… | |
… | |
9 | # exported functions, they croak on error |
9 | # exported functions, they croak on error |
10 | # and expect/generate UTF-8 |
10 | # and expect/generate UTF-8 |
11 | |
11 | |
12 | $utf8_encoded_json_text = to_json $perl_hash_or_arrayref; |
12 | $utf8_encoded_json_text = to_json $perl_hash_or_arrayref; |
13 | $perl_hash_or_arrayref = from_json $utf8_encoded_json_text; |
13 | $perl_hash_or_arrayref = from_json $utf8_encoded_json_text; |
14 | |
|
|
15 | # objToJson and jsonToObj aliases to to_json and from_json |
|
|
16 | # are exported for compatibility to the JSON module, |
|
|
17 | # but should not be used in new code. |
|
|
18 | |
14 | |
19 | # OO-interface |
15 | # OO-interface |
20 | |
16 | |
21 | $coder = JSON::XS->new->ascii->pretty->allow_nonref; |
17 | $coder = JSON::XS->new->ascii->pretty->allow_nonref; |
22 | $pretty_printed_unencoded = $coder->encode ($perl_scalar); |
18 | $pretty_printed_unencoded = $coder->encode ($perl_scalar); |
… | |
… | |
85 | |
81 | |
86 | package JSON::XS; |
82 | package JSON::XS; |
87 | |
83 | |
88 | use strict; |
84 | use strict; |
89 | |
85 | |
90 | BEGIN { |
|
|
91 | our $VERSION = '1.12'; |
86 | our $VERSION = '1.4'; |
92 | our @ISA = qw(Exporter); |
87 | our @ISA = qw(Exporter); |
93 | |
88 | |
94 | our @EXPORT = qw(to_json from_json objToJson jsonToObj); |
89 | our @EXPORT = qw(to_json from_json); |
95 | require Exporter; |
|
|
96 | |
90 | |
97 | require XSLoader; |
91 | use Exporter; |
98 | XSLoader::load JSON::XS::, $VERSION; |
92 | use XSLoader; |
99 | } |
|
|
100 | |
93 | |
101 | =head1 FUNCTIONAL INTERFACE |
94 | =head1 FUNCTIONAL INTERFACE |
102 | |
95 | |
103 | The following convinience methods are provided by this module. They are |
96 | The following convinience methods are provided by this module. They are |
104 | exported by default: |
97 | exported by default: |
… | |
… | |
126 | This function call is functionally identical to: |
119 | This function call is functionally identical to: |
127 | |
120 | |
128 | $perl_scalar = JSON::XS->new->utf8->decode ($json_text) |
121 | $perl_scalar = JSON::XS->new->utf8->decode ($json_text) |
129 | |
122 | |
130 | except being faster. |
123 | except being faster. |
|
|
124 | |
|
|
125 | =item $is_boolean = JSON::XS::is_bool $scalar |
|
|
126 | |
|
|
127 | Returns true if the passed scalar represents either JSON::XS::true or |
|
|
128 | JSON::XS::false, two constants that act like C<1> and C<0>, respectively |
|
|
129 | and are used to represent JSON C<true> and C<false> values in Perl. |
|
|
130 | |
|
|
131 | See MAPPING, below, for more information on how JSON values are mapped to |
|
|
132 | Perl. |
131 | |
133 | |
132 | =back |
134 | =back |
133 | |
135 | |
134 | |
136 | |
135 | =head1 OBJECT-ORIENTED INTERFACE |
137 | =head1 OBJECT-ORIENTED INTERFACE |
… | |
… | |
309 | Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>, |
311 | Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>, |
310 | resulting in an invalid JSON text: |
312 | resulting in an invalid JSON text: |
311 | |
313 | |
312 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
314 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
313 | => "Hello, World!" |
315 | => "Hello, World!" |
|
|
316 | |
|
|
317 | =item $json = $json->allow_blessed ([$enable]) |
|
|
318 | |
|
|
319 | If C<$enable> is true (or missing), then the C<encode> method will not |
|
|
320 | barf when it encounters a blessed reference. Instead, the value of the |
|
|
321 | B<convert_blessed> option will decide wether C<null> (C<convert_blessed> |
|
|
322 | disabled or no C<to_json> method found) or a representation of the |
|
|
323 | object (C<convert_blessed> enabled and C<to_json> method found) is being |
|
|
324 | encoded. Has no effect on C<decode>. |
|
|
325 | |
|
|
326 | If C<$enable> is false (the default), then C<encode> will throw an |
|
|
327 | exception when it encounters a blessed object. |
|
|
328 | |
|
|
329 | =item $json = $json->convert_blessed ([$enable]) |
|
|
330 | |
|
|
331 | If C<$enable> is true (or missing), then C<encode>, upon encountering a |
|
|
332 | blessed object, will check for the availability of the C<TO_JSON> method |
|
|
333 | on the object's class. If found, it will be called in scalar context |
|
|
334 | and the resulting scalar will be encoded instead of the object. If no |
|
|
335 | C<TO_JSON> method is found, the value of C<allow_blessed> will decide what |
|
|
336 | to do. |
|
|
337 | |
|
|
338 | The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON> |
|
|
339 | returns other blessed objects, those will be handled in the same |
|
|
340 | way. C<TO_JSON> must take care of not causing an endless recursion cycle |
|
|
341 | (== crash) in this case. The name of C<TO_JSON> was chosen because other |
|
|
342 | methods called by the Perl core (== not by the user of the object) are |
|
|
343 | usually in upper case letters and to avoid collisions with the C<to_json> |
|
|
344 | function. |
|
|
345 | |
|
|
346 | This setting does not yet influence C<decode> in any way, but in the |
|
|
347 | future, global hooks might get installed that influence C<decode> and are |
|
|
348 | enabled by this setting. |
|
|
349 | |
|
|
350 | If C<$enable> is false, then the C<allow_blessed> setting will decide what |
|
|
351 | to do when a blessed object is found. |
|
|
352 | |
|
|
353 | =item $json = $json->filter_json_object ([$coderef]) |
|
|
354 | |
|
|
355 | When C<$coderef> is specified, it will be called from C<decode> each |
|
|
356 | time it decodes a JSON object. The only argument is a reference to the |
|
|
357 | newly-created hash. If the code references returns a single scalar (which |
|
|
358 | need not be a reference), this value (i.e. a copy of that scalar to avoid |
|
|
359 | aliasing) is inserted into the deserialised data structure. If it returns |
|
|
360 | an empty list (NOTE: I<not> C<undef>, which is a valid scalar), the |
|
|
361 | original deserialised hash will be inserted. This setting can slow down |
|
|
362 | decoding considerably. |
|
|
363 | |
|
|
364 | When C<$coderef> is omitted or undefined, C<decode> will not change the |
|
|
365 | deserialised hash in any way. This is maximally fast. |
|
|
366 | |
|
|
367 | Example, convert all JSON objects into the integer 5: |
|
|
368 | |
|
|
369 | my $js = JSON::XS->new->filter_json_object (sub { 5 }); |
|
|
370 | # returns [5] |
|
|
371 | $js->decode ('[{}]') |
|
|
372 | # throw an exception because allow_nonref is not enabled: |
|
|
373 | $js->decode ('{"a":1, "b":2}'); |
|
|
374 | |
|
|
375 | =item $json = $json->filter_json_single_key_object ([$coderef]) |
|
|
376 | |
|
|
377 | Works like C<filter_json_object>, but is only called for JSON objects |
|
|
378 | having only a single key. |
|
|
379 | |
|
|
380 | This C<$coderef> is called before the one specified via |
|
|
381 | C<filter_json_object>, if any. If it returns something, that will be |
|
|
382 | inserted into the data structure. If it returns nothing, the callback |
|
|
383 | from C<filter_json_object> will be called next. If you want to force |
|
|
384 | insertion of single-key objects even in the presence of a mutating |
|
|
385 | C<filter_json_object> callback, simply return the passed hash. |
|
|
386 | |
|
|
387 | As this callback gets called less often then the C<filter_json_object> |
|
|
388 | one, decoding speed will not usually suffer as much. Therefore, single-key |
|
|
389 | objects make excellent targets to serialise Perl objects into, especially |
|
|
390 | as single-key JSON objects are as close to the type-tagged value concept |
|
|
391 | as JSON gets (its basically an ID/VALUE tuple). Of course, JSON does not |
|
|
392 | support this in any way, so you need to make sure your data never looks |
|
|
393 | like a serialised Perl hash. |
|
|
394 | |
|
|
395 | Typical names for the single object key are C<__class_whatever__>, or |
|
|
396 | C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even |
|
|
397 | things like C<__class_md5sum(classname)__>, to reduce the risk of clashing |
|
|
398 | with real hashes. |
|
|
399 | |
|
|
400 | Example, decode JSON objects of the form C<< { "__widget__" => <id> } >> |
|
|
401 | into the corresponding C<< $WIDGET{<id>} >> object: |
|
|
402 | |
|
|
403 | # return whatever is in $WIDGET{5}: |
|
|
404 | JSON::XS |
|
|
405 | ->new |
|
|
406 | ->filter_json_single_key_object (sub { |
|
|
407 | exists $_[0]{__widget__} |
|
|
408 | ? $WIDGET{ $_[0]{__widget__} } |
|
|
409 | : () |
|
|
410 | }) |
|
|
411 | ->decode ('{"__widget__": 5') |
|
|
412 | |
|
|
413 | # this can be used with a TO_JSON method in some "widget" class |
|
|
414 | # for serialisation to json: |
|
|
415 | sub WidgetBase::TO_JSON { |
|
|
416 | my ($self) = @_; |
|
|
417 | |
|
|
418 | unless ($self->{id}) { |
|
|
419 | $self->{id} = ..get..some..id..; |
|
|
420 | $WIDGET{$self->{id}} = $self; |
|
|
421 | } |
|
|
422 | |
|
|
423 | { __widget__ => $self->{id} } |
|
|
424 | } |
314 | |
425 | |
315 | =item $json = $json->shrink ([$enable]) |
426 | =item $json = $json->shrink ([$enable]) |
316 | |
427 | |
317 | Perl usually over-allocates memory a bit when allocating space for |
428 | Perl usually over-allocates memory a bit when allocating space for |
318 | strings. This flag optionally resizes strings generated by either |
429 | strings. This flag optionally resizes strings generated by either |
… | |
… | |
351 | given character in a string. |
462 | given character in a string. |
352 | |
463 | |
353 | Setting the maximum depth to one disallows any nesting, so that ensures |
464 | Setting the maximum depth to one disallows any nesting, so that ensures |
354 | that the object is only a single hash/object or array. |
465 | that the object is only a single hash/object or array. |
355 | |
466 | |
356 | The argument to C<max_depth> will be rounded up to the next nearest power |
467 | The argument to C<max_depth> will be rounded up to the next highest power |
357 | of two. |
468 | of two. If no argument is given, the highest possible setting will be |
|
|
469 | used, which is rarely useful. |
|
|
470 | |
|
|
471 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
|
|
472 | |
|
|
473 | =item $json = $json->max_size ([$maximum_string_size]) |
|
|
474 | |
|
|
475 | Set the maximum length a JSON text may have (in bytes) where decoding is |
|
|
476 | being attempted. The default is C<0>, meaning no limit. When C<decode> |
|
|
477 | is called on a string longer then this number of characters it will not |
|
|
478 | attempt to decode the string but throw an exception. This setting has no |
|
|
479 | effect on C<encode> (yet). |
|
|
480 | |
|
|
481 | The argument to C<max_size> will be rounded up to the next B<highest> |
|
|
482 | power of two (so may be more than requested). If no argument is given, the |
|
|
483 | limit check will be deactivated (same as when C<0> is specified). |
358 | |
484 | |
359 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
485 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
360 | |
486 | |
361 | =item $json_text = $json->encode ($perl_scalar) |
487 | =item $json_text = $json->encode ($perl_scalar) |
362 | |
488 | |
… | |
… | |
374 | |
500 | |
375 | JSON numbers and strings become simple Perl scalars. JSON arrays become |
501 | JSON numbers and strings become simple Perl scalars. JSON arrays become |
376 | Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes |
502 | Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes |
377 | C<1>, C<false> becomes C<0> and C<null> becomes C<undef>. |
503 | C<1>, C<false> becomes C<0> and C<null> becomes C<undef>. |
378 | |
504 | |
|
|
505 | =item ($perl_scalar, $characters) = $json->decode_prefix ($json_text) |
|
|
506 | |
|
|
507 | This works like the C<decode> method, but instead of raising an exception |
|
|
508 | when there is trailing garbage after the first JSON object, it will |
|
|
509 | silently stop parsing there and return the number of characters consumed |
|
|
510 | so far. |
|
|
511 | |
|
|
512 | This is useful if your JSON texts are not delimited by an outer protocol |
|
|
513 | (which is not the brightest thing to do in the first place) and you need |
|
|
514 | to know where the JSON text ends. |
|
|
515 | |
|
|
516 | JSON::XS->new->decode_prefix ("[1] the tail") |
|
|
517 | => ([], 3) |
|
|
518 | |
379 | =back |
519 | =back |
380 | |
520 | |
381 | |
521 | |
382 | =head1 MAPPING |
522 | =head1 MAPPING |
383 | |
523 | |
… | |
… | |
387 | (what you put in comes out as something equivalent). |
527 | (what you put in comes out as something equivalent). |
388 | |
528 | |
389 | For the more enlightened: note that in the following descriptions, |
529 | For the more enlightened: note that in the following descriptions, |
390 | lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl> |
530 | lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl> |
391 | refers to the abstract Perl language itself. |
531 | refers to the abstract Perl language itself. |
|
|
532 | |
392 | |
533 | |
393 | =head2 JSON -> PERL |
534 | =head2 JSON -> PERL |
394 | |
535 | |
395 | =over 4 |
536 | =over 4 |
396 | |
537 | |
… | |
… | |
417 | conversion details, but an integer may take slightly less memory and might |
558 | conversion details, but an integer may take slightly less memory and might |
418 | represent more values exactly than (floating point) numbers. |
559 | represent more values exactly than (floating point) numbers. |
419 | |
560 | |
420 | =item true, false |
561 | =item true, false |
421 | |
562 | |
422 | These JSON atoms become C<0>, C<1>, respectively. Information is lost in |
563 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
423 | this process. Future versions might represent those values differently, |
564 | respectively. They are overloaded to act almost exactly like the numbers |
424 | but they will be guarenteed to act like these integers would normally in |
565 | C<1> and C<0>. You can check wether a scalar is a JSON boolean by using |
425 | Perl. |
566 | the C<JSON::XS::is_bool> function. |
426 | |
567 | |
427 | =item null |
568 | =item null |
428 | |
569 | |
429 | A JSON null atom becomes C<undef> in Perl. |
570 | A JSON null atom becomes C<undef> in Perl. |
430 | |
571 | |
431 | =back |
572 | =back |
|
|
573 | |
432 | |
574 | |
433 | =head2 PERL -> JSON |
575 | =head2 PERL -> JSON |
434 | |
576 | |
435 | The mapping from Perl to JSON is slightly more difficult, as Perl is a |
577 | The mapping from Perl to JSON is slightly more difficult, as Perl is a |
436 | truly typeless language, so we can only guess which JSON type is meant by |
578 | truly typeless language, so we can only guess which JSON type is meant by |
… | |
… | |
461 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
603 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
462 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
604 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
463 | |
605 | |
464 | to_json [\0,JSON::XS::true] # yields [false,true] |
606 | to_json [\0,JSON::XS::true] # yields [false,true] |
465 | |
607 | |
|
|
608 | =item JSON::XS::true, JSON::XS::false |
|
|
609 | |
|
|
610 | These special values become JSON true and JSON false values, |
|
|
611 | respectively. You cna alos use C<\1> and C<\0> directly if you want. |
|
|
612 | |
466 | =item blessed objects |
613 | =item blessed objects |
467 | |
614 | |
468 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
615 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
469 | underlying representation (hash- or arrayref), but this behaviour might |
616 | underlying representation (hash- or arrayref), but this behaviour might |
470 | change in future versions. |
617 | change in future versions. |
… | |
… | |
591 | |
738 | |
592 | Does not check input for validity. |
739 | Does not check input for validity. |
593 | |
740 | |
594 | =back |
741 | =back |
595 | |
742 | |
|
|
743 | |
|
|
744 | =head2 JSON and YAML |
|
|
745 | |
|
|
746 | You often hear that JSON is a subset (or a close subset) of YAML. This is, |
|
|
747 | however, a mass hysteria and very far from the truth. In general, there is |
|
|
748 | no way to configure JSON::XS to output a data structure as valid YAML. |
|
|
749 | |
|
|
750 | If you really must use JSON::XS to generate YAML, you should use this |
|
|
751 | algorithm (subject to change in future versions): |
|
|
752 | |
|
|
753 | my $to_yaml = JSON::XS->new->utf8->space_after (1); |
|
|
754 | my $yaml = $to_yaml->encode ($ref) . "\n"; |
|
|
755 | |
|
|
756 | This will usually generate JSON texts that also parse as valid |
|
|
757 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
|
|
758 | lengths that JSON doesn't have, so you should make sure that your hash |
|
|
759 | keys are noticably shorter than the 1024 characters YAML allows. |
|
|
760 | |
|
|
761 | There might be other incompatibilities that I am not aware of. In general |
|
|
762 | you should not try to generate YAML with a JSON generator or vice versa, |
|
|
763 | or try to parse JSON with a YAML parser or vice versa: chances are high |
|
|
764 | that you will run into severe interoperability problems. |
|
|
765 | |
|
|
766 | |
596 | =head2 SPEED |
767 | =head2 SPEED |
597 | |
768 | |
598 | It seems that JSON::XS is surprisingly fast, as shown in the following |
769 | It seems that JSON::XS is surprisingly fast, as shown in the following |
599 | tables. They have been generated with the help of the C<eg/bench> program |
770 | tables. They have been generated with the help of the C<eg/bench> program |
600 | in the JSON::XS distribution, to make it easy to compare on your own |
771 | in the JSON::XS distribution, to make it easy to compare on your own |
601 | system. |
772 | system. |
602 | |
773 | |
603 | First comes a comparison between various modules using a very short JSON |
774 | First comes a comparison between various modules using a very short |
604 | string: |
775 | single-line JSON string: |
605 | |
776 | |
606 | {"method": "handleMessage", "params": ["user1", "we were just talking"], "id": null} |
777 | {"method": "handleMessage", "params": ["user1", "we were just talking"], \ |
|
|
778 | "id": null, "array":[1,11,234,-5,1e5,1e7, true, false]} |
607 | |
779 | |
608 | It shows the number of encodes/decodes per second (JSON::XS uses the |
780 | It shows the number of encodes/decodes per second (JSON::XS uses |
609 | functional interface, while JSON::XS/2 uses the OO interface with |
781 | the functional interface, while JSON::XS/2 uses the OO interface |
610 | pretty-printing and hashkey sorting enabled). Higher is better: |
782 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
|
|
783 | shrink). Higher is better: |
611 | |
784 | |
|
|
785 | Storable | 15779.925 | 14169.946 | |
|
|
786 | -----------+------------+------------+ |
612 | module | encode | decode | |
787 | module | encode | decode | |
613 | -----------|------------|------------| |
788 | -----------|------------|------------| |
614 | JSON | 11488.516 | 7823.035 | |
789 | JSON | 4990.842 | 4088.813 | |
615 | JSON::DWIW | 94708.054 | 129094.260 | |
790 | JSON::DWIW | 51653.990 | 71575.154 | |
616 | JSON::PC | 63884.157 | 128528.212 | |
791 | JSON::PC | 65948.176 | 74631.744 | |
617 | JSON::Syck | 34898.677 | 42096.911 | |
792 | JSON::PP | 8931.652 | 3817.168 | |
618 | JSON::XS | 654027.064 | 396423.669 | |
793 | JSON::Syck | 24877.248 | 27776.848 | |
619 | JSON::XS/2 | 371564.190 | 371725.613 | |
794 | JSON::XS | 388361.481 | 227951.304 | |
|
|
795 | JSON::XS/2 | 227951.304 | 218453.333 | |
|
|
796 | JSON::XS/3 | 338250.323 | 218453.333 | |
|
|
797 | Storable | 16500.016 | 135300.129 | |
620 | -----------+------------+------------+ |
798 | -----------+------------+------------+ |
621 | |
799 | |
622 | That is, JSON::XS is more than six times faster than JSON::DWIW on |
800 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
623 | encoding, more than three times faster on decoding, and about thirty times |
801 | about three times faster on decoding, and over fourty times faster |
624 | faster than JSON, even with pretty-printing and key sorting. |
802 | than JSON, even with pretty-printing and key sorting. It also compares |
|
|
803 | favourably to Storable for small amounts of data. |
625 | |
804 | |
626 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
805 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
627 | search API (http://nanoref.com/yahooapis/mgPdGg): |
806 | search API (http://nanoref.com/yahooapis/mgPdGg): |
628 | |
807 | |
629 | module | encode | decode | |
808 | module | encode | decode | |
630 | -----------|------------|------------| |
809 | -----------|------------|------------| |
631 | JSON | 273.023 | 44.674 | |
810 | JSON | 55.260 | 34.971 | |
632 | JSON::DWIW | 1089.383 | 1145.704 | |
811 | JSON::DWIW | 825.228 | 1082.513 | |
633 | JSON::PC | 3097.419 | 2393.921 | |
812 | JSON::PC | 3571.444 | 2394.829 | |
634 | JSON::Syck | 514.060 | 843.053 | |
813 | JSON::PP | 210.987 | 32.574 | |
635 | JSON::XS | 6479.668 | 3636.364 | |
814 | JSON::Syck | 552.551 | 787.544 | |
636 | JSON::XS/2 | 3774.221 | 3599.124 | |
815 | JSON::XS | 5780.463 | 4854.519 | |
|
|
816 | JSON::XS/2 | 3869.998 | 4798.975 | |
|
|
817 | JSON::XS/3 | 5862.880 | 4798.975 | |
|
|
818 | Storable | 4445.002 | 5235.027 | |
637 | -----------+------------+------------+ |
819 | -----------+------------+------------+ |
638 | |
820 | |
639 | Again, JSON::XS leads by far. |
821 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
|
|
822 | decodes faster). |
640 | |
823 | |
641 | On large strings containing lots of high unicode characters, some modules |
824 | On large strings containing lots of high unicode characters, some modules |
642 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
825 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
643 | will be broken due to missing (or wrong) unicode handling. Others refuse |
826 | will be broken due to missing (or wrong) unicode handling. Others refuse |
644 | to decode or encode properly, so it was impossible to prepare a fair |
827 | to decode or encode properly, so it was impossible to prepare a fair |
… | |
… | |
657 | Second, you need to avoid resource-starving attacks. That means you should |
840 | Second, you need to avoid resource-starving attacks. That means you should |
658 | limit the size of JSON texts you accept, or make sure then when your |
841 | limit the size of JSON texts you accept, or make sure then when your |
659 | resources run out, thats just fine (e.g. by using a separate process that |
842 | resources run out, thats just fine (e.g. by using a separate process that |
660 | can crash safely). The size of a JSON text in octets or characters is |
843 | can crash safely). The size of a JSON text in octets or characters is |
661 | usually a good indication of the size of the resources required to decode |
844 | usually a good indication of the size of the resources required to decode |
662 | it into a Perl structure. |
845 | it into a Perl structure. While JSON::XS can check the size of the JSON |
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|
846 | text, it might be too late when you already have it in memory, so you |
|
|
847 | might want to check the size before you accept the string. |
663 | |
848 | |
664 | Third, JSON::XS recurses using the C stack when decoding objects and |
849 | Third, JSON::XS recurses using the C stack when decoding objects and |
665 | arrays. The C stack is a limited resource: for instance, on my amd64 |
850 | arrays. The C stack is a limited resource: for instance, on my amd64 |
666 | machine with 8MB of stack size I can decode around 180k nested arrays but |
851 | machine with 8MB of stack size I can decode around 180k nested arrays but |
667 | only 14k nested JSON objects (due to perl itself recursing deeply on croak |
852 | only 14k nested JSON objects (due to perl itself recursing deeply on croak |
… | |
… | |
672 | |
857 | |
673 | And last but least, something else could bomb you that I forgot to think |
858 | And last but least, something else could bomb you that I forgot to think |
674 | of. In that case, you get to keep the pieces. I am always open for hints, |
859 | of. In that case, you get to keep the pieces. I am always open for hints, |
675 | though... |
860 | though... |
676 | |
861 | |
|
|
862 | If you are using JSON::XS to return packets to consumption |
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|
863 | by javascript scripts in a browser you should have a look at |
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|
864 | L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether |
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|
865 | you are vulnerable to some common attack vectors (which really are browser |
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|
866 | design bugs, but it is still you who will have to deal with it, as major |
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|
867 | browser developers care only for features, not about doing security |
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|
868 | right). |
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|
869 | |
677 | |
870 | |
678 | =head1 BUGS |
871 | =head1 BUGS |
679 | |
872 | |
680 | While the goal of this module is to be correct, that unfortunately does |
873 | While the goal of this module is to be correct, that unfortunately does |
681 | not mean its bug-free, only that I think its design is bug-free. It is |
874 | not mean its bug-free, only that I think its design is bug-free. It is |
682 | still relatively early in its development. If you keep reporting bugs they |
875 | still relatively early in its development. If you keep reporting bugs they |
683 | will be fixed swiftly, though. |
876 | will be fixed swiftly, though. |
684 | |
877 | |
685 | =cut |
878 | =cut |
686 | |
879 | |
|
|
880 | our $true = do { bless \(my $dummy = "1"), "JSON::XS::Boolean" }; |
|
|
881 | our $false = do { bless \(my $dummy = "0"), "JSON::XS::Boolean" }; |
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|
882 | |
687 | sub true() { \1 } |
883 | sub true() { $true } |
688 | sub false() { \0 } |
884 | sub false() { $false } |
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|
885 | |
|
|
886 | sub is_bool($) { |
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887 | UNIVERSAL::isa $_[0], "JSON::XS::Boolean" |
|
|
888 | # or UNIVERSAL::isa $_[0], "JSON::Literal" |
|
|
889 | } |
|
|
890 | |
|
|
891 | XSLoader::load "JSON::XS", $VERSION; |
|
|
892 | |
|
|
893 | package JSON::XS::Boolean; |
|
|
894 | |
|
|
895 | use overload |
|
|
896 | "0+" => sub { ${$_[0]} }, |
|
|
897 | "++" => sub { $_[0] = ${$_[0]} + 1 }, |
|
|
898 | "--" => sub { $_[0] = ${$_[0]} - 1 }, |
|
|
899 | fallback => 1; |
689 | |
900 | |
690 | 1; |
901 | 1; |
691 | |
902 | |
692 | =head1 AUTHOR |
903 | =head1 AUTHOR |
693 | |
904 | |