… | |
… | |
83 | this module usually compares favourably in terms of speed, too. |
83 | this module usually compares favourably in terms of speed, too. |
84 | |
84 | |
85 | =item * simple to use |
85 | =item * simple to use |
86 | |
86 | |
87 | This module has both a simple functional interface as well as an object |
87 | This module has both a simple functional interface as well as an object |
88 | oriented interface interface. |
88 | oriented interface. |
89 | |
89 | |
90 | =item * reasonably versatile output formats |
90 | =item * reasonably versatile output formats |
91 | |
91 | |
92 | You can choose between the most compact guaranteed-single-line format |
92 | You can choose between the most compact guaranteed-single-line format |
93 | possible (nice for simple line-based protocols), a pure-ASCII format |
93 | possible (nice for simple line-based protocols), a pure-ASCII format |
… | |
… | |
104 | use common::sense; |
104 | use common::sense; |
105 | |
105 | |
106 | our $VERSION = 2.34; |
106 | our $VERSION = 2.34; |
107 | our @ISA = qw(Exporter); |
107 | our @ISA = qw(Exporter); |
108 | |
108 | |
109 | our @EXPORT = qw(encode_json decode_json to_json from_json); |
109 | our @EXPORT = qw(encode_json decode_json); |
110 | |
|
|
111 | sub to_json($) { |
|
|
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; |
123 | |
113 | |
124 | =head1 FUNCTIONAL INTERFACE |
114 | =head1 FUNCTIONAL INTERFACE |
… | |
… | |
667 | |
657 | |
668 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
658 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
669 | |
659 | |
670 | =item $json_text = $json->encode ($perl_scalar) |
660 | =item $json_text = $json->encode ($perl_scalar) |
671 | |
661 | |
672 | Converts the given Perl data structure (a simple scalar or a reference |
662 | 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 |
663 | 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 | |
664 | |
679 | =item $perl_scalar = $json->decode ($json_text) |
665 | =item $perl_scalar = $json->decode ($json_text) |
680 | |
666 | |
681 | The opposite of C<encode>: expects a JSON text and tries to parse it, |
667 | 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. |
668 | 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 | |
669 | |
688 | =item ($perl_scalar, $characters) = $json->decode_prefix ($json_text) |
670 | =item ($perl_scalar, $characters) = $json->decode_prefix ($json_text) |
689 | |
671 | |
690 | This works like the C<decode> method, but instead of raising an exception |
672 | 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 |
673 | when there is trailing garbage after the first JSON object, it will |
692 | silently stop parsing there and return the number of characters consumed |
674 | silently stop parsing there and return the number of characters consumed |
693 | so far. |
675 | so far. |
694 | |
676 | |
695 | This is useful if your JSON texts are not delimited by an outer protocol |
677 | 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. |
678 | and you need to know where the JSON text ends. |
698 | |
679 | |
699 | JSON::XS->new->decode_prefix ("[1] the tail") |
680 | JSON::XS->new->decode_prefix ("[1] the tail") |
700 | => ([], 3) |
681 | => ([], 3) |
701 | |
682 | |
702 | =back |
683 | =back |
… | |
… | |
741 | |
722 | |
742 | If the method is called in scalar context, then it will try to extract |
723 | If the method is called in scalar context, then it will try to extract |
743 | exactly I<one> JSON object. If that is successful, it will return this |
724 | exactly I<one> JSON object. If that is successful, it will return this |
744 | object, otherwise it will return C<undef>. If there is a parse error, |
725 | object, otherwise it will return C<undef>. If there is a parse error, |
745 | this method will croak just as C<decode> would do (one can then use |
726 | this method will croak just as C<decode> would do (one can then use |
746 | C<incr_skip> to skip the errornous part). This is the most common way of |
727 | C<incr_skip> to skip the erroneous part). This is the most common way of |
747 | using the method. |
728 | using the method. |
748 | |
729 | |
749 | And finally, in list context, it will try to extract as many objects |
730 | And finally, in list context, it will try to extract as many objects |
750 | from the stream as it can find and return them, or the empty list |
731 | from the stream as it can find and return them, or the empty list |
751 | otherwise. For this to work, there must be no separators between the JSON |
732 | otherwise. For this to work, there must be no separators between the JSON |
… | |
… | |
780 | C<incr_parse> died, in which case the input buffer and incremental parser |
761 | C<incr_parse> died, in which case the input buffer and incremental parser |
781 | state is left unchanged, to skip the text parsed so far and to reset the |
762 | state is left unchanged, to skip the text parsed so far and to reset the |
782 | parse state. |
763 | parse state. |
783 | |
764 | |
784 | The difference to C<incr_reset> is that only text until the parse error |
765 | The difference to C<incr_reset> is that only text until the parse error |
785 | occured is removed. |
766 | occurred is removed. |
786 | |
767 | |
787 | =item $json->incr_reset |
768 | =item $json->incr_reset |
788 | |
769 | |
789 | This completely resets the incremental parser, that is, after this call, |
770 | This completely resets the incremental parser, that is, after this call, |
790 | it will be as if the parser had never parsed anything. |
771 | it will be as if the parser had never parsed anything. |
… | |
… | |
796 | =back |
777 | =back |
797 | |
778 | |
798 | =head2 LIMITATIONS |
779 | =head2 LIMITATIONS |
799 | |
780 | |
800 | All options that affect decoding are supported, except |
781 | All options that affect decoding are supported, except |
801 | C<allow_nonref>. The reason for this is that it cannot be made to |
782 | 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 |
783 | 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 |
784 | concatenate them back to back and still decode them perfectly. This does |
804 | for JSON numbers, however. |
785 | not hold true for JSON numbers, however. |
805 | |
786 | |
806 | For example, is the string C<1> a single JSON number, or is it simply the |
787 | 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 |
788 | 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 |
789 | 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. |
790 | takes the conservative route and disallows this case. |
… | |
… | |
988 | If the number consists of digits only, JSON::XS will try to represent |
969 | If the number consists of digits only, JSON::XS will try to represent |
989 | it as an integer value. If that fails, it will try to represent it as |
970 | it as an integer value. If that fails, it will try to represent it as |
990 | a numeric (floating point) value if that is possible without loss of |
971 | a numeric (floating point) value if that is possible without loss of |
991 | precision. Otherwise it will preserve the number as a string value (in |
972 | precision. Otherwise it will preserve the number as a string value (in |
992 | which case you lose roundtripping ability, as the JSON number will be |
973 | which case you lose roundtripping ability, as the JSON number will be |
993 | re-encoded toa JSON string). |
974 | re-encoded to a JSON string). |
994 | |
975 | |
995 | Numbers containing a fractional or exponential part will always be |
976 | Numbers containing a fractional or exponential part will always be |
996 | represented as numeric (floating point) values, possibly at a loss of |
977 | represented as numeric (floating point) values, possibly at a loss of |
997 | precision (in which case you might lose perfect roundtripping ability, but |
978 | precision (in which case you might lose perfect roundtripping ability, but |
998 | the JSON number will still be re-encoded as a JSON number). |
979 | the JSON number will still be re-encoded as a JSON number). |
999 | |
980 | |
1000 | Note that precision is not accuracy - binary floating point values cannot |
981 | Note that precision is not accuracy - binary floating point values cannot |
1001 | represent most decimal fractions exactly, and when converting from and to |
982 | represent most decimal fractions exactly, and when converting from and to |
1002 | floating point, JSON::XS only guarantees precision up to but not including |
983 | floating point, JSON::XS only guarantees precision up to but not including |
1003 | the leats significant bit. |
984 | the least significant bit. |
1004 | |
985 | |
1005 | =item true, false |
986 | =item true, false |
1006 | |
987 | |
1007 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
988 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
1008 | respectively. They are overloaded to act almost exactly like the numbers |
989 | respectively. They are overloaded to act almost exactly like the numbers |
… | |
… | |
1024 | |
1005 | |
1025 | =over 4 |
1006 | =over 4 |
1026 | |
1007 | |
1027 | =item hash references |
1008 | =item hash references |
1028 | |
1009 | |
1029 | Perl hash references become JSON objects. As there is no inherent ordering |
1010 | 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 |
1011 | 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 |
1012 | 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 |
1013 | (determined by the I<canonical> flag), so the same datastructure will |
1033 | optionally sort the hash keys (determined by the I<canonical> flag), so |
1014 | 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 |
1015 | 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 |
1016 | 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 | |
1017 | |
1039 | =item array references |
1018 | =item array references |
1040 | |
1019 | |
1041 | Perl array references become JSON arrays. |
1020 | Perl array references become JSON arrays. |
1042 | |
1021 | |
… | |
… | |
1138 | =item C<utf8> flag disabled |
1117 | =item C<utf8> flag disabled |
1139 | |
1118 | |
1140 | When C<utf8> is disabled (the default), then C<encode>/C<decode> generate |
1119 | When C<utf8> is disabled (the default), then C<encode>/C<decode> generate |
1141 | and expect Unicode strings, that is, characters with high ordinal Unicode |
1120 | and expect Unicode strings, that is, characters with high ordinal Unicode |
1142 | values (> 255) will be encoded as such characters, and likewise such |
1121 | values (> 255) will be encoded as such characters, and likewise such |
1143 | characters are decoded as-is, no canges to them will be done, except |
1122 | characters are decoded as-is, no changes to them will be done, except |
1144 | "(re-)interpreting" them as Unicode codepoints or Unicode characters, |
1123 | "(re-)interpreting" them as Unicode codepoints or Unicode characters, |
1145 | respectively (to Perl, these are the same thing in strings unless you do |
1124 | respectively (to Perl, these are the same thing in strings unless you do |
1146 | funny/weird/dumb stuff). |
1125 | funny/weird/dumb stuff). |
1147 | |
1126 | |
1148 | This is useful when you want to do the encoding yourself (e.g. when you |
1127 | This is useful when you want to do the encoding yourself (e.g. when you |
… | |
… | |
1264 | output for these property strings, e.g.: |
1243 | output for these property strings, e.g.: |
1265 | |
1244 | |
1266 | $json =~ s/"__proto__"\s*:/"__proto__renamed":/g; |
1245 | $json =~ s/"__proto__"\s*:/"__proto__renamed":/g; |
1267 | |
1246 | |
1268 | This works because C<__proto__> is not valid outside of strings, so every |
1247 | This works because C<__proto__> is not valid outside of strings, so every |
1269 | occurence of C<"__proto__"\s*:> must be a string used as property name. |
1248 | occurrence of C<"__proto__"\s*:> must be a string used as property name. |
1270 | |
1249 | |
1271 | If you know of other incompatibilities, please let me know. |
1250 | If you know of other incompatibilities, please let me know. |
1272 | |
1251 | |
1273 | |
1252 | |
1274 | =head2 JSON and YAML |
1253 | =head2 JSON and YAML |
… | |
… | |
1452 | |
1431 | |
1453 | Sometimes people avoid the Perl locale support and directly call the |
1432 | Sometimes people avoid the Perl locale support and directly call the |
1454 | system's setlocale function with C<LC_ALL>. |
1433 | system's setlocale function with C<LC_ALL>. |
1455 | |
1434 | |
1456 | This breaks both perl and modules such as JSON::XS, as stringification of |
1435 | This breaks both perl and modules such as JSON::XS, as stringification of |
1457 | numbers no longer works correcly (e.g. C<$x = 0.1; print "$x"+1> might |
1436 | numbers no longer works correctly (e.g. C<$x = 0.1; print "$x"+1> might |
1458 | print C<1>, and JSON::XS might output illegal JSON as JSON::XS relies on |
1437 | print C<1>, and JSON::XS might output illegal JSON as JSON::XS relies on |
1459 | perl to stringify numbers). |
1438 | perl to stringify numbers). |
1460 | |
1439 | |
1461 | The solution is simple: don't call C<setlocale>, or use it for only those |
1440 | The solution is simple: don't call C<setlocale>, or use it for only those |
1462 | categories you need, such as C<LC_MESSAGES> or C<LC_CTYPE>. |
1441 | categories you need, such as C<LC_MESSAGES> or C<LC_CTYPE>. |