… | |
… | |
101 | |
101 | |
102 | package JSON::XS; |
102 | package JSON::XS; |
103 | |
103 | |
104 | use common::sense; |
104 | use common::sense; |
105 | |
105 | |
106 | our $VERSION = 2.34; |
106 | our $VERSION = '3.0'; |
107 | our @ISA = qw(Exporter); |
107 | our @ISA = qw(Exporter); |
108 | |
108 | |
109 | our @EXPORT = qw(encode_json decode_json to_json from_json); |
109 | our @EXPORT = qw(encode_json decode_json); |
110 | |
|
|
111 | sub to_json($) { |
|
|
112 | require Carp; |
|
|
113 | Carp::croak ("JSON::XS::to_json has been renamed to encode_json, either downgrade to pre-2.0 versions of JSON::XS or rename the call"); |
|
|
114 | } |
|
|
115 | |
|
|
116 | sub from_json($) { |
|
|
117 | require Carp; |
|
|
118 | Carp::croak ("JSON::XS::from_json has been renamed to decode_json, either downgrade to pre-2.0 versions of JSON::XS or rename the call"); |
|
|
119 | } |
|
|
120 | |
110 | |
121 | use Exporter; |
111 | use Exporter; |
122 | use XSLoader; |
112 | use XSLoader; |
|
|
113 | |
|
|
114 | use Types::Serialiser (); |
123 | |
115 | |
124 | =head1 FUNCTIONAL INTERFACE |
116 | =head1 FUNCTIONAL INTERFACE |
125 | |
117 | |
126 | The following convenience methods are provided by this module. They are |
118 | The following convenience methods are provided by this module. They are |
127 | exported by default: |
119 | exported by default: |
… | |
… | |
148 | This function call is functionally identical to: |
140 | This function call is functionally identical to: |
149 | |
141 | |
150 | $perl_scalar = JSON::XS->new->utf8->decode ($json_text) |
142 | $perl_scalar = JSON::XS->new->utf8->decode ($json_text) |
151 | |
143 | |
152 | Except being faster. |
144 | Except being faster. |
153 | |
|
|
154 | =item $is_boolean = JSON::XS::is_bool $scalar |
|
|
155 | |
|
|
156 | Returns true if the passed scalar represents either JSON::XS::true or |
|
|
157 | JSON::XS::false, two constants that act like C<1> and C<0>, respectively |
|
|
158 | and are used to represent JSON C<true> and C<false> values in Perl. |
|
|
159 | |
|
|
160 | See MAPPING, below, for more information on how JSON values are mapped to |
|
|
161 | Perl. |
|
|
162 | |
145 | |
163 | =back |
146 | =back |
164 | |
147 | |
165 | |
148 | |
166 | =head1 A FEW NOTES ON UNICODE AND PERL |
149 | =head1 A FEW NOTES ON UNICODE AND PERL |
… | |
… | |
667 | |
650 | |
668 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
651 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
669 | |
652 | |
670 | =item $json_text = $json->encode ($perl_scalar) |
653 | =item $json_text = $json->encode ($perl_scalar) |
671 | |
654 | |
672 | Converts the given Perl data structure (a simple scalar or a reference |
655 | Converts the given Perl value or data structure to its JSON |
673 | to a hash or array) to its JSON representation. Simple scalars will be |
656 | representation. Croaks on error. |
674 | converted into JSON string or number sequences, while references to arrays |
|
|
675 | become JSON arrays and references to hashes become JSON objects. Undefined |
|
|
676 | Perl values (e.g. C<undef>) become JSON C<null> values. Neither C<true> |
|
|
677 | nor C<false> values will be generated. |
|
|
678 | |
657 | |
679 | =item $perl_scalar = $json->decode ($json_text) |
658 | =item $perl_scalar = $json->decode ($json_text) |
680 | |
659 | |
681 | The opposite of C<encode>: expects a JSON text and tries to parse it, |
660 | The opposite of C<encode>: expects a JSON text and tries to parse it, |
682 | returning the resulting simple scalar or reference. Croaks on error. |
661 | returning the resulting simple scalar or reference. Croaks on error. |
683 | |
|
|
684 | JSON numbers and strings become simple Perl scalars. JSON arrays become |
|
|
685 | Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes |
|
|
686 | C<1>, C<false> becomes C<0> and C<null> becomes C<undef>. |
|
|
687 | |
662 | |
688 | =item ($perl_scalar, $characters) = $json->decode_prefix ($json_text) |
663 | =item ($perl_scalar, $characters) = $json->decode_prefix ($json_text) |
689 | |
664 | |
690 | This works like the C<decode> method, but instead of raising an exception |
665 | This works like the C<decode> method, but instead of raising an exception |
691 | when there is trailing garbage after the first JSON object, it will |
666 | when there is trailing garbage after the first JSON object, it will |
692 | silently stop parsing there and return the number of characters consumed |
667 | silently stop parsing there and return the number of characters consumed |
693 | so far. |
668 | so far. |
694 | |
669 | |
695 | This is useful if your JSON texts are not delimited by an outer protocol |
670 | This is useful if your JSON texts are not delimited by an outer protocol |
696 | (which is not the brightest thing to do in the first place) and you need |
|
|
697 | to know where the JSON text ends. |
671 | and you need to know where the JSON text ends. |
698 | |
672 | |
699 | JSON::XS->new->decode_prefix ("[1] the tail") |
673 | JSON::XS->new->decode_prefix ("[1] the tail") |
700 | => ([], 3) |
674 | => ([], 3) |
701 | |
675 | |
702 | =back |
676 | =back |
… | |
… | |
796 | =back |
770 | =back |
797 | |
771 | |
798 | =head2 LIMITATIONS |
772 | =head2 LIMITATIONS |
799 | |
773 | |
800 | All options that affect decoding are supported, except |
774 | All options that affect decoding are supported, except |
801 | C<allow_nonref>. The reason for this is that it cannot be made to |
775 | C<allow_nonref>. The reason for this is that it cannot be made to work |
802 | work sensibly: JSON objects and arrays are self-delimited, i.e. you can concatenate |
776 | sensibly: JSON objects and arrays are self-delimited, i.e. you can |
803 | them back to back and still decode them perfectly. This does not hold true |
777 | concatenate them back to back and still decode them perfectly. This does |
804 | for JSON numbers, however. |
778 | not hold true for JSON numbers, however. |
805 | |
779 | |
806 | For example, is the string C<1> a single JSON number, or is it simply the |
780 | For example, is the string C<1> a single JSON number, or is it simply the |
807 | start of C<12>? Or is C<12> a single JSON number, or the concatenation |
781 | start of C<12>? Or is C<12> a single JSON number, or the concatenation |
808 | of C<1> and C<2>? In neither case you can tell, and this is why JSON::XS |
782 | of C<1> and C<2>? In neither case you can tell, and this is why JSON::XS |
809 | takes the conservative route and disallows this case. |
783 | takes the conservative route and disallows this case. |
… | |
… | |
1002 | floating point, JSON::XS only guarantees precision up to but not including |
976 | floating point, JSON::XS only guarantees precision up to but not including |
1003 | the least significant bit. |
977 | the least significant bit. |
1004 | |
978 | |
1005 | =item true, false |
979 | =item true, false |
1006 | |
980 | |
1007 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
981 | These JSON atoms become C<Types::Serialiser::true> and |
1008 | respectively. They are overloaded to act almost exactly like the numbers |
982 | C<Types::Serialiser::false>, respectively. They are overloaded to act |
1009 | C<1> and C<0>. You can check whether a scalar is a JSON boolean by using |
983 | almost exactly like the numbers C<1> and C<0>. You can check whether |
1010 | the C<JSON::XS::is_bool> function. |
984 | a scalar is a JSON boolean by using the C<Types::Serialiser::is_bool> |
|
|
985 | function (after C<use Types::Serialier>, of course). |
1011 | |
986 | |
1012 | =item null |
987 | =item null |
1013 | |
988 | |
1014 | A JSON null atom becomes C<undef> in Perl. |
989 | A JSON null atom becomes C<undef> in Perl. |
|
|
990 | |
|
|
991 | =item shell-style comments (C<< # I<text> >>) |
|
|
992 | |
|
|
993 | As a nonstandard extension to the JSON syntax that is enabled by the |
|
|
994 | C<relaxed> setting, shell-style comments are allowed. They can start |
|
|
995 | anywhere outside strings and go till the end of the line. |
|
|
996 | |
|
|
997 | =item tagged values (C<< (I<tag>)I<value> >>). |
|
|
998 | |
|
|
999 | Another nonstandard extension to the JSON syntax, enabled with the |
|
|
1000 | C<allow_tags> setting, are tagged values. In this implementation, the |
|
|
1001 | I<tag> must be a perl package/class name encoded as a JSON string, and the |
|
|
1002 | I<value> must be a JSON array encoding optional constructor arguments. |
|
|
1003 | |
|
|
1004 | See "OBJECT SERIALISATION", below, for details. |
1015 | |
1005 | |
1016 | =back |
1006 | =back |
1017 | |
1007 | |
1018 | |
1008 | |
1019 | =head2 PERL -> JSON |
1009 | =head2 PERL -> JSON |
… | |
… | |
1024 | |
1014 | |
1025 | =over 4 |
1015 | =over 4 |
1026 | |
1016 | |
1027 | =item hash references |
1017 | =item hash references |
1028 | |
1018 | |
1029 | Perl hash references become JSON objects. As there is no inherent ordering |
1019 | Perl hash references become JSON objects. As there is no inherent |
1030 | in hash keys (or JSON objects), they will usually be encoded in a |
1020 | ordering in hash keys (or JSON objects), they will usually be encoded |
1031 | pseudo-random order that can change between runs of the same program but |
1021 | in a pseudo-random order. JSON::XS can optionally sort the hash keys |
1032 | stays generally the same within a single run of a program. JSON::XS can |
1022 | (determined by the I<canonical> flag), so the same datastructure will |
1033 | optionally sort the hash keys (determined by the I<canonical> flag), so |
1023 | serialise to the same JSON text (given same settings and version of |
1034 | the same datastructure will serialise to the same JSON text (given same |
1024 | JSON::XS), but this incurs a runtime overhead and is only rarely useful, |
1035 | settings and version of JSON::XS), but this incurs a runtime overhead |
1025 | e.g. when you want to compare some JSON text against another for equality. |
1036 | and is only rarely useful, e.g. when you want to compare some JSON text |
|
|
1037 | against another for equality. |
|
|
1038 | |
1026 | |
1039 | =item array references |
1027 | =item array references |
1040 | |
1028 | |
1041 | Perl array references become JSON arrays. |
1029 | Perl array references become JSON arrays. |
1042 | |
1030 | |
1043 | =item other references |
1031 | =item other references |
1044 | |
1032 | |
1045 | Other unblessed references are generally not allowed and will cause an |
1033 | Other unblessed references are generally not allowed and will cause an |
1046 | exception to be thrown, except for references to the integers C<0> and |
1034 | exception to be thrown, except for references to the integers C<0> and |
1047 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
1035 | C<1>, which get turned into C<false> and C<true> atoms in JSON. |
1048 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
|
|
1049 | |
1036 | |
|
|
1037 | Since C<JSON::XS> uses the boolean model from L<Types::Serialiser>, you |
|
|
1038 | can also C<use Types::Serialiser> and then use C<Types::Serialiser::false> |
|
|
1039 | and C<Types::Serialiser::true> to improve readability. |
|
|
1040 | |
|
|
1041 | use Types::Serialiser; |
1050 | encode_json [\0, JSON::XS::true] # yields [false,true] |
1042 | encode_json [\0, Types::Serialiser::true] # yields [false,true] |
1051 | |
1043 | |
1052 | =item JSON::XS::true, JSON::XS::false |
1044 | =item Types::Serialiser::true, Types::Serialiser::false |
1053 | |
1045 | |
1054 | These special values become JSON true and JSON false values, |
1046 | These special values from the L<Types::Serialiser> module become JSON true |
1055 | respectively. You can also use C<\1> and C<\0> directly if you want. |
1047 | and JSON false values, respectively. You can also use C<\1> and C<\0> |
|
|
1048 | directly if you want. |
1056 | |
1049 | |
1057 | =item blessed objects |
1050 | =item blessed objects |
1058 | |
1051 | |
1059 | Blessed objects are not directly representable in JSON. See the |
1052 | Blessed objects are not directly representable in JSON, but C<JSON::XS> |
1060 | C<allow_blessed> and C<convert_blessed> methods on various options on |
1053 | allows various ways of handling objects. See "OBJECT SERIALISATION", |
1061 | how to deal with this: basically, you can choose between throwing an |
1054 | below, for details. |
1062 | exception, encoding the reference as if it weren't blessed, or provide |
|
|
1063 | your own serialiser method. |
|
|
1064 | |
1055 | |
1065 | =item simple scalars |
1056 | =item simple scalars |
1066 | |
1057 | |
1067 | Simple Perl scalars (any scalar that is not a reference) are the most |
1058 | Simple Perl scalars (any scalar that is not a reference) are the most |
1068 | difficult objects to encode: JSON::XS will encode undefined scalars as |
1059 | difficult objects to encode: JSON::XS will encode undefined scalars as |
… | |
… | |
1104 | extensions to the floating point numbers of your platform, such as |
1095 | extensions to the floating point numbers of your platform, such as |
1105 | infinities or NaN's - these cannot be represented in JSON, and it is an |
1096 | infinities or NaN's - these cannot be represented in JSON, and it is an |
1106 | error to pass those in. |
1097 | error to pass those in. |
1107 | |
1098 | |
1108 | =back |
1099 | =back |
|
|
1100 | |
|
|
1101 | =head2 OBJECT SERIALISATION |
|
|
1102 | |
|
|
1103 | As JSON cannot directly represent Perl objects, you have to choose between |
|
|
1104 | a pure JSON representation (without the ability to deserialise the object |
|
|
1105 | automatically again), and a nonstandard extension to the JSON syntax, |
|
|
1106 | tagged values. |
|
|
1107 | |
|
|
1108 | =head3 SERIALISATION |
|
|
1109 | |
|
|
1110 | What happens when C<JSON::XS> encounters a Perl object depends on the |
|
|
1111 | C<allow_blessed>, C<convert_blessed> and C<allow_tags> settings, which are |
|
|
1112 | used in this order: |
|
|
1113 | |
|
|
1114 | =over 4 |
|
|
1115 | |
|
|
1116 | =item 1. C<allow_tags> is enabled and object has a C<FREEZE> method. |
|
|
1117 | |
|
|
1118 | In this case, C<JSON::XS> uses the L<Types::Serialiser> object |
|
|
1119 | serialisation protocol to create a tagged JSON value, using a nonstandard |
|
|
1120 | extension to the JSON syntax. |
|
|
1121 | |
|
|
1122 | This works by invoking the C<FREEZE> method on the object, with the first |
|
|
1123 | argument being the object to serialise, and the second argument being the |
|
|
1124 | constant string C<JSON> to distinguish it from other serialisers. |
|
|
1125 | |
|
|
1126 | The C<FREEZE> method can return any number of values (i.e. zero or |
|
|
1127 | more). These values and the paclkage/classname of the object will then be |
|
|
1128 | encoded as a tagged JSON value in the following format: |
|
|
1129 | |
|
|
1130 | ("classname")[FREEZE return values...] |
|
|
1131 | |
|
|
1132 | For example, the hypothetical C<My::Object> C<FREEZE> method might use the |
|
|
1133 | objects C<type> and C<id> members to encode the object: |
|
|
1134 | |
|
|
1135 | sub My::Object::FREEZE { |
|
|
1136 | my ($self, $serialiser) = @_; |
|
|
1137 | |
|
|
1138 | ($self->{type}, $self->{id}) |
|
|
1139 | } |
|
|
1140 | |
|
|
1141 | =item 2. C<convert_blessed> is enabled and object has a C<TO_JSON> method. |
|
|
1142 | |
|
|
1143 | In this case, the C<TO_JSON> method of the object is invoked in scalar |
|
|
1144 | context. It must return a single scalar that can be directly encoded into |
|
|
1145 | JSON. This scalar replaces the object in the JSON text. |
|
|
1146 | |
|
|
1147 | For example, the following C<TO_JSON> method will convert all L<URI> |
|
|
1148 | objects to JSON strings when serialised. The fatc that these values |
|
|
1149 | originally were L<URI> objects is lost. |
|
|
1150 | |
|
|
1151 | sub URI::TO_JSON { |
|
|
1152 | my ($uri) = @_; |
|
|
1153 | $uri->as_string |
|
|
1154 | } |
|
|
1155 | |
|
|
1156 | =item 3. C<allow_blessed> is enabled. |
|
|
1157 | |
|
|
1158 | The object will be serialised as a JSON null value. |
|
|
1159 | |
|
|
1160 | =item 4. none of the above |
|
|
1161 | |
|
|
1162 | If none of the settings are enabled or the respective methods are missing, |
|
|
1163 | C<JSON::XS> throws an exception. |
|
|
1164 | |
|
|
1165 | =back |
|
|
1166 | |
|
|
1167 | =head3 DESERIALISATION |
|
|
1168 | |
|
|
1169 | For deserialisation there are only two cases to consider: either |
|
|
1170 | nonstandard tagging was used, in which case C<allow_tags> decides, |
|
|
1171 | or objects cannot be automatically be deserialised, in which |
|
|
1172 | case you can use postprocessing or the C<filter_json_object> or |
|
|
1173 | C<filter_json_single_key_object> callbacks to get some real objects our of |
|
|
1174 | your JSON. |
|
|
1175 | |
|
|
1176 | This section only considers the tagged value case: I a tagged JSON object |
|
|
1177 | is encountered during decoding and C<allow_tags> is disabled, a parse |
|
|
1178 | error will result (as if tagged values were not part of the grammar). |
|
|
1179 | |
|
|
1180 | If C<allow_tags> is enabled, C<JSON::XS> will look up the C<THAW> method |
|
|
1181 | of the package/classname used during serialisation. If there is no such |
|
|
1182 | method, the decoding will fail with an error. |
|
|
1183 | |
|
|
1184 | Otherwise, the C<THAW> method is invoked with the classname as first |
|
|
1185 | argument, the constant string C<JSON> as second argument, and all the |
|
|
1186 | values from the JSON array (the values originally returned by the |
|
|
1187 | C<FREEZE> method) as remaining arguments. |
|
|
1188 | |
|
|
1189 | The method must then return the object. While technically you can return |
|
|
1190 | any Perl scalar, you might have to enable the C<enable_nonref> setting to |
|
|
1191 | make that work in all cases, so better return an actual blessed reference. |
|
|
1192 | |
|
|
1193 | As an example, let's implement a C<THAW> function that regenerates the |
|
|
1194 | C<My::Object> from the C<FREEZE> example earlier: |
|
|
1195 | |
|
|
1196 | sub My::Object::THAW { |
|
|
1197 | my ($class, $serialiser, $type, $id) = @_; |
|
|
1198 | |
|
|
1199 | $class->new (type => $type, id => $id) |
|
|
1200 | } |
1109 | |
1201 | |
1110 | |
1202 | |
1111 | =head1 ENCODING/CODESET FLAG NOTES |
1203 | =head1 ENCODING/CODESET FLAG NOTES |
1112 | |
1204 | |
1113 | The interested reader might have seen a number of flags that signify |
1205 | The interested reader might have seen a number of flags that signify |
… | |
… | |
1436 | are browser design bugs, but it is still you who will have to deal with |
1528 | are browser design bugs, but it is still you who will have to deal with |
1437 | it, as major browser developers care only for features, not about getting |
1529 | it, as major browser developers care only for features, not about getting |
1438 | security right). |
1530 | security right). |
1439 | |
1531 | |
1440 | |
1532 | |
|
|
1533 | =head1 INTEROPERABILITY WITH OTHER MODULES |
|
|
1534 | |
|
|
1535 | C<JSON::XS> uses the L<Types::Serialiser> module to provide boolean |
|
|
1536 | constants. That means that the JSON true and false values will be |
|
|
1537 | comaptible to true and false values of iother modules that do the same, |
|
|
1538 | such as L<JSON::PP> and L<CBOR::XS>. |
|
|
1539 | |
|
|
1540 | |
1441 | =head1 THREADS |
1541 | =head1 THREADS |
1442 | |
1542 | |
1443 | This module is I<not> guaranteed to be thread safe and there are no |
1543 | This module is I<not> guaranteed to be thread safe and there are no |
1444 | plans to change this until Perl gets thread support (as opposed to the |
1544 | plans to change this until Perl gets thread support (as opposed to the |
1445 | horribly slow so-called "threads" which are simply slow and bloated |
1545 | horribly slow so-called "threads" which are simply slow and bloated |
… | |
… | |
1475 | Please refrain from using rt.cpan.org or any other bug reporting |
1575 | Please refrain from using rt.cpan.org or any other bug reporting |
1476 | service. I put the contact address into my modules for a reason. |
1576 | service. I put the contact address into my modules for a reason. |
1477 | |
1577 | |
1478 | =cut |
1578 | =cut |
1479 | |
1579 | |
1480 | our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" }; |
1580 | BEGIN { |
1481 | our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" }; |
1581 | *true = \$Types::Serialiser::true; |
|
|
1582 | *true = \&Types::Serialiser::true; |
|
|
1583 | *false = \$Types::Serialiser::false; |
|
|
1584 | *false = \&Types::Serialiser::false; |
|
|
1585 | *is_bool = \&Types::Serialiser::is_bool; |
1482 | |
1586 | |
1483 | sub true() { $true } |
1587 | *JSON::XS::Boolean:: = *Types::Serialiser::Boolean::; |
1484 | sub false() { $false } |
|
|
1485 | |
|
|
1486 | sub is_bool($) { |
|
|
1487 | UNIVERSAL::isa $_[0], "JSON::XS::Boolean" |
|
|
1488 | # or UNIVERSAL::isa $_[0], "JSON::Literal" |
|
|
1489 | } |
1588 | } |
1490 | |
1589 | |
1491 | XSLoader::load "JSON::XS", $VERSION; |
1590 | XSLoader::load "JSON::XS", $VERSION; |
1492 | |
|
|
1493 | package JSON::XS::Boolean; |
|
|
1494 | |
|
|
1495 | use overload |
|
|
1496 | "0+" => sub { ${$_[0]} }, |
|
|
1497 | "++" => sub { $_[0] = ${$_[0]} + 1 }, |
|
|
1498 | "--" => sub { $_[0] = ${$_[0]} - 1 }, |
|
|
1499 | fallback => 1; |
|
|
1500 | |
|
|
1501 | 1; |
|
|
1502 | |
1591 | |
1503 | =head1 SEE ALSO |
1592 | =head1 SEE ALSO |
1504 | |
1593 | |
1505 | The F<json_xs> command line utility for quick experiments. |
1594 | The F<json_xs> command line utility for quick experiments. |
1506 | |
1595 | |
… | |
… | |
1509 | Marc Lehmann <schmorp@schmorp.de> |
1598 | Marc Lehmann <schmorp@schmorp.de> |
1510 | http://home.schmorp.de/ |
1599 | http://home.schmorp.de/ |
1511 | |
1600 | |
1512 | =cut |
1601 | =cut |
1513 | |
1602 | |
|
|
1603 | 1 |
|
|
1604 | |