ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/JSON-XS/XS.pm
(Generate patch)

Comparing JSON-XS/XS.pm (file contents):
Revision 1.36 by root, Wed May 23 22:07:43 2007 UTC vs.
Revision 1.43 by root, Sat Jun 23 23:49:29 2007 UTC

… …
85 85
86package JSON::XS; 86package JSON::XS;
87 87
88use strict; 88use strict;
89 89
90BEGIN {
91 our $VERSION = '1.22'; 90our $VERSION = '1.3';
92 our @ISA = qw(Exporter); 91our @ISA = qw(Exporter);
93 92
94 our @EXPORT = qw(to_json from_json objToJson jsonToObj); 93our @EXPORT = qw(to_json from_json objToJson jsonToObj);
95 require Exporter;
96 94
97 require XSLoader; 95use Exporter;
98 XSLoader::load JSON::XS::, $VERSION; 96use XSLoader;
99}
100 97
101=head1 FUNCTIONAL INTERFACE 98=head1 FUNCTIONAL INTERFACE
102 99
103The following convinience methods are provided by this module. They are 100The following convinience methods are provided by this module. They are
104exported by default: 101exported by default:
… …
126This function call is functionally identical to: 123This 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
130except being faster. 127except being faster.
128
129=item $is_boolean = JSON::XS::is_bool $scalar
130
131Returns true if the passed scalar represents either JSON::XS::true or
132JSON::XS::false, two constants that act like C<1> and C<0>, respectively
133and are used to represent JSON C<true> and C<false> values in Perl.
134
135See MAPPING, below, for more information on how JSON values are mapped to
136Perl.
131 137
132=back 138=back
133 139
134 140
135=head1 OBJECT-ORIENTED INTERFACE 141=head1 OBJECT-ORIENTED INTERFACE
… …
402 408
403For the more enlightened: note that in the following descriptions, 409For the more enlightened: note that in the following descriptions,
404lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl> 410lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl>
405refers to the abstract Perl language itself. 411refers to the abstract Perl language itself.
406 412
413
407=head2 JSON -> PERL 414=head2 JSON -> PERL
408 415
409=over 4 416=over 4
410 417
411=item object 418=item object
… …
431conversion details, but an integer may take slightly less memory and might 438conversion details, but an integer may take slightly less memory and might
432represent more values exactly than (floating point) numbers. 439represent more values exactly than (floating point) numbers.
433 440
434=item true, false 441=item true, false
435 442
436These JSON atoms become C<0>, C<1>, respectively. Information is lost in 443These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,
437this process. Future versions might represent those values differently, 444respectively. They are overloaded to act almost exactly like the numbers
438but they will be guarenteed to act like these integers would normally in 445C<1> and C<0>. You can check wether a scalar is a JSON boolean by using
439Perl. 446the C<JSON::XS::is_bool> function.
440 447
441=item null 448=item null
442 449
443A JSON null atom becomes C<undef> in Perl. 450A JSON null atom becomes C<undef> in Perl.
444 451
445=back 452=back
453
446 454
447=head2 PERL -> JSON 455=head2 PERL -> JSON
448 456
449The mapping from Perl to JSON is slightly more difficult, as Perl is a 457The mapping from Perl to JSON is slightly more difficult, as Perl is a
450truly typeless language, so we can only guess which JSON type is meant by 458truly typeless language, so we can only guess which JSON type is meant by
… …
475C<1>, which get turned into C<false> and C<true> atoms in JSON. You can 483C<1>, which get turned into C<false> and C<true> atoms in JSON. You can
476also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. 484also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
477 485
478 to_json [\0,JSON::XS::true] # yields [false,true] 486 to_json [\0,JSON::XS::true] # yields [false,true]
479 487
488=item JSON::XS::true, JSON::XS::false
489
490These special values become JSON true and JSON false values,
491respectively. You cna alos use C<\1> and C<\0> directly if you want.
492
480=item blessed objects 493=item blessed objects
481 494
482Blessed objects are not allowed. JSON::XS currently tries to encode their 495Blessed objects are not allowed. JSON::XS currently tries to encode their
483underlying representation (hash- or arrayref), but this behaviour might 496underlying representation (hash- or arrayref), but this behaviour might
484change in future versions. 497change in future versions.
… …
605 618
606Does not check input for validity. 619Does not check input for validity.
607 620
608=back 621=back
609 622
623
624=head2 JSON and YAML
625
626You often hear that JSON is a subset (or a close subset) of YAML. This is,
627however, a mass hysteria and very far from the truth. In general, there is
628no way to configure JSON::XS to output a data structure as valid YAML.
629
630If you really must use JSON::XS to generate YAML, you should use this
631algorithm (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
636This will usually generate JSON texts that also parse as valid
637YAML. Please note that YAML has hardcoded limits on (simple) object key
638lengths that JSON doesn't have, so you should make sure that your hash
639keys are noticably shorter than the 1024 characters YAML allows.
640
641There might be other incompatibilities that I am not aware of. In general
642you should not try to generate YAML with a JSON generator or vice versa,
643or try to parse JSON with a YAML parser or vice versa: chances are high
644that you will run into severe interoperability problems.
645
646
610=head2 SPEED 647=head2 SPEED
611 648
612It seems that JSON::XS is surprisingly fast, as shown in the following 649It seems that JSON::XS is surprisingly fast, as shown in the following
613tables. They have been generated with the help of the C<eg/bench> program 650tables. They have been generated with the help of the C<eg/bench> program
614in the JSON::XS distribution, to make it easy to compare on your own 651in the JSON::XS distribution, to make it easy to compare on your own
615system. 652system.
616 653
617First comes a comparison between various modules using a very short JSON 654First comes a comparison between various modules using a very short
618string: 655single-line JSON string:
619 656
620 {"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]}
621 659
622It shows the number of encodes/decodes per second (JSON::XS uses the 660It shows the number of encodes/decodes per second (JSON::XS uses
623functional interface, while JSON::XS/2 uses the OO interface with 661the functional interface, while JSON::XS/2 uses the OO interface
624pretty-printing and hashkey sorting enabled). Higher is better: 662with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables
663shrink). Higher is better:
625 664
626 module | encode | decode | 665 module | encode | decode |
627 -----------|------------|------------| 666 -----------|------------|------------|
628 JSON | 11488.516 | 7823.035 | 667 JSON | 7645.468 | 4208.613 |
629 JSON::DWIW | 94708.054 | 129094.260 | 668 JSON::DWIW | 40721.398 | 77101.176 |
630 JSON::PC | 63884.157 | 128528.212 | 669 JSON::PC | 65948.176 | 78251.940 |
631 JSON::Syck | 34898.677 | 42096.911 | 670 JSON::Syck | 22844.793 | 26479.192 |
632 JSON::XS | 654027.064 | 396423.669 | 671 JSON::XS | 388361.481 | 199728.762 |
633 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 |
634 -----------+------------+------------+ 675 -----------+------------+------------+
635 676
636That is, JSON::XS is more than six times faster than JSON::DWIW on 677That is, JSON::XS is about five times faster than JSON::DWIW on encoding,
637encoding, more than three times faster on decoding, and about thirty times 678about three times faster on decoding, and over fourty times faster
638faster than JSON, even with pretty-printing and key sorting. 679than JSON, even with pretty-printing and key sorting. It also compares
680favourably to Storable for small amounts of data.
639 681
640Using a longer test string (roughly 18KB, generated from Yahoo! Locals 682Using a longer test string (roughly 18KB, generated from Yahoo! Locals
641search API (http://nanoref.com/yahooapis/mgPdGg): 683search API (http://nanoref.com/yahooapis/mgPdGg):
642 684
643 module | encode | decode | 685 module | encode | decode |
644 -----------|------------|------------| 686 -----------|------------|------------|
645 JSON | 273.023 | 44.674 | 687 JSON | 254.685 | 37.665 |
646 JSON::DWIW | 1089.383 | 1145.704 | 688 JSON::DWIW | 843.343 | 1049.731 |
647 JSON::PC | 3097.419 | 2393.921 | 689 JSON::PC | 3602.116 | 2307.352 |
648 JSON::Syck | 514.060 | 843.053 | 690 JSON::Syck | 505.107 | 787.899 |
649 JSON::XS | 6479.668 | 3636.364 | 691 JSON::XS | 5747.196 | 3690.220 |
650 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 |
651 -----------+------------+------------+ 695 -----------+------------+------------+
652 696
653Again, JSON::XS leads by far. 697Again, JSON::XS leads by far (except for Storable which non-surprisingly
698decodes faster).
654 699
655On large strings containing lots of high unicode characters, some modules 700On large strings containing lots of high unicode characters, some modules
656(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
657will be broken due to missing (or wrong) unicode handling. Others refuse 702will be broken due to missing (or wrong) unicode handling. Others refuse
658to decode or encode properly, so it was impossible to prepare a fair 703to decode or encode properly, so it was impossible to prepare a fair
… …
686 731
687And last but least, something else could bomb you that I forgot to think 732And last but least, something else could bomb you that I forgot to think
688of. In that case, you get to keep the pieces. I am always open for hints, 733of. In that case, you get to keep the pieces. I am always open for hints,
689though... 734though...
690 735
736If you are using JSON::XS to return packets to consumption
737by javascript scripts in a browser you should have a look at
738L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether
739you are vulnerable to some common attack vectors (which really are browser
740design bugs, but it is still you who will have to deal with it, as major
741browser developers care only for features, not about doing security
742right).
743
691 744
692=head1 BUGS 745=head1 BUGS
693 746
694While the goal of this module is to be correct, that unfortunately does 747While the goal of this module is to be correct, that unfortunately does
695not mean its bug-free, only that I think its design is bug-free. It is 748not mean its bug-free, only that I think its design is bug-free. It is
696still relatively early in its development. If you keep reporting bugs they 749still relatively early in its development. If you keep reporting bugs they
697will be fixed swiftly, though. 750will be fixed swiftly, though.
698 751
699=cut 752=cut
700 753
754our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" };
755our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" };
756
701sub true() { \1 } 757sub true() { $true }
702sub false() { \0 } 758sub false() { $false }
759
760sub is_bool($) {
761 UNIVERSAL::isa $_[0], "JSON::XS::Boolean"
762 or UNIVERSAL::isa $_[0], "JSON::Literal"
763}
764
765XSLoader::load "JSON::XS", $VERSION;
766
767package JSON::XS::Boolean;
768
769use overload
770 "0+" => sub { ${$_[0]} },
771 "++" => sub { $_[0] = ${$_[0]} + 1 },
772 "--" => sub { $_[0] = ${$_[0]} - 1 },
773 fallback => 1;
703 774
7041; 7751;
705 776
706=head1 AUTHOR 777=head1 AUTHOR
707 778

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines