… | |
… | |
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 = '1.24'; |
86 | our $VERSION = '1.42'; |
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->($hashref)]) |
|
|
354 | |
|
|
355 | When C<$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, any existing callback will |
|
|
365 | be removed and C<decode> will not change the deserialised hash in any |
|
|
366 | way. |
|
|
367 | |
|
|
368 | Example, convert all JSON objects into the integer 5: |
|
|
369 | |
|
|
370 | my $js = JSON::XS->new->filter_json_object (sub { 5 }); |
|
|
371 | # returns [5] |
|
|
372 | $js->decode ('[{}]') |
|
|
373 | # throw an exception because allow_nonref is not enabled |
|
|
374 | # so a lone 5 is not allowed. |
|
|
375 | $js->decode ('{"a":1, "b":2}'); |
|
|
376 | |
|
|
377 | =item $json = $json->filter_json_single_key_object ($key [=> $coderef->($value)]) |
|
|
378 | |
|
|
379 | Works remotely similar to C<filter_json_object>, but is only called for |
|
|
380 | JSON objects having a single key named C<$key>. |
|
|
381 | |
|
|
382 | This C<$coderef> is called before the one specified via |
|
|
383 | C<filter_json_object>, if any. It gets passed the single value in the JSON |
|
|
384 | object. If it returns a single value, it will be inserted into the data |
|
|
385 | structure. If it returns nothing (not even C<undef> but the empty list), |
|
|
386 | the callback from C<filter_json_object> will be called next, as if no |
|
|
387 | single-key callback were specified. |
|
|
388 | |
|
|
389 | If C<$coderef> is omitted or undefined, the corresponding callback will be |
|
|
390 | disabled. There can only ever be one callback for a given key. |
|
|
391 | |
|
|
392 | As this callback gets called less often then the C<filter_json_object> |
|
|
393 | one, decoding speed will not usually suffer as much. Therefore, single-key |
|
|
394 | objects make excellent targets to serialise Perl objects into, especially |
|
|
395 | as single-key JSON objects are as close to the type-tagged value concept |
|
|
396 | as JSON gets (its basically an ID/VALUE tuple). Of course, JSON does not |
|
|
397 | support this in any way, so you need to make sure your data never looks |
|
|
398 | like a serialised Perl hash. |
|
|
399 | |
|
|
400 | Typical names for the single object key are C<__class_whatever__>, or |
|
|
401 | C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even |
|
|
402 | things like C<__class_md5sum(classname)__>, to reduce the risk of clashing |
|
|
403 | with real hashes. |
|
|
404 | |
|
|
405 | Example, decode JSON objects of the form C<< { "__widget__" => <id> } >> |
|
|
406 | into the corresponding C<< $WIDGET{<id>} >> object: |
|
|
407 | |
|
|
408 | # return whatever is in $WIDGET{5}: |
|
|
409 | JSON::XS |
|
|
410 | ->new |
|
|
411 | ->filter_json_single_key_object (__widget__ => sub { |
|
|
412 | $WIDGET{ $_[0] } |
|
|
413 | }) |
|
|
414 | ->decode ('{"__widget__": 5') |
|
|
415 | |
|
|
416 | # this can be used with a TO_JSON method in some "widget" class |
|
|
417 | # for serialisation to json: |
|
|
418 | sub WidgetBase::TO_JSON { |
|
|
419 | my ($self) = @_; |
|
|
420 | |
|
|
421 | unless ($self->{id}) { |
|
|
422 | $self->{id} = ..get..some..id..; |
|
|
423 | $WIDGET{$self->{id}} = $self; |
|
|
424 | } |
|
|
425 | |
|
|
426 | { __widget__ => $self->{id} } |
|
|
427 | } |
314 | |
428 | |
315 | =item $json = $json->shrink ([$enable]) |
429 | =item $json = $json->shrink ([$enable]) |
316 | |
430 | |
317 | Perl usually over-allocates memory a bit when allocating space for |
431 | Perl usually over-allocates memory a bit when allocating space for |
318 | strings. This flag optionally resizes strings generated by either |
432 | strings. This flag optionally resizes strings generated by either |
… | |
… | |
351 | given character in a string. |
465 | given character in a string. |
352 | |
466 | |
353 | Setting the maximum depth to one disallows any nesting, so that ensures |
467 | Setting the maximum depth to one disallows any nesting, so that ensures |
354 | that the object is only a single hash/object or array. |
468 | that the object is only a single hash/object or array. |
355 | |
469 | |
356 | The argument to C<max_depth> will be rounded up to the next nearest power |
470 | The argument to C<max_depth> will be rounded up to the next highest power |
357 | of two. |
471 | of two. If no argument is given, the highest possible setting will be |
|
|
472 | used, which is rarely useful. |
|
|
473 | |
|
|
474 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
|
|
475 | |
|
|
476 | =item $json = $json->max_size ([$maximum_string_size]) |
|
|
477 | |
|
|
478 | Set the maximum length a JSON text may have (in bytes) where decoding is |
|
|
479 | being attempted. The default is C<0>, meaning no limit. When C<decode> |
|
|
480 | is called on a string longer then this number of characters it will not |
|
|
481 | attempt to decode the string but throw an exception. This setting has no |
|
|
482 | effect on C<encode> (yet). |
|
|
483 | |
|
|
484 | The argument to C<max_size> will be rounded up to the next B<highest> |
|
|
485 | power of two (so may be more than requested). If no argument is given, the |
|
|
486 | limit check will be deactivated (same as when C<0> is specified). |
358 | |
487 | |
359 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
488 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
360 | |
489 | |
361 | =item $json_text = $json->encode ($perl_scalar) |
490 | =item $json_text = $json->encode ($perl_scalar) |
362 | |
491 | |
… | |
… | |
432 | conversion details, but an integer may take slightly less memory and might |
561 | conversion details, but an integer may take slightly less memory and might |
433 | represent more values exactly than (floating point) numbers. |
562 | represent more values exactly than (floating point) numbers. |
434 | |
563 | |
435 | =item true, false |
564 | =item true, false |
436 | |
565 | |
437 | These JSON atoms become C<0>, C<1>, respectively. Information is lost in |
566 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
438 | this process. Future versions might represent those values differently, |
567 | respectively. They are overloaded to act almost exactly like the numbers |
439 | but they will be guarenteed to act like these integers would normally in |
568 | C<1> and C<0>. You can check wether a scalar is a JSON boolean by using |
440 | Perl. |
569 | the C<JSON::XS::is_bool> function. |
441 | |
570 | |
442 | =item null |
571 | =item null |
443 | |
572 | |
444 | A JSON null atom becomes C<undef> in Perl. |
573 | A JSON null atom becomes C<undef> in Perl. |
445 | |
574 | |
… | |
… | |
477 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
606 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
478 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
607 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
479 | |
608 | |
480 | to_json [\0,JSON::XS::true] # yields [false,true] |
609 | to_json [\0,JSON::XS::true] # yields [false,true] |
481 | |
610 | |
|
|
611 | =item JSON::XS::true, JSON::XS::false |
|
|
612 | |
|
|
613 | These special values become JSON true and JSON false values, |
|
|
614 | respectively. You cna alos use C<\1> and C<\0> directly if you want. |
|
|
615 | |
482 | =item blessed objects |
616 | =item blessed objects |
483 | |
617 | |
484 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
618 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
485 | underlying representation (hash- or arrayref), but this behaviour might |
619 | underlying representation (hash- or arrayref), but this behaviour might |
486 | change in future versions. |
620 | change in future versions. |
… | |
… | |
649 | It shows the number of encodes/decodes per second (JSON::XS uses |
783 | It shows the number of encodes/decodes per second (JSON::XS uses |
650 | the functional interface, while JSON::XS/2 uses the OO interface |
784 | the functional interface, while JSON::XS/2 uses the OO interface |
651 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
785 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
652 | shrink). Higher is better: |
786 | shrink). Higher is better: |
653 | |
787 | |
|
|
788 | Storable | 15779.925 | 14169.946 | |
|
|
789 | -----------+------------+------------+ |
654 | module | encode | decode | |
790 | module | encode | decode | |
655 | -----------|------------|------------| |
791 | -----------|------------|------------| |
656 | JSON | 7645.468 | 4208.613 | |
792 | JSON | 4990.842 | 4088.813 | |
657 | JSON::DWIW | 40721.398 | 77101.176 | |
793 | JSON::DWIW | 51653.990 | 71575.154 | |
658 | JSON::PC | 65948.176 | 78251.940 | |
794 | JSON::PC | 65948.176 | 74631.744 | |
659 | JSON::Syck | 22844.793 | 26479.192 | |
795 | JSON::PP | 8931.652 | 3817.168 | |
|
|
796 | JSON::Syck | 24877.248 | 27776.848 | |
660 | JSON::XS | 388361.481 | 199728.762 | |
797 | JSON::XS | 388361.481 | 227951.304 | |
661 | JSON::XS/2 | 218453.333 | 192399.266 | |
798 | JSON::XS/2 | 227951.304 | 218453.333 | |
662 | JSON::XS/3 | 338250.323 | 192399.266 | |
799 | JSON::XS/3 | 338250.323 | 218453.333 | |
663 | Storable | 15779.925 | 14169.946 | |
800 | Storable | 16500.016 | 135300.129 | |
664 | -----------+------------+------------+ |
801 | -----------+------------+------------+ |
665 | |
802 | |
666 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
803 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
667 | about three times faster on decoding, and over fourty times faster |
804 | about three times faster on decoding, and over fourty times faster |
668 | than JSON, even with pretty-printing and key sorting. It also compares |
805 | than JSON, even with pretty-printing and key sorting. It also compares |
… | |
… | |
671 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
808 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
672 | search API (http://nanoref.com/yahooapis/mgPdGg): |
809 | search API (http://nanoref.com/yahooapis/mgPdGg): |
673 | |
810 | |
674 | module | encode | decode | |
811 | module | encode | decode | |
675 | -----------|------------|------------| |
812 | -----------|------------|------------| |
676 | JSON | 254.685 | 37.665 | |
813 | JSON | 55.260 | 34.971 | |
677 | JSON::DWIW | 843.343 | 1049.731 | |
814 | JSON::DWIW | 825.228 | 1082.513 | |
678 | JSON::PC | 3602.116 | 2307.352 | |
815 | JSON::PC | 3571.444 | 2394.829 | |
|
|
816 | JSON::PP | 210.987 | 32.574 | |
679 | JSON::Syck | 505.107 | 787.899 | |
817 | JSON::Syck | 552.551 | 787.544 | |
680 | JSON::XS | 5747.196 | 3690.220 | |
818 | JSON::XS | 5780.463 | 4854.519 | |
681 | JSON::XS/2 | 3968.121 | 3676.634 | |
819 | JSON::XS/2 | 3869.998 | 4798.975 | |
682 | JSON::XS/3 | 6105.246 | 3662.508 | |
820 | JSON::XS/3 | 5862.880 | 4798.975 | |
683 | Storable | 4417.337 | 5285.161 | |
821 | Storable | 4445.002 | 5235.027 | |
684 | -----------+------------+------------+ |
822 | -----------+------------+------------+ |
685 | |
823 | |
686 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
824 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
687 | decodes faster). |
825 | decodes faster). |
688 | |
826 | |
… | |
… | |
705 | Second, you need to avoid resource-starving attacks. That means you should |
843 | Second, you need to avoid resource-starving attacks. That means you should |
706 | limit the size of JSON texts you accept, or make sure then when your |
844 | limit the size of JSON texts you accept, or make sure then when your |
707 | resources run out, thats just fine (e.g. by using a separate process that |
845 | resources run out, thats just fine (e.g. by using a separate process that |
708 | can crash safely). The size of a JSON text in octets or characters is |
846 | can crash safely). The size of a JSON text in octets or characters is |
709 | usually a good indication of the size of the resources required to decode |
847 | usually a good indication of the size of the resources required to decode |
710 | it into a Perl structure. |
848 | it into a Perl structure. While JSON::XS can check the size of the JSON |
|
|
849 | text, it might be too late when you already have it in memory, so you |
|
|
850 | might want to check the size before you accept the string. |
711 | |
851 | |
712 | Third, JSON::XS recurses using the C stack when decoding objects and |
852 | Third, JSON::XS recurses using the C stack when decoding objects and |
713 | arrays. The C stack is a limited resource: for instance, on my amd64 |
853 | arrays. The C stack is a limited resource: for instance, on my amd64 |
714 | machine with 8MB of stack size I can decode around 180k nested arrays but |
854 | machine with 8MB of stack size I can decode around 180k nested arrays but |
715 | only 14k nested JSON objects (due to perl itself recursing deeply on croak |
855 | only 14k nested JSON objects (due to perl itself recursing deeply on croak |
… | |
… | |
720 | |
860 | |
721 | And last but least, something else could bomb you that I forgot to think |
861 | And last but least, something else could bomb you that I forgot to think |
722 | of. In that case, you get to keep the pieces. I am always open for hints, |
862 | of. In that case, you get to keep the pieces. I am always open for hints, |
723 | though... |
863 | though... |
724 | |
864 | |
|
|
865 | If you are using JSON::XS to return packets to consumption |
|
|
866 | by javascript scripts in a browser you should have a look at |
|
|
867 | L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether |
|
|
868 | you are vulnerable to some common attack vectors (which really are browser |
|
|
869 | design bugs, but it is still you who will have to deal with it, as major |
|
|
870 | browser developers care only for features, not about doing security |
|
|
871 | right). |
|
|
872 | |
725 | |
873 | |
726 | =head1 BUGS |
874 | =head1 BUGS |
727 | |
875 | |
728 | While the goal of this module is to be correct, that unfortunately does |
876 | While the goal of this module is to be correct, that unfortunately does |
729 | not mean its bug-free, only that I think its design is bug-free. It is |
877 | not mean its bug-free, only that I think its design is bug-free. It is |
730 | still relatively early in its development. If you keep reporting bugs they |
878 | still relatively early in its development. If you keep reporting bugs they |
731 | will be fixed swiftly, though. |
879 | will be fixed swiftly, though. |
732 | |
880 | |
733 | =cut |
881 | =cut |
734 | |
882 | |
|
|
883 | our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" }; |
|
|
884 | our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" }; |
|
|
885 | |
735 | sub true() { \1 } |
886 | sub true() { $true } |
736 | sub false() { \0 } |
887 | sub false() { $false } |
|
|
888 | |
|
|
889 | sub is_bool($) { |
|
|
890 | UNIVERSAL::isa $_[0], "JSON::XS::Boolean" |
|
|
891 | # or UNIVERSAL::isa $_[0], "JSON::Literal" |
|
|
892 | } |
|
|
893 | |
|
|
894 | XSLoader::load "JSON::XS", $VERSION; |
|
|
895 | |
|
|
896 | package JSON::XS::Boolean; |
|
|
897 | |
|
|
898 | use overload |
|
|
899 | "0+" => sub { ${$_[0]} }, |
|
|
900 | "++" => sub { $_[0] = ${$_[0]} + 1 }, |
|
|
901 | "--" => sub { $_[0] = ${$_[0]} - 1 }, |
|
|
902 | fallback => 1; |
737 | |
903 | |
738 | 1; |
904 | 1; |
739 | |
905 | |
740 | =head1 AUTHOR |
906 | =head1 AUTHOR |
741 | |
907 | |