2268 lines
66 KiB
Perl
2268 lines
66 KiB
Perl
package JSON;
|
|
|
|
|
|
use strict;
|
|
use Carp ();
|
|
use base qw(Exporter);
|
|
@JSON::EXPORT = qw(from_json to_json jsonToObj objToJson encode_json decode_json);
|
|
|
|
BEGIN {
|
|
$JSON::VERSION = '2.53';
|
|
$JSON::DEBUG = 0 unless (defined $JSON::DEBUG);
|
|
$JSON::DEBUG = $ENV{ PERL_JSON_DEBUG } if exists $ENV{ PERL_JSON_DEBUG };
|
|
}
|
|
|
|
my $Module_XS = 'JSON::XS';
|
|
my $Module_PP = 'JSON::PP';
|
|
my $Module_bp = 'JSON::backportPP'; # included in JSON distribution
|
|
my $PP_Version = '2.27200';
|
|
my $XS_Version = '2.27';
|
|
|
|
|
|
# XS and PP common methods
|
|
|
|
my @PublicMethods = qw/
|
|
ascii latin1 utf8 pretty indent space_before space_after relaxed canonical allow_nonref
|
|
allow_blessed convert_blessed filter_json_object filter_json_single_key_object
|
|
shrink max_depth max_size encode decode decode_prefix allow_unknown
|
|
/;
|
|
|
|
my @Properties = qw/
|
|
ascii latin1 utf8 indent space_before space_after relaxed canonical allow_nonref
|
|
allow_blessed convert_blessed shrink max_depth max_size allow_unknown
|
|
/;
|
|
|
|
my @XSOnlyMethods = qw//; # Currently nothing
|
|
|
|
my @PPOnlyMethods = qw/
|
|
indent_length sort_by
|
|
allow_singlequote allow_bignum loose allow_barekey escape_slash as_nonblessed
|
|
/; # JSON::PP specific
|
|
|
|
|
|
# used in _load_xs and _load_pp ($INSTALL_ONLY is not used currently)
|
|
my $_INSTALL_DONT_DIE = 1; # When _load_xs fails to load XS, don't die.
|
|
my $_INSTALL_ONLY = 2; # Don't call _set_methods()
|
|
my $_ALLOW_UNSUPPORTED = 0;
|
|
my $_UNIV_CONV_BLESSED = 0;
|
|
my $_USSING_bpPP = 0;
|
|
|
|
|
|
# Check the environment variable to decide worker module.
|
|
|
|
unless ($JSON::Backend) {
|
|
$JSON::DEBUG and Carp::carp("Check used worker module...");
|
|
|
|
my $backend = exists $ENV{PERL_JSON_BACKEND} ? $ENV{PERL_JSON_BACKEND} : 1;
|
|
|
|
if ($backend eq '1' or $backend =~ /JSON::XS\s*,\s*JSON::PP/) {
|
|
_load_xs($_INSTALL_DONT_DIE) or _load_pp();
|
|
}
|
|
elsif ($backend eq '0' or $backend eq 'JSON::PP') {
|
|
_load_pp();
|
|
}
|
|
elsif ($backend eq '2' or $backend eq 'JSON::XS') {
|
|
_load_xs();
|
|
}
|
|
elsif ($backend eq 'JSON::backportPP') {
|
|
$_USSING_bpPP = 1;
|
|
_load_pp();
|
|
}
|
|
else {
|
|
Carp::croak "The value of environmental variable 'PERL_JSON_BACKEND' is invalid.";
|
|
}
|
|
}
|
|
|
|
|
|
sub import {
|
|
my $pkg = shift;
|
|
my @what_to_export;
|
|
my $no_export;
|
|
|
|
for my $tag (@_) {
|
|
if ($tag eq '-support_by_pp') {
|
|
if (!$_ALLOW_UNSUPPORTED++) {
|
|
JSON::Backend::XS
|
|
->support_by_pp(@PPOnlyMethods) if ($JSON::Backend eq $Module_XS);
|
|
}
|
|
next;
|
|
}
|
|
elsif ($tag eq '-no_export') {
|
|
$no_export++, next;
|
|
}
|
|
elsif ( $tag eq '-convert_blessed_universally' ) {
|
|
eval q|
|
|
require B;
|
|
*UNIVERSAL::TO_JSON = sub {
|
|
my $b_obj = B::svref_2object( $_[0] );
|
|
return $b_obj->isa('B::HV') ? { %{ $_[0] } }
|
|
: $b_obj->isa('B::AV') ? [ @{ $_[0] } ]
|
|
: undef
|
|
;
|
|
}
|
|
| if ( !$_UNIV_CONV_BLESSED++ );
|
|
next;
|
|
}
|
|
push @what_to_export, $tag;
|
|
}
|
|
|
|
return if ($no_export);
|
|
|
|
__PACKAGE__->export_to_level(1, $pkg, @what_to_export);
|
|
}
|
|
|
|
|
|
# OBSOLETED
|
|
|
|
sub jsonToObj {
|
|
my $alternative = 'from_json';
|
|
if (defined $_[0] and UNIVERSAL::isa($_[0], 'JSON')) {
|
|
shift @_; $alternative = 'decode';
|
|
}
|
|
Carp::carp "'jsonToObj' will be obsoleted. Please use '$alternative' instead.";
|
|
return JSON::from_json(@_);
|
|
};
|
|
|
|
sub objToJson {
|
|
my $alternative = 'to_json';
|
|
if (defined $_[0] and UNIVERSAL::isa($_[0], 'JSON')) {
|
|
shift @_; $alternative = 'encode';
|
|
}
|
|
Carp::carp "'objToJson' will be obsoleted. Please use '$alternative' instead.";
|
|
JSON::to_json(@_);
|
|
};
|
|
|
|
|
|
# INTERFACES
|
|
|
|
sub to_json ($@) {
|
|
if (
|
|
ref($_[0]) eq 'JSON'
|
|
or (@_ > 2 and $_[0] eq 'JSON')
|
|
) {
|
|
Carp::croak "to_json should not be called as a method.";
|
|
}
|
|
my $json = new JSON;
|
|
|
|
if (@_ == 2 and ref $_[1] eq 'HASH') {
|
|
my $opt = $_[1];
|
|
for my $method (keys %$opt) {
|
|
$json->$method( $opt->{$method} );
|
|
}
|
|
}
|
|
|
|
$json->encode($_[0]);
|
|
}
|
|
|
|
|
|
sub from_json ($@) {
|
|
if ( ref($_[0]) eq 'JSON' or $_[0] eq 'JSON' ) {
|
|
Carp::croak "from_json should not be called as a method.";
|
|
}
|
|
my $json = new JSON;
|
|
|
|
if (@_ == 2 and ref $_[1] eq 'HASH') {
|
|
my $opt = $_[1];
|
|
for my $method (keys %$opt) {
|
|
$json->$method( $opt->{$method} );
|
|
}
|
|
}
|
|
|
|
return $json->decode( $_[0] );
|
|
}
|
|
|
|
|
|
sub true { $JSON::true }
|
|
|
|
sub false { $JSON::false }
|
|
|
|
sub null { undef; }
|
|
|
|
|
|
sub require_xs_version { $XS_Version; }
|
|
|
|
sub backend {
|
|
my $proto = shift;
|
|
$JSON::Backend;
|
|
}
|
|
|
|
#*module = *backend;
|
|
|
|
|
|
sub is_xs {
|
|
return $_[0]->module eq $Module_XS;
|
|
}
|
|
|
|
|
|
sub is_pp {
|
|
return not $_[0]->xs;
|
|
}
|
|
|
|
|
|
sub pureperl_only_methods { @PPOnlyMethods; }
|
|
|
|
|
|
sub property {
|
|
my ($self, $name, $value) = @_;
|
|
|
|
if (@_ == 1) {
|
|
my %props;
|
|
for $name (@Properties) {
|
|
my $method = 'get_' . $name;
|
|
if ($name eq 'max_size') {
|
|
my $value = $self->$method();
|
|
$props{$name} = $value == 1 ? 0 : $value;
|
|
next;
|
|
}
|
|
$props{$name} = $self->$method();
|
|
}
|
|
return \%props;
|
|
}
|
|
elsif (@_ > 3) {
|
|
Carp::croak('property() can take only the option within 2 arguments.');
|
|
}
|
|
elsif (@_ == 2) {
|
|
if ( my $method = $self->can('get_' . $name) ) {
|
|
if ($name eq 'max_size') {
|
|
my $value = $self->$method();
|
|
return $value == 1 ? 0 : $value;
|
|
}
|
|
$self->$method();
|
|
}
|
|
}
|
|
else {
|
|
$self->$name($value);
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
# INTERNAL
|
|
|
|
sub _load_xs {
|
|
my $opt = shift;
|
|
|
|
$JSON::DEBUG and Carp::carp "Load $Module_XS.";
|
|
|
|
# if called after install module, overload is disable.... why?
|
|
JSON::Boolean::_overrride_overload($Module_XS);
|
|
JSON::Boolean::_overrride_overload($Module_PP);
|
|
|
|
eval qq|
|
|
use $Module_XS $XS_Version ();
|
|
|;
|
|
|
|
if ($@) {
|
|
if (defined $opt and $opt & $_INSTALL_DONT_DIE) {
|
|
$JSON::DEBUG and Carp::carp "Can't load $Module_XS...($@)";
|
|
return 0;
|
|
}
|
|
Carp::croak $@;
|
|
}
|
|
|
|
unless (defined $opt and $opt & $_INSTALL_ONLY) {
|
|
_set_module( $JSON::Backend = $Module_XS );
|
|
my $data = join("", <DATA>); # this code is from Jcode 2.xx.
|
|
close(DATA);
|
|
eval $data;
|
|
JSON::Backend::XS->init;
|
|
}
|
|
|
|
return 1;
|
|
};
|
|
|
|
|
|
sub _load_pp {
|
|
my $opt = shift;
|
|
my $backend = $_USSING_bpPP ? $Module_bp : $Module_PP;
|
|
|
|
$JSON::DEBUG and Carp::carp "Load $backend.";
|
|
|
|
# if called after install module, overload is disable.... why?
|
|
JSON::Boolean::_overrride_overload($Module_XS);
|
|
JSON::Boolean::_overrride_overload($backend);
|
|
|
|
if ( $_USSING_bpPP ) {
|
|
eval qq| require $backend |;
|
|
}
|
|
else {
|
|
eval qq| use $backend $PP_Version () |;
|
|
}
|
|
|
|
if ($@) {
|
|
if ( $backend eq $Module_PP ) {
|
|
$JSON::DEBUG and Carp::carp "Can't load $Module_PP ($@), so try to load $Module_bp";
|
|
$_USSING_bpPP++;
|
|
$backend = $Module_bp;
|
|
JSON::Boolean::_overrride_overload($backend);
|
|
local $^W; # if PP installed but invalid version, backportPP redifines methods.
|
|
eval qq| require $Module_bp |;
|
|
}
|
|
Carp::croak $@ if $@;
|
|
}
|
|
|
|
unless (defined $opt and $opt & $_INSTALL_ONLY) {
|
|
_set_module( $JSON::Backend = $Module_PP ); # even if backportPP, set $Backend with 'JSON::PP'
|
|
JSON::Backend::PP->init;
|
|
}
|
|
};
|
|
|
|
|
|
sub _set_module {
|
|
return if defined $JSON::true;
|
|
|
|
my $module = shift;
|
|
|
|
local $^W;
|
|
no strict qw(refs);
|
|
|
|
$JSON::true = ${"$module\::true"};
|
|
$JSON::false = ${"$module\::false"};
|
|
|
|
push @JSON::ISA, $module;
|
|
push @{"$module\::Boolean::ISA"}, qw(JSON::Boolean);
|
|
|
|
*{"JSON::is_bool"} = \&{"$module\::is_bool"};
|
|
|
|
for my $method ($module eq $Module_XS ? @PPOnlyMethods : @XSOnlyMethods) {
|
|
*{"JSON::$method"} = sub {
|
|
Carp::carp("$method is not supported in $module.");
|
|
$_[0];
|
|
};
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
|
|
|
|
#
|
|
# JSON Boolean
|
|
#
|
|
|
|
package JSON::Boolean;
|
|
|
|
my %Installed;
|
|
|
|
sub _overrride_overload {
|
|
return if ($Installed{ $_[0] }++);
|
|
|
|
my $boolean = $_[0] . '::Boolean';
|
|
|
|
eval sprintf(q|
|
|
package %s;
|
|
use overload (
|
|
'""' => sub { ${$_[0]} == 1 ? 'true' : 'false' },
|
|
'eq' => sub {
|
|
my ($obj, $op) = ref ($_[0]) ? ($_[0], $_[1]) : ($_[1], $_[0]);
|
|
if ($op eq 'true' or $op eq 'false') {
|
|
return "$obj" eq 'true' ? 'true' eq $op : 'false' eq $op;
|
|
}
|
|
else {
|
|
return $obj ? 1 == $op : 0 == $op;
|
|
}
|
|
},
|
|
);
|
|
|, $boolean);
|
|
|
|
if ($@) { Carp::croak $@; }
|
|
|
|
return 1;
|
|
}
|
|
|
|
|
|
#
|
|
# Helper classes for Backend Module (PP)
|
|
#
|
|
|
|
package JSON::Backend::PP;
|
|
|
|
sub init {
|
|
local $^W;
|
|
no strict qw(refs); # this routine may be called after JSON::Backend::XS init was called.
|
|
*{"JSON::decode_json"} = \&{"JSON::PP::decode_json"};
|
|
*{"JSON::encode_json"} = \&{"JSON::PP::encode_json"};
|
|
*{"JSON::PP::is_xs"} = sub { 0 };
|
|
*{"JSON::PP::is_pp"} = sub { 1 };
|
|
return 1;
|
|
}
|
|
|
|
#
|
|
# To save memory, the below lines are read only when XS backend is used.
|
|
#
|
|
|
|
package JSON;
|
|
|
|
1;
|
|
__DATA__
|
|
|
|
|
|
#
|
|
# Helper classes for Backend Module (XS)
|
|
#
|
|
|
|
package JSON::Backend::XS;
|
|
|
|
use constant INDENT_LENGTH_FLAG => 15 << 12;
|
|
|
|
use constant UNSUPPORTED_ENCODE_FLAG => {
|
|
ESCAPE_SLASH => 0x00000010,
|
|
ALLOW_BIGNUM => 0x00000020,
|
|
AS_NONBLESSED => 0x00000040,
|
|
EXPANDED => 0x10000000, # for developer's
|
|
};
|
|
|
|
use constant UNSUPPORTED_DECODE_FLAG => {
|
|
LOOSE => 0x00000001,
|
|
ALLOW_BIGNUM => 0x00000002,
|
|
ALLOW_BAREKEY => 0x00000004,
|
|
ALLOW_SINGLEQUOTE => 0x00000008,
|
|
EXPANDED => 0x20000000, # for developer's
|
|
};
|
|
|
|
|
|
sub init {
|
|
local $^W;
|
|
no strict qw(refs);
|
|
*{"JSON::decode_json"} = \&{"JSON::XS::decode_json"};
|
|
*{"JSON::encode_json"} = \&{"JSON::XS::encode_json"};
|
|
*{"JSON::XS::is_xs"} = sub { 1 };
|
|
*{"JSON::XS::is_pp"} = sub { 0 };
|
|
return 1;
|
|
}
|
|
|
|
|
|
sub support_by_pp {
|
|
my ($class, @methods) = @_;
|
|
|
|
local $^W;
|
|
no strict qw(refs);
|
|
|
|
my $JSON_XS_encode_orignal = \&JSON::XS::encode;
|
|
my $JSON_XS_decode_orignal = \&JSON::XS::decode;
|
|
my $JSON_XS_incr_parse_orignal = \&JSON::XS::incr_parse;
|
|
|
|
*JSON::XS::decode = \&JSON::Backend::XS::Supportable::_decode;
|
|
*JSON::XS::encode = \&JSON::Backend::XS::Supportable::_encode;
|
|
*JSON::XS::incr_parse = \&JSON::Backend::XS::Supportable::_incr_parse;
|
|
|
|
*{JSON::XS::_original_decode} = $JSON_XS_decode_orignal;
|
|
*{JSON::XS::_original_encode} = $JSON_XS_encode_orignal;
|
|
*{JSON::XS::_original_incr_parse} = $JSON_XS_incr_parse_orignal;
|
|
|
|
push @JSON::Backend::XS::Supportable::ISA, 'JSON';
|
|
|
|
my $pkg = 'JSON::Backend::XS::Supportable';
|
|
|
|
*{JSON::new} = sub {
|
|
my $proto = new JSON::XS; $$proto = 0;
|
|
bless $proto, $pkg;
|
|
};
|
|
|
|
|
|
for my $method (@methods) {
|
|
my $flag = uc($method);
|
|
my $type |= (UNSUPPORTED_ENCODE_FLAG->{$flag} || 0);
|
|
$type |= (UNSUPPORTED_DECODE_FLAG->{$flag} || 0);
|
|
|
|
next unless($type);
|
|
|
|
$pkg->_make_unsupported_method($method => $type);
|
|
}
|
|
|
|
push @{"JSON::XS::Boolean::ISA"}, qw(JSON::PP::Boolean);
|
|
push @{"JSON::PP::Boolean::ISA"}, qw(JSON::Boolean);
|
|
|
|
$JSON::DEBUG and Carp::carp("set -support_by_pp mode.");
|
|
|
|
return 1;
|
|
}
|
|
|
|
|
|
|
|
|
|
#
|
|
# Helper classes for XS
|
|
#
|
|
|
|
package JSON::Backend::XS::Supportable;
|
|
|
|
$Carp::Internal{'JSON::Backend::XS::Supportable'} = 1;
|
|
|
|
sub _make_unsupported_method {
|
|
my ($pkg, $method, $type) = @_;
|
|
|
|
local $^W;
|
|
no strict qw(refs);
|
|
|
|
*{"$pkg\::$method"} = sub {
|
|
local $^W;
|
|
if (defined $_[1] ? $_[1] : 1) {
|
|
${$_[0]} |= $type;
|
|
}
|
|
else {
|
|
${$_[0]} &= ~$type;
|
|
}
|
|
$_[0];
|
|
};
|
|
|
|
*{"$pkg\::get_$method"} = sub {
|
|
${$_[0]} & $type ? 1 : '';
|
|
};
|
|
|
|
}
|
|
|
|
|
|
sub _set_for_pp {
|
|
JSON::_load_pp( $_INSTALL_ONLY );
|
|
|
|
my $type = shift;
|
|
my $pp = new JSON::PP;
|
|
my $prop = $_[0]->property;
|
|
|
|
for my $name (keys %$prop) {
|
|
$pp->$name( $prop->{$name} ? $prop->{$name} : 0 );
|
|
}
|
|
|
|
my $unsupported = $type eq 'encode' ? JSON::Backend::XS::UNSUPPORTED_ENCODE_FLAG
|
|
: JSON::Backend::XS::UNSUPPORTED_DECODE_FLAG;
|
|
my $flags = ${$_[0]} || 0;
|
|
|
|
for my $name (keys %$unsupported) {
|
|
next if ($name eq 'EXPANDED'); # for developer's
|
|
my $enable = ($flags & $unsupported->{$name}) ? 1 : 0;
|
|
my $method = lc $name;
|
|
$pp->$method($enable);
|
|
}
|
|
|
|
$pp->indent_length( $_[0]->get_indent_length );
|
|
|
|
return $pp;
|
|
}
|
|
|
|
sub _encode { # using with PP encod
|
|
if (${$_[0]}) {
|
|
_set_for_pp('encode' => @_)->encode($_[1]);
|
|
}
|
|
else {
|
|
$_[0]->_original_encode( $_[1] );
|
|
}
|
|
}
|
|
|
|
|
|
sub _decode { # if unsupported-flag is set, use PP
|
|
if (${$_[0]}) {
|
|
_set_for_pp('decode' => @_)->decode($_[1]);
|
|
}
|
|
else {
|
|
$_[0]->_original_decode( $_[1] );
|
|
}
|
|
}
|
|
|
|
|
|
sub decode_prefix { # if unsupported-flag is set, use PP
|
|
_set_for_pp('decode' => @_)->decode_prefix($_[1]);
|
|
}
|
|
|
|
|
|
sub _incr_parse {
|
|
if (${$_[0]}) {
|
|
_set_for_pp('decode' => @_)->incr_parse($_[1]);
|
|
}
|
|
else {
|
|
$_[0]->_original_incr_parse( $_[1] );
|
|
}
|
|
}
|
|
|
|
|
|
sub get_indent_length {
|
|
${$_[0]} << 4 >> 16;
|
|
}
|
|
|
|
|
|
sub indent_length {
|
|
my $length = $_[1];
|
|
|
|
if (!defined $length or $length > 15 or $length < 0) {
|
|
Carp::carp "The acceptable range of indent_length() is 0 to 15.";
|
|
}
|
|
else {
|
|
local $^W;
|
|
$length <<= 12;
|
|
${$_[0]} &= ~ JSON::Backend::XS::INDENT_LENGTH_FLAG;
|
|
${$_[0]} |= $length;
|
|
*JSON::XS::encode = \&JSON::Backend::XS::Supportable::_encode;
|
|
}
|
|
|
|
$_[0];
|
|
}
|
|
|
|
|
|
1;
|
|
__END__
|
|
|
|
=head1 NAME
|
|
|
|
JSON - JSON (JavaScript Object Notation) encoder/decoder
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
use JSON; # imports encode_json, decode_json, to_json and from_json.
|
|
|
|
# simple and fast interfaces (expect/generate UTF-8)
|
|
|
|
$utf8_encoded_json_text = encode_json $perl_hash_or_arrayref;
|
|
$perl_hash_or_arrayref = decode_json $utf8_encoded_json_text;
|
|
|
|
# OO-interface
|
|
|
|
$json = JSON->new->allow_nonref;
|
|
|
|
$json_text = $json->encode( $perl_scalar );
|
|
$perl_scalar = $json->decode( $json_text );
|
|
|
|
$pretty_printed = $json->pretty->encode( $perl_scalar ); # pretty-printing
|
|
|
|
# If you want to use PP only support features, call with '-support_by_pp'
|
|
# When XS unsupported feature is enable, using PP (de|en)code instead of XS ones.
|
|
|
|
use JSON -support_by_pp;
|
|
|
|
# option-acceptable interfaces (expect/generate UNICODE by default)
|
|
|
|
$json_text = to_json( $perl_scalar, { ascii => 1, pretty => 1 } );
|
|
$perl_scalar = from_json( $json_text, { utf8 => 1 } );
|
|
|
|
# Between (en|de)code_json and (to|from)_json, if you want to write
|
|
# a code which communicates to an outer world (encoded in UTF-8),
|
|
# recommend to use (en|de)code_json.
|
|
|
|
=head1 VERSION
|
|
|
|
2.53
|
|
|
|
This version is compatible with JSON::XS B<2.27> and later.
|
|
|
|
|
|
=head1 NOTE
|
|
|
|
JSON::PP was inculded in C<JSON> distribution.
|
|
It comes to be a perl core module in Perl 5.14.
|
|
And L<JSON::PP> will be split away it.
|
|
|
|
C<JSON> distribution will inculde yet another JSON::PP modules.
|
|
They are JSNO::backportPP and so on. JSON.pm should work as it did at all.
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
************************** CAUTION ********************************
|
|
* This is 'JSON module version 2' and there are many differences *
|
|
* to version 1.xx *
|
|
* Please check your applications useing old version. *
|
|
* See to 'INCOMPATIBLE CHANGES TO OLD VERSION' *
|
|
*******************************************************************
|
|
|
|
JSON (JavaScript Object Notation) is a simple data format.
|
|
See to L<http://www.json.org/> and C<RFC4627>(L<http://www.ietf.org/rfc/rfc4627.txt>).
|
|
|
|
This module converts Perl data structures to JSON and vice versa using either
|
|
L<JSON::XS> or L<JSON::PP>.
|
|
|
|
JSON::XS is the fastest and most proper JSON module on CPAN which must be
|
|
compiled and installed in your environment.
|
|
JSON::PP is a pure-Perl module which is bundled in this distribution and
|
|
has a strong compatibility to JSON::XS.
|
|
|
|
This module try to use JSON::XS by default and fail to it, use JSON::PP instead.
|
|
So its features completely depend on JSON::XS or JSON::PP.
|
|
|
|
See to L<BACKEND MODULE DECISION>.
|
|
|
|
To distinguish the module name 'JSON' and the format type JSON,
|
|
the former is quoted by CE<lt>E<gt> (its results vary with your using media),
|
|
and the latter is left just as it is.
|
|
|
|
Module name : C<JSON>
|
|
|
|
Format type : JSON
|
|
|
|
=head2 FEATURES
|
|
|
|
=over
|
|
|
|
=item * correct unicode handling
|
|
|
|
This module (i.e. backend modules) knows how to handle Unicode, documents
|
|
how and when it does so, and even documents what "correct" means.
|
|
|
|
Even though there are limitations, this feature is available since Perl version 5.6.
|
|
|
|
JSON::XS requires Perl 5.8.2 (but works correctly in 5.8.8 or later), so in older versions
|
|
C<JSON> sholud call JSON::PP as the backend which can be used since Perl 5.005.
|
|
|
|
With Perl 5.8.x JSON::PP works, but from 5.8.0 to 5.8.2, because of a Perl side problem,
|
|
JSON::PP works slower in the versions. And in 5.005, the Unicode handling is not available.
|
|
See to L<JSON::PP/UNICODE HANDLING ON PERLS> for more information.
|
|
|
|
See also to L<JSON::XS/A FEW NOTES ON UNICODE AND PERL>
|
|
and L<JSON::XS/ENCODING/CODESET_FLAG_NOTES>.
|
|
|
|
|
|
=item * round-trip integrity
|
|
|
|
When you serialise a perl data structure using only data types supported
|
|
by JSON and Perl, the deserialised data structure is identical on the Perl
|
|
level. (e.g. the string "2.0" doesn't suddenly become "2" just because
|
|
it looks like a number). There I<are> minor exceptions to this, read the
|
|
L</MAPPING> section below to learn about those.
|
|
|
|
|
|
=item * strict checking of JSON correctness
|
|
|
|
There is no guessing, no generating of illegal JSON texts by default,
|
|
and only JSON is accepted as input by default (the latter is a security
|
|
feature).
|
|
|
|
See to L<JSON::XS/FEATURES> and L<JSON::PP/FEATURES>.
|
|
|
|
=item * fast
|
|
|
|
This module returns a JSON::XS object itself if available.
|
|
Compared to other JSON modules and other serialisers such as Storable,
|
|
JSON::XS usually compares favourably in terms of speed, too.
|
|
|
|
If not available, C<JSON> returns a JSON::PP object instead of JSON::XS and
|
|
it is very slow as pure-Perl.
|
|
|
|
=item * simple to use
|
|
|
|
This module has both a simple functional interface as well as an
|
|
object oriented interface interface.
|
|
|
|
=item * reasonably versatile output formats
|
|
|
|
You can choose between the most compact guaranteed-single-line format possible
|
|
(nice for simple line-based protocols), a pure-ASCII format (for when your transport
|
|
is not 8-bit clean, still supports the whole Unicode range), or a pretty-printed
|
|
format (for when you want to read that stuff). Or you can combine those features
|
|
in whatever way you like.
|
|
|
|
=back
|
|
|
|
=head1 FUNCTIONAL INTERFACE
|
|
|
|
Some documents are copied and modified from L<JSON::XS/FUNCTIONAL INTERFACE>.
|
|
C<to_json> and C<from_json> are additional functions.
|
|
|
|
=head2 encode_json
|
|
|
|
$json_text = encode_json $perl_scalar
|
|
|
|
Converts the given Perl data structure to a UTF-8 encoded, binary string.
|
|
|
|
This function call is functionally identical to:
|
|
|
|
$json_text = JSON->new->utf8->encode($perl_scalar)
|
|
|
|
=head2 decode_json
|
|
|
|
$perl_scalar = decode_json $json_text
|
|
|
|
The opposite of C<encode_json>: expects an UTF-8 (binary) string and tries
|
|
to parse that as an UTF-8 encoded JSON text, returning the resulting
|
|
reference.
|
|
|
|
This function call is functionally identical to:
|
|
|
|
$perl_scalar = JSON->new->utf8->decode($json_text)
|
|
|
|
|
|
=head2 to_json
|
|
|
|
$json_text = to_json($perl_scalar)
|
|
|
|
Converts the given Perl data structure to a json string.
|
|
|
|
This function call is functionally identical to:
|
|
|
|
$json_text = JSON->new->encode($perl_scalar)
|
|
|
|
Takes a hash reference as the second.
|
|
|
|
$json_text = to_json($perl_scalar, $flag_hashref)
|
|
|
|
So,
|
|
|
|
$json_text = to_json($perl_scalar, {utf8 => 1, pretty => 1})
|
|
|
|
equivalent to:
|
|
|
|
$json_text = JSON->new->utf8(1)->pretty(1)->encode($perl_scalar)
|
|
|
|
If you want to write a modern perl code which communicates to outer world,
|
|
you should use C<encode_json> (supposed that JSON data are encoded in UTF-8).
|
|
|
|
=head2 from_json
|
|
|
|
$perl_scalar = from_json($json_text)
|
|
|
|
The opposite of C<to_json>: expects a json string and tries
|
|
to parse it, returning the resulting reference.
|
|
|
|
This function call is functionally identical to:
|
|
|
|
$perl_scalar = JSON->decode($json_text)
|
|
|
|
Takes a hash reference as the second.
|
|
|
|
$perl_scalar = from_json($json_text, $flag_hashref)
|
|
|
|
So,
|
|
|
|
$perl_scalar = from_json($json_text, {utf8 => 1})
|
|
|
|
equivalent to:
|
|
|
|
$perl_scalar = JSON->new->utf8(1)->decode($json_text)
|
|
|
|
If you want to write a modern perl code which communicates to outer world,
|
|
you should use C<decode_json> (supposed that JSON data are encoded in UTF-8).
|
|
|
|
=head2 JSON::is_bool
|
|
|
|
$is_boolean = JSON::is_bool($scalar)
|
|
|
|
Returns true if the passed scalar represents either JSON::true or
|
|
JSON::false, two constants that act like C<1> and C<0> respectively
|
|
and are also used to represent JSON C<true> and C<false> in Perl strings.
|
|
|
|
=head2 JSON::true
|
|
|
|
Returns JSON true value which is blessed object.
|
|
It C<isa> JSON::Boolean object.
|
|
|
|
=head2 JSON::false
|
|
|
|
Returns JSON false value which is blessed object.
|
|
It C<isa> JSON::Boolean object.
|
|
|
|
=head2 JSON::null
|
|
|
|
Returns C<undef>.
|
|
|
|
See L<MAPPING>, below, for more information on how JSON values are mapped to
|
|
Perl.
|
|
|
|
=head1 HOW DO I DECODE A DATA FROM OUTER AND ENCODE TO OUTER
|
|
|
|
This section supposes that your perl vresion is 5.8 or later.
|
|
|
|
If you know a JSON text from an outer world - a network, a file content, and so on,
|
|
is encoded in UTF-8, you should use C<decode_json> or C<JSON> module object
|
|
with C<utf8> enable. And the decoded result will contain UNICODE characters.
|
|
|
|
# from network
|
|
my $json = JSON->new->utf8;
|
|
my $json_text = CGI->new->param( 'json_data' );
|
|
my $perl_scalar = $json->decode( $json_text );
|
|
|
|
# from file content
|
|
local $/;
|
|
open( my $fh, '<', 'json.data' );
|
|
$json_text = <$fh>;
|
|
$perl_scalar = decode_json( $json_text );
|
|
|
|
If an outer data is not encoded in UTF-8, firstly you should C<decode> it.
|
|
|
|
use Encode;
|
|
local $/;
|
|
open( my $fh, '<', 'json.data' );
|
|
my $encoding = 'cp932';
|
|
my $unicode_json_text = decode( $encoding, <$fh> ); # UNICODE
|
|
|
|
# or you can write the below code.
|
|
#
|
|
# open( my $fh, "<:encoding($encoding)", 'json.data' );
|
|
# $unicode_json_text = <$fh>;
|
|
|
|
In this case, C<$unicode_json_text> is of course UNICODE string.
|
|
So you B<cannot> use C<decode_json> nor C<JSON> module object with C<utf8> enable.
|
|
Instead of them, you use C<JSON> module object with C<utf8> disable or C<from_json>.
|
|
|
|
$perl_scalar = $json->utf8(0)->decode( $unicode_json_text );
|
|
# or
|
|
$perl_scalar = from_json( $unicode_json_text );
|
|
|
|
Or C<encode 'utf8'> and C<decode_json>:
|
|
|
|
$perl_scalar = decode_json( encode( 'utf8', $unicode_json_text ) );
|
|
# this way is not efficient.
|
|
|
|
And now, you want to convert your C<$perl_scalar> into JSON data and
|
|
send it to an outer world - a network or a file content, and so on.
|
|
|
|
Your data usually contains UNICODE strings and you want the converted data to be encoded
|
|
in UTF-8, you should use C<encode_json> or C<JSON> module object with C<utf8> enable.
|
|
|
|
print encode_json( $perl_scalar ); # to a network? file? or display?
|
|
# or
|
|
print $json->utf8->encode( $perl_scalar );
|
|
|
|
If C<$perl_scalar> does not contain UNICODE but C<$encoding>-encoded strings
|
|
for some reason, then its characters are regarded as B<latin1> for perl
|
|
(because it does not concern with your $encoding).
|
|
You B<cannot> use C<encode_json> nor C<JSON> module object with C<utf8> enable.
|
|
Instead of them, you use C<JSON> module object with C<utf8> disable or C<to_json>.
|
|
Note that the resulted text is a UNICODE string but no problem to print it.
|
|
|
|
# $perl_scalar contains $encoding encoded string values
|
|
$unicode_json_text = $json->utf8(0)->encode( $perl_scalar );
|
|
# or
|
|
$unicode_json_text = to_json( $perl_scalar );
|
|
# $unicode_json_text consists of characters less than 0x100
|
|
print $unicode_json_text;
|
|
|
|
Or C<decode $encoding> all string values and C<encode_json>:
|
|
|
|
$perl_scalar->{ foo } = decode( $encoding, $perl_scalar->{ foo } );
|
|
# ... do it to each string values, then encode_json
|
|
$json_text = encode_json( $perl_scalar );
|
|
|
|
This method is a proper way but probably not efficient.
|
|
|
|
See to L<Encode>, L<perluniintro>.
|
|
|
|
|
|
=head1 COMMON OBJECT-ORIENTED INTERFACE
|
|
|
|
=head2 new
|
|
|
|
$json = new JSON
|
|
|
|
Returns a new C<JSON> object inherited from either JSON::XS or JSON::PP
|
|
that can be used to de/encode JSON strings.
|
|
|
|
All boolean flags described below are by default I<disabled>.
|
|
|
|
The mutators for flags all return the JSON object again and thus calls can
|
|
be chained:
|
|
|
|
my $json = JSON->new->utf8->space_after->encode({a => [1,2]})
|
|
=> {"a": [1, 2]}
|
|
|
|
=head2 ascii
|
|
|
|
$json = $json->ascii([$enable])
|
|
|
|
$enabled = $json->get_ascii
|
|
|
|
If $enable is true (or missing), then the encode method will not generate characters outside
|
|
the code range 0..127. Any Unicode characters outside that range will be escaped using either
|
|
a single \uXXXX or a double \uHHHH\uLLLLL escape sequence, as per RFC4627.
|
|
|
|
If $enable is false, then the encode method will not escape Unicode characters unless
|
|
required by the JSON syntax or other flags. This results in a faster and more compact format.
|
|
|
|
This feature depends on the used Perl version and environment.
|
|
|
|
See to L<JSON::PP/UNICODE HANDLING ON PERLS> if the backend is PP.
|
|
|
|
JSON->new->ascii(1)->encode([chr 0x10401])
|
|
=> ["\ud801\udc01"]
|
|
|
|
=head2 latin1
|
|
|
|
$json = $json->latin1([$enable])
|
|
|
|
$enabled = $json->get_latin1
|
|
|
|
If $enable is true (or missing), then the encode method will encode the resulting JSON
|
|
text as latin1 (or iso-8859-1), escaping any characters outside the code range 0..255.
|
|
|
|
If $enable is false, then the encode method will not escape Unicode characters
|
|
unless required by the JSON syntax or other flags.
|
|
|
|
JSON->new->latin1->encode (["\x{89}\x{abc}"]
|
|
=> ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not)
|
|
|
|
=head2 utf8
|
|
|
|
$json = $json->utf8([$enable])
|
|
|
|
$enabled = $json->get_utf8
|
|
|
|
If $enable is true (or missing), then the encode method will encode the JSON result
|
|
into UTF-8, as required by many protocols, while the decode method expects to be handled
|
|
an UTF-8-encoded string. Please note that UTF-8-encoded strings do not contain any
|
|
characters outside the range 0..255, they are thus useful for bytewise/binary I/O.
|
|
|
|
In future versions, enabling this option might enable autodetection of the UTF-16 and UTF-32
|
|
encoding families, as described in RFC4627.
|
|
|
|
If $enable is false, then the encode method will return the JSON string as a (non-encoded)
|
|
Unicode string, while decode expects thus a Unicode string. Any decoding or encoding
|
|
(e.g. to UTF-8 or UTF-16) needs to be done yourself, e.g. using the Encode module.
|
|
|
|
|
|
Example, output UTF-16BE-encoded JSON:
|
|
|
|
use Encode;
|
|
$jsontext = encode "UTF-16BE", JSON::XS->new->encode ($object);
|
|
|
|
Example, decode UTF-32LE-encoded JSON:
|
|
|
|
use Encode;
|
|
$object = JSON::XS->new->decode (decode "UTF-32LE", $jsontext);
|
|
|
|
See to L<JSON::PP/UNICODE HANDLING ON PERLS> if the backend is PP.
|
|
|
|
|
|
=head2 pretty
|
|
|
|
$json = $json->pretty([$enable])
|
|
|
|
This enables (or disables) all of the C<indent>, C<space_before> and
|
|
C<space_after> (and in the future possibly more) flags in one call to
|
|
generate the most readable (or most compact) form possible.
|
|
|
|
Equivalent to:
|
|
|
|
$json->indent->space_before->space_after
|
|
|
|
The indent space length is three and JSON::XS cannot change the indent
|
|
space length.
|
|
|
|
=head2 indent
|
|
|
|
$json = $json->indent([$enable])
|
|
|
|
$enabled = $json->get_indent
|
|
|
|
If C<$enable> is true (or missing), then the C<encode> method will use a multiline
|
|
format as output, putting every array member or object/hash key-value pair
|
|
into its own line, identing them properly.
|
|
|
|
If C<$enable> is false, no newlines or indenting will be produced, and the
|
|
resulting JSON text is guarenteed not to contain any C<newlines>.
|
|
|
|
This setting has no effect when decoding JSON texts.
|
|
|
|
The indent space length is three.
|
|
With JSON::PP, you can also access C<indent_length> to change indent space length.
|
|
|
|
|
|
=head2 space_before
|
|
|
|
$json = $json->space_before([$enable])
|
|
|
|
$enabled = $json->get_space_before
|
|
|
|
If C<$enable> is true (or missing), then the C<encode> method will add an extra
|
|
optional space before the C<:> separating keys from values in JSON objects.
|
|
|
|
If C<$enable> is false, then the C<encode> method will not add any extra
|
|
space at those places.
|
|
|
|
This setting has no effect when decoding JSON texts.
|
|
|
|
Example, space_before enabled, space_after and indent disabled:
|
|
|
|
{"key" :"value"}
|
|
|
|
|
|
=head2 space_after
|
|
|
|
$json = $json->space_after([$enable])
|
|
|
|
$enabled = $json->get_space_after
|
|
|
|
If C<$enable> is true (or missing), then the C<encode> method will add an extra
|
|
optional space after the C<:> separating keys from values in JSON objects
|
|
and extra whitespace after the C<,> separating key-value pairs and array
|
|
members.
|
|
|
|
If C<$enable> is false, then the C<encode> method will not add any extra
|
|
space at those places.
|
|
|
|
This setting has no effect when decoding JSON texts.
|
|
|
|
Example, space_before and indent disabled, space_after enabled:
|
|
|
|
{"key": "value"}
|
|
|
|
|
|
=head2 relaxed
|
|
|
|
$json = $json->relaxed([$enable])
|
|
|
|
$enabled = $json->get_relaxed
|
|
|
|
If C<$enable> is true (or missing), then C<decode> will accept some
|
|
extensions to normal JSON syntax (see below). C<encode> will not be
|
|
affected in anyway. I<Be aware that this option makes you accept invalid
|
|
JSON texts as if they were valid!>. I suggest only to use this option to
|
|
parse application-specific files written by humans (configuration files,
|
|
resource files etc.)
|
|
|
|
If C<$enable> is false (the default), then C<decode> will only accept
|
|
valid JSON texts.
|
|
|
|
Currently accepted extensions are:
|
|
|
|
=over 4
|
|
|
|
=item * list items can have an end-comma
|
|
|
|
JSON I<separates> array elements and key-value pairs with commas. This
|
|
can be annoying if you write JSON texts manually and want to be able to
|
|
quickly append elements, so this extension accepts comma at the end of
|
|
such items not just between them:
|
|
|
|
[
|
|
1,
|
|
2, <- this comma not normally allowed
|
|
]
|
|
{
|
|
"k1": "v1",
|
|
"k2": "v2", <- this comma not normally allowed
|
|
}
|
|
|
|
=item * shell-style '#'-comments
|
|
|
|
Whenever JSON allows whitespace, shell-style comments are additionally
|
|
allowed. They are terminated by the first carriage-return or line-feed
|
|
character, after which more white-space and comments are allowed.
|
|
|
|
[
|
|
1, # this comment not allowed in JSON
|
|
# neither this one...
|
|
]
|
|
|
|
=back
|
|
|
|
|
|
=head2 canonical
|
|
|
|
$json = $json->canonical([$enable])
|
|
|
|
$enabled = $json->get_canonical
|
|
|
|
If C<$enable> is true (or missing), then the C<encode> method will output JSON objects
|
|
by sorting their keys. This is adding a comparatively high overhead.
|
|
|
|
If C<$enable> is false, then the C<encode> method will output key-value
|
|
pairs in the order Perl stores them (which will likely change between runs
|
|
of the same script).
|
|
|
|
This option is useful if you want the same data structure to be encoded as
|
|
the same JSON text (given the same overall settings). If it is disabled,
|
|
the same hash might be encoded differently even if contains the same data,
|
|
as key-value pairs have no inherent ordering in Perl.
|
|
|
|
This setting has no effect when decoding JSON texts.
|
|
|
|
=head2 allow_nonref
|
|
|
|
$json = $json->allow_nonref([$enable])
|
|
|
|
$enabled = $json->get_allow_nonref
|
|
|
|
If C<$enable> is true (or missing), then the C<encode> method can convert a
|
|
non-reference into its corresponding string, number or null JSON value,
|
|
which is an extension to RFC4627. Likewise, C<decode> will accept those JSON
|
|
values instead of croaking.
|
|
|
|
If C<$enable> is false, then the C<encode> method will croak if it isn't
|
|
passed an arrayref or hashref, as JSON texts must either be an object
|
|
or array. Likewise, C<decode> will croak if given something that is not a
|
|
JSON object or array.
|
|
|
|
JSON->new->allow_nonref->encode ("Hello, World!")
|
|
=> "Hello, World!"
|
|
|
|
=head2 allow_unknown
|
|
|
|
$json = $json->allow_unknown ([$enable])
|
|
|
|
$enabled = $json->get_allow_unknown
|
|
|
|
If $enable is true (or missing), then "encode" will *not* throw an
|
|
exception when it encounters values it cannot represent in JSON (for
|
|
example, filehandles) but instead will encode a JSON "null" value.
|
|
Note that blessed objects are not included here and are handled
|
|
separately by c<allow_nonref>.
|
|
|
|
If $enable is false (the default), then "encode" will throw an
|
|
exception when it encounters anything it cannot encode as JSON.
|
|
|
|
This option does not affect "decode" in any way, and it is
|
|
recommended to leave it off unless you know your communications
|
|
partner.
|
|
|
|
=head2 allow_blessed
|
|
|
|
$json = $json->allow_blessed([$enable])
|
|
|
|
$enabled = $json->get_allow_blessed
|
|
|
|
If C<$enable> is true (or missing), then the C<encode> method will not
|
|
barf when it encounters a blessed reference. Instead, the value of the
|
|
B<convert_blessed> option will decide whether C<null> (C<convert_blessed>
|
|
disabled or no C<TO_JSON> method found) or a representation of the
|
|
object (C<convert_blessed> enabled and C<TO_JSON> method found) is being
|
|
encoded. Has no effect on C<decode>.
|
|
|
|
If C<$enable> is false (the default), then C<encode> will throw an
|
|
exception when it encounters a blessed object.
|
|
|
|
|
|
=head2 convert_blessed
|
|
|
|
$json = $json->convert_blessed([$enable])
|
|
|
|
$enabled = $json->get_convert_blessed
|
|
|
|
If C<$enable> is true (or missing), then C<encode>, upon encountering a
|
|
blessed object, will check for the availability of the C<TO_JSON> method
|
|
on the object's class. If found, it will be called in scalar context
|
|
and the resulting scalar will be encoded instead of the object. If no
|
|
C<TO_JSON> method is found, the value of C<allow_blessed> will decide what
|
|
to do.
|
|
|
|
The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
|
|
returns other blessed objects, those will be handled in the same
|
|
way. C<TO_JSON> must take care of not causing an endless recursion cycle
|
|
(== crash) in this case. The name of C<TO_JSON> was chosen because other
|
|
methods called by the Perl core (== not by the user of the object) are
|
|
usually in upper case letters and to avoid collisions with the C<to_json>
|
|
function or method.
|
|
|
|
This setting does not yet influence C<decode> in any way.
|
|
|
|
If C<$enable> is false, then the C<allow_blessed> setting will decide what
|
|
to do when a blessed object is found.
|
|
|
|
=over
|
|
|
|
=item convert_blessed_universally mode
|
|
|
|
If use C<JSON> with C<-convert_blessed_universally>, the C<UNIVERSAL::TO_JSON>
|
|
subroutine is defined as the below code:
|
|
|
|
*UNIVERSAL::TO_JSON = sub {
|
|
my $b_obj = B::svref_2object( $_[0] );
|
|
return $b_obj->isa('B::HV') ? { %{ $_[0] } }
|
|
: $b_obj->isa('B::AV') ? [ @{ $_[0] } ]
|
|
: undef
|
|
;
|
|
}
|
|
|
|
This will cause that C<encode> method converts simple blessed objects into
|
|
JSON objects as non-blessed object.
|
|
|
|
JSON -convert_blessed_universally;
|
|
$json->allow_blessed->convert_blessed->encode( $blessed_object )
|
|
|
|
This feature is experimental and may be removed in the future.
|
|
|
|
=back
|
|
|
|
=head2 filter_json_object
|
|
|
|
$json = $json->filter_json_object([$coderef])
|
|
|
|
When C<$coderef> is specified, it will be called from C<decode> each
|
|
time it decodes a JSON object. The only argument passed to the coderef
|
|
is a reference to the newly-created hash. If the code references returns
|
|
a single scalar (which need not be a reference), this value
|
|
(i.e. a copy of that scalar to avoid aliasing) is inserted into the
|
|
deserialised data structure. If it returns an empty list
|
|
(NOTE: I<not> C<undef>, which is a valid scalar), the original deserialised
|
|
hash will be inserted. This setting can slow down decoding considerably.
|
|
|
|
When C<$coderef> is omitted or undefined, any existing callback will
|
|
be removed and C<decode> will not change the deserialised hash in any
|
|
way.
|
|
|
|
Example, convert all JSON objects into the integer 5:
|
|
|
|
my $js = JSON->new->filter_json_object (sub { 5 });
|
|
# returns [5]
|
|
$js->decode ('[{}]'); # the given subroutine takes a hash reference.
|
|
# throw an exception because allow_nonref is not enabled
|
|
# so a lone 5 is not allowed.
|
|
$js->decode ('{"a":1, "b":2}');
|
|
|
|
|
|
=head2 filter_json_single_key_object
|
|
|
|
$json = $json->filter_json_single_key_object($key [=> $coderef])
|
|
|
|
Works remotely similar to C<filter_json_object>, but is only called for
|
|
JSON objects having a single key named C<$key>.
|
|
|
|
This C<$coderef> is called before the one specified via
|
|
C<filter_json_object>, if any. It gets passed the single value in the JSON
|
|
object. If it returns a single value, it will be inserted into the data
|
|
structure. If it returns nothing (not even C<undef> but the empty list),
|
|
the callback from C<filter_json_object> will be called next, as if no
|
|
single-key callback were specified.
|
|
|
|
If C<$coderef> is omitted or undefined, the corresponding callback will be
|
|
disabled. There can only ever be one callback for a given key.
|
|
|
|
As this callback gets called less often then the C<filter_json_object>
|
|
one, decoding speed will not usually suffer as much. Therefore, single-key
|
|
objects make excellent targets to serialise Perl objects into, especially
|
|
as single-key JSON objects are as close to the type-tagged value concept
|
|
as JSON gets (it's basically an ID/VALUE tuple). Of course, JSON does not
|
|
support this in any way, so you need to make sure your data never looks
|
|
like a serialised Perl hash.
|
|
|
|
Typical names for the single object key are C<__class_whatever__>, or
|
|
C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even
|
|
things like C<__class_md5sum(classname)__>, to reduce the risk of clashing
|
|
with real hashes.
|
|
|
|
Example, decode JSON objects of the form C<< { "__widget__" => <id> } >>
|
|
into the corresponding C<< $WIDGET{<id>} >> object:
|
|
|
|
# return whatever is in $WIDGET{5}:
|
|
JSON
|
|
->new
|
|
->filter_json_single_key_object (__widget__ => sub {
|
|
$WIDGET{ $_[0] }
|
|
})
|
|
->decode ('{"__widget__": 5')
|
|
|
|
# this can be used with a TO_JSON method in some "widget" class
|
|
# for serialisation to json:
|
|
sub WidgetBase::TO_JSON {
|
|
my ($self) = @_;
|
|
|
|
unless ($self->{id}) {
|
|
$self->{id} = ..get..some..id..;
|
|
$WIDGET{$self->{id}} = $self;
|
|
}
|
|
|
|
{ __widget__ => $self->{id} }
|
|
}
|
|
|
|
|
|
=head2 shrink
|
|
|
|
$json = $json->shrink([$enable])
|
|
|
|
$enabled = $json->get_shrink
|
|
|
|
With JSON::XS, this flag resizes strings generated by either
|
|
C<encode> or C<decode> to their minimum size possible. This can save
|
|
memory when your JSON texts are either very very long or you have many
|
|
short strings. It will also try to downgrade any strings to octet-form
|
|
if possible: perl stores strings internally either in an encoding called
|
|
UTF-X or in octet-form. The latter cannot store everything but uses less
|
|
space in general (and some buggy Perl or C code might even rely on that
|
|
internal representation being used).
|
|
|
|
With JSON::PP, it is noop about resizing strings but tries
|
|
C<utf8::downgrade> to the returned string by C<encode>. See to L<utf8>.
|
|
|
|
See to L<JSON::XS/OBJECT-ORIENTED INTERFACE> and L<JSON::PP/METHODS>.
|
|
|
|
=head2 max_depth
|
|
|
|
$json = $json->max_depth([$maximum_nesting_depth])
|
|
|
|
$max_depth = $json->get_max_depth
|
|
|
|
Sets the maximum nesting level (default C<512>) accepted while encoding
|
|
or decoding. If a higher nesting level is detected in JSON text or a Perl
|
|
data structure, then the encoder and decoder will stop and croak at that
|
|
point.
|
|
|
|
Nesting level is defined by number of hash- or arrayrefs that the encoder
|
|
needs to traverse to reach a given point or the number of C<{> or C<[>
|
|
characters without their matching closing parenthesis crossed to reach a
|
|
given character in a string.
|
|
|
|
If no argument is given, the highest possible setting will be used, which
|
|
is rarely useful.
|
|
|
|
Note that nesting is implemented by recursion in C. The default value has
|
|
been chosen to be as large as typical operating systems allow without
|
|
crashing. (JSON::XS)
|
|
|
|
With JSON::PP as the backend, when a large value (100 or more) was set and
|
|
it de/encodes a deep nested object/text, it may raise a warning
|
|
'Deep recursion on subroutin' at the perl runtime phase.
|
|
|
|
See L<JSON::XS/SECURITY CONSIDERATIONS> for more info on why this is useful.
|
|
|
|
=head2 max_size
|
|
|
|
$json = $json->max_size([$maximum_string_size])
|
|
|
|
$max_size = $json->get_max_size
|
|
|
|
Set the maximum length a JSON text may have (in bytes) where decoding is
|
|
being attempted. The default is C<0>, meaning no limit. When C<decode>
|
|
is called on a string that is longer then this many bytes, it will not
|
|
attempt to decode the string but throw an exception. This setting has no
|
|
effect on C<encode> (yet).
|
|
|
|
If no argument is given, the limit check will be deactivated (same as when
|
|
C<0> is specified).
|
|
|
|
See L<JSON::XS/SECURITY CONSIDERATIONS>, below, for more info on why this is useful.
|
|
|
|
=head2 encode
|
|
|
|
$json_text = $json->encode($perl_scalar)
|
|
|
|
Converts the given Perl data structure (a simple scalar or a reference
|
|
to a hash or array) to its JSON representation. Simple scalars will be
|
|
converted into JSON string or number sequences, while references to arrays
|
|
become JSON arrays and references to hashes become JSON objects. Undefined
|
|
Perl values (e.g. C<undef>) become JSON C<null> values.
|
|
References to the integers C<0> and C<1> are converted into C<true> and C<false>.
|
|
|
|
=head2 decode
|
|
|
|
$perl_scalar = $json->decode($json_text)
|
|
|
|
The opposite of C<encode>: expects a JSON text and tries to parse it,
|
|
returning the resulting simple scalar or reference. Croaks on error.
|
|
|
|
JSON numbers and strings become simple Perl scalars. JSON arrays become
|
|
Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes
|
|
C<1> (C<JSON::true>), C<false> becomes C<0> (C<JSON::false>) and
|
|
C<null> becomes C<undef>.
|
|
|
|
=head2 decode_prefix
|
|
|
|
($perl_scalar, $characters) = $json->decode_prefix($json_text)
|
|
|
|
This works like the C<decode> method, but instead of raising an exception
|
|
when there is trailing garbage after the first JSON object, it will
|
|
silently stop parsing there and return the number of characters consumed
|
|
so far.
|
|
|
|
JSON->new->decode_prefix ("[1] the tail")
|
|
=> ([], 3)
|
|
|
|
See to L<JSON::XS/OBJECT-ORIENTED INTERFACE>
|
|
|
|
=head2 property
|
|
|
|
$boolean = $json->property($property_name)
|
|
|
|
Returns a boolean value about above some properties.
|
|
|
|
The available properties are C<ascii>, C<latin1>, C<utf8>,
|
|
C<indent>,C<space_before>, C<space_after>, C<relaxed>, C<canonical>,
|
|
C<allow_nonref>, C<allow_unknown>, C<allow_blessed>, C<convert_blessed>,
|
|
C<shrink>, C<max_depth> and C<max_size>.
|
|
|
|
$boolean = $json->property('utf8');
|
|
=> 0
|
|
$json->utf8;
|
|
$boolean = $json->property('utf8');
|
|
=> 1
|
|
|
|
Sets the property with a given boolean value.
|
|
|
|
$json = $json->property($property_name => $boolean);
|
|
|
|
With no argumnt, it returns all the above properties as a hash reference.
|
|
|
|
$flag_hashref = $json->property();
|
|
|
|
=head1 INCREMENTAL PARSING
|
|
|
|
Most of this section are copied and modified from L<JSON::XS/INCREMENTAL PARSING>.
|
|
|
|
In some cases, there is the need for incremental parsing of JSON texts.
|
|
This module does allow you to parse a JSON stream incrementally.
|
|
It does so by accumulating text until it has a full JSON object, which
|
|
it then can decode. This process is similar to using C<decode_prefix>
|
|
to see if a full JSON object is available, but is much more efficient
|
|
(and can be implemented with a minimum of method calls).
|
|
|
|
The backend module will only attempt to parse the JSON text once it is sure it
|
|
has enough text to get a decisive result, using a very simple but
|
|
truly incremental parser. This means that it sometimes won't stop as
|
|
early as the full parser, for example, it doesn't detect parenthese
|
|
mismatches. The only thing it guarantees is that it starts decoding as
|
|
soon as a syntactically valid JSON text has been seen. This means you need
|
|
to set resource limits (e.g. C<max_size>) to ensure the parser will stop
|
|
parsing in the presence if syntax errors.
|
|
|
|
The following methods implement this incremental parser.
|
|
|
|
=head2 incr_parse
|
|
|
|
$json->incr_parse( [$string] ) # void context
|
|
|
|
$obj_or_undef = $json->incr_parse( [$string] ) # scalar context
|
|
|
|
@obj_or_empty = $json->incr_parse( [$string] ) # list context
|
|
|
|
This is the central parsing function. It can both append new text and
|
|
extract objects from the stream accumulated so far (both of these
|
|
functions are optional).
|
|
|
|
If C<$string> is given, then this string is appended to the already
|
|
existing JSON fragment stored in the C<$json> object.
|
|
|
|
After that, if the function is called in void context, it will simply
|
|
return without doing anything further. This can be used to add more text
|
|
in as many chunks as you want.
|
|
|
|
If the method is called in scalar context, then it will try to extract
|
|
exactly I<one> JSON object. If that is successful, it will return this
|
|
object, otherwise it will return C<undef>. If there is a parse error,
|
|
this method will croak just as C<decode> would do (one can then use
|
|
C<incr_skip> to skip the errornous part). This is the most common way of
|
|
using the method.
|
|
|
|
And finally, in list context, it will try to extract as many objects
|
|
from the stream as it can find and return them, or the empty list
|
|
otherwise. For this to work, there must be no separators between the JSON
|
|
objects or arrays, instead they must be concatenated back-to-back. If
|
|
an error occurs, an exception will be raised as in the scalar context
|
|
case. Note that in this case, any previously-parsed JSON texts will be
|
|
lost.
|
|
|
|
Example: Parse some JSON arrays/objects in a given string and return them.
|
|
|
|
my @objs = JSON->new->incr_parse ("[5][7][1,2]");
|
|
|
|
=head2 incr_text
|
|
|
|
$lvalue_string = $json->incr_text
|
|
|
|
This method returns the currently stored JSON fragment as an lvalue, that
|
|
is, you can manipulate it. This I<only> works when a preceding call to
|
|
C<incr_parse> in I<scalar context> successfully returned an object. Under
|
|
all other circumstances you must not call this function (I mean it.
|
|
although in simple tests it might actually work, it I<will> fail under
|
|
real world conditions). As a special exception, you can also call this
|
|
method before having parsed anything.
|
|
|
|
This function is useful in two cases: a) finding the trailing text after a
|
|
JSON object or b) parsing multiple JSON objects separated by non-JSON text
|
|
(such as commas).
|
|
|
|
$json->incr_text =~ s/\s*,\s*//;
|
|
|
|
In Perl 5.005, C<lvalue> attribute is not available.
|
|
You must write codes like the below:
|
|
|
|
$string = $json->incr_text;
|
|
$string =~ s/\s*,\s*//;
|
|
$json->incr_text( $string );
|
|
|
|
=head2 incr_skip
|
|
|
|
$json->incr_skip
|
|
|
|
This will reset the state of the incremental parser and will remove the
|
|
parsed text from the input buffer. This is useful after C<incr_parse>
|
|
died, in which case the input buffer and incremental parser state is left
|
|
unchanged, to skip the text parsed so far and to reset the parse state.
|
|
|
|
=head2 incr_reset
|
|
|
|
$json->incr_reset
|
|
|
|
This completely resets the incremental parser, that is, after this call,
|
|
it will be as if the parser had never parsed anything.
|
|
|
|
This is useful if you want ot repeatedly parse JSON objects and want to
|
|
ignore any trailing data, which means you have to reset the parser after
|
|
each successful decode.
|
|
|
|
See to L<JSON::XS/INCREMENTAL PARSING> for examples.
|
|
|
|
|
|
=head1 JSON::PP SUPPORT METHODS
|
|
|
|
The below methods are JSON::PP own methods, so when C<JSON> works
|
|
with JSON::PP (i.e. the created object is a JSON::PP object), available.
|
|
See to L<JSON::PP/JSON::PP OWN METHODS> in detail.
|
|
|
|
If you use C<JSON> with additonal C<-support_by_pp>, some methods
|
|
are available even with JSON::XS. See to L<USE PP FEATURES EVEN THOUGH XS BACKEND>.
|
|
|
|
BEING { $ENV{PERL_JSON_BACKEND} = 'JSON::XS' }
|
|
|
|
use JSON -support_by_pp;
|
|
|
|
my $json = new JSON;
|
|
$json->allow_nonref->escape_slash->encode("/");
|
|
|
|
# functional interfaces too.
|
|
print to_json(["/"], {escape_slash => 1});
|
|
print from_json('["foo"]', {utf8 => 1});
|
|
|
|
If you do not want to all functions but C<-support_by_pp>,
|
|
use C<-no_export>.
|
|
|
|
use JSON -support_by_pp, -no_export;
|
|
# functional interfaces are not exported.
|
|
|
|
=head2 allow_singlequote
|
|
|
|
$json = $json->allow_singlequote([$enable])
|
|
|
|
If C<$enable> is true (or missing), then C<decode> will accept
|
|
any JSON strings quoted by single quotations that are invalid JSON
|
|
format.
|
|
|
|
$json->allow_singlequote->decode({"foo":'bar'});
|
|
$json->allow_singlequote->decode({'foo':"bar"});
|
|
$json->allow_singlequote->decode({'foo':'bar'});
|
|
|
|
As same as the C<relaxed> option, this option may be used to parse
|
|
application-specific files written by humans.
|
|
|
|
=head2 allow_barekey
|
|
|
|
$json = $json->allow_barekey([$enable])
|
|
|
|
If C<$enable> is true (or missing), then C<decode> will accept
|
|
bare keys of JSON object that are invalid JSON format.
|
|
|
|
As same as the C<relaxed> option, this option may be used to parse
|
|
application-specific files written by humans.
|
|
|
|
$json->allow_barekey->decode('{foo:"bar"}');
|
|
|
|
=head2 allow_bignum
|
|
|
|
$json = $json->allow_bignum([$enable])
|
|
|
|
If C<$enable> is true (or missing), then C<decode> will convert
|
|
the big integer Perl cannot handle as integer into a L<Math::BigInt>
|
|
object and convert a floating number (any) into a L<Math::BigFloat>.
|
|
|
|
On the contary, C<encode> converts C<Math::BigInt> objects and C<Math::BigFloat>
|
|
objects into JSON numbers with C<allow_blessed> enable.
|
|
|
|
$json->allow_nonref->allow_blessed->allow_bignum;
|
|
$bigfloat = $json->decode('2.000000000000000000000000001');
|
|
print $json->encode($bigfloat);
|
|
# => 2.000000000000000000000000001
|
|
|
|
See to L<MAPPING> aboout the conversion of JSON number.
|
|
|
|
=head2 loose
|
|
|
|
$json = $json->loose([$enable])
|
|
|
|
The unescaped [\x00-\x1f\x22\x2f\x5c] strings are invalid in JSON strings
|
|
and the module doesn't allow to C<decode> to these (except for \x2f).
|
|
If C<$enable> is true (or missing), then C<decode> will accept these
|
|
unescaped strings.
|
|
|
|
$json->loose->decode(qq|["abc
|
|
def"]|);
|
|
|
|
See to L<JSON::PP/JSON::PP OWN METHODS>.
|
|
|
|
=head2 escape_slash
|
|
|
|
$json = $json->escape_slash([$enable])
|
|
|
|
According to JSON Grammar, I<slash> (U+002F) is escaped. But by default
|
|
JSON backend modules encode strings without escaping slash.
|
|
|
|
If C<$enable> is true (or missing), then C<encode> will escape slashes.
|
|
|
|
=head2 indent_length
|
|
|
|
$json = $json->indent_length($length)
|
|
|
|
With JSON::XS, The indent space length is 3 and cannot be changed.
|
|
With JSON::PP, it sets the indent space length with the given $length.
|
|
The default is 3. The acceptable range is 0 to 15.
|
|
|
|
=head2 sort_by
|
|
|
|
$json = $json->sort_by($function_name)
|
|
$json = $json->sort_by($subroutine_ref)
|
|
|
|
If $function_name or $subroutine_ref are set, its sort routine are used.
|
|
|
|
$js = $pc->sort_by(sub { $JSON::PP::a cmp $JSON::PP::b })->encode($obj);
|
|
# is($js, q|{"a":1,"b":2,"c":3,"d":4,"e":5,"f":6,"g":7,"h":8,"i":9}|);
|
|
|
|
$js = $pc->sort_by('own_sort')->encode($obj);
|
|
# is($js, q|{"a":1,"b":2,"c":3,"d":4,"e":5,"f":6,"g":7,"h":8,"i":9}|);
|
|
|
|
sub JSON::PP::own_sort { $JSON::PP::a cmp $JSON::PP::b }
|
|
|
|
As the sorting routine runs in the JSON::PP scope, the given
|
|
subroutine name and the special variables C<$a>, C<$b> will begin
|
|
with 'JSON::PP::'.
|
|
|
|
If $integer is set, then the effect is same as C<canonical> on.
|
|
|
|
See to L<JSON::PP/JSON::PP OWN METHODS>.
|
|
|
|
=head1 MAPPING
|
|
|
|
This section is copied from JSON::XS and modified to C<JSON>.
|
|
JSON::XS and JSON::PP mapping mechanisms are almost equivalent.
|
|
|
|
See to L<JSON::XS/MAPPING>.
|
|
|
|
=head2 JSON -> PERL
|
|
|
|
=over 4
|
|
|
|
=item object
|
|
|
|
A JSON object becomes a reference to a hash in Perl. No ordering of object
|
|
keys is preserved (JSON does not preserver object key ordering itself).
|
|
|
|
=item array
|
|
|
|
A JSON array becomes a reference to an array in Perl.
|
|
|
|
=item string
|
|
|
|
A JSON string becomes a string scalar in Perl - Unicode codepoints in JSON
|
|
are represented by the same codepoints in the Perl string, so no manual
|
|
decoding is necessary.
|
|
|
|
=item number
|
|
|
|
A JSON number becomes either an integer, numeric (floating point) or
|
|
string scalar in perl, depending on its range and any fractional parts. On
|
|
the Perl level, there is no difference between those as Perl handles all
|
|
the conversion details, but an integer may take slightly less memory and
|
|
might represent more values exactly than floating point numbers.
|
|
|
|
If the number consists of digits only, C<JSON> will try to represent
|
|
it as an integer value. If that fails, it will try to represent it as
|
|
a numeric (floating point) value if that is possible without loss of
|
|
precision. Otherwise it will preserve the number as a string value (in
|
|
which case you lose roundtripping ability, as the JSON number will be
|
|
re-encoded toa JSON string).
|
|
|
|
Numbers containing a fractional or exponential part will always be
|
|
represented as numeric (floating point) values, possibly at a loss of
|
|
precision (in which case you might lose perfect roundtripping ability, but
|
|
the JSON number will still be re-encoded as a JSON number).
|
|
|
|
Note that precision is not accuracy - binary floating point values cannot
|
|
represent most decimal fractions exactly, and when converting from and to
|
|
floating point, C<JSON> only guarantees precision up to but not including
|
|
the leats significant bit.
|
|
|
|
If the backend is JSON::PP and C<allow_bignum> is enable, the big integers
|
|
and the numeric can be optionally converted into L<Math::BigInt> and
|
|
L<Math::BigFloat> objects.
|
|
|
|
=item true, false
|
|
|
|
These JSON atoms become C<JSON::true> and C<JSON::false>,
|
|
respectively. They are overloaded to act almost exactly like the numbers
|
|
C<1> and C<0>. You can check wether a scalar is a JSON boolean by using
|
|
the C<JSON::is_bool> function.
|
|
|
|
If C<JSON::true> and C<JSON::false> are used as strings or compared as strings,
|
|
they represent as C<true> and C<false> respectively.
|
|
|
|
print JSON::true . "\n";
|
|
=> true
|
|
print JSON::true + 1;
|
|
=> 1
|
|
|
|
ok(JSON::true eq 'true');
|
|
ok(JSON::true eq '1');
|
|
ok(JSON::true == 1);
|
|
|
|
C<JSON> will install these missing overloading features to the backend modules.
|
|
|
|
|
|
=item null
|
|
|
|
A JSON null atom becomes C<undef> in Perl.
|
|
|
|
C<JSON::null> returns C<unddef>.
|
|
|
|
=back
|
|
|
|
|
|
=head2 PERL -> JSON
|
|
|
|
The mapping from Perl to JSON is slightly more difficult, as Perl is a
|
|
truly typeless language, so we can only guess which JSON type is meant by
|
|
a Perl value.
|
|
|
|
=over 4
|
|
|
|
=item hash references
|
|
|
|
Perl hash references become JSON objects. As there is no inherent ordering
|
|
in hash keys (or JSON objects), they will usually be encoded in a
|
|
pseudo-random order that can change between runs of the same program but
|
|
stays generally the same within a single run of a program. C<JSON>
|
|
optionally sort the hash keys (determined by the I<canonical> flag), so
|
|
the same datastructure will serialise to the same JSON text (given same
|
|
settings and version of JSON::XS), but this incurs a runtime overhead
|
|
and is only rarely useful, e.g. when you want to compare some JSON text
|
|
against another for equality.
|
|
|
|
In future, the ordered object feature will be added to JSON::PP using C<tie> mechanism.
|
|
|
|
|
|
=item array references
|
|
|
|
Perl array references become JSON arrays.
|
|
|
|
=item other references
|
|
|
|
Other unblessed references are generally not allowed and will cause an
|
|
exception to be thrown, except for references to the integers C<0> and
|
|
C<1>, which get turned into C<false> and C<true> atoms in JSON. You can
|
|
also use C<JSON::false> and C<JSON::true> to improve readability.
|
|
|
|
to_json [\0,JSON::true] # yields [false,true]
|
|
|
|
=item JSON::true, JSON::false, JSON::null
|
|
|
|
These special values become JSON true and JSON false values,
|
|
respectively. You can also use C<\1> and C<\0> directly if you want.
|
|
|
|
JSON::null returns C<undef>.
|
|
|
|
=item blessed objects
|
|
|
|
Blessed objects are not directly representable in JSON. See the
|
|
C<allow_blessed> and C<convert_blessed> methods on various options on
|
|
how to deal with this: basically, you can choose between throwing an
|
|
exception, encoding the reference as if it weren't blessed, or provide
|
|
your own serialiser method.
|
|
|
|
With C<convert_blessed_universally> mode, C<encode> converts blessed
|
|
hash references or blessed array references (contains other blessed references)
|
|
into JSON members and arrays.
|
|
|
|
use JSON -convert_blessed_universally;
|
|
JSON->new->allow_blessed->convert_blessed->encode( $blessed_object );
|
|
|
|
See to L<convert_blessed>.
|
|
|
|
=item simple scalars
|
|
|
|
Simple Perl scalars (any scalar that is not a reference) are the most
|
|
difficult objects to encode: JSON::XS and JSON::PP will encode undefined scalars as
|
|
JSON C<null> values, scalars that have last been used in a string context
|
|
before encoding as JSON strings, and anything else as number value:
|
|
|
|
# dump as number
|
|
encode_json [2] # yields [2]
|
|
encode_json [-3.0e17] # yields [-3e+17]
|
|
my $value = 5; encode_json [$value] # yields [5]
|
|
|
|
# used as string, so dump as string
|
|
print $value;
|
|
encode_json [$value] # yields ["5"]
|
|
|
|
# undef becomes null
|
|
encode_json [undef] # yields [null]
|
|
|
|
You can force the type to be a string by stringifying it:
|
|
|
|
my $x = 3.1; # some variable containing a number
|
|
"$x"; # stringified
|
|
$x .= ""; # another, more awkward way to stringify
|
|
print $x; # perl does it for you, too, quite often
|
|
|
|
You can force the type to be a number by numifying it:
|
|
|
|
my $x = "3"; # some variable containing a string
|
|
$x += 0; # numify it, ensuring it will be dumped as a number
|
|
$x *= 1; # same thing, the choise is yours.
|
|
|
|
You can not currently force the type in other, less obscure, ways.
|
|
|
|
Note that numerical precision has the same meaning as under Perl (so
|
|
binary to decimal conversion follows the same rules as in Perl, which
|
|
can differ to other languages). Also, your perl interpreter might expose
|
|
extensions to the floating point numbers of your platform, such as
|
|
infinities or NaN's - these cannot be represented in JSON, and it is an
|
|
error to pass those in.
|
|
|
|
=item Big Number
|
|
|
|
If the backend is JSON::PP and C<allow_bignum> is enable,
|
|
C<encode> converts C<Math::BigInt> objects and C<Math::BigFloat>
|
|
objects into JSON numbers.
|
|
|
|
|
|
=back
|
|
|
|
=head1 JSON and ECMAscript
|
|
|
|
See to L<JSON::XS/JSON and ECMAscript>.
|
|
|
|
=head1 JSON and YAML
|
|
|
|
JSON is not a subset of YAML.
|
|
See to L<JSON::XS/JSON and YAML>.
|
|
|
|
|
|
=head1 BACKEND MODULE DECISION
|
|
|
|
When you use C<JSON>, C<JSON> tries to C<use> JSON::XS. If this call failed, it will
|
|
C<uses> JSON::PP. The required JSON::XS version is I<2.2> or later.
|
|
|
|
The C<JSON> constructor method returns an object inherited from the backend module,
|
|
and JSON::XS object is a blessed scaler reference while JSON::PP is a blessed hash
|
|
reference.
|
|
|
|
So, your program should not depend on the backend module, especially
|
|
returned objects should not be modified.
|
|
|
|
my $json = JSON->new; # XS or PP?
|
|
$json->{stash} = 'this is xs object'; # this code may raise an error!
|
|
|
|
To check the backend module, there are some methods - C<backend>, C<is_pp> and C<is_xs>.
|
|
|
|
JSON->backend; # 'JSON::XS' or 'JSON::PP'
|
|
|
|
JSON->backend->is_pp: # 0 or 1
|
|
|
|
JSON->backend->is_xs: # 1 or 0
|
|
|
|
$json->is_xs; # 1 or 0
|
|
|
|
$json->is_pp; # 0 or 1
|
|
|
|
|
|
If you set an enviornment variable C<PERL_JSON_BACKEND>, The calling action will be changed.
|
|
|
|
=over
|
|
|
|
=item PERL_JSON_BACKEND = 0 or PERL_JSON_BACKEND = 'JSON::PP'
|
|
|
|
Always use JSON::PP
|
|
|
|
=item PERL_JSON_BACKEND == 1 or PERL_JSON_BACKEND = 'JSON::XS,JSON::PP'
|
|
|
|
(The default) Use compiled JSON::XS if it is properly compiled & installed,
|
|
otherwise use JSON::PP.
|
|
|
|
=item PERL_JSON_BACKEND == 2 or PERL_JSON_BACKEND = 'JSON::XS'
|
|
|
|
Always use compiled JSON::XS, die if it isn't properly compiled & installed.
|
|
|
|
=item PERL_JSON_BACKEND = 'JSON::backportPP'
|
|
|
|
Always use JSON::backportPP.
|
|
JSON::backportPP is JSON::PP back port module.
|
|
C<JSON> includs JSON::backportPP instead of JSON::PP.
|
|
|
|
=back
|
|
|
|
These ideas come from L<DBI::PurePerl> mechanism.
|
|
|
|
example:
|
|
|
|
BEGIN { $ENV{PERL_JSON_BACKEND} = 'JSON::PP' }
|
|
use JSON; # always uses JSON::PP
|
|
|
|
In future, it may be able to specify another module.
|
|
|
|
=head1 USE PP FEATURES EVEN THOUGH XS BACKEND
|
|
|
|
Many methods are available with either JSON::XS or JSON::PP and
|
|
when the backend module is JSON::XS, if any JSON::PP specific (i.e. JSON::XS unspported)
|
|
method is called, it will C<warn> and be noop.
|
|
|
|
But If you C<use> C<JSON> passing the optional string C<-support_by_pp>,
|
|
it makes a part of those unupported methods available.
|
|
This feature is achieved by using JSON::PP in C<de/encode>.
|
|
|
|
BEGIN { $ENV{PERL_JSON_BACKEND} = 2 } # with JSON::XS
|
|
use JSON -support_by_pp;
|
|
my $json = new JSON;
|
|
$json->allow_nonref->escape_slash->encode("/");
|
|
|
|
At this time, the returned object is a C<JSON::Backend::XS::Supportable>
|
|
object (re-blessed XS object), and by checking JSON::XS unsupported flags
|
|
in de/encoding, can support some unsupported methods - C<loose>, C<allow_bignum>,
|
|
C<allow_barekey>, C<allow_singlequote>, C<escape_slash> and C<indent_length>.
|
|
|
|
When any unsupported methods are not enable, C<XS de/encode> will be
|
|
used as is. The switch is achieved by changing the symbolic tables.
|
|
|
|
C<-support_by_pp> is effective only when the backend module is JSON::XS
|
|
and it makes the de/encoding speed down a bit.
|
|
|
|
See to L<JSON::PP SUPPORT METHODS>.
|
|
|
|
=head1 INCOMPATIBLE CHANGES TO OLD VERSION
|
|
|
|
There are big incompatibility between new version (2.00) and old (1.xx).
|
|
If you use old C<JSON> 1.xx in your code, please check it.
|
|
|
|
See to L<Transition ways from 1.xx to 2.xx.>
|
|
|
|
=over
|
|
|
|
=item jsonToObj and objToJson are obsoleted.
|
|
|
|
Non Perl-style name C<jsonToObj> and C<objToJson> are obsoleted
|
|
(but not yet deleted from the source).
|
|
If you use these functions in your code, please replace them
|
|
with C<from_json> and C<to_json>.
|
|
|
|
|
|
=item Global variables are no longer available.
|
|
|
|
C<JSON> class variables - C<$JSON::AUTOCONVERT>, C<$JSON::BareKey>, etc...
|
|
- are not available any longer.
|
|
Instead, various features can be used through object methods.
|
|
|
|
|
|
=item Package JSON::Converter and JSON::Parser are deleted.
|
|
|
|
Now C<JSON> bundles with JSON::PP which can handle JSON more properly than them.
|
|
|
|
=item Package JSON::NotString is deleted.
|
|
|
|
There was C<JSON::NotString> class which represents JSON value C<true>, C<false>, C<null>
|
|
and numbers. It was deleted and replaced by C<JSON::Boolean>.
|
|
|
|
C<JSON::Boolean> represents C<true> and C<false>.
|
|
|
|
C<JSON::Boolean> does not represent C<null>.
|
|
|
|
C<JSON::null> returns C<undef>.
|
|
|
|
C<JSON> makes L<JSON::XS::Boolean> and L<JSON::PP::Boolean> is-a relation
|
|
to L<JSON::Boolean>.
|
|
|
|
=item function JSON::Number is obsoleted.
|
|
|
|
C<JSON::Number> is now needless because JSON::XS and JSON::PP have
|
|
round-trip integrity.
|
|
|
|
=item JSONRPC modules are deleted.
|
|
|
|
Perl implementation of JSON-RPC protocol - C<JSONRPC >, C<JSONRPC::Transport::HTTP>
|
|
and C<Apache::JSONRPC > are deleted in this distribution.
|
|
Instead of them, there is L<JSON::RPC> which supports JSON-RPC protocol version 1.1.
|
|
|
|
=back
|
|
|
|
=head2 Transition ways from 1.xx to 2.xx.
|
|
|
|
You should set C<suport_by_pp> mode firstly, because
|
|
it is always successful for the below codes even with JSON::XS.
|
|
|
|
use JSON -support_by_pp;
|
|
|
|
=over
|
|
|
|
=item Exported jsonToObj (simple)
|
|
|
|
from_json($json_text);
|
|
|
|
=item Exported objToJson (simple)
|
|
|
|
to_json($perl_scalar);
|
|
|
|
=item Exported jsonToObj (advanced)
|
|
|
|
$flags = {allow_barekey => 1, allow_singlequote => 1};
|
|
from_json($json_text, $flags);
|
|
|
|
equivalent to:
|
|
|
|
$JSON::BareKey = 1;
|
|
$JSON::QuotApos = 1;
|
|
jsonToObj($json_text);
|
|
|
|
=item Exported objToJson (advanced)
|
|
|
|
$flags = {allow_blessed => 1, allow_barekey => 1};
|
|
to_json($perl_scalar, $flags);
|
|
|
|
equivalent to:
|
|
|
|
$JSON::BareKey = 1;
|
|
objToJson($perl_scalar);
|
|
|
|
=item jsonToObj as object method
|
|
|
|
$json->decode($json_text);
|
|
|
|
=item objToJson as object method
|
|
|
|
$json->encode($perl_scalar);
|
|
|
|
=item new method with parameters
|
|
|
|
The C<new> method in 2.x takes any parameters no longer.
|
|
You can set parameters instead;
|
|
|
|
$json = JSON->new->pretty;
|
|
|
|
=item $JSON::Pretty, $JSON::Indent, $JSON::Delimiter
|
|
|
|
If C<indent> is enable, that means C<$JSON::Pretty> flag set. And
|
|
C<$JSON::Delimiter> was substituted by C<space_before> and C<space_after>.
|
|
In conclusion:
|
|
|
|
$json->indent->space_before->space_after;
|
|
|
|
Equivalent to:
|
|
|
|
$json->pretty;
|
|
|
|
To change indent length, use C<indent_length>.
|
|
|
|
(Only with JSON::PP, if C<-support_by_pp> is not used.)
|
|
|
|
$json->pretty->indent_length(2)->encode($perl_scalar);
|
|
|
|
=item $JSON::BareKey
|
|
|
|
(Only with JSON::PP, if C<-support_by_pp> is not used.)
|
|
|
|
$json->allow_barekey->decode($json_text)
|
|
|
|
=item $JSON::ConvBlessed
|
|
|
|
use C<-convert_blessed_universally>. See to L<convert_blessed>.
|
|
|
|
=item $JSON::QuotApos
|
|
|
|
(Only with JSON::PP, if C<-support_by_pp> is not used.)
|
|
|
|
$json->allow_singlequote->decode($json_text)
|
|
|
|
=item $JSON::SingleQuote
|
|
|
|
Disable. C<JSON> does not make such a invalid JSON string any longer.
|
|
|
|
=item $JSON::KeySort
|
|
|
|
$json->canonical->encode($perl_scalar)
|
|
|
|
This is the ascii sort.
|
|
|
|
If you want to use with your own sort routine, check the C<sort_by> method.
|
|
|
|
(Only with JSON::PP, even if C<-support_by_pp> is used currently.)
|
|
|
|
$json->sort_by($sort_routine_ref)->encode($perl_scalar)
|
|
|
|
$json->sort_by(sub { $JSON::PP::a <=> $JSON::PP::b })->encode($perl_scalar)
|
|
|
|
Can't access C<$a> and C<$b> but C<$JSON::PP::a> and C<$JSON::PP::b>.
|
|
|
|
=item $JSON::SkipInvalid
|
|
|
|
$json->allow_unknown
|
|
|
|
=item $JSON::AUTOCONVERT
|
|
|
|
Needless. C<JSON> backend modules have the round-trip integrity.
|
|
|
|
=item $JSON::UTF8
|
|
|
|
Needless because C<JSON> (JSON::XS/JSON::PP) sets
|
|
the UTF8 flag on properly.
|
|
|
|
# With UTF8-flagged strings
|
|
|
|
$json->allow_nonref;
|
|
$str = chr(1000); # UTF8-flagged
|
|
|
|
$json_text = $json->utf8(0)->encode($str);
|
|
utf8::is_utf8($json_text);
|
|
# true
|
|
$json_text = $json->utf8(1)->encode($str);
|
|
utf8::is_utf8($json_text);
|
|
# false
|
|
|
|
$str = '"' . chr(1000) . '"'; # UTF8-flagged
|
|
|
|
$perl_scalar = $json->utf8(0)->decode($str);
|
|
utf8::is_utf8($perl_scalar);
|
|
# true
|
|
$perl_scalar = $json->utf8(1)->decode($str);
|
|
# died because of 'Wide character in subroutine'
|
|
|
|
See to L<JSON::XS/A FEW NOTES ON UNICODE AND PERL>.
|
|
|
|
=item $JSON::UnMapping
|
|
|
|
Disable. See to L<MAPPING>.
|
|
|
|
=item $JSON::SelfConvert
|
|
|
|
This option was deleted.
|
|
Instead of it, if a givien blessed object has the C<TO_JSON> method,
|
|
C<TO_JSON> will be executed with C<convert_blessed>.
|
|
|
|
$json->convert_blessed->encode($bleesed_hashref_or_arrayref)
|
|
# if need, call allow_blessed
|
|
|
|
Note that it was C<toJson> in old version, but now not C<toJson> but C<TO_JSON>.
|
|
|
|
=back
|
|
|
|
=head1 TODO
|
|
|
|
=over
|
|
|
|
=item example programs
|
|
|
|
=back
|
|
|
|
=head1 THREADS
|
|
|
|
No test with JSON::PP. If with JSON::XS, See to L<JSON::XS/THREADS>.
|
|
|
|
|
|
=head1 BUGS
|
|
|
|
Please report bugs relevant to C<JSON> to E<lt>makamaka[at]cpan.orgE<gt>.
|
|
|
|
|
|
=head1 SEE ALSO
|
|
|
|
Most of the document is copied and modified from JSON::XS doc.
|
|
|
|
L<JSON::XS>, L<JSON::PP>
|
|
|
|
C<RFC4627>(L<http://www.ietf.org/rfc/rfc4627.txt>)
|
|
|
|
=head1 AUTHOR
|
|
|
|
Makamaka Hannyaharamitu, E<lt>makamaka[at]cpan.orgE<gt>
|
|
|
|
JSON::XS was written by Marc Lehmann <schmorp[at]schmorp.de>
|
|
|
|
The relese of this new version owes to the courtesy of Marc Lehmann.
|
|
|
|
|
|
=head1 COPYRIGHT AND LICENSE
|
|
|
|
Copyright 2005-2011 by Makamaka Hannyaharamitu
|
|
|
|
This library is free software; you can redistribute it and/or modify
|
|
it under the same terms as Perl itself.
|
|
|
|
=cut
|
|
|