… | |
… | |
64 | so, and even documents what "correct" means. |
64 | so, and even documents what "correct" means. |
65 | |
65 | |
66 | =item * round-trip integrity |
66 | =item * round-trip integrity |
67 | |
67 | |
68 | When you serialise a perl data structure using only data types supported |
68 | When you serialise a perl data structure using only data types supported |
69 | by JSON, the deserialised data structure is identical on the Perl level. |
69 | by JSON and Perl, the deserialised data structure is identical on the Perl |
70 | (e.g. the string "2.0" doesn't suddenly become "2" just because it looks |
70 | level. (e.g. the string "2.0" doesn't suddenly become "2" just because |
71 | like a number). There minor I<are> exceptions to this, read the MAPPING |
71 | it looks like a number). There I<are> minor exceptions to this, read the |
72 | section below to learn about those. |
72 | MAPPING section below to learn about those. |
73 | |
73 | |
74 | =item * strict checking of JSON correctness |
74 | =item * strict checking of JSON correctness |
75 | |
75 | |
76 | There is no guessing, no generating of illegal JSON texts by default, |
76 | There is no guessing, no generating of illegal JSON texts by default, |
77 | and only JSON is accepted as input by default (the latter is a security |
77 | and only JSON is accepted as input by default (the latter is a security |
… | |
… | |
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 |
… | |
… | |
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 = '2.24'; |
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; |
|
|
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 $scalar |
|
|
155 | |
|
|
156 | Returns true if the passed scalar represents either JSON::XS::true or |
|
|
157 | JSON::XS::false, two constants that act like C<1> and C<0>, respectively |
|
|
158 | and are used to represent JSON C<true> and C<false> values in Perl. |
|
|
159 | |
|
|
160 | See MAPPING, below, for more information on how JSON values are mapped to |
|
|
161 | Perl. |
|
|
162 | |
145 | |
163 | =back |
146 | =back |
164 | |
147 | |
165 | |
148 | |
166 | =head1 A FEW NOTES ON UNICODE AND PERL |
149 | =head1 A FEW NOTES ON UNICODE AND PERL |
… | |
… | |
432 | If C<$enable> is true (or missing), then the C<encode> method will output JSON objects |
415 | If C<$enable> is true (or missing), then the C<encode> method will output JSON objects |
433 | by sorting their keys. This is adding a comparatively high overhead. |
416 | by sorting their keys. This is adding a comparatively high overhead. |
434 | |
417 | |
435 | If C<$enable> is false, then the C<encode> method will output key-value |
418 | If C<$enable> is false, then the C<encode> method will output key-value |
436 | pairs in the order Perl stores them (which will likely change between runs |
419 | pairs in the order Perl stores them (which will likely change between runs |
437 | of the same script). |
420 | of the same script, and can change even within the same run from 5.18 |
|
|
421 | onwards). |
438 | |
422 | |
439 | This option is useful if you want the same data structure to be encoded as |
423 | This option is useful if you want the same data structure to be encoded as |
440 | the same JSON text (given the same overall settings). If it is disabled, |
424 | the same JSON text (given the same overall settings). If it is disabled, |
441 | the same hash might be encoded differently even if contains the same data, |
425 | the same hash might be encoded differently even if contains the same data, |
442 | as key-value pairs have no inherent ordering in Perl. |
426 | as key-value pairs have no inherent ordering in Perl. |
… | |
… | |
666 | |
650 | |
667 | 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. |
668 | |
652 | |
669 | =item $json_text = $json->encode ($perl_scalar) |
653 | =item $json_text = $json->encode ($perl_scalar) |
670 | |
654 | |
671 | Converts the given Perl data structure (a simple scalar or a reference |
655 | Converts the given Perl value or data structure to its JSON |
672 | to a hash or array) to its JSON representation. Simple scalars will be |
656 | representation. Croaks on error. |
673 | converted into JSON string or number sequences, while references to arrays |
|
|
674 | become JSON arrays and references to hashes become JSON objects. Undefined |
|
|
675 | Perl values (e.g. C<undef>) become JSON C<null> values. Neither C<true> |
|
|
676 | nor C<false> values will be generated. |
|
|
677 | |
657 | |
678 | =item $perl_scalar = $json->decode ($json_text) |
658 | =item $perl_scalar = $json->decode ($json_text) |
679 | |
659 | |
680 | 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, |
681 | returning the resulting simple scalar or reference. Croaks on error. |
661 | returning the resulting simple scalar or reference. Croaks on error. |
682 | |
|
|
683 | JSON numbers and strings become simple Perl scalars. JSON arrays become |
|
|
684 | Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes |
|
|
685 | C<1>, C<false> becomes C<0> and C<null> becomes C<undef>. |
|
|
686 | |
662 | |
687 | =item ($perl_scalar, $characters) = $json->decode_prefix ($json_text) |
663 | =item ($perl_scalar, $characters) = $json->decode_prefix ($json_text) |
688 | |
664 | |
689 | 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 |
690 | 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 |
691 | silently stop parsing there and return the number of characters consumed |
667 | silently stop parsing there and return the number of characters consumed |
692 | so far. |
668 | so far. |
693 | |
669 | |
694 | 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 |
695 | (which is not the brightest thing to do in the first place) and you need |
|
|
696 | to know where the JSON text ends. |
671 | and you need to know where the JSON text ends. |
697 | |
672 | |
698 | JSON::XS->new->decode_prefix ("[1] the tail") |
673 | JSON::XS->new->decode_prefix ("[1] the tail") |
699 | => ([], 3) |
674 | => ([], 3) |
700 | |
675 | |
701 | =back |
676 | =back |
… | |
… | |
713 | calls). |
688 | calls). |
714 | |
689 | |
715 | JSON::XS will only attempt to parse the JSON text once it is sure it |
690 | JSON::XS will only attempt to parse the JSON text once it is sure it |
716 | has enough text to get a decisive result, using a very simple but |
691 | has enough text to get a decisive result, using a very simple but |
717 | truly incremental parser. This means that it sometimes won't stop as |
692 | truly incremental parser. This means that it sometimes won't stop as |
718 | early as the full parser, for example, it doesn't detect parenthese |
693 | early as the full parser, for example, it doesn't detect mismatched |
719 | mismatches. The only thing it guarantees is that it starts decoding as |
694 | parentheses. The only thing it guarantees is that it starts decoding as |
720 | soon as a syntactically valid JSON text has been seen. This means you need |
695 | soon as a syntactically valid JSON text has been seen. This means you need |
721 | to set resource limits (e.g. C<max_size>) to ensure the parser will stop |
696 | to set resource limits (e.g. C<max_size>) to ensure the parser will stop |
722 | parsing in the presence if syntax errors. |
697 | parsing in the presence if syntax errors. |
723 | |
698 | |
724 | The following methods implement this incremental parser. |
699 | The following methods implement this incremental parser. |
… | |
… | |
740 | |
715 | |
741 | If the method is called in scalar context, then it will try to extract |
716 | If the method is called in scalar context, then it will try to extract |
742 | exactly I<one> JSON object. If that is successful, it will return this |
717 | exactly I<one> JSON object. If that is successful, it will return this |
743 | object, otherwise it will return C<undef>. If there is a parse error, |
718 | object, otherwise it will return C<undef>. If there is a parse error, |
744 | this method will croak just as C<decode> would do (one can then use |
719 | this method will croak just as C<decode> would do (one can then use |
745 | C<incr_skip> to skip the errornous part). This is the most common way of |
720 | C<incr_skip> to skip the erroneous part). This is the most common way of |
746 | using the method. |
721 | using the method. |
747 | |
722 | |
748 | And finally, in list context, it will try to extract as many objects |
723 | And finally, in list context, it will try to extract as many objects |
749 | from the stream as it can find and return them, or the empty list |
724 | from the stream as it can find and return them, or the empty list |
750 | otherwise. For this to work, there must be no separators between the JSON |
725 | otherwise. For this to work, there must be no separators between the JSON |
751 | objects or arrays, instead they must be concatenated back-to-back. If |
726 | objects or arrays, instead they must be concatenated back-to-back. If |
752 | an error occurs, an exception will be raised as in the scalar context |
727 | an error occurs, an exception will be raised as in the scalar context |
753 | case. Note that in this case, any previously-parsed JSON texts will be |
728 | case. Note that in this case, any previously-parsed JSON texts will be |
754 | lost. |
729 | lost. |
755 | |
730 | |
|
|
731 | Example: Parse some JSON arrays/objects in a given string and return |
|
|
732 | them. |
|
|
733 | |
|
|
734 | my @objs = JSON::XS->new->incr_parse ("[5][7][1,2]"); |
|
|
735 | |
756 | =item $lvalue_string = $json->incr_text |
736 | =item $lvalue_string = $json->incr_text |
757 | |
737 | |
758 | This method returns the currently stored JSON fragment as an lvalue, that |
738 | This method returns the currently stored JSON fragment as an lvalue, that |
759 | is, you can manipulate it. This I<only> works when a preceding call to |
739 | is, you can manipulate it. This I<only> works when a preceding call to |
760 | C<incr_parse> in I<scalar context> successfully returned an object. Under |
740 | C<incr_parse> in I<scalar context> successfully returned an object. Under |
… | |
… | |
774 | C<incr_parse> died, in which case the input buffer and incremental parser |
754 | C<incr_parse> died, in which case the input buffer and incremental parser |
775 | state is left unchanged, to skip the text parsed so far and to reset the |
755 | state is left unchanged, to skip the text parsed so far and to reset the |
776 | parse state. |
756 | parse state. |
777 | |
757 | |
778 | The difference to C<incr_reset> is that only text until the parse error |
758 | The difference to C<incr_reset> is that only text until the parse error |
779 | occured is removed. |
759 | occurred is removed. |
780 | |
760 | |
781 | =item $json->incr_reset |
761 | =item $json->incr_reset |
782 | |
762 | |
783 | This completely resets the incremental parser, that is, after this call, |
763 | This completely resets the incremental parser, that is, after this call, |
784 | it will be as if the parser had never parsed anything. |
764 | it will be as if the parser had never parsed anything. |
… | |
… | |
790 | =back |
770 | =back |
791 | |
771 | |
792 | =head2 LIMITATIONS |
772 | =head2 LIMITATIONS |
793 | |
773 | |
794 | All options that affect decoding are supported, except |
774 | All options that affect decoding are supported, except |
795 | 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 |
796 | 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 |
797 | 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 |
798 | for JSON numbers, however. |
778 | not hold true for JSON numbers, however. |
799 | |
779 | |
800 | 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 |
801 | 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 |
802 | 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 |
803 | takes the conservative route and disallows this case. |
783 | takes the conservative route and disallows this case. |
… | |
… | |
982 | If the number consists of digits only, JSON::XS will try to represent |
962 | If the number consists of digits only, JSON::XS will try to represent |
983 | it as an integer value. If that fails, it will try to represent it as |
963 | it as an integer value. If that fails, it will try to represent it as |
984 | a numeric (floating point) value if that is possible without loss of |
964 | a numeric (floating point) value if that is possible without loss of |
985 | precision. Otherwise it will preserve the number as a string value (in |
965 | precision. Otherwise it will preserve the number as a string value (in |
986 | which case you lose roundtripping ability, as the JSON number will be |
966 | which case you lose roundtripping ability, as the JSON number will be |
987 | re-encoded toa JSON string). |
967 | re-encoded to a JSON string). |
988 | |
968 | |
989 | Numbers containing a fractional or exponential part will always be |
969 | Numbers containing a fractional or exponential part will always be |
990 | represented as numeric (floating point) values, possibly at a loss of |
970 | represented as numeric (floating point) values, possibly at a loss of |
991 | precision (in which case you might lose perfect roundtripping ability, but |
971 | precision (in which case you might lose perfect roundtripping ability, but |
992 | the JSON number will still be re-encoded as a JSON number). |
972 | the JSON number will still be re-encoded as a JSON number). |
993 | |
973 | |
|
|
974 | Note that precision is not accuracy - binary floating point values cannot |
|
|
975 | represent most decimal fractions exactly, and when converting from and to |
|
|
976 | floating point, JSON::XS only guarantees precision up to but not including |
|
|
977 | the least significant bit. |
|
|
978 | |
994 | =item true, false |
979 | =item true, false |
995 | |
980 | |
996 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
981 | These JSON atoms become C<Types::Serialiser::true> and |
997 | respectively. They are overloaded to act almost exactly like the numbers |
982 | C<Types::Serialiser::false>, respectively. They are overloaded to act |
998 | 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 |
999 | 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). |
1000 | |
986 | |
1001 | =item null |
987 | =item null |
1002 | |
988 | |
1003 | A JSON null atom becomes C<undef> in Perl. |
989 | A JSON null atom becomes C<undef> in Perl. |
1004 | |
990 | |
… | |
… | |
1013 | |
999 | |
1014 | =over 4 |
1000 | =over 4 |
1015 | |
1001 | |
1016 | =item hash references |
1002 | =item hash references |
1017 | |
1003 | |
1018 | Perl hash references become JSON objects. As there is no inherent ordering |
1004 | Perl hash references become JSON objects. As there is no inherent |
1019 | in hash keys (or JSON objects), they will usually be encoded in a |
1005 | ordering in hash keys (or JSON objects), they will usually be encoded |
1020 | pseudo-random order that can change between runs of the same program but |
1006 | in a pseudo-random order. JSON::XS can optionally sort the hash keys |
1021 | stays generally the same within a single run of a program. JSON::XS can |
1007 | (determined by the I<canonical> flag), so the same datastructure will |
1022 | optionally sort the hash keys (determined by the I<canonical> flag), so |
1008 | serialise to the same JSON text (given same settings and version of |
1023 | the same datastructure will serialise to the same JSON text (given same |
1009 | JSON::XS), but this incurs a runtime overhead and is only rarely useful, |
1024 | settings and version of JSON::XS), but this incurs a runtime overhead |
1010 | e.g. when you want to compare some JSON text against another for equality. |
1025 | and is only rarely useful, e.g. when you want to compare some JSON text |
|
|
1026 | against another for equality. |
|
|
1027 | |
1011 | |
1028 | =item array references |
1012 | =item array references |
1029 | |
1013 | |
1030 | Perl array references become JSON arrays. |
1014 | Perl array references become JSON arrays. |
1031 | |
1015 | |
1032 | =item other references |
1016 | =item other references |
1033 | |
1017 | |
1034 | Other unblessed references are generally not allowed and will cause an |
1018 | Other unblessed references are generally not allowed and will cause an |
1035 | exception to be thrown, except for references to the integers C<0> and |
1019 | exception to be thrown, except for references to the integers C<0> and |
1036 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
1020 | C<1>, which get turned into C<false> and C<true> atoms in JSON. |
1037 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
|
|
1038 | |
1021 | |
|
|
1022 | Since C<JSON::XS> uses the boolean model from L<Types::Serialiser>, you |
|
|
1023 | can also C<use Types::Serialiser> and then use C<Types::Serialiser::false> |
|
|
1024 | and C<Types::Serialiser::true> to improve readability. |
|
|
1025 | |
|
|
1026 | use Types::Serialiser; |
1039 | encode_json [\0, JSON::XS::true] # yields [false,true] |
1027 | encode_json [\0, Types::Serialiser::true] # yields [false,true] |
1040 | |
1028 | |
1041 | =item JSON::XS::true, JSON::XS::false |
1029 | =item Types::Serialiser::true, Types::Serialiser::false |
1042 | |
1030 | |
1043 | These special values become JSON true and JSON false values, |
1031 | These special values from the L<Types::Serialiser> module become JSON true |
1044 | respectively. You can also use C<\1> and C<\0> directly if you want. |
1032 | and JSON false values, respectively. You can also use C<\1> and C<\0> |
|
|
1033 | directly if you want. |
1045 | |
1034 | |
1046 | =item blessed objects |
1035 | =item blessed objects |
1047 | |
1036 | |
1048 | Blessed objects are not directly representable in JSON. See the |
1037 | Blessed objects are not directly representable in JSON. See the |
1049 | C<allow_blessed> and C<convert_blessed> methods on various options on |
1038 | C<allow_blessed> and C<convert_blessed> methods on various options on |
… | |
… | |
1084 | $x *= 1; # same thing, the choice is yours. |
1073 | $x *= 1; # same thing, the choice is yours. |
1085 | |
1074 | |
1086 | You can not currently force the type in other, less obscure, ways. Tell me |
1075 | You can not currently force the type in other, less obscure, ways. Tell me |
1087 | if you need this capability (but don't forget to explain why it's needed |
1076 | if you need this capability (but don't forget to explain why it's needed |
1088 | :). |
1077 | :). |
|
|
1078 | |
|
|
1079 | Note that numerical precision has the same meaning as under Perl (so |
|
|
1080 | binary to decimal conversion follows the same rules as in Perl, which |
|
|
1081 | can differ to other languages). Also, your perl interpreter might expose |
|
|
1082 | extensions to the floating point numbers of your platform, such as |
|
|
1083 | infinities or NaN's - these cannot be represented in JSON, and it is an |
|
|
1084 | error to pass those in. |
1089 | |
1085 | |
1090 | =back |
1086 | =back |
1091 | |
1087 | |
1092 | |
1088 | |
1093 | =head1 ENCODING/CODESET FLAG NOTES |
1089 | =head1 ENCODING/CODESET FLAG NOTES |
… | |
… | |
1120 | =item C<utf8> flag disabled |
1116 | =item C<utf8> flag disabled |
1121 | |
1117 | |
1122 | When C<utf8> is disabled (the default), then C<encode>/C<decode> generate |
1118 | When C<utf8> is disabled (the default), then C<encode>/C<decode> generate |
1123 | and expect Unicode strings, that is, characters with high ordinal Unicode |
1119 | and expect Unicode strings, that is, characters with high ordinal Unicode |
1124 | values (> 255) will be encoded as such characters, and likewise such |
1120 | values (> 255) will be encoded as such characters, and likewise such |
1125 | characters are decoded as-is, no canges to them will be done, except |
1121 | characters are decoded as-is, no changes to them will be done, except |
1126 | "(re-)interpreting" them as Unicode codepoints or Unicode characters, |
1122 | "(re-)interpreting" them as Unicode codepoints or Unicode characters, |
1127 | respectively (to Perl, these are the same thing in strings unless you do |
1123 | respectively (to Perl, these are the same thing in strings unless you do |
1128 | funny/weird/dumb stuff). |
1124 | funny/weird/dumb stuff). |
1129 | |
1125 | |
1130 | This is useful when you want to do the encoding yourself (e.g. when you |
1126 | This is useful when you want to do the encoding yourself (e.g. when you |
… | |
… | |
1238 | well - using C<eval> naively simply I<will> cause problems. |
1234 | well - using C<eval> naively simply I<will> cause problems. |
1239 | |
1235 | |
1240 | Another problem is that some javascript implementations reserve |
1236 | Another problem is that some javascript implementations reserve |
1241 | some property names for their own purposes (which probably makes |
1237 | some property names for their own purposes (which probably makes |
1242 | them non-ECMAscript-compliant). For example, Iceweasel reserves the |
1238 | them non-ECMAscript-compliant). For example, Iceweasel reserves the |
1243 | C<__proto__> property name for it's own purposes. |
1239 | C<__proto__> property name for its own purposes. |
1244 | |
1240 | |
1245 | If that is a problem, you could parse try to filter the resulting JSON |
1241 | If that is a problem, you could parse try to filter the resulting JSON |
1246 | output for these property strings, e.g.: |
1242 | output for these property strings, e.g.: |
1247 | |
1243 | |
1248 | $json =~ s/"__proto__"\s*:/"__proto__renamed":/g; |
1244 | $json =~ s/"__proto__"\s*:/"__proto__renamed":/g; |
1249 | |
1245 | |
1250 | This works because C<__proto__> is not valid outside of strings, so every |
1246 | This works because C<__proto__> is not valid outside of strings, so every |
1251 | occurence of C<"__proto__"\s*:> must be a string used as property name. |
1247 | occurrence of C<"__proto__"\s*:> must be a string used as property name. |
1252 | |
1248 | |
1253 | If you know of other incompatibilities, please let me know. |
1249 | If you know of other incompatibilities, please let me know. |
1254 | |
1250 | |
1255 | |
1251 | |
1256 | =head2 JSON and YAML |
1252 | =head2 JSON and YAML |
… | |
… | |
1268 | my $yaml = $to_yaml->encode ($ref) . "\n"; |
1264 | my $yaml = $to_yaml->encode ($ref) . "\n"; |
1269 | |
1265 | |
1270 | This will I<usually> generate JSON texts that also parse as valid |
1266 | This will I<usually> generate JSON texts that also parse as valid |
1271 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
1267 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
1272 | lengths that JSON doesn't have and also has different and incompatible |
1268 | lengths that JSON doesn't have and also has different and incompatible |
1273 | unicode handling, so you should make sure that your hash keys are |
1269 | unicode character escape syntax, so you should make sure that your hash |
1274 | noticeably shorter than the 1024 "stream characters" YAML allows and that |
1270 | keys are noticeably shorter than the 1024 "stream characters" YAML allows |
1275 | you do not have characters with codepoint values outside the Unicode BMP |
1271 | and that you do not have characters with codepoint values outside the |
1276 | (basic multilingual page). YAML also does not allow C<\/> sequences in |
1272 | Unicode BMP (basic multilingual page). YAML also does not allow C<\/> |
1277 | strings (which JSON::XS does not I<currently> generate, but other JSON |
1273 | sequences in strings (which JSON::XS does not I<currently> generate, but |
1278 | generators might). |
1274 | other JSON generators might). |
1279 | |
1275 | |
1280 | There might be other incompatibilities that I am not aware of (or the YAML |
1276 | There might be other incompatibilities that I am not aware of (or the YAML |
1281 | specification has been changed yet again - it does so quite often). In |
1277 | specification has been changed yet again - it does so quite often). In |
1282 | general you should not try to generate YAML with a JSON generator or vice |
1278 | general you should not try to generate YAML with a JSON generator or vice |
1283 | versa, or try to parse JSON with a YAML parser or vice versa: chances are |
1279 | versa, or try to parse JSON with a YAML parser or vice versa: chances are |
… | |
… | |
1302 | that difficult or long) and finally make YAML compatible to it, and |
1298 | that difficult or long) and finally make YAML compatible to it, and |
1303 | educating users about the changes, instead of spreading lies about the |
1299 | educating users about the changes, instead of spreading lies about the |
1304 | real compatibility for many I<years> and trying to silence people who |
1300 | real compatibility for many I<years> and trying to silence people who |
1305 | point out that it isn't true. |
1301 | point out that it isn't true. |
1306 | |
1302 | |
|
|
1303 | Addendum/2009: the YAML 1.2 spec is still incompatible with JSON, even |
|
|
1304 | though the incompatibilities have been documented (and are known to Brian) |
|
|
1305 | for many years and the spec makes explicit claims that YAML is a superset |
|
|
1306 | of JSON. It would be so easy to fix, but apparently, bullying people and |
|
|
1307 | corrupting userdata is so much easier. |
|
|
1308 | |
1307 | =back |
1309 | =back |
1308 | |
1310 | |
1309 | |
1311 | |
1310 | =head2 SPEED |
1312 | =head2 SPEED |
1311 | |
1313 | |
… | |
… | |
1318 | a very short single-line JSON string (also available at |
1320 | a very short single-line JSON string (also available at |
1319 | L<http://dist.schmorp.de/misc/json/short.json>). |
1321 | L<http://dist.schmorp.de/misc/json/short.json>). |
1320 | |
1322 | |
1321 | {"method": "handleMessage", "params": ["user1", |
1323 | {"method": "handleMessage", "params": ["user1", |
1322 | "we were just talking"], "id": null, "array":[1,11,234,-5,1e5,1e7, |
1324 | "we were just talking"], "id": null, "array":[1,11,234,-5,1e5,1e7, |
1323 | true, false]} |
1325 | 1, 0]} |
1324 | |
1326 | |
1325 | It shows the number of encodes/decodes per second (JSON::XS uses |
1327 | It shows the number of encodes/decodes per second (JSON::XS uses |
1326 | the functional interface, while JSON::XS/2 uses the OO interface |
1328 | the functional interface, while JSON::XS/2 uses the OO interface |
1327 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
1329 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
1328 | shrink). Higher is better: |
1330 | shrink. JSON::DWIW/DS uses the deserialise function, while JSON::DWIW::FJ |
|
|
1331 | uses the from_json method). Higher is better: |
1329 | |
1332 | |
1330 | module | encode | decode | |
1333 | module | encode | decode | |
1331 | -----------|------------|------------| |
1334 | --------------|------------|------------| |
1332 | JSON 1.x | 4990.842 | 4088.813 | |
1335 | JSON::DWIW/DS | 86302.551 | 102300.098 | |
1333 | JSON::DWIW | 51653.990 | 71575.154 | |
1336 | JSON::DWIW/FJ | 86302.551 | 75983.768 | |
1334 | JSON::PC | 65948.176 | 74631.744 | |
1337 | JSON::PP | 15827.562 | 6638.658 | |
1335 | JSON::PP | 8931.652 | 3817.168 | |
1338 | JSON::Syck | 63358.066 | 47662.545 | |
1336 | JSON::Syck | 24877.248 | 27776.848 | |
1339 | JSON::XS | 511500.488 | 511500.488 | |
1337 | JSON::XS | 388361.481 | 227951.304 | |
1340 | JSON::XS/2 | 291271.111 | 388361.481 | |
1338 | JSON::XS/2 | 227951.304 | 218453.333 | |
1341 | JSON::XS/3 | 361577.931 | 361577.931 | |
1339 | JSON::XS/3 | 338250.323 | 218453.333 | |
1342 | Storable | 66788.280 | 265462.278 | |
1340 | Storable | 16500.016 | 135300.129 | |
|
|
1341 | -----------+------------+------------+ |
1343 | --------------+------------+------------+ |
1342 | |
1344 | |
1343 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
1345 | That is, JSON::XS is almost six times faster than JSON::DWIW on encoding, |
1344 | about three times faster on decoding, and over forty times faster |
1346 | about five times faster on decoding, and over thirty to seventy times |
1345 | than JSON, even with pretty-printing and key sorting. It also compares |
1347 | faster than JSON's pure perl implementation. It also compares favourably |
1346 | favourably to Storable for small amounts of data. |
1348 | to Storable for small amounts of data. |
1347 | |
1349 | |
1348 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
1350 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
1349 | search API (L<http://dist.schmorp.de/misc/json/long.json>). |
1351 | search API (L<http://dist.schmorp.de/misc/json/long.json>). |
1350 | |
1352 | |
1351 | module | encode | decode | |
1353 | module | encode | decode | |
1352 | -----------|------------|------------| |
1354 | --------------|------------|------------| |
1353 | JSON 1.x | 55.260 | 34.971 | |
1355 | JSON::DWIW/DS | 1647.927 | 2673.916 | |
1354 | JSON::DWIW | 825.228 | 1082.513 | |
1356 | JSON::DWIW/FJ | 1630.249 | 2596.128 | |
1355 | JSON::PC | 3571.444 | 2394.829 | |
|
|
1356 | JSON::PP | 210.987 | 32.574 | |
1357 | JSON::PP | 400.640 | 62.311 | |
1357 | JSON::Syck | 552.551 | 787.544 | |
1358 | JSON::Syck | 1481.040 | 1524.869 | |
1358 | JSON::XS | 5780.463 | 4854.519 | |
1359 | JSON::XS | 20661.596 | 9541.183 | |
1359 | JSON::XS/2 | 3869.998 | 4798.975 | |
1360 | JSON::XS/2 | 10683.403 | 9416.938 | |
1360 | JSON::XS/3 | 5862.880 | 4798.975 | |
1361 | JSON::XS/3 | 20661.596 | 9400.054 | |
1361 | Storable | 4445.002 | 5235.027 | |
1362 | Storable | 19765.806 | 10000.725 | |
1362 | -----------+------------+------------+ |
1363 | --------------+------------+------------+ |
1363 | |
1364 | |
1364 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
1365 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
1365 | decodes faster). |
1366 | decodes a bit faster). |
1366 | |
1367 | |
1367 | On large strings containing lots of high Unicode characters, some modules |
1368 | On large strings containing lots of high Unicode characters, some modules |
1368 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
1369 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
1369 | will be broken due to missing (or wrong) Unicode handling. Others refuse |
1370 | will be broken due to missing (or wrong) Unicode handling. Others refuse |
1370 | to decode or encode properly, so it was impossible to prepare a fair |
1371 | to decode or encode properly, so it was impossible to prepare a fair |
… | |
… | |
1406 | information you might want to make sure that exceptions thrown by JSON::XS |
1407 | information you might want to make sure that exceptions thrown by JSON::XS |
1407 | will not end up in front of untrusted eyes. |
1408 | will not end up in front of untrusted eyes. |
1408 | |
1409 | |
1409 | If you are using JSON::XS to return packets to consumption |
1410 | If you are using JSON::XS to return packets to consumption |
1410 | by JavaScript scripts in a browser you should have a look at |
1411 | by JavaScript scripts in a browser you should have a look at |
1411 | L<http://jpsykes.com/47/practical-csrf-and-json-security> to see whether |
1412 | L<http://blog.archive.jpsykes.com/47/practical-csrf-and-json-security/> to |
1412 | you are vulnerable to some common attack vectors (which really are browser |
1413 | see whether you are vulnerable to some common attack vectors (which really |
1413 | design bugs, but it is still you who will have to deal with it, as major |
1414 | are browser design bugs, but it is still you who will have to deal with |
1414 | browser developers care only for features, not about getting security |
1415 | it, as major browser developers care only for features, not about getting |
1415 | right). |
1416 | security right). |
|
|
1417 | |
|
|
1418 | |
|
|
1419 | =head1 INTEROPERABILITY WITH OTHER MODULES |
|
|
1420 | |
|
|
1421 | C<JSON::XS> uses the L<Types::Serialiser> module to provide boolean |
|
|
1422 | constants. That means that the JSON true and false values will be |
|
|
1423 | comaptible to true and false values of iother modules that do the same, |
|
|
1424 | such as L<JSON::PP> and L<CBOR::XS>. |
1416 | |
1425 | |
1417 | |
1426 | |
1418 | =head1 THREADS |
1427 | =head1 THREADS |
1419 | |
1428 | |
1420 | This module is I<not> guaranteed to be thread safe and there are no |
1429 | This module is I<not> guaranteed to be thread safe and there are no |
… | |
… | |
1423 | process simulations - use fork, it's I<much> faster, cheaper, better). |
1432 | process simulations - use fork, it's I<much> faster, cheaper, better). |
1424 | |
1433 | |
1425 | (It might actually work, but you have been warned). |
1434 | (It might actually work, but you have been warned). |
1426 | |
1435 | |
1427 | |
1436 | |
|
|
1437 | =head1 THE PERILS OF SETLOCALE |
|
|
1438 | |
|
|
1439 | Sometimes people avoid the Perl locale support and directly call the |
|
|
1440 | system's setlocale function with C<LC_ALL>. |
|
|
1441 | |
|
|
1442 | This breaks both perl and modules such as JSON::XS, as stringification of |
|
|
1443 | numbers no longer works correctly (e.g. C<$x = 0.1; print "$x"+1> might |
|
|
1444 | print C<1>, and JSON::XS might output illegal JSON as JSON::XS relies on |
|
|
1445 | perl to stringify numbers). |
|
|
1446 | |
|
|
1447 | The solution is simple: don't call C<setlocale>, or use it for only those |
|
|
1448 | categories you need, such as C<LC_MESSAGES> or C<LC_CTYPE>. |
|
|
1449 | |
|
|
1450 | If you need C<LC_NUMERIC>, you should enable it only around the code that |
|
|
1451 | actually needs it (avoiding stringification of numbers), and restore it |
|
|
1452 | afterwards. |
|
|
1453 | |
|
|
1454 | |
1428 | =head1 BUGS |
1455 | =head1 BUGS |
1429 | |
1456 | |
1430 | While the goal of this module is to be correct, that unfortunately does |
1457 | While the goal of this module is to be correct, that unfortunately does |
1431 | not mean it's bug-free, only that I think its design is bug-free. If you |
1458 | not mean it's bug-free, only that I think its design is bug-free. If you |
1432 | keep reporting bugs they will be fixed swiftly, though. |
1459 | keep reporting bugs they will be fixed swiftly, though. |
… | |
… | |
1434 | Please refrain from using rt.cpan.org or any other bug reporting |
1461 | Please refrain from using rt.cpan.org or any other bug reporting |
1435 | service. I put the contact address into my modules for a reason. |
1462 | service. I put the contact address into my modules for a reason. |
1436 | |
1463 | |
1437 | =cut |
1464 | =cut |
1438 | |
1465 | |
1439 | our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" }; |
1466 | BEGIN { |
1440 | our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" }; |
1467 | *true = \$Types::Serialiser::true; |
|
|
1468 | *true = \&Types::Serialiser::true; |
|
|
1469 | *false = \$Types::Serialiser::false; |
|
|
1470 | *false = \&Types::Serialiser::false; |
|
|
1471 | *is_bool = \&Types::Serialiser::is_bool; |
1441 | |
1472 | |
1442 | sub true() { $true } |
1473 | *JSON::XS::Boolean:: = *Types::Serialiser::Boolean::; |
1443 | sub false() { $false } |
|
|
1444 | |
|
|
1445 | sub is_bool($) { |
|
|
1446 | UNIVERSAL::isa $_[0], "JSON::XS::Boolean" |
|
|
1447 | # or UNIVERSAL::isa $_[0], "JSON::Literal" |
|
|
1448 | } |
1474 | } |
1449 | |
1475 | |
1450 | XSLoader::load "JSON::XS", $VERSION; |
1476 | XSLoader::load "JSON::XS", $VERSION; |
1451 | |
|
|
1452 | package JSON::XS::Boolean; |
|
|
1453 | |
|
|
1454 | use overload |
|
|
1455 | "0+" => sub { ${$_[0]} }, |
|
|
1456 | "++" => sub { $_[0] = ${$_[0]} + 1 }, |
|
|
1457 | "--" => sub { $_[0] = ${$_[0]} - 1 }, |
|
|
1458 | fallback => 1; |
|
|
1459 | |
|
|
1460 | 1; |
|
|
1461 | |
1477 | |
1462 | =head1 SEE ALSO |
1478 | =head1 SEE ALSO |
1463 | |
1479 | |
1464 | The F<json_xs> command line utility for quick experiments. |
1480 | The F<json_xs> command line utility for quick experiments. |
1465 | |
1481 | |
… | |
… | |
1468 | Marc Lehmann <schmorp@schmorp.de> |
1484 | Marc Lehmann <schmorp@schmorp.de> |
1469 | http://home.schmorp.de/ |
1485 | http://home.schmorp.de/ |
1470 | |
1486 | |
1471 | =cut |
1487 | =cut |
1472 | |
1488 | |
|
|
1489 | 1 |
|
|
1490 | |