… | |
… | |
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 = 3.01; |
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; |
… | |
… | |
402 | character, after which more white-space and comments are allowed. |
402 | character, after which more white-space and comments are allowed. |
403 | |
403 | |
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... |
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407 | ] |
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408 | |
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409 | =item * literal ASCII TAB characters in strings |
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410 | |
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411 | Literal ASCII TAB characters are now allowed in strings (and treated as |
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412 | C<\t>). |
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413 | |
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414 | [ |
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415 | "Hello\tWorld", |
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416 | "Hello<TAB>World", # literal <TAB> would not normally be allowed |
407 | ] |
417 | ] |
408 | |
418 | |
409 | =back |
419 | =back |
410 | |
420 | |
411 | =item $json = $json->canonical ([$enable]) |
421 | =item $json = $json->canonical ([$enable]) |
… | |
… | |
1129 | 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 |
1130 | used in this order: |
1140 | used in this order: |
1131 | |
1141 | |
1132 | =over 4 |
1142 | =over 4 |
1133 | |
1143 | |
1134 | =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. |
1135 | |
1145 | |
1136 | 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 |
1137 | serialisation protocol to create a tagged JSON value, using a nonstandard |
1147 | serialisation protocol to create a tagged JSON value, using a nonstandard |
1138 | extension to the JSON syntax. |
1148 | extension to the JSON syntax. |
1139 | |
1149 | |
… | |
… | |
1145 | 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 |
1146 | encoded as a tagged JSON value in the following format: |
1156 | encoded as a tagged JSON value in the following format: |
1147 | |
1157 | |
1148 | ("classname")[FREEZE return values...] |
1158 | ("classname")[FREEZE return values...] |
1149 | |
1159 | |
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1160 | e.g.: |
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1161 | |
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1162 | ("URI")["http://www.google.com/"] |
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1163 | ("MyDate")[2013,10,29] |
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1164 | ("ImageData::JPEG")["Z3...VlCg=="] |
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1165 | |
1150 | 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 |
1151 | objects C<type> and C<id> members to encode the object: |
1167 | objects C<type> and C<id> members to encode the object: |
1152 | |
1168 | |
1153 | sub My::Object::FREEZE { |
1169 | sub My::Object::FREEZE { |
1154 | my ($self, $serialiser) = @_; |
1170 | my ($self, $serialiser) = @_; |
1155 | |
1171 | |
1156 | ($self->{type}, $self->{id}) |
1172 | ($self->{type}, $self->{id}) |
1157 | } |
1173 | } |
1158 | |
1174 | |
1159 | =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. |
1160 | |
1176 | |
1161 | 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 |
1162 | 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 |
1163 | JSON. This scalar replaces the object in the JSON text. |
1179 | JSON. This scalar replaces the object in the JSON text. |
1164 | |
1180 | |
… | |
… | |
1555 | constants. That means that the JSON true and false values will be |
1571 | constants. That means that the JSON true and false values will be |
1556 | comaptible to true and false values of iother modules that do the same, |
1572 | comaptible to true and false values of iother modules that do the same, |
1557 | such as L<JSON::PP> and L<CBOR::XS>. |
1573 | such as L<JSON::PP> and L<CBOR::XS>. |
1558 | |
1574 | |
1559 | |
1575 | |
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1576 | =head1 INTEROPERABILITY WITH OTHER JSON DECODERS |
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1577 | |
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1578 | As long as you only serialise data that can be directly expressed in JSON, |
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1579 | C<JSON::XS> is incapable of generating invalid JSON output (modulo bugs, |
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1580 | but C<JSON::XS> has found more bugs in the official JSON testsuite (1) |
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1581 | than the official JSON testsuite has found in C<JSON::XS> (0)). |
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1582 | |
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1583 | When you have trouble decoding JSON generated by this module using other |
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1584 | decoders, then it is very likely that you have an encoding mismatch or the |
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1585 | other decoder is broken. |
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1586 | |
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1587 | When decoding, C<JSON::XS> is strict by default and will likely catch all |
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1588 | errors. There are currently two settings that change this: C<relaxed> |
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1589 | makes C<JSON::XS> accept (but not generate) some non-standard extensions, |
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1590 | and C<allow_tags> will allow you to encode and decode Perl objects, at the |
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1591 | cost of not outputting valid JSON anymore. |
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1592 | |
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1593 | =head2 TAGGED VALUE SYNTAX AND STANDARD JSON EN/DECODERS |
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1594 | |
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1595 | When you use C<allow_tags> to use the extended (and also nonstandard and |
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1596 | invalid) JSON syntax for serialised objects, and you still want to decode |
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1597 | the generated When you want to serialise objects, you can run a regex |
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1598 | to replace the tagged syntax by standard JSON arrays (it only works for |
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1599 | "normal" packagesnames without comma, newlines or single colons). First, |
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1600 | the readable Perl version: |
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1601 | |
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1602 | # if your FREEZE methods return no values, you need this replace first: |
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1603 | $json =~ s/\( \s* (" (?: [^\\":,]+|\\.|::)* ") \s* \) \s* \[\s*\]/[$1]/gx; |
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1604 | |
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1605 | # this works for non-empty constructor arg lists: |
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1606 | $json =~ s/\( \s* (" (?: [^\\":,]+|\\.|::)* ") \s* \) \s* \[/[$1,/gx; |
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1607 | |
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1608 | And here is a less readable version that is easy to adapt to other |
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1609 | languages: |
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1610 | |
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1611 | $json =~ s/\(\s*("([^\\":,]+|\\.|::)*")\s*\)\s*\[/[$1,/g; |
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1612 | |
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1613 | Here is an ECMAScript version (same regex): |
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1614 | |
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1615 | json = json.replace (/\(\s*("([^\\":,]+|\\.|::)*")\s*\)\s*\[/g, "[$1,"); |
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1616 | |
|
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1617 | Since this syntax converts to standard JSON arrays, it might be hard to |
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1618 | distinguish serialised objects from normal arrays. You can prepend a |
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1619 | "magic number" as first array element to reduce chances of a collision: |
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1620 | |
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1621 | $json =~ s/\(\s*("([^\\":,]+|\\.|::)*")\s*\)\s*\[/["XU1peReLzT4ggEllLanBYq4G9VzliwKF",$1,/g; |
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1622 | |
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1623 | And after decoding the JSON text, you could walk the data |
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1624 | structure looking for arrays with a first element of |
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1625 | C<XU1peReLzT4ggEllLanBYq4G9VzliwKF>. |
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1626 | |
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1627 | The same approach can be used to create the tagged format with another |
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1628 | encoder. First, you create an array with the magic string as first member, |
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1629 | the classname as second, and constructor arguments last, encode it as part |
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1630 | of your JSON structure, and then: |
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1631 | |
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1632 | $json =~ s/\[\s*"XU1peReLzT4ggEllLanBYq4G9VzliwKF"\s*,\s*("([^\\":,]+|\\.|::)*")\s*,/($1)[/g; |
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1633 | |
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1634 | Again, this has some limitations - the magic string must not be encoded |
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1635 | with character escapes, and the constructor arguments must be non-empty. |
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1636 | |
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1637 | |
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1638 | =head1 RFC7159 |
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1639 | |
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1640 | Since this module was written, Google has written a new JSON RFC, RFC 7159 |
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1641 | (and RFC7158). Unfortunately, this RFC breaks compatibility with both the |
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1642 | original JSON specification on www.json.org and RFC4627. |
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1643 | |
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1644 | As far as I can see, you can get partial compatibility when parsing by |
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1645 | using C<< ->allow_nonref >>. However, consider thew security implications |
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1646 | of doing so. |
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1647 | |
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1648 | I haven't decided yet when to break compatibility with RFC4627 by default |
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1649 | (and potentially leave applications insecure) and change the default to |
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1650 | follow RFC7159, but application authors are well advised to call C<< |
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1651 | ->allow_nonref(0) >> even if this is the current default, if they cannot |
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1652 | handle non-reference values, in preparation for the day when the4 default |
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1653 | will change. |
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1654 | |
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1655 | |
1560 | =head1 THREADS |
1656 | =head1 THREADS |
1561 | |
1657 | |
1562 | This module is I<not> guaranteed to be thread safe and there are no |
1658 | This module is I<not> guaranteed to be thread safe and there are no |
1563 | plans to change this until Perl gets thread support (as opposed to the |
1659 | plans to change this until Perl gets thread support (as opposed to the |
1564 | horribly slow so-called "threads" which are simply slow and bloated |
1660 | horribly slow so-called "threads" which are simply slow and bloated |