… | |
… | |
85 | |
85 | |
86 | package JSON::XS; |
86 | package JSON::XS; |
87 | |
87 | |
88 | use strict; |
88 | use strict; |
89 | |
89 | |
90 | BEGIN { |
|
|
91 | our $VERSION = '1.01'; |
90 | our $VERSION = '1.3'; |
92 | our @ISA = qw(Exporter); |
91 | our @ISA = qw(Exporter); |
93 | |
92 | |
94 | our @EXPORT = qw(to_json from_json objToJson jsonToObj); |
93 | our @EXPORT = qw(to_json from_json objToJson jsonToObj); |
95 | require Exporter; |
|
|
96 | |
94 | |
97 | require XSLoader; |
95 | use Exporter; |
98 | XSLoader::load JSON::XS::, $VERSION; |
96 | use XSLoader; |
99 | } |
|
|
100 | |
97 | |
101 | =head1 FUNCTIONAL INTERFACE |
98 | =head1 FUNCTIONAL INTERFACE |
102 | |
99 | |
103 | The following convinience methods are provided by this module. They are |
100 | The following convinience methods are provided by this module. They are |
104 | exported by default: |
101 | exported by default: |
… | |
… | |
126 | This function call is functionally identical to: |
123 | This function call is functionally identical to: |
127 | |
124 | |
128 | $perl_scalar = JSON::XS->new->utf8->decode ($json_text) |
125 | $perl_scalar = JSON::XS->new->utf8->decode ($json_text) |
129 | |
126 | |
130 | except being faster. |
127 | except being faster. |
|
|
128 | |
|
|
129 | =item $is_boolean = JSON::XS::is_bool $scalar |
|
|
130 | |
|
|
131 | Returns true if the passed scalar represents either JSON::XS::true or |
|
|
132 | JSON::XS::false, two constants that act like C<1> and C<0>, respectively |
|
|
133 | and are used to represent JSON C<true> and C<false> values in Perl. |
|
|
134 | |
|
|
135 | See MAPPING, below, for more information on how JSON values are mapped to |
|
|
136 | Perl. |
131 | |
137 | |
132 | =back |
138 | =back |
133 | |
139 | |
134 | |
140 | |
135 | =head1 OBJECT-ORIENTED INTERFACE |
141 | =head1 OBJECT-ORIENTED INTERFACE |
… | |
… | |
154 | |
160 | |
155 | If C<$enable> is true (or missing), then the C<encode> method will not |
161 | If C<$enable> is true (or missing), then the C<encode> method will not |
156 | generate characters outside the code range C<0..127> (which is ASCII). Any |
162 | generate characters outside the code range C<0..127> (which is ASCII). Any |
157 | unicode characters outside that range will be escaped using either a |
163 | unicode characters outside that range will be escaped using either a |
158 | single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, |
164 | single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, |
159 | as per RFC4627. |
165 | as per RFC4627. The resulting encoded JSON text can be treated as a native |
|
|
166 | unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string, |
|
|
167 | or any other superset of ASCII. |
160 | |
168 | |
161 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
169 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
162 | characters unless required by the JSON syntax. This results in a faster |
170 | characters unless required by the JSON syntax or other flags. This results |
163 | and more compact format. |
171 | in a faster and more compact format. |
|
|
172 | |
|
|
173 | The main use for this flag is to produce JSON texts that can be |
|
|
174 | transmitted over a 7-bit channel, as the encoded JSON texts will not |
|
|
175 | contain any 8 bit characters. |
164 | |
176 | |
165 | JSON::XS->new->ascii (1)->encode ([chr 0x10401]) |
177 | JSON::XS->new->ascii (1)->encode ([chr 0x10401]) |
166 | => ["\ud801\udc01"] |
178 | => ["\ud801\udc01"] |
|
|
179 | |
|
|
180 | =item $json = $json->latin1 ([$enable]) |
|
|
181 | |
|
|
182 | If C<$enable> is true (or missing), then the C<encode> method will encode |
|
|
183 | the resulting JSON text as latin1 (or iso-8859-1), escaping any characters |
|
|
184 | outside the code range C<0..255>. The resulting string can be treated as a |
|
|
185 | latin1-encoded JSON text or a native unicode string. The C<decode> method |
|
|
186 | will not be affected in any way by this flag, as C<decode> by default |
|
|
187 | expects unicode, which is a strict superset of latin1. |
|
|
188 | |
|
|
189 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
|
|
190 | characters unless required by the JSON syntax or other flags. |
|
|
191 | |
|
|
192 | The main use for this flag is efficiently encoding binary data as JSON |
|
|
193 | text, as most octets will not be escaped, resulting in a smaller encoded |
|
|
194 | size. The disadvantage is that the resulting JSON text is encoded |
|
|
195 | in latin1 (and must correctly be treated as such when storing and |
|
|
196 | transfering), a rare encoding for JSON. It is therefore most useful when |
|
|
197 | you want to store data structures known to contain binary data efficiently |
|
|
198 | in files or databases, not when talking to other JSON encoders/decoders. |
|
|
199 | |
|
|
200 | JSON::XS->new->latin1->encode (["\x{89}\x{abc}"] |
|
|
201 | => ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not) |
167 | |
202 | |
168 | =item $json = $json->utf8 ([$enable]) |
203 | =item $json = $json->utf8 ([$enable]) |
169 | |
204 | |
170 | If C<$enable> is true (or missing), then the C<encode> method will encode |
205 | If C<$enable> is true (or missing), then the C<encode> method will encode |
171 | the JSON result into UTF-8, as required by many protocols, while the |
206 | the JSON result into UTF-8, as required by many protocols, while the |
… | |
… | |
309 | strings that look like integers or floats into integers or floats |
344 | strings that look like integers or floats into integers or floats |
310 | internally (there is no difference on the Perl level), saving space. |
345 | internally (there is no difference on the Perl level), saving space. |
311 | |
346 | |
312 | =item $json = $json->max_depth ([$maximum_nesting_depth]) |
347 | =item $json = $json->max_depth ([$maximum_nesting_depth]) |
313 | |
348 | |
314 | Sets the maximum nesting level (default C<4096>) accepted while encoding |
349 | Sets the maximum nesting level (default C<512>) accepted while encoding |
315 | or decoding. If the JSON text or Perl data structure has an equal or |
350 | or decoding. If the JSON text or Perl data structure has an equal or |
316 | higher nesting level then this limit, then the encoder and decoder will |
351 | higher nesting level then this limit, then the encoder and decoder will |
317 | stop and croak at that point. |
352 | stop and croak at that point. |
318 | |
353 | |
319 | Nesting level is defined by number of hash- or arrayrefs that the encoder |
354 | Nesting level is defined by number of hash- or arrayrefs that the encoder |
… | |
… | |
345 | |
380 | |
346 | JSON numbers and strings become simple Perl scalars. JSON arrays become |
381 | JSON numbers and strings become simple Perl scalars. JSON arrays become |
347 | Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes |
382 | Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes |
348 | C<1>, C<false> becomes C<0> and C<null> becomes C<undef>. |
383 | C<1>, C<false> becomes C<0> and C<null> becomes C<undef>. |
349 | |
384 | |
|
|
385 | =item ($perl_scalar, $characters) = $json->decode_prefix ($json_text) |
|
|
386 | |
|
|
387 | This works like the C<decode> method, but instead of raising an exception |
|
|
388 | when there is trailing garbage after the first JSON object, it will |
|
|
389 | silently stop parsing there and return the number of characters consumed |
|
|
390 | so far. |
|
|
391 | |
|
|
392 | This is useful if your JSON texts are not delimited by an outer protocol |
|
|
393 | (which is not the brightest thing to do in the first place) and you need |
|
|
394 | to know where the JSON text ends. |
|
|
395 | |
|
|
396 | JSON::XS->new->decode_prefix ("[1] the tail") |
|
|
397 | => ([], 3) |
|
|
398 | |
350 | =back |
399 | =back |
351 | |
400 | |
352 | |
401 | |
353 | =head1 MAPPING |
402 | =head1 MAPPING |
354 | |
403 | |
… | |
… | |
358 | (what you put in comes out as something equivalent). |
407 | (what you put in comes out as something equivalent). |
359 | |
408 | |
360 | For the more enlightened: note that in the following descriptions, |
409 | For the more enlightened: note that in the following descriptions, |
361 | lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl> |
410 | lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl> |
362 | refers to the abstract Perl language itself. |
411 | refers to the abstract Perl language itself. |
|
|
412 | |
363 | |
413 | |
364 | =head2 JSON -> PERL |
414 | =head2 JSON -> PERL |
365 | |
415 | |
366 | =over 4 |
416 | =over 4 |
367 | |
417 | |
… | |
… | |
388 | conversion details, but an integer may take slightly less memory and might |
438 | conversion details, but an integer may take slightly less memory and might |
389 | represent more values exactly than (floating point) numbers. |
439 | represent more values exactly than (floating point) numbers. |
390 | |
440 | |
391 | =item true, false |
441 | =item true, false |
392 | |
442 | |
393 | These JSON atoms become C<0>, C<1>, respectively. Information is lost in |
443 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
394 | this process. Future versions might represent those values differently, |
444 | respectively. They are overloaded to act almost exactly like the numbers |
395 | but they will be guarenteed to act like these integers would normally in |
445 | C<1> and C<0>. You can check wether a scalar is a JSON boolean by using |
396 | Perl. |
446 | the C<JSON::XS::is_bool> function. |
397 | |
447 | |
398 | =item null |
448 | =item null |
399 | |
449 | |
400 | A JSON null atom becomes C<undef> in Perl. |
450 | A JSON null atom becomes C<undef> in Perl. |
401 | |
451 | |
402 | =back |
452 | =back |
|
|
453 | |
403 | |
454 | |
404 | =head2 PERL -> JSON |
455 | =head2 PERL -> JSON |
405 | |
456 | |
406 | The mapping from Perl to JSON is slightly more difficult, as Perl is a |
457 | The mapping from Perl to JSON is slightly more difficult, as Perl is a |
407 | truly typeless language, so we can only guess which JSON type is meant by |
458 | truly typeless language, so we can only guess which JSON type is meant by |
… | |
… | |
432 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
483 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
433 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
484 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
434 | |
485 | |
435 | to_json [\0,JSON::XS::true] # yields [false,true] |
486 | to_json [\0,JSON::XS::true] # yields [false,true] |
436 | |
487 | |
|
|
488 | =item JSON::XS::true, JSON::XS::false |
|
|
489 | |
|
|
490 | These special values become JSON true and JSON false values, |
|
|
491 | respectively. You cna alos use C<\1> and C<\0> directly if you want. |
|
|
492 | |
437 | =item blessed objects |
493 | =item blessed objects |
438 | |
494 | |
439 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
495 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
440 | underlying representation (hash- or arrayref), but this behaviour might |
496 | underlying representation (hash- or arrayref), but this behaviour might |
441 | change in future versions. |
497 | change in future versions. |
… | |
… | |
472 | $x += 0; # numify it, ensuring it will be dumped as a number |
528 | $x += 0; # numify it, ensuring it will be dumped as a number |
473 | $x *= 1; # same thing, the choise is yours. |
529 | $x *= 1; # same thing, the choise is yours. |
474 | |
530 | |
475 | You can not currently output JSON booleans or force the type in other, |
531 | You can not currently output JSON booleans or force the type in other, |
476 | less obscure, ways. Tell me if you need this capability. |
532 | less obscure, ways. Tell me if you need this capability. |
477 | |
|
|
478 | =item circular data structures |
|
|
479 | |
|
|
480 | Those will be encoded until memory or stackspace runs out. |
|
|
481 | |
533 | |
482 | =back |
534 | =back |
483 | |
535 | |
484 | |
536 | |
485 | =head1 COMPARISON |
537 | =head1 COMPARISON |
… | |
… | |
566 | |
618 | |
567 | Does not check input for validity. |
619 | Does not check input for validity. |
568 | |
620 | |
569 | =back |
621 | =back |
570 | |
622 | |
|
|
623 | |
|
|
624 | =head2 JSON and YAML |
|
|
625 | |
|
|
626 | You often hear that JSON is a subset (or a close subset) of YAML. This is, |
|
|
627 | however, a mass hysteria and very far from the truth. In general, there is |
|
|
628 | no way to configure JSON::XS to output a data structure as valid YAML. |
|
|
629 | |
|
|
630 | If you really must use JSON::XS to generate YAML, you should use this |
|
|
631 | algorithm (subject to change in future versions): |
|
|
632 | |
|
|
633 | my $to_yaml = JSON::XS->new->utf8->space_after (1); |
|
|
634 | my $yaml = $to_yaml->encode ($ref) . "\n"; |
|
|
635 | |
|
|
636 | This will usually generate JSON texts that also parse as valid |
|
|
637 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
|
|
638 | lengths that JSON doesn't have, so you should make sure that your hash |
|
|
639 | keys are noticably shorter than the 1024 characters YAML allows. |
|
|
640 | |
|
|
641 | There might be other incompatibilities that I am not aware of. In general |
|
|
642 | you should not try to generate YAML with a JSON generator or vice versa, |
|
|
643 | or try to parse JSON with a YAML parser or vice versa: chances are high |
|
|
644 | that you will run into severe interoperability problems. |
|
|
645 | |
|
|
646 | |
571 | =head2 SPEED |
647 | =head2 SPEED |
572 | |
648 | |
573 | It seems that JSON::XS is surprisingly fast, as shown in the following |
649 | It seems that JSON::XS is surprisingly fast, as shown in the following |
574 | tables. They have been generated with the help of the C<eg/bench> program |
650 | tables. They have been generated with the help of the C<eg/bench> program |
575 | in the JSON::XS distribution, to make it easy to compare on your own |
651 | in the JSON::XS distribution, to make it easy to compare on your own |
576 | system. |
652 | system. |
577 | |
653 | |
578 | First comes a comparison between various modules using a very short JSON |
654 | First comes a comparison between various modules using a very short |
579 | string: |
655 | single-line JSON string: |
580 | |
656 | |
581 | {"method": "handleMessage", "params": ["user1", "we were just talking"], "id": null} |
657 | {"method": "handleMessage", "params": ["user1", "we were just talking"], \ |
|
|
658 | "id": null, "array":[1,11,234,-5,1e5,1e7, true, false]} |
582 | |
659 | |
583 | It shows the number of encodes/decodes per second (JSON::XS uses the |
660 | It shows the number of encodes/decodes per second (JSON::XS uses |
584 | functional interface, while JSON::XS/2 uses the OO interface with |
661 | the functional interface, while JSON::XS/2 uses the OO interface |
585 | pretty-printing and hashkey sorting enabled). Higher is better: |
662 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
|
|
663 | shrink). Higher is better: |
586 | |
664 | |
587 | module | encode | decode | |
665 | module | encode | decode | |
588 | -----------|------------|------------| |
666 | -----------|------------|------------| |
589 | JSON | 11488.516 | 7823.035 | |
667 | JSON | 7645.468 | 4208.613 | |
590 | JSON::DWIW | 94708.054 | 129094.260 | |
668 | JSON::DWIW | 40721.398 | 77101.176 | |
591 | JSON::PC | 63884.157 | 128528.212 | |
669 | JSON::PC | 65948.176 | 78251.940 | |
592 | JSON::Syck | 34898.677 | 42096.911 | |
670 | JSON::Syck | 22844.793 | 26479.192 | |
593 | JSON::XS | 654027.064 | 396423.669 | |
671 | JSON::XS | 388361.481 | 199728.762 | |
594 | JSON::XS/2 | 371564.190 | 371725.613 | |
672 | JSON::XS/2 | 218453.333 | 192399.266 | |
|
|
673 | JSON::XS/3 | 338250.323 | 192399.266 | |
|
|
674 | Storable | 15779.925 | 14169.946 | |
595 | -----------+------------+------------+ |
675 | -----------+------------+------------+ |
596 | |
676 | |
597 | That is, JSON::XS is more than six times faster than JSON::DWIW on |
677 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
598 | encoding, more than three times faster on decoding, and about thirty times |
678 | about three times faster on decoding, and over fourty times faster |
599 | faster than JSON, even with pretty-printing and key sorting. |
679 | than JSON, even with pretty-printing and key sorting. It also compares |
|
|
680 | favourably to Storable for small amounts of data. |
600 | |
681 | |
601 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
682 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
602 | search API (http://nanoref.com/yahooapis/mgPdGg): |
683 | search API (http://nanoref.com/yahooapis/mgPdGg): |
603 | |
684 | |
604 | module | encode | decode | |
685 | module | encode | decode | |
605 | -----------|------------|------------| |
686 | -----------|------------|------------| |
606 | JSON | 273.023 | 44.674 | |
687 | JSON | 254.685 | 37.665 | |
607 | JSON::DWIW | 1089.383 | 1145.704 | |
688 | JSON::DWIW | 843.343 | 1049.731 | |
608 | JSON::PC | 3097.419 | 2393.921 | |
689 | JSON::PC | 3602.116 | 2307.352 | |
609 | JSON::Syck | 514.060 | 843.053 | |
690 | JSON::Syck | 505.107 | 787.899 | |
610 | JSON::XS | 6479.668 | 3636.364 | |
691 | JSON::XS | 5747.196 | 3690.220 | |
611 | JSON::XS/2 | 3774.221 | 3599.124 | |
692 | JSON::XS/2 | 3968.121 | 3676.634 | |
|
|
693 | JSON::XS/3 | 6105.246 | 3662.508 | |
|
|
694 | Storable | 4417.337 | 5285.161 | |
612 | -----------+------------+------------+ |
695 | -----------+------------+------------+ |
613 | |
696 | |
614 | Again, JSON::XS leads by far. |
697 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
|
|
698 | decodes faster). |
615 | |
699 | |
616 | On large strings containing lots of high unicode characters, some modules |
700 | On large strings containing lots of high unicode characters, some modules |
617 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
701 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
618 | will be broken due to missing (or wrong) unicode handling. Others refuse |
702 | will be broken due to missing (or wrong) unicode handling. Others refuse |
619 | to decode or encode properly, so it was impossible to prepare a fair |
703 | to decode or encode properly, so it was impossible to prepare a fair |
… | |
… | |
636 | usually a good indication of the size of the resources required to decode |
720 | usually a good indication of the size of the resources required to decode |
637 | it into a Perl structure. |
721 | it into a Perl structure. |
638 | |
722 | |
639 | Third, JSON::XS recurses using the C stack when decoding objects and |
723 | Third, JSON::XS recurses using the C stack when decoding objects and |
640 | arrays. The C stack is a limited resource: for instance, on my amd64 |
724 | arrays. The C stack is a limited resource: for instance, on my amd64 |
641 | machine with 8MB of stack size I can decode around 180k nested arrays |
725 | machine with 8MB of stack size I can decode around 180k nested arrays but |
642 | but only 14k nested JSON objects. If that is exceeded, the program |
726 | only 14k nested JSON objects (due to perl itself recursing deeply on croak |
643 | crashes. Thats why the default nesting limit is set to 4096. If your |
727 | to free the temporary). If that is exceeded, the program crashes. to be |
|
|
728 | conservative, the default nesting limit is set to 512. If your process |
644 | process has a smaller stack, you should adjust this setting accordingly |
729 | has a smaller stack, you should adjust this setting accordingly with the |
645 | with the C<max_depth> method. |
730 | C<max_depth> method. |
646 | |
731 | |
647 | And last but least, something else could bomb you that I forgot to think |
732 | And last but least, something else could bomb you that I forgot to think |
648 | of. In that case, you get to keep the pieces. I am alway sopen for hints, |
733 | of. In that case, you get to keep the pieces. I am always open for hints, |
649 | though... |
734 | though... |
|
|
735 | |
|
|
736 | If you are using JSON::XS to return packets to consumption |
|
|
737 | by javascript scripts in a browser you should have a look at |
|
|
738 | L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether |
|
|
739 | you are vulnerable to some common attack vectors (which really are browser |
|
|
740 | design bugs, but it is still you who will have to deal with it, as major |
|
|
741 | browser developers care only for features, not about doing security |
|
|
742 | right). |
650 | |
743 | |
651 | |
744 | |
652 | =head1 BUGS |
745 | =head1 BUGS |
653 | |
746 | |
654 | While the goal of this module is to be correct, that unfortunately does |
747 | While the goal of this module is to be correct, that unfortunately does |
… | |
… | |
656 | still relatively early in its development. If you keep reporting bugs they |
749 | still relatively early in its development. If you keep reporting bugs they |
657 | will be fixed swiftly, though. |
750 | will be fixed swiftly, though. |
658 | |
751 | |
659 | =cut |
752 | =cut |
660 | |
753 | |
|
|
754 | our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" }; |
|
|
755 | our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" }; |
|
|
756 | |
661 | sub true() { \1 } |
757 | sub true() { $true } |
662 | sub false() { \0 } |
758 | sub false() { $false } |
|
|
759 | |
|
|
760 | sub is_bool($) { |
|
|
761 | UNIVERSAL::isa $_[0], "JSON::XS::Boolean" |
|
|
762 | or UNIVERSAL::isa $_[0], "JSON::Literal" |
|
|
763 | } |
|
|
764 | |
|
|
765 | XSLoader::load "JSON::XS", $VERSION; |
|
|
766 | |
|
|
767 | package JSON::XS::Boolean; |
|
|
768 | |
|
|
769 | use overload |
|
|
770 | "0+" => sub { ${$_[0]} }, |
|
|
771 | "++" => sub { $_[0] = ${$_[0]} + 1 }, |
|
|
772 | "--" => sub { $_[0] = ${$_[0]} - 1 }, |
|
|
773 | fallback => 1; |
663 | |
774 | |
664 | 1; |
775 | 1; |
665 | |
776 | |
666 | =head1 AUTHOR |
777 | =head1 AUTHOR |
667 | |
778 | |