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Data::MessagePack - MessagePack serializing/deserializing


    use Data::MessagePack;

    my $mp = Data::MessagePack->new();
    $mp->canonical->utf8->prefer_integer if $needed;

    my $packed   = $mp->pack($dat);
    my $unpacked = $mp->unpack($dat);


This module converts Perl data structures to MessagePack and vice versa.


MessagePack is a binary-based efficient object serialization format. It enables to exchange structured objects between many languages like JSON. But unlike JSON, it is very fast and small.



The MessagePack format does not depend on language nor byte order.

    say length(JSON::XS::encode_json({a=>1, b=>2}));   # => 13
    say length(Storable::nfreeze({a=>1, b=>2}));       # => 21
    say length(Data::MessagePack->pack({a=>1, b=>2})); # => 7

The MessagePack format saves memory than JSON and Storable format.


MessagePack supports streaming deserializer. It is useful for networking such as RPC. See Data::MessagePack::Unpacker for details.

If you want to get more information about the MessagePack format, please visit to


my $packed = Data::MessagePack->pack($data[, $max_depth]);

Pack the $data to messagepack format string.

This method throws an exception when the perl structure is nested more than $max_depth levels(default: 512) in order to detect circular references.

Data::MessagePack->pack() throws an exception when encountering a blessed perl object, because MessagePack is a language-independent format.

my $unpacked = Data::MessagePack->unpack($msgpackstr);

unpack the $msgpackstr to a MessagePack format string.

my $mp = Data::MesssagePack->new()

Creates a new MessagePack instance.

$mp = $mp->prefer_integer([ $enable ])
$enabled = $mp->get_prefer_integer()

If $enable is true (or missing), then the pack method tries a string as an integer if the string looks like an integer.

$mp = $mp->canonical([ $enable ])
$enabled = $mp->get_canonical()

If $enable is true (or missing), then the pack method will output packed data by sorting their keys. This is adding a comparatively high overhead.

$mp = $mp->utf8([ $enable ])
$enabled = $mp->get_utf8()

If $enable is true (or missing), then the pack method will apply utf8::encode() to all the string values.

In other words, this property tell $mp to deal with text strings. See perlunifaq for the meaning of text string.

$packed = $mp->pack($data)
$packed = $mp->encode($data)

Same as Data::MessagePack->pack(), but properties are respected.

$data = $mp->unpack($data)
$data = $mp->decode($data)

Same as Data::MessagePack->unpack(), but properties are respected.

Configuration Variables (DEPRECATED)


Packs a string as an integer, when it looks like an integer.

This variable is deprecated. Use $msgpack->prefer_integer property instead.


This is a result of benchmark/ and benchmark/ on my SC440(Linux 2.6.32-23-server #37-Ubuntu SMP). (You should benchmark them with your data if the speed matters, of course.)

    -- serialize
    JSON::XS: 2.3
    Data::MessagePack: 0.24
    Storable: 2.21
    Benchmark: running json, mp, storable for at least 1 CPU seconds...
          json:  1 wallclock secs ( 1.00 usr +  0.01 sys =  1.01 CPU) @ 141939.60/s (n=143359)
            mp:  1 wallclock secs ( 1.06 usr +  0.00 sys =  1.06 CPU) @ 355500.94/s (n=376831)
      storable:  1 wallclock secs ( 1.12 usr +  0.00 sys =  1.12 CPU) @ 38399.11/s (n=43007)
                 Rate storable     json       mp
    storable  38399/s       --     -73%     -89%
    json     141940/s     270%       --     -60%
    mp       355501/s     826%     150%       --

    -- deserialize
    JSON::XS: 2.3
    Data::MessagePack: 0.24
    Storable: 2.21
    Benchmark: running json, mp, storable for at least 1 CPU seconds...
          json:  0 wallclock secs ( 1.05 usr +  0.00 sys =  1.05 CPU) @ 179442.86/s (n=188415)
            mp:  0 wallclock secs ( 1.01 usr +  0.00 sys =  1.01 CPU) @ 212909.90/s (n=215039)
      storable:  2 wallclock secs ( 1.14 usr +  0.00 sys =  1.14 CPU) @ 114974.56/s (n=131071)
                 Rate storable     json       mp
    storable 114975/s       --     -36%     -46%
    json     179443/s      56%       --     -16%
    mp       212910/s      85%      19%       --


Unpacking 64 bit integers

This module can unpack 64 bit integers even if your perl does not support them (i.e. where perl -V:ivsize is 4), but you cannot calculate these values unless you use Math::BigInt.


Error handling

MessagePack cannot deal with complex scalars such as object references, filehandles, and code references. We should report the errors more kindly.

Streaming deserializer

The current implementation of the streaming deserializer does not have internal buffers while some other bindings (such as Ruby binding) does. This limitation will astonish those who try to unpack byte streams with an arbitrary buffer size (e.g. while(read($socket, $buffer, $arbitrary_buffer_size)) { ... }). We should implement the internal buffer for the unpacker.


Why does Data::MessagePack have pure perl implementations?

msgpack C library uses C99 feature, VC++6 does not support C99. So pure perl version is needed for VC++ users.


Tokuhiro Matsuno

Makamaka Hannyaharamitu



Jun Kuriyama

Dan Kogai



Kazuho Oku



This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO is the official web site for the MessagePack format.