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JSON.pm
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JSON.pm
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package Mojo::JSON;
use Mojo::Base -strict;
use Carp qw(croak);
use Exporter qw(import);
use JSON::PP ();
use Mojo::Util qw(decode encode monkey_patch);
use Scalar::Util qw(blessed);
# For better performance Cpanel::JSON::XS is required
use constant JSON_XS => $ENV{MOJO_NO_JSON_XS}
? 0
: !!eval { require Cpanel::JSON::XS; Cpanel::JSON::XS->VERSION('4.09'); 1 };
use constant CORE_BOOLS => defined &builtin::is_bool;
BEGIN {
warnings->unimport('experimental::builtin') if CORE_BOOLS;
}
our @EXPORT_OK = qw(decode_json encode_json false from_json j to_json true);
# Escaped special character map
my %ESCAPE
= ('"' => '"', '\\' => '\\', '/' => '/', 'b' => "\x08", 'f' => "\x0c", 'n' => "\x0a", 'r' => "\x0d", 't' => "\x09");
my %REVERSE = map { $ESCAPE{$_} => "\\$_" } keys %ESCAPE;
for (0x00 .. 0x1f) { $REVERSE{pack 'C', $_} //= sprintf '\u%.4X', $_ }
# Replace pure-Perl fallbacks if Cpanel::JSON::XS is available
if (JSON_XS) {
my $BINARY = Cpanel::JSON::XS->new->utf8;
my $TEXT = Cpanel::JSON::XS->new;
$_->canonical->allow_nonref->allow_unknown->allow_blessed->convert_blessed->stringify_infnan->escape_slash
->allow_dupkeys
for $BINARY, $TEXT;
monkey_patch __PACKAGE__, 'encode_json', sub { $BINARY->encode($_[0]) };
monkey_patch __PACKAGE__, 'decode_json', sub { $BINARY->decode($_[0]) };
monkey_patch __PACKAGE__, 'to_json', sub { $TEXT->encode($_[0]) };
monkey_patch __PACKAGE__, 'from_json', sub { $TEXT->decode($_[0]) };
}
sub decode_json {
my $err = _decode(\my $value, shift);
return defined $err ? croak $err : $value;
}
sub encode_json { encode('UTF-8', _encode_value(shift)) }
sub false () {JSON::PP::false}
sub from_json {
my $err = _decode(\my $value, shift, 1);
return defined $err ? croak $err : $value;
}
sub j {
return encode_json($_[0]) if ref $_[0] eq 'ARRAY' || ref $_[0] eq 'HASH';
return scalar eval { decode_json($_[0]) };
}
sub to_json { _encode_value(shift) }
sub true () {JSON::PP::true}
sub _decode {
my $valueref = shift;
eval {
# Missing input
die "Missing or empty input at offset 0\n" unless length(local $_ = shift);
# UTF-8
$_ = decode('UTF-8', $_) unless shift;
die "Input is not UTF-8 encoded\n" unless defined;
# Value
$$valueref = _decode_value();
# Leftover data
/\G[\x20\x09\x0a\x0d]*\z/gc or _throw('Unexpected data');
} ? return undef : chomp $@;
return $@;
}
sub _decode_array {
my @array;
until (m/\G[\x20\x09\x0a\x0d]*\]/gc) {
# Value
push @array, _decode_value();
# Separator
redo if /\G[\x20\x09\x0a\x0d]*,/gc;
# End
last if /\G[\x20\x09\x0a\x0d]*\]/gc;
# Invalid character
_throw('Expected comma or right square bracket while parsing array');
}
return \@array;
}
sub _decode_object {
my %hash;
until (m/\G[\x20\x09\x0a\x0d]*\}/gc) {
# Quote
/\G[\x20\x09\x0a\x0d]*"/gc or _throw('Expected string while parsing object');
# Key
my $key = _decode_string();
# Colon
/\G[\x20\x09\x0a\x0d]*:/gc or _throw('Expected colon while parsing object');
# Value
$hash{$key} = _decode_value();
# Separator
redo if /\G[\x20\x09\x0a\x0d]*,/gc;
# End
last if /\G[\x20\x09\x0a\x0d]*\}/gc;
# Invalid character
_throw('Expected comma or right curly bracket while parsing object');
}
return \%hash;
}
sub _decode_string {
my $pos = pos;
# Extract string with escaped characters
m!\G((?:(?:[^\x00-\x1f\\"]|\\(?:["\\/bfnrt]|u[0-9a-fA-F]{4})){0,32766})*)!gc;
my $str = $1;
# Invalid character
unless (m/\G"/gc) {
_throw('Unexpected character or invalid escape while parsing string') if /\G[\x00-\x1f\\]/;
_throw('Unterminated string');
}
# Unescape popular characters
if (index($str, '\\u') < 0) {
$str =~ s!\\(["\\/bfnrt])!$ESCAPE{$1}!gs;
return $str;
}
# Unescape everything else
my $buffer = '';
while ($str =~ /\G([^\\]*)\\(?:([^u])|u(.{4}))/gc) {
$buffer .= $1;
# Popular character
if ($2) { $buffer .= $ESCAPE{$2} }
# Escaped
else {
my $ord = hex $3;
# Surrogate pair
if (($ord & 0xf800) == 0xd800) {
# High surrogate
($ord & 0xfc00) == 0xd800 or pos = $pos + pos($str), _throw('Missing high-surrogate');
# Low surrogate
$str =~ /\G\\u([Dd][C-Fc-f]..)/gc or pos = $pos + pos($str), _throw('Missing low-surrogate');
$ord = 0x10000 + ($ord - 0xd800) * 0x400 + (hex($1) - 0xdc00);
}
# Character
$buffer .= pack 'U', $ord;
}
}
# The rest
return $buffer . substr $str, pos($str), length($str);
}
sub _decode_value {
# Leading whitespace
/\G[\x20\x09\x0a\x0d]*/gc;
# String
return _decode_string() if /\G"/gc;
# Object
return _decode_object() if /\G\{/gc;
# Array
return _decode_array() if /\G\[/gc;
# Number
return 0 + $1 if /\G([-]?(?:0|[1-9][0-9]*)(?:\.[0-9]*)?(?:[eE][+-]?[0-9]+)?)/gc;
# True
return true() if /\Gtrue/gc;
# False
return false() if /\Gfalse/gc;
# Null
return undef if /\Gnull/gc;
# Invalid character
_throw('Expected string, array, object, number, boolean or null');
}
sub _encode_array {
'[' . join(',', map { _encode_value($_) } @{$_[0]}) . ']';
}
sub _encode_object {
my $object = shift;
my @pairs = map { _encode_string($_) . ':' . _encode_value($object->{$_}) } sort keys %$object;
return '{' . join(',', @pairs) . '}';
}
sub _encode_string {
my $str = shift;
$str =~ s!([\x00-\x1f\\"/])!$REVERSE{$1}!gs;
return "\"$str\"";
}
sub _encode_value {
my $value = shift;
# Reference
if (my $ref = ref $value) {
# Object
return _encode_object($value) if $ref eq 'HASH';
# Array
return _encode_array($value) if $ref eq 'ARRAY';
# True or false
return $$value ? 'true' : 'false' if $ref eq 'SCALAR';
return $value ? 'true' : 'false' if $ref eq 'JSON::PP::Boolean';
# Everything else
return 'null' unless blessed $value;
return _encode_string($value) unless my $sub = $value->can('TO_JSON');
return _encode_value($value->$sub);
}
# Null
return 'null' unless defined $value;
# Boolean
return $value ? 'true' : 'false' if CORE_BOOLS && builtin::is_bool($value);
# Number
no warnings 'numeric';
return $value
if !utf8::is_utf8($value) && length((my $dummy = '') & $value) && 0 + $value eq $value && $value * 0 == 0;
# String
return _encode_string($value);
}
sub _throw {
# Leading whitespace
/\G[\x20\x09\x0a\x0d]*/gc;
# Context
my $context = 'Malformed JSON: ' . shift;
if (m/\G\z/gc) { $context .= ' before end of data' }
else {
my @lines = split /\n/, substr($_, 0, pos);
$context .= ' at line ' . @lines . ', offset ' . length(pop @lines || '');
}
die "$context\n";
}
1;
=encoding utf8
=head1 NAME
Mojo::JSON - Minimalistic JSON
=head1 SYNOPSIS
use Mojo::JSON qw(decode_json encode_json);
my $bytes = encode_json {foo => [1, 2], bar => 'hello!', baz => \1};
my $hash = decode_json $bytes;
=head1 DESCRIPTION
L<Mojo::JSON> is a minimalistic and possibly the fastest pure-Perl implementation of L<RFC
8259|https://tools.ietf.org/html/rfc8259>.
It supports normal Perl data types like scalar, array reference, hash reference and will try to call the C<TO_JSON>
method on blessed references, or stringify them if it doesn't exist. Differentiating between strings and numbers in
Perl is hard, depending on how it has been used, a scalar can be both at the same time. The string value has a higher
precedence unless both representations are equivalent.
[1, -2, 3] -> [1, -2, 3]
{"foo": "bar"} -> {foo => 'bar'}
Literal names will be translated to and from L<Mojo::JSON> constants or a similar native Perl value.
true -> Mojo::JSON->true
false -> Mojo::JSON->false
null -> undef
In addition scalar references will be used to generate booleans, based on if their values are true or false.
\1 -> true
\0 -> false
The character C</> will always be escaped to prevent XSS attacks.
"</script>" -> "<\/script>"
For better performance the optional module L<Cpanel::JSON::XS> (4.09+) will be used automatically if possible. This can
also be disabled with the C<MOJO_NO_JSON_XS> environment variable.
=head1 FUNCTIONS
L<Mojo::JSON> implements the following functions, which can be imported individually.
=head2 decode_json
my $value = decode_json $bytes;
Decode JSON to Perl value and die if decoding fails.
=head2 encode_json
my $bytes = encode_json {i => '♥ mojolicious'};
Encode Perl value to JSON.
=head2 false
my $false = false;
False value, used because Perl has no native equivalent.
=head2 from_json
my $value = from_json $chars;
Decode JSON text that is not C<UTF-8> encoded to Perl value and die if decoding fails.
=head2 j
my $bytes = j [1, 2, 3];
my $bytes = j {i => '♥ mojolicious'};
my $value = j $bytes;
Encode Perl data structure (which may only be an array reference or hash reference) or decode JSON, an C<undef> return
value indicates a bare C<null> or that decoding failed.
=head2 to_json
my $chars = to_json {i => '♥ mojolicious'};
Encode Perl value to JSON text without C<UTF-8> encoding it.
=head2 true
my $true = true;
True value, used because Perl has no native equivalent.
=head1 SEE ALSO
L<Mojolicious>, L<Mojolicious::Guides>, L<https://mojolicious.org>.
=cut