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Diffstat (limited to 'data/lib/JSON.pm')
| -rw-r--r-- | data/lib/JSON.pm | 2267 |
1 files changed, 2267 insertions, 0 deletions
diff --git a/data/lib/JSON.pm b/data/lib/JSON.pm new file mode 100644 index 0000000..f57c555 --- /dev/null +++ b/data/lib/JSON.pm @@ -0,0 +1,2267 @@ +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 + |