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85 | |
85 | |
86 | package JSON::XS; |
86 | package JSON::XS; |
87 | |
87 | |
88 | use strict; |
88 | use strict; |
89 | |
89 | |
90 | our $VERSION = '1.3'; |
90 | our $VERSION = '1.4'; |
91 | our @ISA = qw(Exporter); |
91 | our @ISA = qw(Exporter); |
92 | |
92 | |
93 | our @EXPORT = qw(to_json from_json objToJson jsonToObj); |
93 | our @EXPORT = qw(to_json from_json objToJson jsonToObj); |
94 | |
94 | |
95 | use Exporter; |
95 | use Exporter; |
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315 | Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>, |
315 | Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>, |
316 | resulting in an invalid JSON text: |
316 | resulting in an invalid JSON text: |
317 | |
317 | |
318 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
318 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
319 | => "Hello, World!" |
319 | => "Hello, World!" |
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320 | |
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321 | =item $json = $json->allow_blessed ([$enable]) |
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322 | |
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323 | If C<$enable> is true (or missing), then the C<encode> method will not |
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324 | barf when it encounters a blessed reference. Instead, the value of the |
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325 | B<convert_blessed> option will decide wether C<null> (C<convert_blessed> |
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326 | disabled or no C<to_json> method found) or a representation of the |
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327 | object (C<convert_blessed> enabled and C<to_json> method found) is being |
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328 | encoded. Has no effect on C<decode>. |
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329 | |
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330 | If C<$enable> is false (the default), then C<encode> will throw an |
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331 | exception when it encounters a blessed object. |
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332 | |
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333 | =item $json = $json->convert_blessed ([$enable]) |
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334 | |
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335 | If C<$enable> is true (or missing), then C<encode>, upon encountering a |
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336 | blessed object, will check for the availability of the C<TO_JSON> method |
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337 | on the object's class. If found, it will be called in scalar context |
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338 | and the resulting scalar will be encoded instead of the object. If no |
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339 | C<TO_JSON> method is found, the value of C<allow_blessed> will decide what |
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340 | to do. |
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341 | |
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342 | The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON> |
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343 | returns other blessed objects, those will be handled in the same |
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344 | way. C<TO_JSON> must take care of not causing an endless recursion cycle |
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345 | (== crash) in this case. The name of C<TO_JSON> was chosen because other |
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346 | methods called by the Perl core (== not by the user of the object) are |
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347 | usually in upper case letters and to avoid collisions with the C<to_json> |
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348 | function. |
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349 | |
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350 | This setting does not yet influence C<decode> in any way, but in the |
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351 | future, global hooks might get installed that influence C<decode> and are |
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352 | enabled by this setting. |
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353 | |
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354 | If C<$enable> is false, then the C<allow_blessed> setting will decide what |
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355 | to do when a blessed object is found. |
320 | |
356 | |
321 | =item $json = $json->shrink ([$enable]) |
357 | =item $json = $json->shrink ([$enable]) |
322 | |
358 | |
323 | Perl usually over-allocates memory a bit when allocating space for |
359 | Perl usually over-allocates memory a bit when allocating space for |
324 | strings. This flag optionally resizes strings generated by either |
360 | strings. This flag optionally resizes strings generated by either |
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357 | given character in a string. |
393 | given character in a string. |
358 | |
394 | |
359 | Setting the maximum depth to one disallows any nesting, so that ensures |
395 | Setting the maximum depth to one disallows any nesting, so that ensures |
360 | that the object is only a single hash/object or array. |
396 | that the object is only a single hash/object or array. |
361 | |
397 | |
362 | The argument to C<max_depth> will be rounded up to the next nearest power |
398 | The argument to C<max_depth> will be rounded up to the next highest power |
363 | of two. |
399 | of two. If no argument is given, the highest possible setting will be |
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400 | used, which is rarely useful. |
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401 | |
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402 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
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403 | |
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404 | =item $json = $json->max_size ([$maximum_string_size]) |
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405 | |
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406 | Set the maximum length a JSON text may have (in bytes) where decoding is |
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407 | being attempted. The default is C<0>, meaning no limit. When C<decode> |
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408 | is called on a string longer then this number of characters it will not |
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409 | attempt to decode the string but throw an exception. This setting has no |
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410 | effect on C<encode> (yet). |
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411 | |
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412 | The argument to C<max_size> will be rounded up to the next B<highest> |
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413 | power of two (so may be more than requested). If no argument is given, the |
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414 | limit check will be deactivated (same as when C<0> is specified). |
364 | |
415 | |
365 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
416 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
366 | |
417 | |
367 | =item $json_text = $json->encode ($perl_scalar) |
418 | =item $json_text = $json->encode ($perl_scalar) |
368 | |
419 | |
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660 | It shows the number of encodes/decodes per second (JSON::XS uses |
711 | It shows the number of encodes/decodes per second (JSON::XS uses |
661 | the functional interface, while JSON::XS/2 uses the OO interface |
712 | the functional interface, while JSON::XS/2 uses the OO interface |
662 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
713 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
663 | shrink). Higher is better: |
714 | shrink). Higher is better: |
664 | |
715 | |
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716 | Storable | 15779.925 | 14169.946 | |
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717 | -----------+------------+------------+ |
665 | module | encode | decode | |
718 | module | encode | decode | |
666 | -----------|------------|------------| |
719 | -----------|------------|------------| |
667 | JSON | 7645.468 | 4208.613 | |
720 | JSON | 4990.842 | 4088.813 | |
668 | JSON::DWIW | 40721.398 | 77101.176 | |
721 | JSON::DWIW | 51653.990 | 71575.154 | |
669 | JSON::PC | 65948.176 | 78251.940 | |
722 | JSON::PC | 65948.176 | 74631.744 | |
670 | JSON::Syck | 22844.793 | 26479.192 | |
723 | JSON::PP | 8931.652 | 3817.168 | |
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724 | JSON::Syck | 24877.248 | 27776.848 | |
671 | JSON::XS | 388361.481 | 199728.762 | |
725 | JSON::XS | 388361.481 | 227951.304 | |
672 | JSON::XS/2 | 218453.333 | 192399.266 | |
726 | JSON::XS/2 | 227951.304 | 218453.333 | |
673 | JSON::XS/3 | 338250.323 | 192399.266 | |
727 | JSON::XS/3 | 338250.323 | 218453.333 | |
674 | Storable | 15779.925 | 14169.946 | |
728 | Storable | 16500.016 | 135300.129 | |
675 | -----------+------------+------------+ |
729 | -----------+------------+------------+ |
676 | |
730 | |
677 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
731 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
678 | about three times faster on decoding, and over fourty times faster |
732 | about three times faster on decoding, and over fourty times faster |
679 | than JSON, even with pretty-printing and key sorting. It also compares |
733 | than JSON, even with pretty-printing and key sorting. It also compares |
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682 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
736 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
683 | search API (http://nanoref.com/yahooapis/mgPdGg): |
737 | search API (http://nanoref.com/yahooapis/mgPdGg): |
684 | |
738 | |
685 | module | encode | decode | |
739 | module | encode | decode | |
686 | -----------|------------|------------| |
740 | -----------|------------|------------| |
687 | JSON | 254.685 | 37.665 | |
741 | JSON | 55.260 | 34.971 | |
688 | JSON::DWIW | 843.343 | 1049.731 | |
742 | JSON::DWIW | 825.228 | 1082.513 | |
689 | JSON::PC | 3602.116 | 2307.352 | |
743 | JSON::PC | 3571.444 | 2394.829 | |
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744 | JSON::PP | 210.987 | 32.574 | |
690 | JSON::Syck | 505.107 | 787.899 | |
745 | JSON::Syck | 552.551 | 787.544 | |
691 | JSON::XS | 5747.196 | 3690.220 | |
746 | JSON::XS | 5780.463 | 4854.519 | |
692 | JSON::XS/2 | 3968.121 | 3676.634 | |
747 | JSON::XS/2 | 3869.998 | 4798.975 | |
693 | JSON::XS/3 | 6105.246 | 3662.508 | |
748 | JSON::XS/3 | 5862.880 | 4798.975 | |
694 | Storable | 4417.337 | 5285.161 | |
749 | Storable | 4445.002 | 5235.027 | |
695 | -----------+------------+------------+ |
750 | -----------+------------+------------+ |
696 | |
751 | |
697 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
752 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
698 | decodes faster). |
753 | decodes faster). |
699 | |
754 | |
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716 | Second, you need to avoid resource-starving attacks. That means you should |
771 | Second, you need to avoid resource-starving attacks. That means you should |
717 | limit the size of JSON texts you accept, or make sure then when your |
772 | limit the size of JSON texts you accept, or make sure then when your |
718 | resources run out, thats just fine (e.g. by using a separate process that |
773 | resources run out, thats just fine (e.g. by using a separate process that |
719 | can crash safely). The size of a JSON text in octets or characters is |
774 | can crash safely). The size of a JSON text in octets or characters is |
720 | usually a good indication of the size of the resources required to decode |
775 | usually a good indication of the size of the resources required to decode |
721 | it into a Perl structure. |
776 | it into a Perl structure. While JSON::XS can check the size of the JSON |
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777 | text, it might be too late when you already have it in memory, so you |
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778 | might want to check the size before you accept the string. |
722 | |
779 | |
723 | Third, JSON::XS recurses using the C stack when decoding objects and |
780 | Third, JSON::XS recurses using the C stack when decoding objects and |
724 | arrays. The C stack is a limited resource: for instance, on my amd64 |
781 | arrays. The C stack is a limited resource: for instance, on my amd64 |
725 | machine with 8MB of stack size I can decode around 180k nested arrays but |
782 | machine with 8MB of stack size I can decode around 180k nested arrays but |
726 | only 14k nested JSON objects (due to perl itself recursing deeply on croak |
783 | only 14k nested JSON objects (due to perl itself recursing deeply on croak |
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757 | sub true() { $true } |
814 | sub true() { $true } |
758 | sub false() { $false } |
815 | sub false() { $false } |
759 | |
816 | |
760 | sub is_bool($) { |
817 | sub is_bool($) { |
761 | UNIVERSAL::isa $_[0], "JSON::XS::Boolean" |
818 | UNIVERSAL::isa $_[0], "JSON::XS::Boolean" |
762 | or UNIVERSAL::isa $_[0], "JSON::Literal" |
819 | # or UNIVERSAL::isa $_[0], "JSON::Literal" |
763 | } |
820 | } |
764 | |
821 | |
765 | XSLoader::load "JSON::XS", $VERSION; |
822 | XSLoader::load "JSON::XS", $VERSION; |
766 | |
823 | |
767 | package JSON::XS::Boolean; |
824 | package JSON::XS::Boolean; |