NAME

YAML::PP::Schema::Perl - Schema for serializing perl objects and special types

SYNOPSIS

    use YAML::PP;
    # This can be dangerous when loading untrusted YAML!
    my $yp = YAML::PP->new( schema => [qw/ JSON Perl /] );
    # or
    my $yp = YAML::PP->new( schema => [qw/ Core Perl /] );
    my $yaml = $yp->dump_string(sub { return 23 });

    # loading code references
    # This is very dangerous when loading untrusted YAML!!
    my $yp = YAML::PP->new( schema => [qw/ JSON Perl +loadcode /] );
    my $code = $yp->load_string(<<'EOM');
    --- !perl/code |
        {
            use 5.010;
            my ($name) = @_;
            say "Hello $name!";
        }
    EOM
    $code->("Ingy");

DESCRIPTION

This schema allows you to load and dump perl objects and special types.

Please note that loading objects of arbitrary classes can be dangerous in Perl. You have to load the modules yourself, but if an exploitable module is loaded and an object is created, its DESTROY method will be called when the object falls out of scope. File::Temp is an example that can be exploitable and might remove arbitrary files.

This code is pretty new and experimental. Typeglobs are not implemented yet. Dumping code references is on by default, but not loading (because that is easily exploitable since it's using string eval).

TAG STYLES

You can define the style of tags you want to support:

    my $yp_perl_two_one = YAML::PP->new(
        schema => [qw/ JSON Perl tag=!!+! /],
    );

!

Only !perl/type tags are supported.

!!

Only !!perl/type tags are supported.

!+!!

Both !perl/type and !!perl/tag are supported when loading. When dumping, !perl/type is used.

!!+!

Both !perl/type and !!perl/tag are supported when loading. When dumping, !!perl/type is used.

YAML.pm, YAML::Syck and YAML::XS are using !!perl/type when dumping.

YAML.pm and YAML::Syck are supporting both !perl/type and !!perl/type when loading. YAML::XS currently only supports the latter.

EXAMPLES

This is a list of the currently supported types and how they are dumped into YAML:

array

        # Code
        [
            qw/ one two three four /
        ]


        # YAML
        ---
        - one
        - two
        - three
        - four

array_blessed

        # Code
        bless [
            qw/ one two three four /
        ], "Just::An::Arrayref"


        # YAML
        --- !perl/array:Just::An::Arrayref
        - one
        - two
        - three
        - four

circular

        # Code
        my $circle = bless [ 1, 2 ], 'Circle';
        push @$circle, $circle;
        $circle;


        # YAML
        --- &1 !perl/array:Circle
        - 1
        - 2
        - *1

coderef

        # Code
        sub {
            my (%args) = @_;
            return $args{x} + $args{y};
        }


        # YAML
        --- !perl/code |-
          {
              use warnings;
              use strict;
              (my(%args) = @_);
              (return ($args{'x'} + $args{'y'}));
          }

coderef_blessed

        # Code
        bless sub {
            my (%args) = @_;
            return $args{x} - $args{y};
        }, "I::Am::Code"


        # YAML
        --- !perl/code:I::Am::Code |-
          {
              use warnings;
              use strict;
              (my(%args) = @_);
              (return ($args{'x'} - $args{'y'}));
          }

hash

        # Code
        {
            U => 2,
            B => 52,
        }


        # YAML
        ---
        B: 52
        U: 2

hash_blessed

        # Code
        bless {
            U => 2,
            B => 52,
        }, 'A::Very::Exclusive::Class'


        # YAML
        --- !perl/hash:A::Very::Exclusive::Class
        B: 52
        U: 2

refref

        # Code
        my $ref = { a => 'hash' };
        my $refref = \$ref;
        $refref;


        # YAML
        --- !perl/ref
        =:
          a: hash

refref_blessed

        # Code
        my $ref = { a => 'hash' };
        my $refref = bless \$ref, 'Foo';
        $refref;


        # YAML
        --- !perl/ref:Foo
        =:
          a: hash

regexp

        # Code
        qr{unblessed}


        # YAML
        --- !perl/regexp unblessed

regexp_blessed

        # Code
        bless qr{blessed}, "Foo"


        # YAML
        --- !perl/regexp:Foo blessed

scalarref

        # Code
        my $scalar = "some string";
        my $scalarref = \$scalar;
        $scalarref;


        # YAML
        --- !perl/scalar
        =: some string

scalarref_blessed

        # Code
        my $scalar = "some other string";
        my $scalarref = bless \$scalar, 'Foo';
        $scalarref;


        # YAML
        --- !perl/scalar:Foo
        =: some other string

METHODS

register

A class method called by YAML::PP::Schema