```{index} single: IO::Compress::Zip ``` # IO::Compress::Zip Write zip files/buffers ## SYNOPSIS ```perl 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 ; ``` ## DESCRIPTION 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 - Store (0) - Deflate (8) - Bzip2 (12) To write Bzip2 content, the module `IO::Uncompress::Bunzip2` must be installed. - Lzma (14) To write LZMA content, the module `IO::Uncompress::UnLzma` must be installed. - Zstandard (93) To write Zstandard content, the module `IO::Compress::Zstd` must be installed. - Xz (95) To write Xz content, the module `IO::Uncompress::UnXz` must be installed. For reading zip files/buffers, see the companion module [IO::Uncompress::Unzip](../Uncompress/Unzip.md). ## Functional Interface 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. ```perl 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 $input\_filename\_or\_reference => $output\_filename\_or\_reference \[, OPTS\] `zip` expects at least two parameters, `$input_filename_or_reference` and `$output_filename_or_reference` and zero or more optional parameters (see "Optional Parameters") #### The `$input_filename_or_reference` parameter The parameter, `$input_filename_or_reference`, is used to define the source of the uncompressed data. It can take one of the following forms: - A filename If the `$input_filename_or_reference` parameter is a simple scalar, it is assumed to be a filename. This file will be opened for reading and the input data will be read from it. - A filehandle If the `$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. - A scalar reference If `$input_filename_or_reference` is a scalar reference, the input data will be read from `$$input_filename_or_reference`. - An array reference If `$input_filename_or_reference` is an array reference, each element in the array must be a filename. The input data will be read from each file in turn. The complete array will be walked to ensure that it only contains valid filenames before any data is compressed. - An Input FileGlob string If `$input_filename_or_reference` is a string that is delimited by the characters "<" and ">" `zip` will assume that it is an _input fileglob string_. The input is the list of files that match the fileglob. See [File::GlobMapper](../../File/GlobMapper.md) for more details. If the `$input_filename_or_reference` parameter is any other type, `undef` will be returned. In addition, if `$input_filename_or_reference` corresponds to a filename from the filesystem, a number of zip file header fields will be populated by default using the following attributes from the input file - the full filename contained in `$input_filename_or_reference` - the file protection attributes - the UID/GID for the file - the file timestamps If you do not want to use these defaults they can be overridden by explicitly setting one, or more, of the `Name`, `Time`, `TextFlag`, `ExtAttr`, `exUnixN` and `exTime` options or by setting the `Minimal` parameter. #### The `$output_filename_or_reference` parameter The parameter `$output_filename_or_reference` is used to control the destination of the compressed data. This parameter can take one of these forms. - A filename If the `$output_filename_or_reference` parameter is a simple scalar, it is assumed to be a filename. This file will be opened for writing and the compressed data will be written to it. - A filehandle If the `$output_filename_or_reference` parameter is a filehandle, the compressed data will be written to it. The string '-' can be used as an alias for standard output. - A scalar reference If `$output_filename_or_reference` is a scalar reference, the compressed data will be stored in `$$output_filename_or_reference`. - An Array Reference If `$output_filename_or_reference` is an array reference, the compressed data will be pushed onto the array. - An Output FileGlob If `$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](../../File/GlobMapper.md) for more details. If the `$output_filename_or_reference` parameter is any other type, `undef` will be returned. ### Notes When `$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. ### Optional Parameters 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|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` This option is now a no-op. All files will be read in binmode. - `Append => 0|1` The 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. ### Oneshot Examples Here are a few example that show the capabilities of the module. #### Streaming 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. ```perl $ echo hello world | perl -MIO::Compress::Zip=zip -e 'zip \*STDIN => \*STDOUT' >output.zip ``` The special filename "-" can be used as a standin for both `\*STDIN` and `\*STDOUT`, so the above can be rewritten as ```perl $ echo hello world | perl -MIO::Compress::Zip=zip -e 'zip "-" => "-"' >output.zip ``` One 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. ```text $ unzip -l output.zip Archive: output.zip Length Date Time Name --------- ---------- ----- ---- 12 2019-08-16 22:21 --------- ------- 12 1 file ``` The 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 ```perl echo hello world | perl -MIO::Compress::Zip=zip -e 'zip "-" => "-", Name => "hello.txt"' >output.zip ``` Now the contents of the zip file looks like this ```text $ unzip -l output.zip Archive: output.zip Length Date Time Name --------- ---------- ----- ---- 12 2019-08-16 22:22 hello.txt --------- ------- 12 1 file ``` #### Compressing a file from the filesystem To read the contents of the file `file1.txt` and write the compressed data to the file `file1.txt.zip`. ```perl use strict ; use warnings ; use IO::Compress::Zip qw(zip $ZipError) ; my $input = "file1.txt"; zip $input => "$input.zip" or die "zip failed: $ZipError\n"; ``` #### Reading from a Filehandle and writing to an in-memory buffer To read from an existing Perl filehandle, `$input`, and write the compressed data to a buffer, `$buffer`. ```perl use strict ; use warnings ; use IO::Compress::Zip qw(zip $ZipError) ; use IO::File ; my $input = IO::File->new( " \$buffer or die "zip failed: $ZipError\n"; ``` #### Compressing multiple files To create a zip file, `output.zip`, that contains the compressed contents of the files `alpha.txt` and `beta.txt` ```perl 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 ```perl 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 ```perl zip [ <*.txt> ] => 'output.zip' or die "zip failed: $ZipError\n"; ``` ## OO Interface ### Constructor The format of the constructor for `IO::Compress::Zip` is shown below ```perl my $z = IO::Compress::Zip->new( $output [,OPTS] ) or die "IO::Compress::Zip failed: $ZipError\n"; ``` The constructor takes one mandatory parameter, `$output`, defined below and zero or more `OPTS`, defined in "Constructor Options". 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](../File.md) 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 ```perl $z->print("hello world\n"); print $z "hello world\n"; ``` Below is a simple exaple of using the OO interface to create an output file `myfile.zip` and write some data to it. ```perl my $filename = "myfile.zip"; my $z = IO::Compress::Zip->new($filename) or die "IO::Compress::Zip failed: $ZipError\n"; $z->print("abcde"); $z->close(); ``` See the "Examples" for more. The mandatory parameter `$output` is used to control the destination of the compressed data. This parameter can take one of these forms. - A filename If the `$output` parameter is a simple scalar, it is assumed to be a filename. This file will be opened for writing and the compressed data will be written to it. - A filehandle If the `$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`. If the `$output` parameter is any other type, `IO::Compress::Zip`::new will return undef. ### Constructor Options `OPTS` is any combination of zero or more the following options: - `AutoClose => 0|1` This option is only valid when the `$output` parameter is a filehandle. If specified, and the value is true, it will result in the `$output` being closed once either the `close` method is called or the `IO::Compress::Zip` object is destroyed. This parameter defaults to 0. - `Append => 0|1` Opens `$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 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. #### File Naming Options 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 => $string` This option is used to explicitly set the _archive member name_ in the zip archive to `$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|1` This 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. ```text 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`. ```perl sub compressTxtFiles { my $zipfile = shift ; my $dir = shift ; zip [ <$dir/*.txt> ] => $zipfile, FilterName => sub { s[^$dir/][] } ; } ``` - `Efs => 0|1` This 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**. #### Overall Zip Archive Structure - `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`, `exUnixN`, `ExtraFieldLocal` and `ExtraFieldCentral` options will be ignored. This parameter defaults to 0. - `Stream => 0|1` This 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|1` Create 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. #### Deflate Compression Options - -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. ```text 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. ```perl 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. ```text Z_FILTERED Z_HUFFMAN_ONLY Z_RLE Z_FIXED Z_DEFAULT_STRATEGY ``` The default is Z\_DEFAULT\_STRATEGY. #### Bzip2 Compression Options - `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. #### Lzma and Xz Compression Options - `Preset => number` Used 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|1` Makes 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. #### Other Options - `Time => $number` Sets the last modified time field in the zip header to $number. This field defaults to the time the `IO::Compress::Zip` object was created if this option is not specified and the `$input` parameter is not a filename. - `ExtAttr => $attr` This option controls the "external file attributes" field in the central header of the zip file. This is a 4 byte field. If you are running a Unix derivative this value defaults to ```text 0100644 << 16 ``` This should allow read/write access to any files that are extracted from the zip file/buffer\`. For all other systems it defaults to 0. - `exTime => [$atime, $mtime, $ctime]` This option expects an array reference with exactly three elements: `$atime`, `mtime` and `$ctime`. These correspond to the last access time, last modification time and creation time respectively. 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 ```perl 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 `$gid`. These values correspond to the numeric User ID (UID) and Group ID (GID) of the owner of the files respectively. When the `exUnix2` option is present it will trigger the creation of a Unix2 extra field (ID is "Ux") in the local zip header. This will be populated with `$uid` and `$gid`. An empty Unix2 extra field will also be created in the central zip header. Note - The UID & GID are stored as 16-bit integers in the "Ux" field. Use `exUnixN` if your UID or GID are 32-bit. If the `Minimal` option is set to true, this option will be ignored. By default no Unix2 extra field is created. - `exUnixN => [$uid, $gid]` This option expects an array reference with exactly two elements: `$uid` and `$gid`. These values correspond to the numeric User ID (UID) and Group ID (GID) of the owner of the files respectively. When the `exUnixN` option is present it will trigger the creation of a UnixN extra field (ID is "ux") in both the local and central zip headers. This will be populated with `$uid` and `$gid`. The UID & GID are stored as 32-bit integers. If the `Minimal` option is set to true, this option will be ignored. By default no UnixN extra field is created. - `Comment => $comment` Stores the contents of `$comment` in the Central File Header of the zip file. Set the `Efs` option to true if you want to store a UTF8 comment. 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 the compression methods supported are: Store (no compression at all), Deflate, Bzip2, Zstd, Xz and Lzma. The symbols ZIP\_CM\_STORE, ZIP\_CM\_DEFLATE, ZIP\_CM\_BZIP2, ZIP\_CM\_ZSTD, ZIP\_CM\_XZ and ZIP\_CM\_LZMA are used to select the compression method. These constants are not imported by `IO::Compress::Zip` by default. ```perl 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::Compress::Bzip2` must be installed. A fatal error will be thrown if you attempt to create Bzip2 content when `IO::Compress::Bzip2` is not available. Note that to create Lzma content, the module `IO::Compress::Lzma` must be installed. A fatal error will be thrown if you attempt to create Lzma content when `IO::Compress::Lzma` is not available. Note that to create Xz content, the module `IO::Compress::Xz` must be installed. A fatal error will be thrown if you attempt to create Xz content when `IO::Compress::Xz` is not available. Note that to create Zstd content, the module `IO::Compress::Zstd` must be installed. A fatal error will be thrown if you attempt to create Zstd content when `IO::Compress::Zstd` is not available. The default method is ZIP\_CM\_DEFLATE. - `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. In one-shot mode this flag will be set to true if the Perl `-T` operator thinks the file contains text. The default is 0. - `ExtraFieldLocal => $data` - `ExtraFieldCentral => $data` The `ExtraFieldLocal` option is used to store additional metadata in the local header for the zip file/buffer. The `ExtraFieldCentral` does the same for the matching central header. An extra field consists of zero or more subfields. Each subfield consists of a two byte header followed by the subfield data. The list of subfields can be supplied in any of the following formats ```perl ExtraFieldLocal => [$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 SubFields with duplicate ID. Alternatively the list of subfields can by supplied as a scalar, thus ```perl ExtraField => $rawdata ``` In this case `IO::Compress::Zip` will check that `$rawdata` consists of zero or more conformant sub-fields. 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. - `Strict => 0|1` This is a placeholder option. ### Examples #### Streaming This very simple command line example demonstrates the streaming capabilities of the module. The code reads data from STDIN or all the files given on the commandline, compresses it, and writes the compressed data to STDOUT. ```perl use strict ; use warnings ; use IO::Compress::Zip qw(zip $ZipError) ; my $z = IO::Compress::Zip->new("-", Stream => 1) or die "IO::Compress::Zip failed: $ZipError\n"; while (<>) { $z->print("abcde"); } $z->close(); ``` Note the use of `"-"` to means `STDOUT`. Alternatively you can use `\*STDOUT`. One 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 (assumg you have redirected it to a file called `output.zip`). ```text $ unzip -l output.zip Archive: output.zip Length Date Time Name --------- ---------- ----- ---- 12 2019-08-16 22:21 --------- ------- 12 1 file ``` The 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 ```perl my $z = IO::Compress::Zip->new("-", Name => "hello.txt", Stream => 1) ``` Now the contents of the zip file looks like this ```text $ unzip -l output.zip Archive: output.zip Length Date Time Name --------- ---------- ----- ---- 12 2019-08-16 22:22 hello.txt --------- ------- 12 1 file ``` #### Compressing a file from the filesystem To read the contents of the file `file1.txt` and write the compressed data to the file `file1.txt.zip` there are a few options Start by creating the compression object and opening the input file ```perl use strict ; use warnings ; use IO::Compress::Zip qw(zip $ZipError) ; my $input = "file1.txt"; my $z = IO::Compress::Zip->new("file1.txt.zip") or die "IO::Compress::Zip failed: $ZipError\n"; ## open the input file open my $fh, "<", "file1.txt" or die "Cannot open file1.txt: $!\n"; ## loop through the input file & write to the compressed file while (<$fh>) { $z->print($_); } ## not forgetting to close the compressed file $z->close(); ``` #### Compressing multiple files To create a zip file, `output.zip`, that contains the compressed contents of the files `alpha.txt` and `beta.txt` ```perl use strict ; use warnings ; use IO::Compress::Zip qw(zip $ZipError) ; my $z = IO::Compress::Zip->new("output.zip", Name => "alpha.txt") or die "IO::Compress::Zip failed: $ZipError\n"; ## open the input file open my $fh, "<", "file1.txt" or die "Cannot open file1.txt: $!\n"; ## loop through the input file & write to the compressed file while (<$fh>) { $z->print($_); } ## move to next file $z->newStream(Name => "beta.txt") while (<$fh>) { $z->print($_); } $z->close(); ``` ## Methods ### print Usage is ```perl $z->print($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 ```perl $z->printf($format, $data) printf $z $format, $data ``` Compresses and outputs the contents of the `$data` parameter. Returns true if successful. ### syswrite Usage is ```perl $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 unsuccessful. ### write Usage is ```perl $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 unsuccessful. ### flush Usage is ```perl $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 recommended 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 ```perl $z->tell() tell $z ``` Returns the uncompressed file offset. ### eof Usage is ```perl $z->eof(); eof($z); ``` Returns true if the `close` method has been called. ### seek ```perl $z->seek($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 ```perl $z->binmode binmode $z ; ``` This is a noop provided for completeness. ### opened ```perl $z->opened() ``` Returns true if the object currently refers to a opened file/buffer. ### autoflush ```perl 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 filehandle. 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 ```perl $z->input_line_number() $z->input_line_number(EXPR) ``` This method always returns `undef` when compressing. ### fileno ```perl $z->fileno() fileno($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 associated with a buffer, this method will return `undef`. ### close ```perl $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 terminating. 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 ```perl $z->newStream( [OPTS] ) ``` Closes the current compressed data stream and starts a new one. OPTS consists of any of the options that are available when creating the `$z` object. See the "Constructor Options" section for more details. ### deflateParams Usage is ```perl $z->deflateParams ``` TODO ## Importing A number of symbolic constants are required by some methods in `IO::Compress::Zip`. None are imported by default. - :all Imports `zip`, `$ZipError` and all symbolic constants that can be used by `IO::Compress::Zip`. Same as doing this ```perl use IO::Compress::Zip qw(zip $ZipError :constants) ; ``` - :constants Import all symbolic constants. Same as doing this ```perl use IO::Compress::Zip qw(:flush :level :strategy :zip_method) ; ``` - :flush These symbolic constants are used by the `flush` method. ```text 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. ```text 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. ```text 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. ```text ZIP_CM_STORE ZIP_CM_DEFLATE ZIP_CM_BZIP2 ``` ## EXAMPLES ### Apache::GZip Revisited See [IO::Compress::FAQ](https://metacpan.org/pod/IO::Compress::FAQ#Apache-GZip-Revisited) ### Working with Net::FTP See [IO::Compress::FAQ](https://metacpan.org/pod/IO::Compress::FAQ#Compressed-files-and-Net-FTP) ## SUPPORT General feedback/questions/bug reports should be sent to [https://github.com/pmqs/IO-Compress/issues](https://github.com/pmqs/IO-Compress/issues) (preferred) or [https://rt.cpan.org/Public/Dist/Display.html?Name=IO-Compress](https://rt.cpan.org/Public/Dist/Display.html?Name=IO-Compress). ## SEE ALSO [Compress::Zlib](../../Compress/Zlib.md), [IO::Compress::Gzip](Gzip.md), [IO::Uncompress::Gunzip](../Uncompress/Gunzip.md), [IO::Compress::Deflate](Deflate.md), [IO::Uncompress::Inflate](../Uncompress/Inflate.md), [IO::Compress::RawDeflate](RawDeflate.md), [IO::Uncompress::RawInflate](../Uncompress/RawInflate.md), [IO::Compress::Bzip2](Bzip2.md), [IO::Uncompress::Bunzip2](../Uncompress/Bunzip2.md), [IO::Compress::Lzma](https://metacpan.org/pod/IO::Compress::Lzma), [IO::Uncompress::UnLzma](https://metacpan.org/pod/IO::Uncompress::UnLzma), [IO::Compress::Xz](https://metacpan.org/pod/IO::Compress::Xz), [IO::Uncompress::UnXz](https://metacpan.org/pod/IO::Uncompress::UnXz), [IO::Compress::Lzip](https://metacpan.org/pod/IO::Compress::Lzip), [IO::Uncompress::UnLzip](https://metacpan.org/pod/IO::Uncompress::UnLzip), [IO::Compress::Lzop](https://metacpan.org/pod/IO::Compress::Lzop), [IO::Uncompress::UnLzop](https://metacpan.org/pod/IO::Uncompress::UnLzop), [IO::Compress::Lzf](https://metacpan.org/pod/IO::Compress::Lzf), [IO::Uncompress::UnLzf](https://metacpan.org/pod/IO::Uncompress::UnLzf), [IO::Compress::Zstd](https://metacpan.org/pod/IO::Compress::Zstd), [IO::Uncompress::UnZstd](https://metacpan.org/pod/IO::Uncompress::UnZstd), [IO::Uncompress::AnyInflate](../Uncompress/AnyInflate.md), [IO::Uncompress::AnyUncompress](../Uncompress/AnyUncompress.md) [IO::Compress::FAQ](https://metacpan.org/pod/IO::Compress::FAQ) [File::GlobMapper](../../File/GlobMapper.md), [Archive::Zip](https://metacpan.org/pod/Archive::Zip), [Archive::Tar](../../Archive/Tar.md), [IO::Zlib](../Zlib.md) For RFC 1950, 1951 and 1952 see [https://datatracker.ietf.org/doc/html/rfc1950](https://datatracker.ietf.org/doc/html/rfc1950), [https://datatracker.ietf.org/doc/html/rfc1951](https://datatracker.ietf.org/doc/html/rfc1951) and [https://datatracker.ietf.org/doc/html/rfc1952](https://datatracker.ietf.org/doc/html/rfc1952) 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](http://www.zlib.org). The primary site for the _zlib-ng_ compression library is [https://github.com/zlib-ng/zlib-ng](https://github.com/zlib-ng/zlib-ng). The primary site for gzip is [http://www.gzip.org](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) 2005-2026 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.