ZipError) ;
zip ’</my/home/*.txt>’ => ’<*.zip>’
or die "zip failed: $ZipError\n";
and if you want to compress each file one at a time, this will do the
trick
use strict ;
use warnings ;
use IO::Compress::Zip qw(zip $ZipError) ;
for my $input ( glob "/my/home/*.txt" )
{
my $output = "$input.zip" ;
zip $input => $output
or die "Error compressing ’$input’: $ZipError\n";
}
OO Interface
Constructor
The format of the constructor for "IO::Compress::Zip" is shown below
my $z = new IO::Compress::Zip $output [,OPTS]
or die "IO::Compress::Zip failed: $ZipError\n";
It returns an "IO::Compress::Zip" object on success and undef on fail-
ure. 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.
A filename
If the $output parameter is a simple scalar, it is assumed to be
a filename. This file will be opened for writing and the com-
pressed data will be written to it.
A filehandle
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.
A scalar reference
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.
Constructor Options
"OPTS" is any combination of the following options:
"AutoClose => 0│1"
This option is only valid when the $output parameter is a file-
handle. 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│1"
Opens $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 com-
pressed data will be append to the end if $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 posi-
tioned 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.
"Name => $string"
Stores the contents of $string in the zip filename header field.
If "Name" is not specified, no zip filename field will be cre-
ated.
"Time => $number"
Sets 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.
"ExtAttr => $attr"
This option controls the "external file attributes" field in the
central header of the zip file. This is a 4 byte field.
If you are running a Unix derivative this value defaults to
0666 << 16
This should allow read/write access to any files that are
extracted from the zip file/buffer.
For all other systems it defaults to 0.
"exTime => [$atime, $mtime, $ctime]"
This option expects an array reference with exactly three ele-
ments: $atime, "mtime" and $ctime. These correspond to the last
access time, last modification time and creation time respec-
tively.
It uses these values to set the extended timestamp field (ID is
"UT") in the local zip header using the three values, $atime,
$mtime, $ctime. In addition it sets the extended timestamp field
in the central zip header using $mtime.
If any of the three values is "undef" that time value will not be
used. So, for example, to set only the $mtime you would use this
exTime => [undef, $mtime, undef]
If the "Minimal" option is set to true, this option will be
ignored.
By default no extended time field is created.
"exUnix2 => [$uid, $gid]"
This option expects an array reference with exactly two elements:
$uid and $gid. These values correspond to the numeric user ID and
group ID of the owner of the files respectively.
When the "exUnix2" option is present it will trigger the creation
of a Unix2 extra field (ID is "Ux") in the local zip. This will
be populated with $uid and $gid. In addition an empty Unix2 extra
field will also be created in the central zip header
If the "Minimal" option is set to true, this option will be
ignored.
By default no Unix2 extra field is created.
"Comment => $comment"
Stores the contents of $comment in the Central File Header of the
zip file.
By default, no comment field is written to the zip file.
"ZipComment => $comment"
Stores the contents of $comment in the End of Central Directory
record of the zip file.
By default, no comment field is written to the zip file.
"Method => $method"
Controls which compression method is used. At present three com-
pression methods are supported, namely Store (no compression at
all), Deflate and Bzip2.
The symbols, ZIP_CM_STORE, ZIP_CM_DEFLATE and ZIP_CM_BZIP2 are
used to select the compression method.
These constants are not imported by "IO::Compress::Zip" by
default.
use IO::Compress::Zip qw(:zip_method);
use IO::Compress::Zip qw(:constants);
use IO::Compress::Zip qw(:all);
Note that to create Bzip2 content, the module "IO::Com-
press::Bzip2" must be installed. A fatal error will be thrown if
you attempt to create Bzip2 content when "IO::Compress::Bzip2" is
not available.
The default method is ZIP_CM_DEFLATE.
"Stream => 0│1"
This option controls whether the zip file/buffer output is cre-
ated 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│1"
Create a Zip64 zip file/buffer. This option should only be used
if you want to store files larger than 4 Gig.
If you intend to manipulate the Zip64 zip files created with this
module using an external zip/unzip make sure that it supports
streaming 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. At the time of writing both are beta
status.
When the "Zip64" option is enabled, the "Stream" option must be
enabled as well.
The default is 0.
"TextFlag => 0│1"
This parameter controls the setting of a bit in the zip central
header. It is used to signal that the data stored in the zip
file/buffer is probably text.
The default is 0.
"ExtraFieldLocal => $data" =item "ExtraFieldCentral => $data"
The "ExtraFieldLocal" option is used to store additional metadata
in the local header for the zip file/buffer. The "ExtraFieldCen-
tral" does the same for the matching central header.
An extra field consists of zero or more subfields. Each subfield
consists of a two byte header followed by the subfield data.
The list of subfields can be supplied in any of the following
formats
ExtraFieldLocal => [$id1, $data1,
$id2, $data2,
...
]
ExtraFieldLocal => [ [$id1 => $data1],
[$id2 => $data2],
...
]
ExtraFieldLocal => { $id1 => $data1,
$id2 => $data2,
...
}
Where $id1, $id2 are two byte subfield ID’s.
If you use the hash syntax, you have no control over the order in
which the ExtraSubFields are stored, plus you cannot have Sub-
Fields with duplicate ID.
Alternatively the list of subfields can by supplied as a scalar,
thus
ExtraField => $rawdata
The Extended Time field (ID "UT"), set using the "exTime" option,
and the Unix2 extra field (ID "Ux), set using the "exUnix2"
option, are examples of extra fields.
If the "Minimal" option is set to true, this option will be
ignored.
The maximum size of an extra field 65535 bytes.
"Minimal => 1│0"
If specified, this option will disable the creation of all extra
fields in the zip local and central headers. So the "exTime",
"exUnix2", "ExtraFieldLocal" and "ExtraFieldCentral" options will
be ignored.
This parameter defaults to 0.
"BlockSize100K => number"
Specify 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 => number"
Specifies 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.
-Level
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_COMPRESSION
The 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);
-Strategy
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_STRATEGY
The default is Z_DEFAULT_STRATEGY.
"Strict => 0│1"
This is a placeholder option.
Examples
TODO
Methods
print
Usage is
$z->print($data)
print $z $data
Compresses and outputs the contents of the $data parameter. This has
the same behaviour as the "print" built-in.
Returns true if successful.
printf
Usage is
$z->printf($format, $data)
printf $z $format, $data
Compresses and outputs the contents of the $data parameter.
Returns true if successful.
syswrite
Usage is
$z->syswrite $data
$z->syswrite $data, $length
$z->syswrite $data, $length, $offset
Compresses and outputs the contents of the $data parameter.
Returns the number of uncompressed bytes written, or "undef" if unsuc-
cessful.
write
Usage is
$z->write $data
$z->write $data, $length
$z->write $data, $length, $offset
Compresses and outputs the contents of the $data parameter.
Returns the number of uncompressed bytes written, or "undef" if unsuc-
cessful.
flush
Usage is
$z->flush;
$z->flush($flush_type);
Flushes any pending compressed data to the output file/buffer.
This method takes an optional parameter, $flush_type, that controls
how the flushing will be carried out. By default the $flush_type used
is "Z_FINISH". Other valid values for $flush_type are "Z_NO_FLUSH",
"Z_SYNC_FLUSH", "Z_FULL_FLUSH" and "Z_BLOCK". It is strongly recom-
mended that you only set the "flush_type" parameter if you fully
understand the implications of what it does - overuse of "flush" can
seriously degrade the level of compression achieved. See the "zlib"
documentation for details.
Returns true on success.
tell
Usage is
$z->tell()
tell $z
Returns the uncompressed file offset.
eof
Usage is
$z->eof();
eof($z);
Returns true if the "close" method has been called.
seek
$z->seek($position, $whence);
seek($z, $position, $whence);
Provides a sub-set of the "seek" functionality, with the restriction
that it is only legal to seek forward in the output file/buffer. It
is a fatal error to attempt to seek backward.
Empty parts of the file/buffer will have NULL (0x00) bytes written to
them.
The $whence parameter takes one the usual values, namely SEEK_SET,
SEEK_CUR or SEEK_END.
Returns 1 on success, 0 on failure.
binmode
Usage is
$z->binmode
binmode $z ;
This is a noop provided for completeness.
opened
$z->opened()
Returns true if the object currently refers to a opened file/buffer.
autoflush
my $prev = $z->autoflush()
my $prev = $z->autoflush(EXPR)
If the $z object is associated with a file or a filehandle, this
method returns the current autoflush setting for the underlying file-
handle. If "EXPR" is present, and is non-zero, it will enable flushing
after every write/print operation.
If $z is associated with a buffer, this method has no effect and
always returns "undef".
Note that the special variable $│ cannot be used to set or retrieve
the autoflush setting.
input_line_number
$z->input_line_number()
$z->input_line_number(EXPR)
This method always returns "undef" when compressing.
fileno
$z->fileno()
fileno($z)
If the $z object is associated with a file or a filehandle, "fileno"
will return the underlying file descriptor. Once the "close" method is
called "fileno" will return "undef".
If the $z object is is associated with a buffer, this method will
return "undef".
close
$z->close() ;
close $z ;
Flushes any pending compressed data and then closes the output
file/buffer.
For most versions of Perl this method will be automatically invoked if
the IO::Compress::Zip object is destroyed (either explicitly or by the
variable with the reference to the object going out of scope). The
exceptions are Perl versions 5.005 through 5.00504 and 5.8.0. In these
cases, the "close" method will be called automatically, but not until
global destruction of all live objects when the program is terminat-
ing.
Therefore, if you want your scripts to be able to run on all versions
of Perl, you should call "close" explicitly and not rely on automatic
closing.
Returns true on success, otherwise 0.
If the "AutoClose" option has been enabled when the IO::Compress::Zip
object was created, and the object is associated with a file, the
underlying file will also be closed.
newStream([OPTS])
Usage is
$z->newStream( [OPTS] )
Closes the current compressed data stream and starts a new one.
OPTS consists of any of the the options that are available when creat-
ing the $z object.
See the "Constructor Options" section for more details.
deflateParams
Usage is
$z->deflateParams
TODO
Importing
A number of symbolic constants are required by some methods in
"IO::Compress::Zip". None are imported by default.
:all Imports "zip", $ZipError and all symbolic constants that can be
used by "IO::Compress::Zip". Same as doing this
use IO::Compress::Zip qw(zip $ZipError :constants) ;
:constants
Import all symbolic constants. Same as doing this
use IO::Compress::Zip qw(:flush :level :strategy :zip_method) ;
:flush
These symbolic constants are used by the "flush" method.
Z_NO_FLUSH
Z_PARTIAL_FLUSH
Z_SYNC_FLUSH
Z_FULL_FLUSH
Z_FINISH
Z_BLOCK
:level
These symbolic constants are used by the "Level" option in the
constructor.
Z_NO_COMPRESSION
Z_BEST_SPEED
Z_BEST_COMPRESSION
Z_DEFAULT_COMPRESSION
:strategy
These symbolic constants are used by the "Strategy" option in the
constructor.
Z_FILTERED
Z_HUFFMAN_ONLY
Z_RLE
Z_FIXED
Z_DEFAULT_STRATEGY
:zip_method
These symbolic constants are used by the "Method" option in the
constructor.
ZIP_CM_STORE
ZIP_CM_DEFLATE
ZIP_CM_BZIP2
EXAMPLES
Apache::GZip Revisited
See IO::Compress::FAQ
Working with Net::FTP
See IO::Compress::FAQ
SEE ALSO
Compress::Zlib, IO::Compress::Gzip, IO::Uncompress::Gunzip, IO::Com-
press::Deflate, IO::Uncompress::Inflate, IO::Compress::RawDeflate,
IO::Uncompress::RawInflate, IO::Compress::Bzip2, IO::Uncompress::Bun-
zip2, IO::Compress::Lzop, IO::Uncompress::UnLzop, IO::Compress::Lzf,
IO::Uncompress::UnLzf, IO::Uncompress::AnyInflate, IO::Uncom-
press::AnyUncompress
Compress::Zlib::FAQ
File::GlobMapper, Archive::Zip, Archive::Tar, IO::Zlib
For RFC 1950, 1951 and 1952 see http://www.faqs.org/rfcs/rfc1950.html,
http://www.faqs.org/rfcs/rfc1951.html and
http://www.faqs.org/rfcs/rfc1952.html
The zlib compression library was written by Jean-loup Gailly
gzip@prep.ai.mit.edu and Mark Adler madler@alumni.caltech.edu.
The primary site for the zlib compression library is
http://www.zlib.org.
The primary site for gzip is http://www.gzip.org.
AUTHOR
This module was written by Paul Marquess, pmqs@cpan.org.
MODIFICATION HISTORY
See the Changes file.
COPYRIGHT AND LICENSE
Copyright (c) 2005-2009 Paul Marquess. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
perl v5.8.8 2009-03-28 IO::Compress::Zip(3)
