… | |
… | |
40 | Beginning with version 2.0 of the JSON module, when both JSON and |
40 | Beginning with version 2.0 of the JSON module, when both JSON and |
41 | JSON::XS are installed, then JSON will fall back on JSON::XS (this can be |
41 | JSON::XS are installed, then JSON will fall back on JSON::XS (this can be |
42 | overridden) with no overhead due to emulation (by inheriting constructor |
42 | overridden) with no overhead due to emulation (by inheriting constructor |
43 | and methods). If JSON::XS is not available, it will fall back to the |
43 | and methods). If JSON::XS is not available, it will fall back to the |
44 | compatible JSON::PP module as backend, so using JSON instead of JSON::XS |
44 | compatible JSON::PP module as backend, so using JSON instead of JSON::XS |
45 | gives you a portable JSON API that can be fast when you need and doesn't |
45 | gives you a portable JSON API that can be fast when you need it and |
46 | require a C compiler when that is a problem. |
46 | doesn't require a C compiler when that is a problem. |
47 | |
47 | |
48 | As this is the n-th-something JSON module on CPAN, what was the reason |
48 | As this is the n-th-something JSON module on CPAN, what was the reason |
49 | to write yet another JSON module? While it seems there are many JSON |
49 | to write yet another JSON module? While it seems there are many JSON |
50 | modules, none of them correctly handle all corner cases, and in most cases |
50 | modules, none of them correctly handle all corner cases, and in most cases |
51 | their maintainers are unresponsive, gone missing, or not listening to bug |
51 | their maintainers are unresponsive, gone missing, or not listening to bug |
… | |
… | |
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 = '2.25'; |
106 | our $VERSION = 3.04; |
107 | our @ISA = qw(Exporter); |
107 | our @ISA = qw(Exporter); |
108 | |
108 | |
109 | our @EXPORT = qw(encode_json decode_json to_json from_json); |
109 | our @EXPORT = qw(encode_json decode_json); |
110 | |
|
|
111 | sub to_json($) { |
|
|
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 | |
|
|
114 | use Types::Serialiser (); |
|
|
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: |
128 | |
120 | |
… | |
… | |
139 | |
131 | |
140 | Except being faster. |
132 | Except being faster. |
141 | |
133 | |
142 | =item $perl_scalar = decode_json $json_text |
134 | =item $perl_scalar = decode_json $json_text |
143 | |
135 | |
144 | The opposite of C<encode_json>: expects an UTF-8 (binary) string and tries |
136 | The opposite of C<encode_json>: expects a UTF-8 (binary) string and tries |
145 | to parse that as an UTF-8 encoded JSON text, returning the resulting |
137 | to parse that as a UTF-8 encoded JSON text, returning the resulting |
146 | reference. Croaks on error. |
138 | reference. Croaks on error. |
147 | |
139 | |
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 |
… | |
… | |
287 | |
270 | |
288 | =item $enabled = $json->get_utf8 |
271 | =item $enabled = $json->get_utf8 |
289 | |
272 | |
290 | If C<$enable> is true (or missing), then the C<encode> method will encode |
273 | If C<$enable> is true (or missing), then the C<encode> method will encode |
291 | the JSON result into UTF-8, as required by many protocols, while the |
274 | the JSON result into UTF-8, as required by many protocols, while the |
292 | C<decode> method expects to be handled an UTF-8-encoded string. Please |
275 | C<decode> method expects to be handed a UTF-8-encoded string. Please |
293 | note that UTF-8-encoded strings do not contain any characters outside the |
276 | note that UTF-8-encoded strings do not contain any characters outside the |
294 | range C<0..255>, they are thus useful for bytewise/binary I/O. In future |
277 | range C<0..255>, they are thus useful for bytewise/binary I/O. In future |
295 | versions, enabling this option might enable autodetection of the UTF-16 |
278 | versions, enabling this option might enable autodetection of the UTF-16 |
296 | and UTF-32 encoding families, as described in RFC4627. |
279 | and UTF-32 encoding families, as described in RFC4627. |
297 | |
280 | |
… | |
… | |
382 | |
365 | |
383 | =item $enabled = $json->get_relaxed |
366 | =item $enabled = $json->get_relaxed |
384 | |
367 | |
385 | If C<$enable> is true (or missing), then C<decode> will accept some |
368 | If C<$enable> is true (or missing), then C<decode> will accept some |
386 | extensions to normal JSON syntax (see below). C<encode> will not be |
369 | extensions to normal JSON syntax (see below). C<encode> will not be |
387 | affected in anyway. I<Be aware that this option makes you accept invalid |
370 | affected in any way. I<Be aware that this option makes you accept invalid |
388 | JSON texts as if they were valid!>. I suggest only to use this option to |
371 | JSON texts as if they were valid!>. I suggest only to use this option to |
389 | parse application-specific files written by humans (configuration files, |
372 | parse application-specific files written by humans (configuration files, |
390 | resource files etc.) |
373 | resource files etc.) |
391 | |
374 | |
392 | If C<$enable> is false (the default), then C<decode> will only accept |
375 | If C<$enable> is false (the default), then C<decode> will only accept |
… | |
… | |
421 | [ |
404 | [ |
422 | 1, # this comment not allowed in JSON |
405 | 1, # this comment not allowed in JSON |
423 | # neither this one... |
406 | # neither this one... |
424 | ] |
407 | ] |
425 | |
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 | |
426 | =back |
419 | =back |
427 | |
420 | |
428 | =item $json = $json->canonical ([$enable]) |
421 | =item $json = $json->canonical ([$enable]) |
429 | |
422 | |
430 | =item $enabled = $json->get_canonical |
423 | =item $enabled = $json->get_canonical |
… | |
… | |
432 | If C<$enable> is true (or missing), then the C<encode> method will output JSON objects |
425 | If C<$enable> is true (or missing), then the C<encode> method will output JSON objects |
433 | by sorting their keys. This is adding a comparatively high overhead. |
426 | by sorting their keys. This is adding a comparatively high overhead. |
434 | |
427 | |
435 | If C<$enable> is false, then the C<encode> method will output key-value |
428 | 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 |
429 | pairs in the order Perl stores them (which will likely change between runs |
437 | of the same script). |
430 | of the same script, and can change even within the same run from 5.18 |
|
|
431 | onwards). |
438 | |
432 | |
439 | This option is useful if you want the same data structure to be encoded as |
433 | 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, |
434 | 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, |
435 | the same hash might be encoded differently even if contains the same data, |
442 | as key-value pairs have no inherent ordering in Perl. |
436 | as key-value pairs have no inherent ordering in Perl. |
… | |
… | |
483 | |
477 | |
484 | =item $json = $json->allow_blessed ([$enable]) |
478 | =item $json = $json->allow_blessed ([$enable]) |
485 | |
479 | |
486 | =item $enabled = $json->get_allow_blessed |
480 | =item $enabled = $json->get_allow_blessed |
487 | |
481 | |
|
|
482 | See L<OBJECT SERIALISATION> for details. |
|
|
483 | |
488 | If C<$enable> is true (or missing), then the C<encode> method will not |
484 | If C<$enable> is true (or missing), then the C<encode> method will not |
489 | barf when it encounters a blessed reference. Instead, the value of the |
485 | barf when it encounters a blessed reference that it cannot convert |
490 | B<convert_blessed> option will decide whether C<null> (C<convert_blessed> |
486 | otherwise. Instead, a JSON C<null> value is encoded instead of the object. |
491 | disabled or no C<TO_JSON> method found) or a representation of the |
|
|
492 | object (C<convert_blessed> enabled and C<TO_JSON> method found) is being |
|
|
493 | encoded. Has no effect on C<decode>. |
|
|
494 | |
487 | |
495 | If C<$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 |
496 | 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>. |
497 | |
493 | |
498 | =item $json = $json->convert_blessed ([$enable]) |
494 | =item $json = $json->convert_blessed ([$enable]) |
499 | |
495 | |
500 | =item $enabled = $json->get_convert_blessed |
496 | =item $enabled = $json->get_convert_blessed |
|
|
497 | |
|
|
498 | See L<OBJECT SERIALISATION> for details. |
501 | |
499 | |
502 | If C<$enable> is true (or missing), then C<encode>, upon encountering a |
500 | If C<$enable> is true (or missing), then C<encode>, upon encountering a |
503 | blessed object, will check for the availability of the C<TO_JSON> method |
501 | blessed object, will check for the availability of the C<TO_JSON> method |
504 | on the object's class. If found, it will be called in scalar context |
502 | on the object's class. If found, it will be called in scalar context and |
505 | and the resulting scalar will be encoded instead of the object. If no |
503 | the resulting scalar will be encoded instead of the object. |
506 | C<TO_JSON> method is found, the value of C<allow_blessed> will decide what |
|
|
507 | to do. |
|
|
508 | |
504 | |
509 | The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON> |
505 | The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON> |
510 | returns other blessed objects, those will be handled in the same |
506 | returns other blessed objects, those will be handled in the same |
511 | way. C<TO_JSON> must take care of not causing an endless recursion cycle |
507 | way. C<TO_JSON> must take care of not causing an endless recursion cycle |
512 | (== crash) in this case. The name of C<TO_JSON> was chosen because other |
508 | (== crash) in this case. The name of C<TO_JSON> was chosen because other |
513 | methods called by the Perl core (== not by the user of the object) are |
509 | methods called by the Perl core (== not by the user of the object) are |
514 | usually in upper case letters and to avoid collisions with any C<to_json> |
510 | usually in upper case letters and to avoid collisions with any C<to_json> |
515 | function or method. |
511 | function or method. |
516 | |
512 | |
517 | This setting does not yet influence C<decode> in any way, but in the |
513 | If C<$enable> is false (the default), then C<encode> will not consider |
518 | future, global hooks might get installed that influence C<decode> and are |
514 | this type of conversion. |
519 | enabled by this setting. |
|
|
520 | |
515 | |
521 | If C<$enable> is false, then the C<allow_blessed> setting will decide what |
516 | This setting has no effect on C<decode>. |
522 | to do when a blessed object is found. |
517 | |
|
|
518 | =item $json = $json->allow_tags ([$enable]) |
|
|
519 | |
|
|
520 | =item $enabled = $json->get_allow_tags |
|
|
521 | |
|
|
522 | See L<OBJECT SERIALISATION> for details. |
|
|
523 | |
|
|
524 | If C<$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. |
523 | |
535 | |
524 | =item $json = $json->filter_json_object ([$coderef->($hashref)]) |
536 | =item $json = $json->filter_json_object ([$coderef->($hashref)]) |
525 | |
537 | |
526 | When C<$coderef> is specified, it will be called from C<decode> each |
538 | When C<$coderef> is specified, it will be called from C<decode> each |
527 | time it decodes a JSON object. The only argument is a reference to the |
539 | time it decodes a JSON object. The only argument is a reference to |
528 | newly-created hash. If the code references returns a single scalar (which |
540 | the newly-created hash. If the code reference returns a single scalar |
529 | need not be a reference), this value (i.e. a copy of that scalar to avoid |
541 | (which need not be a reference), this value (or rather a copy of it) is |
530 | aliasing) is inserted into the deserialised data structure. If it returns |
542 | inserted into the deserialised data structure. If it returns an empty |
531 | an empty list (NOTE: I<not> C<undef>, which is a valid scalar), the |
543 | list (NOTE: I<not> C<undef>, which is a valid scalar), the original |
532 | original deserialised hash will be inserted. This setting can slow down |
544 | deserialised hash will be inserted. This setting can slow down decoding |
533 | decoding considerably. |
545 | considerably. |
534 | |
546 | |
535 | When C<$coderef> is omitted or undefined, any existing callback will |
547 | When C<$coderef> is omitted or undefined, any existing callback will |
536 | be removed and C<decode> will not change the deserialised hash in any |
548 | be removed and C<decode> will not change the deserialised hash in any |
537 | way. |
549 | way. |
538 | |
550 | |
… | |
… | |
666 | |
678 | |
667 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
679 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
668 | |
680 | |
669 | =item $json_text = $json->encode ($perl_scalar) |
681 | =item $json_text = $json->encode ($perl_scalar) |
670 | |
682 | |
671 | Converts the given Perl data structure (a simple scalar or a reference |
683 | 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 |
684 | 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 | |
685 | |
678 | =item $perl_scalar = $json->decode ($json_text) |
686 | =item $perl_scalar = $json->decode ($json_text) |
679 | |
687 | |
680 | The opposite of C<encode>: expects a JSON text and tries to parse it, |
688 | 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. |
689 | 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 | |
690 | |
687 | =item ($perl_scalar, $characters) = $json->decode_prefix ($json_text) |
691 | =item ($perl_scalar, $characters) = $json->decode_prefix ($json_text) |
688 | |
692 | |
689 | This works like the C<decode> method, but instead of raising an exception |
693 | 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 |
694 | when there is trailing garbage after the first JSON object, it will |
691 | silently stop parsing there and return the number of characters consumed |
695 | silently stop parsing there and return the number of characters consumed |
692 | so far. |
696 | so far. |
693 | |
697 | |
694 | 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 |
695 | (which is not the brightest thing to do in the first place) and you need |
|
|
696 | to know where the JSON text ends. |
699 | and you need to know where the JSON text ends. |
697 | |
700 | |
698 | JSON::XS->new->decode_prefix ("[1] the tail") |
701 | JSON::XS->new->decode_prefix ("[1] the tail") |
699 | => ([], 3) |
702 | => ([1], 3) |
700 | |
703 | |
701 | =back |
704 | =back |
702 | |
705 | |
703 | |
706 | |
704 | =head1 INCREMENTAL PARSING |
707 | =head1 INCREMENTAL PARSING |
… | |
… | |
713 | calls). |
716 | calls). |
714 | |
717 | |
715 | JSON::XS will only attempt to parse the JSON text once it is sure it |
718 | 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 |
719 | 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 |
720 | 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 |
721 | 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 |
722 | 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 |
723 | 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 |
724 | to set resource limits (e.g. C<max_size>) to ensure the parser will stop |
722 | parsing in the presence if syntax errors. |
725 | parsing in the presence if syntax errors. |
723 | |
726 | |
724 | The following methods implement this incremental parser. |
727 | The following methods implement this incremental parser. |
… | |
… | |
740 | |
743 | |
741 | If the method is called in scalar context, then it will try to extract |
744 | 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 |
745 | 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, |
746 | 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 |
747 | 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 |
748 | C<incr_skip> to skip the erroneous part). This is the most common way of |
746 | using the method. |
749 | using the method. |
747 | |
750 | |
748 | And finally, in list context, it will try to extract as many objects |
751 | 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 |
752 | 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 |
753 | otherwise. For this to work, there must be no separators (other than |
751 | objects or arrays, instead they must be concatenated back-to-back. If |
754 | whitespace) between the JSON objects or arrays, instead they must be |
752 | an error occurs, an exception will be raised as in the scalar context |
755 | concatenated back-to-back. If an error occurs, an exception will be |
753 | case. Note that in this case, any previously-parsed JSON texts will be |
756 | raised as in the scalar context case. Note that in this case, any |
754 | lost. |
757 | previously-parsed JSON texts will be lost. |
|
|
758 | |
|
|
759 | Example: Parse some JSON arrays/objects in a given string and return |
|
|
760 | them. |
|
|
761 | |
|
|
762 | my @objs = JSON::XS->new->incr_parse ("[5][7][1,2]"); |
755 | |
763 | |
756 | =item $lvalue_string = $json->incr_text |
764 | =item $lvalue_string = $json->incr_text |
757 | |
765 | |
758 | This method returns the currently stored JSON fragment as an lvalue, that |
766 | 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 |
767 | is, you can manipulate it. This I<only> works when a preceding call to |
… | |
… | |
761 | all other circumstances you must not call this function (I mean it. |
769 | all other circumstances you must not call this function (I mean it. |
762 | although in simple tests it might actually work, it I<will> fail under |
770 | although in simple tests it might actually work, it I<will> fail under |
763 | real world conditions). As a special exception, you can also call this |
771 | real world conditions). As a special exception, you can also call this |
764 | method before having parsed anything. |
772 | method before having parsed anything. |
765 | |
773 | |
|
|
774 | That means you can only use this function to look at or manipulate text |
|
|
775 | before or after complete JSON objects, not while the parser is in the |
|
|
776 | middle of parsing a JSON object. |
|
|
777 | |
766 | This function is useful in two cases: a) finding the trailing text after a |
778 | This function is useful in two cases: a) finding the trailing text after a |
767 | JSON object or b) parsing multiple JSON objects separated by non-JSON text |
779 | JSON object or b) parsing multiple JSON objects separated by non-JSON text |
768 | (such as commas). |
780 | (such as commas). |
769 | |
781 | |
770 | =item $json->incr_skip |
782 | =item $json->incr_skip |
… | |
… | |
774 | C<incr_parse> died, in which case the input buffer and incremental parser |
786 | 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 |
787 | state is left unchanged, to skip the text parsed so far and to reset the |
776 | parse state. |
788 | parse state. |
777 | |
789 | |
778 | The difference to C<incr_reset> is that only text until the parse error |
790 | The difference to C<incr_reset> is that only text until the parse error |
779 | occured is removed. |
791 | occurred is removed. |
780 | |
792 | |
781 | =item $json->incr_reset |
793 | =item $json->incr_reset |
782 | |
794 | |
783 | This completely resets the incremental parser, that is, after this call, |
795 | This completely resets the incremental parser, that is, after this call, |
784 | it will be as if the parser had never parsed anything. |
796 | it will be as if the parser had never parsed anything. |
… | |
… | |
790 | =back |
802 | =back |
791 | |
803 | |
792 | =head2 LIMITATIONS |
804 | =head2 LIMITATIONS |
793 | |
805 | |
794 | All options that affect decoding are supported, except |
806 | All options that affect decoding are supported, except |
795 | C<allow_nonref>. The reason for this is that it cannot be made to |
807 | 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 |
808 | 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 |
809 | concatenate them back to back and still decode them perfectly. This does |
798 | for JSON numbers, however. |
810 | not hold true for JSON numbers, however. |
799 | |
811 | |
800 | For example, is the string C<1> a single JSON number, or is it simply the |
812 | 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 |
813 | 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 |
814 | 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. |
815 | takes the conservative route and disallows this case. |
… | |
… | |
982 | If the number consists of digits only, JSON::XS will try to represent |
994 | 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 |
995 | 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 |
996 | 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 |
997 | 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 |
998 | which case you lose roundtripping ability, as the JSON number will be |
987 | re-encoded toa JSON string). |
999 | re-encoded to a JSON string). |
988 | |
1000 | |
989 | Numbers containing a fractional or exponential part will always be |
1001 | Numbers containing a fractional or exponential part will always be |
990 | represented as numeric (floating point) values, possibly at a loss of |
1002 | represented as numeric (floating point) values, possibly at a loss of |
991 | precision (in which case you might lose perfect roundtripping ability, but |
1003 | precision (in which case you might lose perfect roundtripping ability, but |
992 | the JSON number will still be re-encoded as a JSON number). |
1004 | the JSON number will still be re-encoded as a JSON number). |
993 | |
1005 | |
|
|
1006 | Note that precision is not accuracy - binary floating point values cannot |
|
|
1007 | represent most decimal fractions exactly, and when converting from and to |
|
|
1008 | floating point, JSON::XS only guarantees precision up to but not including |
|
|
1009 | the least significant bit. |
|
|
1010 | |
994 | =item true, false |
1011 | =item true, false |
995 | |
1012 | |
996 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
1013 | These JSON atoms become C<Types::Serialiser::true> and |
997 | respectively. They are overloaded to act almost exactly like the numbers |
1014 | 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 |
1015 | almost exactly like the numbers C<1> and C<0>. You can check whether |
999 | the C<JSON::XS::is_bool> function. |
1016 | a scalar is a JSON boolean by using the C<Types::Serialiser::is_bool> |
|
|
1017 | function (after C<use Types::Serialier>, of course). |
1000 | |
1018 | |
1001 | =item null |
1019 | =item null |
1002 | |
1020 | |
1003 | A JSON null atom becomes C<undef> in Perl. |
1021 | A JSON null atom becomes C<undef> in Perl. |
|
|
1022 | |
|
|
1023 | =item shell-style comments (C<< # I<text> >>) |
|
|
1024 | |
|
|
1025 | As a nonstandard extension to the JSON syntax that is enabled by the |
|
|
1026 | C<relaxed> setting, shell-style comments are allowed. They can start |
|
|
1027 | anywhere outside strings and go till the end of the line. |
|
|
1028 | |
|
|
1029 | =item tagged values (C<< (I<tag>)I<value> >>). |
|
|
1030 | |
|
|
1031 | Another nonstandard extension to the JSON syntax, enabled with the |
|
|
1032 | C<allow_tags> setting, are tagged values. In this implementation, the |
|
|
1033 | I<tag> must be a perl package/class name encoded as a JSON string, and the |
|
|
1034 | I<value> must be a JSON array encoding optional constructor arguments. |
|
|
1035 | |
|
|
1036 | See L<OBJECT SERIALISATION>, below, for details. |
1004 | |
1037 | |
1005 | =back |
1038 | =back |
1006 | |
1039 | |
1007 | |
1040 | |
1008 | =head2 PERL -> JSON |
1041 | =head2 PERL -> JSON |
… | |
… | |
1013 | |
1046 | |
1014 | =over 4 |
1047 | =over 4 |
1015 | |
1048 | |
1016 | =item hash references |
1049 | =item hash references |
1017 | |
1050 | |
1018 | Perl hash references become JSON objects. As there is no inherent ordering |
1051 | 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 |
1052 | 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 |
1053 | 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 |
1054 | (determined by the I<canonical> flag), so the same datastructure will |
1022 | optionally sort the hash keys (determined by the I<canonical> flag), so |
1055 | 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 |
1056 | 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 |
1057 | 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 | |
1058 | |
1028 | =item array references |
1059 | =item array references |
1029 | |
1060 | |
1030 | Perl array references become JSON arrays. |
1061 | Perl array references become JSON arrays. |
1031 | |
1062 | |
1032 | =item other references |
1063 | =item other references |
1033 | |
1064 | |
1034 | Other unblessed references are generally not allowed and will cause an |
1065 | 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 |
1066 | 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 |
1067 | 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 | |
1068 | |
|
|
1069 | Since C<JSON::XS> uses the boolean model from L<Types::Serialiser>, you |
|
|
1070 | can also C<use Types::Serialiser> and then use C<Types::Serialiser::false> |
|
|
1071 | and C<Types::Serialiser::true> to improve readability. |
|
|
1072 | |
|
|
1073 | use Types::Serialiser; |
1039 | encode_json [\0, JSON::XS::true] # yields [false,true] |
1074 | encode_json [\0, Types::Serialiser::true] # yields [false,true] |
1040 | |
1075 | |
1041 | =item JSON::XS::true, JSON::XS::false |
1076 | =item Types::Serialiser::true, Types::Serialiser::false |
1042 | |
1077 | |
1043 | These special values become JSON true and JSON false values, |
1078 | 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. |
1079 | and JSON false values, respectively. You can also use C<\1> and C<\0> |
|
|
1080 | directly if you want. |
1045 | |
1081 | |
1046 | =item blessed objects |
1082 | =item blessed objects |
1047 | |
1083 | |
1048 | Blessed objects are not directly representable in JSON. See the |
1084 | Blessed objects are not directly representable in JSON, but C<JSON::XS> |
1049 | C<allow_blessed> and C<convert_blessed> methods on various options on |
1085 | allows various ways of handling objects. See L<OBJECT SERIALISATION>, |
1050 | how to deal with this: basically, you can choose between throwing an |
1086 | below, for details. |
1051 | exception, encoding the reference as if it weren't blessed, or provide |
|
|
1052 | your own serialiser method. |
|
|
1053 | |
1087 | |
1054 | =item simple scalars |
1088 | =item simple scalars |
1055 | |
1089 | |
1056 | Simple Perl scalars (any scalar that is not a reference) are the most |
1090 | Simple Perl scalars (any scalar that is not a reference) are the most |
1057 | difficult objects to encode: JSON::XS will encode undefined scalars as |
1091 | difficult objects to encode: JSON::XS will encode undefined scalars as |
… | |
… | |
1085 | |
1119 | |
1086 | You can not currently force the type in other, less obscure, ways. Tell me |
1120 | 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 |
1121 | if you need this capability (but don't forget to explain why it's needed |
1088 | :). |
1122 | :). |
1089 | |
1123 | |
|
|
1124 | Note that numerical precision has the same meaning as under Perl (so |
|
|
1125 | binary to decimal conversion follows the same rules as in Perl, which |
|
|
1126 | can differ to other languages). Also, your perl interpreter might expose |
|
|
1127 | extensions to the floating point numbers of your platform, such as |
|
|
1128 | infinities or NaN's - these cannot be represented in JSON, and it is an |
|
|
1129 | error to pass those in. |
|
|
1130 | |
1090 | =back |
1131 | =back |
|
|
1132 | |
|
|
1133 | =head2 OBJECT SERIALISATION |
|
|
1134 | |
|
|
1135 | As JSON cannot directly represent Perl objects, you have to choose between |
|
|
1136 | a pure JSON representation (without the ability to deserialise the object |
|
|
1137 | automatically again), and a nonstandard extension to the JSON syntax, |
|
|
1138 | tagged values. |
|
|
1139 | |
|
|
1140 | =head3 SERIALISATION |
|
|
1141 | |
|
|
1142 | What happens when C<JSON::XS> encounters a Perl object depends on the |
|
|
1143 | C<allow_blessed>, C<convert_blessed> and C<allow_tags> settings, which are |
|
|
1144 | used in this order: |
|
|
1145 | |
|
|
1146 | =over 4 |
|
|
1147 | |
|
|
1148 | =item 1. C<allow_tags> is enabled and the object has a C<FREEZE> method. |
|
|
1149 | |
|
|
1150 | In this case, C<JSON::XS> uses the L<Types::Serialiser> object |
|
|
1151 | serialisation protocol to create a tagged JSON value, using a nonstandard |
|
|
1152 | extension to the JSON syntax. |
|
|
1153 | |
|
|
1154 | This works by invoking the C<FREEZE> method on the object, with the first |
|
|
1155 | argument being the object to serialise, and the second argument being the |
|
|
1156 | constant string C<JSON> to distinguish it from other serialisers. |
|
|
1157 | |
|
|
1158 | The C<FREEZE> method can return any number of values (i.e. zero or |
|
|
1159 | more). These values and the paclkage/classname of the object will then be |
|
|
1160 | encoded as a tagged JSON value in the following format: |
|
|
1161 | |
|
|
1162 | ("classname")[FREEZE return values...] |
|
|
1163 | |
|
|
1164 | e.g.: |
|
|
1165 | |
|
|
1166 | ("URI")["http://www.google.com/"] |
|
|
1167 | ("MyDate")[2013,10,29] |
|
|
1168 | ("ImageData::JPEG")["Z3...VlCg=="] |
|
|
1169 | |
|
|
1170 | For example, the hypothetical C<My::Object> C<FREEZE> method might use the |
|
|
1171 | objects C<type> and C<id> members to encode the object: |
|
|
1172 | |
|
|
1173 | sub My::Object::FREEZE { |
|
|
1174 | my ($self, $serialiser) = @_; |
|
|
1175 | |
|
|
1176 | ($self->{type}, $self->{id}) |
|
|
1177 | } |
|
|
1178 | |
|
|
1179 | =item 2. C<convert_blessed> is enabled and the object has a C<TO_JSON> method. |
|
|
1180 | |
|
|
1181 | In this case, the C<TO_JSON> method of the object is invoked in scalar |
|
|
1182 | context. It must return a single scalar that can be directly encoded into |
|
|
1183 | JSON. This scalar replaces the object in the JSON text. |
|
|
1184 | |
|
|
1185 | For example, the following C<TO_JSON> method will convert all L<URI> |
|
|
1186 | objects to JSON strings when serialised. The fatc that these values |
|
|
1187 | originally were L<URI> objects is lost. |
|
|
1188 | |
|
|
1189 | sub URI::TO_JSON { |
|
|
1190 | my ($uri) = @_; |
|
|
1191 | $uri->as_string |
|
|
1192 | } |
|
|
1193 | |
|
|
1194 | =item 3. C<allow_blessed> is enabled. |
|
|
1195 | |
|
|
1196 | The object will be serialised as a JSON null value. |
|
|
1197 | |
|
|
1198 | =item 4. none of the above |
|
|
1199 | |
|
|
1200 | If none of the settings are enabled or the respective methods are missing, |
|
|
1201 | C<JSON::XS> throws an exception. |
|
|
1202 | |
|
|
1203 | =back |
|
|
1204 | |
|
|
1205 | =head3 DESERIALISATION |
|
|
1206 | |
|
|
1207 | For deserialisation there are only two cases to consider: either |
|
|
1208 | nonstandard tagging was used, in which case C<allow_tags> decides, |
|
|
1209 | or objects cannot be automatically be deserialised, in which |
|
|
1210 | case you can use postprocessing or the C<filter_json_object> or |
|
|
1211 | C<filter_json_single_key_object> callbacks to get some real objects our of |
|
|
1212 | your JSON. |
|
|
1213 | |
|
|
1214 | This section only considers the tagged value case: I a tagged JSON object |
|
|
1215 | is encountered during decoding and C<allow_tags> is disabled, a parse |
|
|
1216 | error will result (as if tagged values were not part of the grammar). |
|
|
1217 | |
|
|
1218 | If C<allow_tags> is enabled, C<JSON::XS> will look up the C<THAW> method |
|
|
1219 | of the package/classname used during serialisation (it will not attempt |
|
|
1220 | to load the package as a Perl module). If there is no such method, the |
|
|
1221 | decoding will fail with an error. |
|
|
1222 | |
|
|
1223 | Otherwise, the C<THAW> method is invoked with the classname as first |
|
|
1224 | argument, the constant string C<JSON> as second argument, and all the |
|
|
1225 | values from the JSON array (the values originally returned by the |
|
|
1226 | C<FREEZE> method) as remaining arguments. |
|
|
1227 | |
|
|
1228 | The method must then return the object. While technically you can return |
|
|
1229 | any Perl scalar, you might have to enable the C<enable_nonref> setting to |
|
|
1230 | make that work in all cases, so better return an actual blessed reference. |
|
|
1231 | |
|
|
1232 | As an example, let's implement a C<THAW> function that regenerates the |
|
|
1233 | C<My::Object> from the C<FREEZE> example earlier: |
|
|
1234 | |
|
|
1235 | sub My::Object::THAW { |
|
|
1236 | my ($class, $serialiser, $type, $id) = @_; |
|
|
1237 | |
|
|
1238 | $class->new (type => $type, id => $id) |
|
|
1239 | } |
1091 | |
1240 | |
1092 | |
1241 | |
1093 | =head1 ENCODING/CODESET FLAG NOTES |
1242 | =head1 ENCODING/CODESET FLAG NOTES |
1094 | |
1243 | |
1095 | The interested reader might have seen a number of flags that signify |
1244 | The interested reader might have seen a number of flags that signify |
… | |
… | |
1120 | =item C<utf8> flag disabled |
1269 | =item C<utf8> flag disabled |
1121 | |
1270 | |
1122 | When C<utf8> is disabled (the default), then C<encode>/C<decode> generate |
1271 | 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 |
1272 | and expect Unicode strings, that is, characters with high ordinal Unicode |
1124 | values (> 255) will be encoded as such characters, and likewise such |
1273 | 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 |
1274 | characters are decoded as-is, no changes to them will be done, except |
1126 | "(re-)interpreting" them as Unicode codepoints or Unicode characters, |
1275 | "(re-)interpreting" them as Unicode codepoints or Unicode characters, |
1127 | respectively (to Perl, these are the same thing in strings unless you do |
1276 | respectively (to Perl, these are the same thing in strings unless you do |
1128 | funny/weird/dumb stuff). |
1277 | funny/weird/dumb stuff). |
1129 | |
1278 | |
1130 | This is useful when you want to do the encoding yourself (e.g. when you |
1279 | This is useful when you want to do the encoding yourself (e.g. when you |
… | |
… | |
1140 | expect your input strings to be encoded as UTF-8, that is, no "character" |
1289 | expect your input strings to be encoded as UTF-8, that is, no "character" |
1141 | of the input string must have any value > 255, as UTF-8 does not allow |
1290 | of the input string must have any value > 255, as UTF-8 does not allow |
1142 | that. |
1291 | that. |
1143 | |
1292 | |
1144 | The C<utf8> flag therefore switches between two modes: disabled means you |
1293 | The C<utf8> flag therefore switches between two modes: disabled means you |
1145 | will get a Unicode string in Perl, enabled means you get an UTF-8 encoded |
1294 | will get a Unicode string in Perl, enabled means you get a UTF-8 encoded |
1146 | octet/binary string in Perl. |
1295 | octet/binary string in Perl. |
1147 | |
1296 | |
1148 | =item C<latin1> or C<ascii> flags enabled |
1297 | =item C<latin1> or C<ascii> flags enabled |
1149 | |
1298 | |
1150 | With C<latin1> (or C<ascii>) enabled, C<encode> will escape characters |
1299 | With C<latin1> (or C<ascii>) enabled, C<encode> will escape characters |
… | |
… | |
1238 | well - using C<eval> naively simply I<will> cause problems. |
1387 | well - using C<eval> naively simply I<will> cause problems. |
1239 | |
1388 | |
1240 | Another problem is that some javascript implementations reserve |
1389 | Another problem is that some javascript implementations reserve |
1241 | some property names for their own purposes (which probably makes |
1390 | some property names for their own purposes (which probably makes |
1242 | them non-ECMAscript-compliant). For example, Iceweasel reserves the |
1391 | them non-ECMAscript-compliant). For example, Iceweasel reserves the |
1243 | C<__proto__> property name for it's own purposes. |
1392 | C<__proto__> property name for its own purposes. |
1244 | |
1393 | |
1245 | If that is a problem, you could parse try to filter the resulting JSON |
1394 | If that is a problem, you could parse try to filter the resulting JSON |
1246 | output for these property strings, e.g.: |
1395 | output for these property strings, e.g.: |
1247 | |
1396 | |
1248 | $json =~ s/"__proto__"\s*:/"__proto__renamed":/g; |
1397 | $json =~ s/"__proto__"\s*:/"__proto__renamed":/g; |
1249 | |
1398 | |
1250 | This works because C<__proto__> is not valid outside of strings, so every |
1399 | 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. |
1400 | occurrence of C<"__proto__"\s*:> must be a string used as property name. |
1252 | |
1401 | |
1253 | If you know of other incompatibilities, please let me know. |
1402 | If you know of other incompatibilities, please let me know. |
1254 | |
1403 | |
1255 | |
1404 | |
1256 | =head2 JSON and YAML |
1405 | =head2 JSON and YAML |
… | |
… | |
1302 | that difficult or long) and finally make YAML compatible to it, and |
1451 | that difficult or long) and finally make YAML compatible to it, and |
1303 | educating users about the changes, instead of spreading lies about the |
1452 | educating users about the changes, instead of spreading lies about the |
1304 | real compatibility for many I<years> and trying to silence people who |
1453 | real compatibility for many I<years> and trying to silence people who |
1305 | point out that it isn't true. |
1454 | point out that it isn't true. |
1306 | |
1455 | |
1307 | Addendum/2009: the YAML 1.2 spec is still incomaptible with JSON, even |
1456 | Addendum/2009: the YAML 1.2 spec is still incompatible with JSON, even |
1308 | though the incompatibilities have been documented (and are known to |
1457 | though the incompatibilities have been documented (and are known to Brian) |
1309 | Brian) for many years and the spec makes explicit claims that YAML is a |
1458 | for many years and the spec makes explicit claims that YAML is a superset |
1310 | superset of JSON. It would be so easy to fix, but apparently, bullying and |
1459 | of JSON. It would be so easy to fix, but apparently, bullying people and |
1311 | corrupting userdata is so much easier. |
1460 | corrupting userdata is so much easier. |
1312 | |
1461 | |
1313 | =back |
1462 | =back |
1314 | |
1463 | |
1315 | |
1464 | |
… | |
… | |
1324 | a very short single-line JSON string (also available at |
1473 | a very short single-line JSON string (also available at |
1325 | L<http://dist.schmorp.de/misc/json/short.json>). |
1474 | L<http://dist.schmorp.de/misc/json/short.json>). |
1326 | |
1475 | |
1327 | {"method": "handleMessage", "params": ["user1", |
1476 | {"method": "handleMessage", "params": ["user1", |
1328 | "we were just talking"], "id": null, "array":[1,11,234,-5,1e5,1e7, |
1477 | "we were just talking"], "id": null, "array":[1,11,234,-5,1e5,1e7, |
1329 | true, false]} |
1478 | 1, 0]} |
1330 | |
1479 | |
1331 | It shows the number of encodes/decodes per second (JSON::XS uses |
1480 | It shows the number of encodes/decodes per second (JSON::XS uses |
1332 | the functional interface, while JSON::XS/2 uses the OO interface |
1481 | the functional interface, while JSON::XS/2 uses the OO interface |
1333 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
1482 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
1334 | shrink). Higher is better: |
1483 | shrink. JSON::DWIW/DS uses the deserialise function, while JSON::DWIW::FJ |
|
|
1484 | uses the from_json method). Higher is better: |
1335 | |
1485 | |
1336 | module | encode | decode | |
1486 | module | encode | decode | |
1337 | -----------|------------|------------| |
1487 | --------------|------------|------------| |
1338 | JSON 1.x | 4990.842 | 4088.813 | |
1488 | JSON::DWIW/DS | 86302.551 | 102300.098 | |
1339 | JSON::DWIW | 51653.990 | 71575.154 | |
1489 | JSON::DWIW/FJ | 86302.551 | 75983.768 | |
1340 | JSON::PC | 65948.176 | 74631.744 | |
1490 | JSON::PP | 15827.562 | 6638.658 | |
1341 | JSON::PP | 8931.652 | 3817.168 | |
1491 | JSON::Syck | 63358.066 | 47662.545 | |
1342 | JSON::Syck | 24877.248 | 27776.848 | |
1492 | JSON::XS | 511500.488 | 511500.488 | |
1343 | JSON::XS | 388361.481 | 227951.304 | |
1493 | JSON::XS/2 | 291271.111 | 388361.481 | |
1344 | JSON::XS/2 | 227951.304 | 218453.333 | |
1494 | JSON::XS/3 | 361577.931 | 361577.931 | |
1345 | JSON::XS/3 | 338250.323 | 218453.333 | |
1495 | Storable | 66788.280 | 265462.278 | |
1346 | Storable | 16500.016 | 135300.129 | |
|
|
1347 | -----------+------------+------------+ |
1496 | --------------+------------+------------+ |
1348 | |
1497 | |
1349 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
1498 | That is, JSON::XS is almost six times faster than JSON::DWIW on encoding, |
1350 | about three times faster on decoding, and over forty times faster |
1499 | about five times faster on decoding, and over thirty to seventy times |
1351 | than JSON, even with pretty-printing and key sorting. It also compares |
1500 | faster than JSON's pure perl implementation. It also compares favourably |
1352 | favourably to Storable for small amounts of data. |
1501 | to Storable for small amounts of data. |
1353 | |
1502 | |
1354 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
1503 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
1355 | search API (L<http://dist.schmorp.de/misc/json/long.json>). |
1504 | search API (L<http://dist.schmorp.de/misc/json/long.json>). |
1356 | |
1505 | |
1357 | module | encode | decode | |
1506 | module | encode | decode | |
1358 | -----------|------------|------------| |
1507 | --------------|------------|------------| |
1359 | JSON 1.x | 55.260 | 34.971 | |
1508 | JSON::DWIW/DS | 1647.927 | 2673.916 | |
1360 | JSON::DWIW | 825.228 | 1082.513 | |
1509 | JSON::DWIW/FJ | 1630.249 | 2596.128 | |
1361 | JSON::PC | 3571.444 | 2394.829 | |
|
|
1362 | JSON::PP | 210.987 | 32.574 | |
1510 | JSON::PP | 400.640 | 62.311 | |
1363 | JSON::Syck | 552.551 | 787.544 | |
1511 | JSON::Syck | 1481.040 | 1524.869 | |
1364 | JSON::XS | 5780.463 | 4854.519 | |
1512 | JSON::XS | 20661.596 | 9541.183 | |
1365 | JSON::XS/2 | 3869.998 | 4798.975 | |
1513 | JSON::XS/2 | 10683.403 | 9416.938 | |
1366 | JSON::XS/3 | 5862.880 | 4798.975 | |
1514 | JSON::XS/3 | 20661.596 | 9400.054 | |
1367 | Storable | 4445.002 | 5235.027 | |
1515 | Storable | 19765.806 | 10000.725 | |
1368 | -----------+------------+------------+ |
1516 | --------------+------------+------------+ |
1369 | |
1517 | |
1370 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
1518 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
1371 | decodes faster). |
1519 | decodes a bit faster). |
1372 | |
1520 | |
1373 | On large strings containing lots of high Unicode characters, some modules |
1521 | On large strings containing lots of high Unicode characters, some modules |
1374 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
1522 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
1375 | will be broken due to missing (or wrong) Unicode handling. Others refuse |
1523 | will be broken due to missing (or wrong) Unicode handling. Others refuse |
1376 | to decode or encode properly, so it was impossible to prepare a fair |
1524 | to decode or encode properly, so it was impossible to prepare a fair |
… | |
… | |
1412 | information you might want to make sure that exceptions thrown by JSON::XS |
1560 | information you might want to make sure that exceptions thrown by JSON::XS |
1413 | will not end up in front of untrusted eyes. |
1561 | will not end up in front of untrusted eyes. |
1414 | |
1562 | |
1415 | If you are using JSON::XS to return packets to consumption |
1563 | If you are using JSON::XS to return packets to consumption |
1416 | by JavaScript scripts in a browser you should have a look at |
1564 | by JavaScript scripts in a browser you should have a look at |
1417 | L<http://jpsykes.com/47/practical-csrf-and-json-security> to see whether |
1565 | L<http://blog.archive.jpsykes.com/47/practical-csrf-and-json-security/> to |
1418 | you are vulnerable to some common attack vectors (which really are browser |
1566 | see whether you are vulnerable to some common attack vectors (which really |
1419 | design bugs, but it is still you who will have to deal with it, as major |
1567 | are browser design bugs, but it is still you who will have to deal with |
1420 | browser developers care only for features, not about getting security |
1568 | it, as major browser developers care only for features, not about getting |
1421 | right). |
1569 | security right). |
1422 | |
1570 | |
1423 | |
1571 | |
|
|
1572 | =head1 "OLD" VS. "NEW" JSON (RFC 4627 VS. RFC 7159) |
|
|
1573 | |
|
|
1574 | TL;DR: Due to security concerns, JSON::XS will not allow scalar data in |
|
|
1575 | JSON texts by default - you need to create your own JSON::XS object and |
|
|
1576 | enable C<allow_nonref>: |
|
|
1577 | |
|
|
1578 | |
|
|
1579 | my $json = JSON::XS->new->allow_nonref; |
|
|
1580 | |
|
|
1581 | $text = $json->encode ($data); |
|
|
1582 | $data = $json->decode ($text); |
|
|
1583 | |
|
|
1584 | The long version: JSON being an important and supposedly stable format, |
|
|
1585 | the IETF standardised it as RFC 4627 in 2006. Unfortunately, the inventor |
|
|
1586 | of JSON, Dougles Crockford, unilaterally changed the definition of JSON in |
|
|
1587 | javascript. Rather than create a fork, the IETF decided to standardise the |
|
|
1588 | new syntax (apparently, so Iw as told, without finding it very amusing). |
|
|
1589 | |
|
|
1590 | The biggest difference between thed original JSON and the new JSON is that |
|
|
1591 | the new JSON supports scalars (anything other than arrays and objects) at |
|
|
1592 | the toplevel of a JSON text. While this is strictly backwards compatible |
|
|
1593 | to older versions, it breaks a number of protocols that relied on sending |
|
|
1594 | JSON back-to-back, and is a minor security concern. |
|
|
1595 | |
|
|
1596 | For example, imagine you have two banks communicating, and on one side, |
|
|
1597 | trhe JSON coder gets upgraded. Two messages, such as C<10> and C<1000> |
|
|
1598 | might then be confused to mean C<101000>, something that couldn't happen |
|
|
1599 | in the original JSON, because niether of these messages would be valid |
|
|
1600 | JSON. |
|
|
1601 | |
|
|
1602 | If one side accepts these messages, then an upgrade in the coder on either |
|
|
1603 | side could result in this becoming exploitable. |
|
|
1604 | |
|
|
1605 | This module has always allowed these messages as an optional extension, by |
|
|
1606 | default disabled. The security concerns are the reason why the default is |
|
|
1607 | still disabled, but future versions might/will likely upgrade to the newer |
|
|
1608 | RFC as default format, so you are advised to check your implementation |
|
|
1609 | and/or override the default with C<< ->allow_nonref (0) >> to ensure that |
|
|
1610 | future versions are safe. |
|
|
1611 | |
|
|
1612 | |
|
|
1613 | =head1 INTEROPERABILITY WITH OTHER MODULES |
|
|
1614 | |
|
|
1615 | C<JSON::XS> uses the L<Types::Serialiser> module to provide boolean |
|
|
1616 | constants. That means that the JSON true and false values will be |
|
|
1617 | comaptible to true and false values of other modules that do the same, |
|
|
1618 | such as L<JSON::PP> and L<CBOR::XS>. |
|
|
1619 | |
|
|
1620 | |
|
|
1621 | =head1 INTEROPERABILITY WITH OTHER JSON DECODERS |
|
|
1622 | |
|
|
1623 | As long as you only serialise data that can be directly expressed in JSON, |
|
|
1624 | C<JSON::XS> is incapable of generating invalid JSON output (modulo bugs, |
|
|
1625 | but C<JSON::XS> has found more bugs in the official JSON testsuite (1) |
|
|
1626 | than the official JSON testsuite has found in C<JSON::XS> (0)). |
|
|
1627 | |
|
|
1628 | When you have trouble decoding JSON generated by this module using other |
|
|
1629 | decoders, then it is very likely that you have an encoding mismatch or the |
|
|
1630 | other decoder is broken. |
|
|
1631 | |
|
|
1632 | When decoding, C<JSON::XS> is strict by default and will likely catch all |
|
|
1633 | errors. There are currently two settings that change this: C<relaxed> |
|
|
1634 | makes C<JSON::XS> accept (but not generate) some non-standard extensions, |
|
|
1635 | and C<allow_tags> will allow you to encode and decode Perl objects, at the |
|
|
1636 | cost of not outputting valid JSON anymore. |
|
|
1637 | |
|
|
1638 | =head2 TAGGED VALUE SYNTAX AND STANDARD JSON EN/DECODERS |
|
|
1639 | |
|
|
1640 | When you use C<allow_tags> to use the extended (and also nonstandard and |
|
|
1641 | invalid) JSON syntax for serialised objects, and you still want to decode |
|
|
1642 | the generated When you want to serialise objects, you can run a regex |
|
|
1643 | to replace the tagged syntax by standard JSON arrays (it only works for |
|
|
1644 | "normal" package names without comma, newlines or single colons). First, |
|
|
1645 | the readable Perl version: |
|
|
1646 | |
|
|
1647 | # if your FREEZE methods return no values, you need this replace first: |
|
|
1648 | $json =~ s/\( \s* (" (?: [^\\":,]+|\\.|::)* ") \s* \) \s* \[\s*\]/[$1]/gx; |
|
|
1649 | |
|
|
1650 | # this works for non-empty constructor arg lists: |
|
|
1651 | $json =~ s/\( \s* (" (?: [^\\":,]+|\\.|::)* ") \s* \) \s* \[/[$1,/gx; |
|
|
1652 | |
|
|
1653 | And here is a less readable version that is easy to adapt to other |
|
|
1654 | languages: |
|
|
1655 | |
|
|
1656 | $json =~ s/\(\s*("([^\\":,]+|\\.|::)*")\s*\)\s*\[/[$1,/g; |
|
|
1657 | |
|
|
1658 | Here is an ECMAScript version (same regex): |
|
|
1659 | |
|
|
1660 | json = json.replace (/\(\s*("([^\\":,]+|\\.|::)*")\s*\)\s*\[/g, "[$1,"); |
|
|
1661 | |
|
|
1662 | Since this syntax converts to standard JSON arrays, it might be hard to |
|
|
1663 | distinguish serialised objects from normal arrays. You can prepend a |
|
|
1664 | "magic number" as first array element to reduce chances of a collision: |
|
|
1665 | |
|
|
1666 | $json =~ s/\(\s*("([^\\":,]+|\\.|::)*")\s*\)\s*\[/["XU1peReLzT4ggEllLanBYq4G9VzliwKF",$1,/g; |
|
|
1667 | |
|
|
1668 | And after decoding the JSON text, you could walk the data |
|
|
1669 | structure looking for arrays with a first element of |
|
|
1670 | C<XU1peReLzT4ggEllLanBYq4G9VzliwKF>. |
|
|
1671 | |
|
|
1672 | The same approach can be used to create the tagged format with another |
|
|
1673 | encoder. First, you create an array with the magic string as first member, |
|
|
1674 | the classname as second, and constructor arguments last, encode it as part |
|
|
1675 | of your JSON structure, and then: |
|
|
1676 | |
|
|
1677 | $json =~ s/\[\s*"XU1peReLzT4ggEllLanBYq4G9VzliwKF"\s*,\s*("([^\\":,]+|\\.|::)*")\s*,/($1)[/g; |
|
|
1678 | |
|
|
1679 | Again, this has some limitations - the magic string must not be encoded |
|
|
1680 | with character escapes, and the constructor arguments must be non-empty. |
|
|
1681 | |
|
|
1682 | |
|
|
1683 | =head1 RFC7159 |
|
|
1684 | |
|
|
1685 | Since this module was written, Google has written a new JSON RFC, RFC 7159 |
|
|
1686 | (and RFC7158). Unfortunately, this RFC breaks compatibility with both the |
|
|
1687 | original JSON specification on www.json.org and RFC4627. |
|
|
1688 | |
|
|
1689 | As far as I can see, you can get partial compatibility when parsing by |
|
|
1690 | using C<< ->allow_nonref >>. However, consider the security implications |
|
|
1691 | of doing so. |
|
|
1692 | |
|
|
1693 | I haven't decided yet when to break compatibility with RFC4627 by default |
|
|
1694 | (and potentially leave applications insecure) and change the default to |
|
|
1695 | follow RFC7159, but application authors are well advised to call C<< |
|
|
1696 | ->allow_nonref(0) >> even if this is the current default, if they cannot |
|
|
1697 | handle non-reference values, in preparation for the day when the default |
|
|
1698 | will change. |
|
|
1699 | |
|
|
1700 | |
1424 | =head1 THREADS |
1701 | =head1 (I-)THREADS |
1425 | |
1702 | |
1426 | This module is I<not> guaranteed to be thread safe and there are no |
1703 | This module is I<not> guaranteed to be ithread (or MULTIPLICITY-) safe |
1427 | plans to change this until Perl gets thread support (as opposed to the |
1704 | and there are no plans to change this. Note that perl's builtin so-called |
1428 | horribly slow so-called "threads" which are simply slow and bloated |
1705 | threads/ithreads are officially deprecated and should not be used. |
1429 | process simulations - use fork, it's I<much> faster, cheaper, better). |
|
|
1430 | |
1706 | |
1431 | (It might actually work, but you have been warned). |
1707 | |
|
|
1708 | =head1 THE PERILS OF SETLOCALE |
|
|
1709 | |
|
|
1710 | Sometimes people avoid the Perl locale support and directly call the |
|
|
1711 | system's setlocale function with C<LC_ALL>. |
|
|
1712 | |
|
|
1713 | This breaks both perl and modules such as JSON::XS, as stringification of |
|
|
1714 | numbers no longer works correctly (e.g. C<$x = 0.1; print "$x"+1> might |
|
|
1715 | print C<1>, and JSON::XS might output illegal JSON as JSON::XS relies on |
|
|
1716 | perl to stringify numbers). |
|
|
1717 | |
|
|
1718 | The solution is simple: don't call C<setlocale>, or use it for only those |
|
|
1719 | categories you need, such as C<LC_MESSAGES> or C<LC_CTYPE>. |
|
|
1720 | |
|
|
1721 | If you need C<LC_NUMERIC>, you should enable it only around the code that |
|
|
1722 | actually needs it (avoiding stringification of numbers), and restore it |
|
|
1723 | afterwards. |
1432 | |
1724 | |
1433 | |
1725 | |
1434 | =head1 BUGS |
1726 | =head1 BUGS |
1435 | |
1727 | |
1436 | While the goal of this module is to be correct, that unfortunately does |
1728 | While the goal of this module is to be correct, that unfortunately does |
… | |
… | |
1440 | Please refrain from using rt.cpan.org or any other bug reporting |
1732 | Please refrain from using rt.cpan.org or any other bug reporting |
1441 | service. I put the contact address into my modules for a reason. |
1733 | service. I put the contact address into my modules for a reason. |
1442 | |
1734 | |
1443 | =cut |
1735 | =cut |
1444 | |
1736 | |
1445 | our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" }; |
1737 | BEGIN { |
1446 | our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" }; |
1738 | *true = \$Types::Serialiser::true; |
|
|
1739 | *true = \&Types::Serialiser::true; |
|
|
1740 | *false = \$Types::Serialiser::false; |
|
|
1741 | *false = \&Types::Serialiser::false; |
|
|
1742 | *is_bool = \&Types::Serialiser::is_bool; |
1447 | |
1743 | |
1448 | sub true() { $true } |
1744 | *JSON::XS::Boolean:: = *Types::Serialiser::Boolean::; |
1449 | sub false() { $false } |
|
|
1450 | |
|
|
1451 | sub is_bool($) { |
|
|
1452 | UNIVERSAL::isa $_[0], "JSON::XS::Boolean" |
|
|
1453 | # or UNIVERSAL::isa $_[0], "JSON::Literal" |
|
|
1454 | } |
1745 | } |
1455 | |
1746 | |
1456 | XSLoader::load "JSON::XS", $VERSION; |
1747 | XSLoader::load "JSON::XS", $VERSION; |
1457 | |
|
|
1458 | package JSON::XS::Boolean; |
|
|
1459 | |
|
|
1460 | use overload |
|
|
1461 | "0+" => sub { ${$_[0]} }, |
|
|
1462 | "++" => sub { $_[0] = ${$_[0]} + 1 }, |
|
|
1463 | "--" => sub { $_[0] = ${$_[0]} - 1 }, |
|
|
1464 | fallback => 1; |
|
|
1465 | |
|
|
1466 | 1; |
|
|
1467 | |
1748 | |
1468 | =head1 SEE ALSO |
1749 | =head1 SEE ALSO |
1469 | |
1750 | |
1470 | The F<json_xs> command line utility for quick experiments. |
1751 | The F<json_xs> command line utility for quick experiments. |
1471 | |
1752 | |
… | |
… | |
1474 | Marc Lehmann <schmorp@schmorp.de> |
1755 | Marc Lehmann <schmorp@schmorp.de> |
1475 | http://home.schmorp.de/ |
1756 | http://home.schmorp.de/ |
1476 | |
1757 | |
1477 | =cut |
1758 | =cut |
1478 | |
1759 | |
|
|
1760 | 1 |
|
|
1761 | |