… | |
… | |
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 = '3.0'; |
106 | our $VERSION = 3.02; |
107 | our @ISA = qw(Exporter); |
107 | our @ISA = qw(Exporter); |
108 | |
108 | |
109 | our @EXPORT = qw(encode_json decode_json); |
109 | our @EXPORT = qw(encode_json decode_json); |
110 | |
110 | |
111 | use Exporter; |
111 | use Exporter; |
… | |
… | |
404 | [ |
404 | [ |
405 | 1, # this comment not allowed in JSON |
405 | 1, # this comment not allowed in JSON |
406 | # neither this one... |
406 | # neither this one... |
407 | ] |
407 | ] |
408 | |
408 | |
|
|
409 | =item * literal ASCII TAB characters in strings |
|
|
410 | |
|
|
411 | Literal ASCII TAB characters are now allowed in strings (and treated as |
|
|
412 | C<\t>). |
|
|
413 | |
|
|
414 | [ |
|
|
415 | "Hello\tWorld", |
|
|
416 | "Hello<TAB>World", # literal <TAB> would not normally be allowed |
|
|
417 | ] |
|
|
418 | |
409 | =back |
419 | =back |
410 | |
420 | |
411 | =item $json = $json->canonical ([$enable]) |
421 | =item $json = $json->canonical ([$enable]) |
412 | |
422 | |
413 | =item $enabled = $json->get_canonical |
423 | =item $enabled = $json->get_canonical |
… | |
… | |
467 | |
477 | |
468 | =item $json = $json->allow_blessed ([$enable]) |
478 | =item $json = $json->allow_blessed ([$enable]) |
469 | |
479 | |
470 | =item $enabled = $json->get_allow_blessed |
480 | =item $enabled = $json->get_allow_blessed |
471 | |
481 | |
|
|
482 | See L<OBJECT SERIALISATION> for details. |
|
|
483 | |
472 | If C<$enable> is true (or missing), then the C<encode> method will not |
484 | If C<$enable> is true (or missing), then the C<encode> method will not |
473 | barf when it encounters a blessed reference. Instead, the value of the |
485 | barf when it encounters a blessed reference that it cannot convert |
474 | B<convert_blessed> option will decide whether C<null> (C<convert_blessed> |
486 | otherwise. Instead, a JSON C<null> value is encoded instead of the object. |
475 | disabled or no C<TO_JSON> method found) or a representation of the |
|
|
476 | object (C<convert_blessed> enabled and C<TO_JSON> method found) is being |
|
|
477 | encoded. Has no effect on C<decode>. |
|
|
478 | |
487 | |
479 | If C<$enable> is false (the default), then C<encode> will throw an |
488 | If C<$enable> is false (the default), then C<encode> will throw an |
480 | exception when it encounters a blessed object. |
489 | exception when it encounters a blessed object that it cannot convert |
|
|
490 | otherwise. |
|
|
491 | |
|
|
492 | This setting has no effect on C<decode>. |
481 | |
493 | |
482 | =item $json = $json->convert_blessed ([$enable]) |
494 | =item $json = $json->convert_blessed ([$enable]) |
483 | |
495 | |
484 | =item $enabled = $json->get_convert_blessed |
496 | =item $enabled = $json->get_convert_blessed |
|
|
497 | |
|
|
498 | See L<OBJECT SERIALISATION> for details. |
485 | |
499 | |
486 | If C<$enable> is true (or missing), then C<encode>, upon encountering a |
500 | If C<$enable> is true (or missing), then C<encode>, upon encountering a |
487 | blessed object, will check for the availability of the C<TO_JSON> method |
501 | blessed object, will check for the availability of the C<TO_JSON> method |
488 | on the object's class. If found, it will be called in scalar context |
502 | on the object's class. If found, it will be called in scalar context and |
489 | and the resulting scalar will be encoded instead of the object. If no |
503 | the resulting scalar will be encoded instead of the object. |
490 | C<TO_JSON> method is found, the value of C<allow_blessed> will decide what |
|
|
491 | to do. |
|
|
492 | |
504 | |
493 | The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON> |
505 | The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON> |
494 | returns other blessed objects, those will be handled in the same |
506 | returns other blessed objects, those will be handled in the same |
495 | way. C<TO_JSON> must take care of not causing an endless recursion cycle |
507 | way. C<TO_JSON> must take care of not causing an endless recursion cycle |
496 | (== crash) in this case. The name of C<TO_JSON> was chosen because other |
508 | (== crash) in this case. The name of C<TO_JSON> was chosen because other |
497 | methods called by the Perl core (== not by the user of the object) are |
509 | methods called by the Perl core (== not by the user of the object) are |
498 | usually in upper case letters and to avoid collisions with any C<to_json> |
510 | usually in upper case letters and to avoid collisions with any C<to_json> |
499 | function or method. |
511 | function or method. |
500 | |
512 | |
501 | This setting does not yet influence C<decode> in any way, but in the |
513 | If C<$enable> is false (the default), then C<encode> will not consider |
502 | future, global hooks might get installed that influence C<decode> and are |
514 | this type of conversion. |
503 | enabled by this setting. |
|
|
504 | |
515 | |
505 | If C<$enable> is false, then the C<allow_blessed> setting will decide what |
516 | This setting has no effect on C<decode>. |
506 | to do when a blessed object is found. |
517 | |
|
|
518 | =item $json = $json->allow_tags ([$enable]) |
|
|
519 | |
|
|
520 | =item $enabled = $json->allow_tags |
|
|
521 | |
|
|
522 | See L<OBJECT SERIALISATION> for details. |
|
|
523 | |
|
|
524 | If C<$enable> is true (or missing), then C<encode>, upon encountering a |
|
|
525 | blessed object, will check for the availability of the C<FREEZE> method on |
|
|
526 | the object's class. If found, it will be used to serialise the object into |
|
|
527 | a nonstandard tagged JSON value (that JSON decoders cannot decode). |
|
|
528 | |
|
|
529 | It also causes C<decode> to parse such tagged JSON values and deserialise |
|
|
530 | them via a call to the C<THAW> method. |
|
|
531 | |
|
|
532 | If C<$enable> is false (the default), then C<encode> will not consider |
|
|
533 | this type of conversion, and tagged JSON values will cause a parse error |
|
|
534 | in C<decode>, as if tags were not part of the grammar. |
507 | |
535 | |
508 | =item $json = $json->filter_json_object ([$coderef->($hashref)]) |
536 | =item $json = $json->filter_json_object ([$coderef->($hashref)]) |
509 | |
537 | |
510 | When C<$coderef> is specified, it will be called from C<decode> each |
538 | When C<$coderef> is specified, it will be called from C<decode> each |
511 | time it decodes a JSON object. The only argument is a reference to the |
539 | time it decodes a JSON object. The only argument is a reference to the |
… | |
… | |
669 | |
697 | |
670 | This is useful if your JSON texts are not delimited by an outer protocol |
698 | This is useful if your JSON texts are not delimited by an outer protocol |
671 | and you need to know where the JSON text ends. |
699 | and you need to know where the JSON text ends. |
672 | |
700 | |
673 | JSON::XS->new->decode_prefix ("[1] the tail") |
701 | JSON::XS->new->decode_prefix ("[1] the tail") |
674 | => ([], 3) |
702 | => ([1], 3) |
675 | |
703 | |
676 | =back |
704 | =back |
677 | |
705 | |
678 | |
706 | |
679 | =head1 INCREMENTAL PARSING |
707 | =head1 INCREMENTAL PARSING |
… | |
… | |
999 | Another nonstandard extension to the JSON syntax, enabled with the |
1027 | Another nonstandard extension to the JSON syntax, enabled with the |
1000 | C<allow_tags> setting, are tagged values. In this implementation, the |
1028 | 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 |
1029 | 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. |
1030 | I<value> must be a JSON array encoding optional constructor arguments. |
1003 | |
1031 | |
1004 | See "OBJECT SERIALISATION", below, for details. |
1032 | See L<OBJECT SERIALISATION>, below, for details. |
1005 | |
1033 | |
1006 | =back |
1034 | =back |
1007 | |
1035 | |
1008 | |
1036 | |
1009 | =head2 PERL -> JSON |
1037 | =head2 PERL -> JSON |
… | |
… | |
1048 | directly if you want. |
1076 | directly if you want. |
1049 | |
1077 | |
1050 | =item blessed objects |
1078 | =item blessed objects |
1051 | |
1079 | |
1052 | Blessed objects are not directly representable in JSON, but C<JSON::XS> |
1080 | Blessed objects are not directly representable in JSON, but C<JSON::XS> |
1053 | allows various ways of handling objects. See "OBJECT SERIALISATION", |
1081 | allows various ways of handling objects. See L<OBJECT SERIALISATION>, |
1054 | below, for details. |
1082 | below, for details. |
1055 | |
1083 | |
1056 | =item simple scalars |
1084 | =item simple scalars |
1057 | |
1085 | |
1058 | Simple Perl scalars (any scalar that is not a reference) are the most |
1086 | Simple Perl scalars (any scalar that is not a reference) are the most |
… | |
… | |
1111 | C<allow_blessed>, C<convert_blessed> and C<allow_tags> settings, which are |
1139 | C<allow_blessed>, C<convert_blessed> and C<allow_tags> settings, which are |
1112 | used in this order: |
1140 | used in this order: |
1113 | |
1141 | |
1114 | =over 4 |
1142 | =over 4 |
1115 | |
1143 | |
1116 | =item 1. C<allow_tags> is enabled and object has a C<FREEZE> method. |
1144 | =item 1. C<allow_tags> is enabled and the object has a C<FREEZE> method. |
1117 | |
1145 | |
1118 | In this case, C<JSON::XS> uses the L<Types::Serialiser> object |
1146 | In this case, C<JSON::XS> uses the L<Types::Serialiser> object |
1119 | serialisation protocol to create a tagged JSON value, using a nonstandard |
1147 | serialisation protocol to create a tagged JSON value, using a nonstandard |
1120 | extension to the JSON syntax. |
1148 | extension to the JSON syntax. |
1121 | |
1149 | |
… | |
… | |
1127 | more). These values and the paclkage/classname of the object will then be |
1155 | more). These values and the paclkage/classname of the object will then be |
1128 | encoded as a tagged JSON value in the following format: |
1156 | encoded as a tagged JSON value in the following format: |
1129 | |
1157 | |
1130 | ("classname")[FREEZE return values...] |
1158 | ("classname")[FREEZE return values...] |
1131 | |
1159 | |
|
|
1160 | e.g.: |
|
|
1161 | |
|
|
1162 | ("URI")["http://www.google.com/"] |
|
|
1163 | ("MyDate")[2013,10,29] |
|
|
1164 | ("ImageData::JPEG")["Z3...VlCg=="] |
|
|
1165 | |
1132 | For example, the hypothetical C<My::Object> C<FREEZE> method might use the |
1166 | 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: |
1167 | objects C<type> and C<id> members to encode the object: |
1134 | |
1168 | |
1135 | sub My::Object::FREEZE { |
1169 | sub My::Object::FREEZE { |
1136 | my ($self, $serialiser) = @_; |
1170 | my ($self, $serialiser) = @_; |
1137 | |
1171 | |
1138 | ($self->{type}, $self->{id}) |
1172 | ($self->{type}, $self->{id}) |
1139 | } |
1173 | } |
1140 | |
1174 | |
1141 | =item 2. C<convert_blessed> is enabled and object has a C<TO_JSON> method. |
1175 | =item 2. C<convert_blessed> is enabled and the object has a C<TO_JSON> method. |
1142 | |
1176 | |
1143 | In this case, the C<TO_JSON> method of the object is invoked in scalar |
1177 | 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 |
1178 | context. It must return a single scalar that can be directly encoded into |
1145 | JSON. This scalar replaces the object in the JSON text. |
1179 | JSON. This scalar replaces the object in the JSON text. |
1146 | |
1180 | |
… | |
… | |
1176 | This section only considers the tagged value case: I a tagged JSON object |
1210 | 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 |
1211 | 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). |
1212 | error will result (as if tagged values were not part of the grammar). |
1179 | |
1213 | |
1180 | If C<allow_tags> is enabled, C<JSON::XS> will look up the C<THAW> method |
1214 | 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 |
1215 | of the package/classname used during serialisation (it will not attempt |
|
|
1216 | to load the package as a Perl module). If there is no such method, the |
1182 | method, the decoding will fail with an error. |
1217 | decoding will fail with an error. |
1183 | |
1218 | |
1184 | Otherwise, the C<THAW> method is invoked with the classname as first |
1219 | 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 |
1220 | argument, the constant string C<JSON> as second argument, and all the |
1186 | values from the JSON array (the values originally returned by the |
1221 | values from the JSON array (the values originally returned by the |
1187 | C<FREEZE> method) as remaining arguments. |
1222 | C<FREEZE> method) as remaining arguments. |
… | |
… | |
1528 | are browser design bugs, but it is still you who will have to deal with |
1563 | are browser design bugs, but it is still you who will have to deal with |
1529 | it, as major browser developers care only for features, not about getting |
1564 | it, as major browser developers care only for features, not about getting |
1530 | security right). |
1565 | security right). |
1531 | |
1566 | |
1532 | |
1567 | |
|
|
1568 | =head1 "OLD" VS. "NEW" JSON (RFC 4627 VS. RFC 7159) |
|
|
1569 | |
|
|
1570 | TL;DR: Due to security concerns, JSON::XS will not allow scalar data in |
|
|
1571 | JSON texts by default - you need to create your own JSON::XS object and |
|
|
1572 | enable C<allow_nonref>: |
|
|
1573 | |
|
|
1574 | |
|
|
1575 | my $json = JSON::XS->new->allow_nonref; |
|
|
1576 | |
|
|
1577 | $text = $json->encode ($data); |
|
|
1578 | $data = $json->decode ($text); |
|
|
1579 | |
|
|
1580 | The long version: JSON being an important and supposedly stable format, |
|
|
1581 | the IETF standardised it as RFC 4627 in 2006. Unfortunately, the inventor |
|
|
1582 | of JSON, Dougles Crockford, unilaterally changed the definition of JSON in |
|
|
1583 | javascript. Rather than create a fork, the IETF decided to standardise the |
|
|
1584 | new syntax (apparently, so Iw as told, without finding it very amusing). |
|
|
1585 | |
|
|
1586 | The biggest difference between thed original JSON and the new JSON is that |
|
|
1587 | the new JSON supports scalars (anything other than arrays and objects) at |
|
|
1588 | the toplevel of a JSON text. While this is strictly backwards compatible |
|
|
1589 | to older versions, it breaks a number of protocols that relied on sending |
|
|
1590 | JSON back-to-back, and is a minor security concern. |
|
|
1591 | |
|
|
1592 | For example, imagine you have two banks communicating, and on one side, |
|
|
1593 | trhe JSON coder gets upgraded. Two messages, such as C<10> and C<1000> |
|
|
1594 | might then be confused to mean C<101000>, something that couldn't happen |
|
|
1595 | in the original JSON, because niether of these messages would be valid |
|
|
1596 | JSON. |
|
|
1597 | |
|
|
1598 | If one side accepts these messages, then an upgrade in the coder on either |
|
|
1599 | side could result in this becoming exploitable. |
|
|
1600 | |
|
|
1601 | This module has always allowed these messages as an optional extension, by |
|
|
1602 | default disabled. The security concerns are the reason why the default is |
|
|
1603 | still disabled, but future versions might/will likely upgrade to the newer |
|
|
1604 | RFC as default format, so you are advised to check your implementation |
|
|
1605 | and/or override the default with C<< ->allow_nonref (0) >> to ensure that |
|
|
1606 | future versions are safe. |
|
|
1607 | |
|
|
1608 | |
1533 | =head1 INTEROPERABILITY WITH OTHER MODULES |
1609 | =head1 INTEROPERABILITY WITH OTHER MODULES |
1534 | |
1610 | |
1535 | C<JSON::XS> uses the L<Types::Serialiser> module to provide boolean |
1611 | 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 |
1612 | 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, |
1613 | comaptible to true and false values of iother modules that do the same, |
1538 | such as L<JSON::PP> and L<CBOR::XS>. |
1614 | such as L<JSON::PP> and L<CBOR::XS>. |
|
|
1615 | |
|
|
1616 | |
|
|
1617 | =head1 INTEROPERABILITY WITH OTHER JSON DECODERS |
|
|
1618 | |
|
|
1619 | As long as you only serialise data that can be directly expressed in JSON, |
|
|
1620 | C<JSON::XS> is incapable of generating invalid JSON output (modulo bugs, |
|
|
1621 | but C<JSON::XS> has found more bugs in the official JSON testsuite (1) |
|
|
1622 | than the official JSON testsuite has found in C<JSON::XS> (0)). |
|
|
1623 | |
|
|
1624 | When you have trouble decoding JSON generated by this module using other |
|
|
1625 | decoders, then it is very likely that you have an encoding mismatch or the |
|
|
1626 | other decoder is broken. |
|
|
1627 | |
|
|
1628 | When decoding, C<JSON::XS> is strict by default and will likely catch all |
|
|
1629 | errors. There are currently two settings that change this: C<relaxed> |
|
|
1630 | makes C<JSON::XS> accept (but not generate) some non-standard extensions, |
|
|
1631 | and C<allow_tags> will allow you to encode and decode Perl objects, at the |
|
|
1632 | cost of not outputting valid JSON anymore. |
|
|
1633 | |
|
|
1634 | =head2 TAGGED VALUE SYNTAX AND STANDARD JSON EN/DECODERS |
|
|
1635 | |
|
|
1636 | When you use C<allow_tags> to use the extended (and also nonstandard and |
|
|
1637 | invalid) JSON syntax for serialised objects, and you still want to decode |
|
|
1638 | the generated When you want to serialise objects, you can run a regex |
|
|
1639 | to replace the tagged syntax by standard JSON arrays (it only works for |
|
|
1640 | "normal" packagesnames without comma, newlines or single colons). First, |
|
|
1641 | the readable Perl version: |
|
|
1642 | |
|
|
1643 | # if your FREEZE methods return no values, you need this replace first: |
|
|
1644 | $json =~ s/\( \s* (" (?: [^\\":,]+|\\.|::)* ") \s* \) \s* \[\s*\]/[$1]/gx; |
|
|
1645 | |
|
|
1646 | # this works for non-empty constructor arg lists: |
|
|
1647 | $json =~ s/\( \s* (" (?: [^\\":,]+|\\.|::)* ") \s* \) \s* \[/[$1,/gx; |
|
|
1648 | |
|
|
1649 | And here is a less readable version that is easy to adapt to other |
|
|
1650 | languages: |
|
|
1651 | |
|
|
1652 | $json =~ s/\(\s*("([^\\":,]+|\\.|::)*")\s*\)\s*\[/[$1,/g; |
|
|
1653 | |
|
|
1654 | Here is an ECMAScript version (same regex): |
|
|
1655 | |
|
|
1656 | json = json.replace (/\(\s*("([^\\":,]+|\\.|::)*")\s*\)\s*\[/g, "[$1,"); |
|
|
1657 | |
|
|
1658 | Since this syntax converts to standard JSON arrays, it might be hard to |
|
|
1659 | distinguish serialised objects from normal arrays. You can prepend a |
|
|
1660 | "magic number" as first array element to reduce chances of a collision: |
|
|
1661 | |
|
|
1662 | $json =~ s/\(\s*("([^\\":,]+|\\.|::)*")\s*\)\s*\[/["XU1peReLzT4ggEllLanBYq4G9VzliwKF",$1,/g; |
|
|
1663 | |
|
|
1664 | And after decoding the JSON text, you could walk the data |
|
|
1665 | structure looking for arrays with a first element of |
|
|
1666 | C<XU1peReLzT4ggEllLanBYq4G9VzliwKF>. |
|
|
1667 | |
|
|
1668 | The same approach can be used to create the tagged format with another |
|
|
1669 | encoder. First, you create an array with the magic string as first member, |
|
|
1670 | the classname as second, and constructor arguments last, encode it as part |
|
|
1671 | of your JSON structure, and then: |
|
|
1672 | |
|
|
1673 | $json =~ s/\[\s*"XU1peReLzT4ggEllLanBYq4G9VzliwKF"\s*,\s*("([^\\":,]+|\\.|::)*")\s*,/($1)[/g; |
|
|
1674 | |
|
|
1675 | Again, this has some limitations - the magic string must not be encoded |
|
|
1676 | with character escapes, and the constructor arguments must be non-empty. |
|
|
1677 | |
|
|
1678 | |
|
|
1679 | =head1 RFC7159 |
|
|
1680 | |
|
|
1681 | Since this module was written, Google has written a new JSON RFC, RFC 7159 |
|
|
1682 | (and RFC7158). Unfortunately, this RFC breaks compatibility with both the |
|
|
1683 | original JSON specification on www.json.org and RFC4627. |
|
|
1684 | |
|
|
1685 | As far as I can see, you can get partial compatibility when parsing by |
|
|
1686 | using C<< ->allow_nonref >>. However, consider thew security implications |
|
|
1687 | of doing so. |
|
|
1688 | |
|
|
1689 | I haven't decided yet when to break compatibility with RFC4627 by default |
|
|
1690 | (and potentially leave applications insecure) and change the default to |
|
|
1691 | follow RFC7159, but application authors are well advised to call C<< |
|
|
1692 | ->allow_nonref(0) >> even if this is the current default, if they cannot |
|
|
1693 | handle non-reference values, in preparation for the day when the4 default |
|
|
1694 | will change. |
1539 | |
1695 | |
1540 | |
1696 | |
1541 | =head1 THREADS |
1697 | =head1 THREADS |
1542 | |
1698 | |
1543 | This module is I<not> guaranteed to be thread safe and there are no |
1699 | This module is I<not> guaranteed to be thread safe and there are no |