… | |
… | |
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 = '0.8'; |
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: |
… | |
… | |
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. |
131 | |
124 | |
|
|
125 | =item $is_boolean = JSON::XS::is_bool $scalar |
|
|
126 | |
|
|
127 | Returns true if the passed scalar represents either JSON::XS::true or |
|
|
128 | JSON::XS::false, two constants that act like C<1> and C<0>, respectively |
|
|
129 | and are used to represent JSON C<true> and C<false> values in Perl. |
|
|
130 | |
|
|
131 | See MAPPING, below, for more information on how JSON values are mapped to |
|
|
132 | Perl. |
|
|
133 | |
132 | =back |
134 | =back |
|
|
135 | |
133 | |
136 | |
134 | =head1 OBJECT-ORIENTED INTERFACE |
137 | =head1 OBJECT-ORIENTED INTERFACE |
135 | |
138 | |
136 | The object oriented interface lets you configure your own encoding or |
139 | The object oriented interface lets you configure your own encoding or |
137 | decoding style, within the limits of supported formats. |
140 | decoding style, within the limits of supported formats. |
… | |
… | |
153 | |
156 | |
154 | If C<$enable> is true (or missing), then the C<encode> method will not |
157 | If C<$enable> is true (or missing), then the C<encode> method will not |
155 | generate characters outside the code range C<0..127> (which is ASCII). Any |
158 | generate characters outside the code range C<0..127> (which is ASCII). Any |
156 | unicode characters outside that range will be escaped using either a |
159 | unicode characters outside that range will be escaped using either a |
157 | single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, |
160 | single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, |
158 | as per RFC4627. |
161 | as per RFC4627. The resulting encoded JSON text can be treated as a native |
|
|
162 | unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string, |
|
|
163 | or any other superset of ASCII. |
159 | |
164 | |
160 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
165 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
161 | characters unless required by the JSON syntax. This results in a faster |
166 | characters unless required by the JSON syntax or other flags. This results |
162 | and more compact format. |
167 | in a faster and more compact format. |
|
|
168 | |
|
|
169 | The main use for this flag is to produce JSON texts that can be |
|
|
170 | transmitted over a 7-bit channel, as the encoded JSON texts will not |
|
|
171 | contain any 8 bit characters. |
163 | |
172 | |
164 | JSON::XS->new->ascii (1)->encode ([chr 0x10401]) |
173 | JSON::XS->new->ascii (1)->encode ([chr 0x10401]) |
165 | => ["\ud801\udc01"] |
174 | => ["\ud801\udc01"] |
|
|
175 | |
|
|
176 | =item $json = $json->latin1 ([$enable]) |
|
|
177 | |
|
|
178 | If C<$enable> is true (or missing), then the C<encode> method will encode |
|
|
179 | the resulting JSON text as latin1 (or iso-8859-1), escaping any characters |
|
|
180 | outside the code range C<0..255>. The resulting string can be treated as a |
|
|
181 | latin1-encoded JSON text or a native unicode string. The C<decode> method |
|
|
182 | will not be affected in any way by this flag, as C<decode> by default |
|
|
183 | expects unicode, which is a strict superset of latin1. |
|
|
184 | |
|
|
185 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
|
|
186 | characters unless required by the JSON syntax or other flags. |
|
|
187 | |
|
|
188 | The main use for this flag is efficiently encoding binary data as JSON |
|
|
189 | text, as most octets will not be escaped, resulting in a smaller encoded |
|
|
190 | size. The disadvantage is that the resulting JSON text is encoded |
|
|
191 | in latin1 (and must correctly be treated as such when storing and |
|
|
192 | transfering), a rare encoding for JSON. It is therefore most useful when |
|
|
193 | you want to store data structures known to contain binary data efficiently |
|
|
194 | in files or databases, not when talking to other JSON encoders/decoders. |
|
|
195 | |
|
|
196 | JSON::XS->new->latin1->encode (["\x{89}\x{abc}"] |
|
|
197 | => ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not) |
166 | |
198 | |
167 | =item $json = $json->utf8 ([$enable]) |
199 | =item $json = $json->utf8 ([$enable]) |
168 | |
200 | |
169 | If C<$enable> is true (or missing), then the C<encode> method will encode |
201 | If C<$enable> is true (or missing), then the C<encode> method will encode |
170 | the JSON result into UTF-8, as required by many protocols, while the |
202 | the JSON result into UTF-8, as required by many protocols, while the |
… | |
… | |
280 | resulting in an invalid JSON text: |
312 | resulting in an invalid JSON text: |
281 | |
313 | |
282 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
314 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
283 | => "Hello, World!" |
315 | => "Hello, World!" |
284 | |
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 | |
285 | =item $json = $json->shrink ([$enable]) |
353 | =item $json = $json->shrink ([$enable]) |
286 | |
354 | |
287 | Perl usually over-allocates memory a bit when allocating space for |
355 | Perl usually over-allocates memory a bit when allocating space for |
288 | strings. This flag optionally resizes strings generated by either |
356 | strings. This flag optionally resizes strings generated by either |
289 | C<encode> or C<decode> to their minimum size possible. This can save |
357 | C<encode> or C<decode> to their minimum size possible. This can save |
290 | memory when your JSON texts are either very very long or you have many |
358 | memory when your JSON texts are either very very long or you have many |
291 | short strings. It will also try to downgrade any strings to octet-form |
359 | short strings. It will also try to downgrade any strings to octet-form |
292 | if possible: perl stores strings internally either in an encoding called |
360 | if possible: perl stores strings internally either in an encoding called |
293 | UTF-X or in octet-form. The latter cannot store everything but uses less |
361 | UTF-X or in octet-form. The latter cannot store everything but uses less |
294 | space in general. |
362 | space in general (and some buggy Perl or C code might even rely on that |
|
|
363 | internal representation being used). |
295 | |
364 | |
|
|
365 | The actual definition of what shrink does might change in future versions, |
|
|
366 | but it will always try to save space at the expense of time. |
|
|
367 | |
296 | If C<$enable> is true (or missing), the string returned by C<encode> will be shrunk-to-fit, |
368 | If C<$enable> is true (or missing), the string returned by C<encode> will |
297 | while all strings generated by C<decode> will also be shrunk-to-fit. |
369 | be shrunk-to-fit, while all strings generated by C<decode> will also be |
|
|
370 | shrunk-to-fit. |
298 | |
371 | |
299 | If C<$enable> is false, then the normal perl allocation algorithms are used. |
372 | If C<$enable> is false, then the normal perl allocation algorithms are used. |
300 | If you work with your data, then this is likely to be faster. |
373 | If you work with your data, then this is likely to be faster. |
301 | |
374 | |
302 | In the future, this setting might control other things, such as converting |
375 | In the future, this setting might control other things, such as converting |
303 | strings that look like integers or floats into integers or floats |
376 | strings that look like integers or floats into integers or floats |
304 | internally (there is no difference on the Perl level), saving space. |
377 | internally (there is no difference on the Perl level), saving space. |
|
|
378 | |
|
|
379 | =item $json = $json->max_depth ([$maximum_nesting_depth]) |
|
|
380 | |
|
|
381 | Sets the maximum nesting level (default C<512>) accepted while encoding |
|
|
382 | or decoding. If the JSON text or Perl data structure has an equal or |
|
|
383 | higher nesting level then this limit, then the encoder and decoder will |
|
|
384 | stop and croak at that point. |
|
|
385 | |
|
|
386 | Nesting level is defined by number of hash- or arrayrefs that the encoder |
|
|
387 | needs to traverse to reach a given point or the number of C<{> or C<[> |
|
|
388 | characters without their matching closing parenthesis crossed to reach a |
|
|
389 | given character in a string. |
|
|
390 | |
|
|
391 | Setting the maximum depth to one disallows any nesting, so that ensures |
|
|
392 | that the object is only a single hash/object or array. |
|
|
393 | |
|
|
394 | The argument to C<max_depth> will be rounded up to the next highest power |
|
|
395 | of two. If no argument is given, the highest possible setting will be |
|
|
396 | used, which is rarely useful. |
|
|
397 | |
|
|
398 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
|
|
399 | |
|
|
400 | =item $json = $json->max_size ([$maximum_string_size]) |
|
|
401 | |
|
|
402 | Set the maximum length a JSON text may have (in bytes) where decoding is |
|
|
403 | being attempted. The default is C<0>, meaning no limit. When C<decode> |
|
|
404 | is called on a string longer then this number of characters it will not |
|
|
405 | attempt to decode the string but throw an exception. This setting has no |
|
|
406 | effect on C<encode> (yet). |
|
|
407 | |
|
|
408 | The argument to C<max_size> will be rounded up to the next B<highest> |
|
|
409 | power of two (so may be more than requested). If no argument is given, the |
|
|
410 | limit check will be deactivated (same as when C<0> is specified). |
|
|
411 | |
|
|
412 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
305 | |
413 | |
306 | =item $json_text = $json->encode ($perl_scalar) |
414 | =item $json_text = $json->encode ($perl_scalar) |
307 | |
415 | |
308 | Converts the given Perl data structure (a simple scalar or a reference |
416 | Converts the given Perl data structure (a simple scalar or a reference |
309 | to a hash or array) to its JSON representation. Simple scalars will be |
417 | to a hash or array) to its JSON representation. Simple scalars will be |
… | |
… | |
319 | |
427 | |
320 | JSON numbers and strings become simple Perl scalars. JSON arrays become |
428 | JSON numbers and strings become simple Perl scalars. JSON arrays become |
321 | Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes |
429 | Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes |
322 | C<1>, C<false> becomes C<0> and C<null> becomes C<undef>. |
430 | C<1>, C<false> becomes C<0> and C<null> becomes C<undef>. |
323 | |
431 | |
|
|
432 | =item ($perl_scalar, $characters) = $json->decode_prefix ($json_text) |
|
|
433 | |
|
|
434 | This works like the C<decode> method, but instead of raising an exception |
|
|
435 | when there is trailing garbage after the first JSON object, it will |
|
|
436 | silently stop parsing there and return the number of characters consumed |
|
|
437 | so far. |
|
|
438 | |
|
|
439 | This is useful if your JSON texts are not delimited by an outer protocol |
|
|
440 | (which is not the brightest thing to do in the first place) and you need |
|
|
441 | to know where the JSON text ends. |
|
|
442 | |
|
|
443 | JSON::XS->new->decode_prefix ("[1] the tail") |
|
|
444 | => ([], 3) |
|
|
445 | |
324 | =back |
446 | =back |
|
|
447 | |
325 | |
448 | |
326 | =head1 MAPPING |
449 | =head1 MAPPING |
327 | |
450 | |
328 | This section describes how JSON::XS maps Perl values to JSON values and |
451 | This section describes how JSON::XS maps Perl values to JSON values and |
329 | vice versa. These mappings are designed to "do the right thing" in most |
452 | vice versa. These mappings are designed to "do the right thing" in most |
… | |
… | |
331 | (what you put in comes out as something equivalent). |
454 | (what you put in comes out as something equivalent). |
332 | |
455 | |
333 | For the more enlightened: note that in the following descriptions, |
456 | For the more enlightened: note that in the following descriptions, |
334 | lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl> |
457 | lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl> |
335 | refers to the abstract Perl language itself. |
458 | refers to the abstract Perl language itself. |
|
|
459 | |
336 | |
460 | |
337 | =head2 JSON -> PERL |
461 | =head2 JSON -> PERL |
338 | |
462 | |
339 | =over 4 |
463 | =over 4 |
340 | |
464 | |
… | |
… | |
361 | conversion details, but an integer may take slightly less memory and might |
485 | conversion details, but an integer may take slightly less memory and might |
362 | represent more values exactly than (floating point) numbers. |
486 | represent more values exactly than (floating point) numbers. |
363 | |
487 | |
364 | =item true, false |
488 | =item true, false |
365 | |
489 | |
366 | These JSON atoms become C<0>, C<1>, respectively. Information is lost in |
490 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
367 | this process. Future versions might represent those values differently, |
491 | respectively. They are overloaded to act almost exactly like the numbers |
368 | but they will be guarenteed to act like these integers would normally in |
492 | C<1> and C<0>. You can check wether a scalar is a JSON boolean by using |
369 | Perl. |
493 | the C<JSON::XS::is_bool> function. |
370 | |
494 | |
371 | =item null |
495 | =item null |
372 | |
496 | |
373 | A JSON null atom becomes C<undef> in Perl. |
497 | A JSON null atom becomes C<undef> in Perl. |
374 | |
498 | |
375 | =back |
499 | =back |
|
|
500 | |
376 | |
501 | |
377 | =head2 PERL -> JSON |
502 | =head2 PERL -> JSON |
378 | |
503 | |
379 | The mapping from Perl to JSON is slightly more difficult, as Perl is a |
504 | The mapping from Perl to JSON is slightly more difficult, as Perl is a |
380 | truly typeless language, so we can only guess which JSON type is meant by |
505 | truly typeless language, so we can only guess which JSON type is meant by |
… | |
… | |
383 | =over 4 |
508 | =over 4 |
384 | |
509 | |
385 | =item hash references |
510 | =item hash references |
386 | |
511 | |
387 | Perl hash references become JSON objects. As there is no inherent ordering |
512 | Perl hash references become JSON objects. As there is no inherent ordering |
388 | in hash keys, they will usually be encoded in a pseudo-random order that |
513 | in hash keys (or JSON objects), they will usually be encoded in a |
389 | can change between runs of the same program but stays generally the same |
514 | pseudo-random order that can change between runs of the same program but |
390 | within a single run of a program. JSON::XS can optionally sort the hash |
515 | stays generally the same within a single run of a program. JSON::XS can |
391 | keys (determined by the I<canonical> flag), so the same datastructure |
516 | optionally sort the hash keys (determined by the I<canonical> flag), so |
392 | will serialise to the same JSON text (given same settings and version of |
517 | the same datastructure will serialise to the same JSON text (given same |
393 | JSON::XS), but this incurs a runtime overhead. |
518 | settings and version of JSON::XS), but this incurs a runtime overhead |
|
|
519 | and is only rarely useful, e.g. when you want to compare some JSON text |
|
|
520 | against another for equality. |
394 | |
521 | |
395 | =item array references |
522 | =item array references |
396 | |
523 | |
397 | Perl array references become JSON arrays. |
524 | Perl array references become JSON arrays. |
|
|
525 | |
|
|
526 | =item other references |
|
|
527 | |
|
|
528 | Other unblessed references are generally not allowed and will cause an |
|
|
529 | exception to be thrown, except for references to the integers C<0> and |
|
|
530 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
|
|
531 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
|
|
532 | |
|
|
533 | to_json [\0,JSON::XS::true] # yields [false,true] |
|
|
534 | |
|
|
535 | =item JSON::XS::true, JSON::XS::false |
|
|
536 | |
|
|
537 | These special values become JSON true and JSON false values, |
|
|
538 | respectively. You cna alos use C<\1> and C<\0> directly if you want. |
398 | |
539 | |
399 | =item blessed objects |
540 | =item blessed objects |
400 | |
541 | |
401 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
542 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
402 | underlying representation (hash- or arrayref), but this behaviour might |
543 | underlying representation (hash- or arrayref), but this behaviour might |
… | |
… | |
435 | $x *= 1; # same thing, the choise is yours. |
576 | $x *= 1; # same thing, the choise is yours. |
436 | |
577 | |
437 | You can not currently output JSON booleans or force the type in other, |
578 | You can not currently output JSON booleans or force the type in other, |
438 | less obscure, ways. Tell me if you need this capability. |
579 | less obscure, ways. Tell me if you need this capability. |
439 | |
580 | |
440 | =item circular data structures |
|
|
441 | |
|
|
442 | Those will be encoded until memory or stackspace runs out. |
|
|
443 | |
|
|
444 | =back |
581 | =back |
|
|
582 | |
445 | |
583 | |
446 | =head1 COMPARISON |
584 | =head1 COMPARISON |
447 | |
585 | |
448 | As already mentioned, this module was created because none of the existing |
586 | As already mentioned, this module was created because none of the existing |
449 | JSON modules could be made to work correctly. First I will describe the |
587 | JSON modules could be made to work correctly. First I will describe the |
… | |
… | |
527 | |
665 | |
528 | Does not check input for validity. |
666 | Does not check input for validity. |
529 | |
667 | |
530 | =back |
668 | =back |
531 | |
669 | |
|
|
670 | |
|
|
671 | =head2 JSON and YAML |
|
|
672 | |
|
|
673 | You often hear that JSON is a subset (or a close subset) of YAML. This is, |
|
|
674 | however, a mass hysteria and very far from the truth. In general, there is |
|
|
675 | no way to configure JSON::XS to output a data structure as valid YAML. |
|
|
676 | |
|
|
677 | If you really must use JSON::XS to generate YAML, you should use this |
|
|
678 | algorithm (subject to change in future versions): |
|
|
679 | |
|
|
680 | my $to_yaml = JSON::XS->new->utf8->space_after (1); |
|
|
681 | my $yaml = $to_yaml->encode ($ref) . "\n"; |
|
|
682 | |
|
|
683 | This will usually generate JSON texts that also parse as valid |
|
|
684 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
|
|
685 | lengths that JSON doesn't have, so you should make sure that your hash |
|
|
686 | keys are noticably shorter than the 1024 characters YAML allows. |
|
|
687 | |
|
|
688 | There might be other incompatibilities that I am not aware of. In general |
|
|
689 | you should not try to generate YAML with a JSON generator or vice versa, |
|
|
690 | or try to parse JSON with a YAML parser or vice versa: chances are high |
|
|
691 | that you will run into severe interoperability problems. |
|
|
692 | |
|
|
693 | |
532 | =head2 SPEED |
694 | =head2 SPEED |
533 | |
695 | |
534 | It seems that JSON::XS is surprisingly fast, as shown in the following |
696 | It seems that JSON::XS is surprisingly fast, as shown in the following |
535 | tables. They have been generated with the help of the C<eg/bench> program |
697 | tables. They have been generated with the help of the C<eg/bench> program |
536 | in the JSON::XS distribution, to make it easy to compare on your own |
698 | in the JSON::XS distribution, to make it easy to compare on your own |
537 | system. |
699 | system. |
538 | |
700 | |
539 | First comes a comparison between various modules using a very short JSON |
701 | First comes a comparison between various modules using a very short |
540 | string: |
702 | single-line JSON string: |
541 | |
703 | |
542 | {"method": "handleMessage", "params": ["user1", "we were just talking"], "id": null} |
704 | {"method": "handleMessage", "params": ["user1", "we were just talking"], \ |
|
|
705 | "id": null, "array":[1,11,234,-5,1e5,1e7, true, false]} |
543 | |
706 | |
544 | It shows the number of encodes/decodes per second (JSON::XS uses the |
707 | It shows the number of encodes/decodes per second (JSON::XS uses |
545 | functional interface, while JSON::XS/2 uses the OO interface with |
708 | the functional interface, while JSON::XS/2 uses the OO interface |
546 | pretty-printing and hashkey sorting enabled). Higher is better: |
709 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
|
|
710 | shrink). Higher is better: |
547 | |
711 | |
|
|
712 | Storable | 15779.925 | 14169.946 | |
|
|
713 | -----------+------------+------------+ |
548 | module | encode | decode | |
714 | module | encode | decode | |
549 | -----------|------------|------------| |
715 | -----------|------------|------------| |
550 | JSON | 11488.516 | 7823.035 | |
716 | JSON | 4990.842 | 4088.813 | |
551 | JSON::DWIW | 94708.054 | 129094.260 | |
717 | JSON::DWIW | 51653.990 | 71575.154 | |
552 | JSON::PC | 63884.157 | 128528.212 | |
718 | JSON::PC | 65948.176 | 74631.744 | |
553 | JSON::Syck | 34898.677 | 42096.911 | |
719 | JSON::PP | 8931.652 | 3817.168 | |
554 | JSON::XS | 654027.064 | 396423.669 | |
720 | JSON::Syck | 24877.248 | 27776.848 | |
555 | JSON::XS/2 | 371564.190 | 371725.613 | |
721 | JSON::XS | 388361.481 | 227951.304 | |
|
|
722 | JSON::XS/2 | 227951.304 | 218453.333 | |
|
|
723 | JSON::XS/3 | 338250.323 | 218453.333 | |
|
|
724 | Storable | 16500.016 | 135300.129 | |
556 | -----------+------------+------------+ |
725 | -----------+------------+------------+ |
557 | |
726 | |
558 | That is, JSON::XS is more than six times faster than JSON::DWIW on |
727 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
559 | encoding, more than three times faster on decoding, and about thirty times |
728 | about three times faster on decoding, and over fourty times faster |
560 | faster than JSON, even with pretty-printing and key sorting. |
729 | than JSON, even with pretty-printing and key sorting. It also compares |
|
|
730 | favourably to Storable for small amounts of data. |
561 | |
731 | |
562 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
732 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
563 | search API (http://nanoref.com/yahooapis/mgPdGg): |
733 | search API (http://nanoref.com/yahooapis/mgPdGg): |
564 | |
734 | |
565 | module | encode | decode | |
735 | module | encode | decode | |
566 | -----------|------------|------------| |
736 | -----------|------------|------------| |
567 | JSON | 273.023 | 44.674 | |
737 | JSON | 55.260 | 34.971 | |
568 | JSON::DWIW | 1089.383 | 1145.704 | |
738 | JSON::DWIW | 825.228 | 1082.513 | |
569 | JSON::PC | 3097.419 | 2393.921 | |
739 | JSON::PC | 3571.444 | 2394.829 | |
570 | JSON::Syck | 514.060 | 843.053 | |
740 | JSON::PP | 210.987 | 32.574 | |
571 | JSON::XS | 6479.668 | 3636.364 | |
741 | JSON::Syck | 552.551 | 787.544 | |
572 | JSON::XS/2 | 3774.221 | 3599.124 | |
742 | JSON::XS | 5780.463 | 4854.519 | |
|
|
743 | JSON::XS/2 | 3869.998 | 4798.975 | |
|
|
744 | JSON::XS/3 | 5862.880 | 4798.975 | |
|
|
745 | Storable | 4445.002 | 5235.027 | |
573 | -----------+------------+------------+ |
746 | -----------+------------+------------+ |
574 | |
747 | |
575 | Again, JSON::XS leads by far. |
748 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
|
|
749 | decodes faster). |
576 | |
750 | |
577 | On large strings containing lots of high unicode characters, some modules |
751 | On large strings containing lots of high unicode characters, some modules |
578 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
752 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
579 | will be broken due to missing (or wrong) unicode handling. Others refuse |
753 | will be broken due to missing (or wrong) unicode handling. Others refuse |
580 | to decode or encode properly, so it was impossible to prepare a fair |
754 | to decode or encode properly, so it was impossible to prepare a fair |
581 | comparison table for that case. |
755 | comparison table for that case. |
582 | |
756 | |
583 | =head1 RESOURCE LIMITS |
|
|
584 | |
757 | |
585 | JSON::XS does not impose any limits on the size of JSON texts or Perl |
758 | =head1 SECURITY CONSIDERATIONS |
586 | values they represent - if your machine can handle it, JSON::XS will |
759 | |
587 | encode or decode it. Future versions might optionally impose structure |
760 | When you are using JSON in a protocol, talking to untrusted potentially |
588 | depth and memory use resource limits. |
761 | hostile creatures requires relatively few measures. |
|
|
762 | |
|
|
763 | First of all, your JSON decoder should be secure, that is, should not have |
|
|
764 | any buffer overflows. Obviously, this module should ensure that and I am |
|
|
765 | trying hard on making that true, but you never know. |
|
|
766 | |
|
|
767 | Second, you need to avoid resource-starving attacks. That means you should |
|
|
768 | limit the size of JSON texts you accept, or make sure then when your |
|
|
769 | resources run out, thats just fine (e.g. by using a separate process that |
|
|
770 | can crash safely). The size of a JSON text in octets or characters is |
|
|
771 | usually a good indication of the size of the resources required to decode |
|
|
772 | it into a Perl structure. While JSON::XS can check the size of the JSON |
|
|
773 | text, it might be too late when you already have it in memory, so you |
|
|
774 | might want to check the size before you accept the string. |
|
|
775 | |
|
|
776 | Third, JSON::XS recurses using the C stack when decoding objects and |
|
|
777 | arrays. The C stack is a limited resource: for instance, on my amd64 |
|
|
778 | machine with 8MB of stack size I can decode around 180k nested arrays but |
|
|
779 | only 14k nested JSON objects (due to perl itself recursing deeply on croak |
|
|
780 | to free the temporary). If that is exceeded, the program crashes. to be |
|
|
781 | conservative, the default nesting limit is set to 512. If your process |
|
|
782 | has a smaller stack, you should adjust this setting accordingly with the |
|
|
783 | C<max_depth> method. |
|
|
784 | |
|
|
785 | And last but least, something else could bomb you that I forgot to think |
|
|
786 | of. In that case, you get to keep the pieces. I am always open for hints, |
|
|
787 | though... |
|
|
788 | |
|
|
789 | If you are using JSON::XS to return packets to consumption |
|
|
790 | by javascript scripts in a browser you should have a look at |
|
|
791 | L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether |
|
|
792 | you are vulnerable to some common attack vectors (which really are browser |
|
|
793 | design bugs, but it is still you who will have to deal with it, as major |
|
|
794 | browser developers care only for features, not about doing security |
|
|
795 | right). |
|
|
796 | |
589 | |
797 | |
590 | =head1 BUGS |
798 | =head1 BUGS |
591 | |
799 | |
592 | While the goal of this module is to be correct, that unfortunately does |
800 | While the goal of this module is to be correct, that unfortunately does |
593 | not mean its bug-free, only that I think its design is bug-free. It is |
801 | not mean its bug-free, only that I think its design is bug-free. It is |
594 | still very young and not well-tested. If you keep reporting bugs they will |
802 | still relatively early in its development. If you keep reporting bugs they |
595 | be fixed swiftly, though. |
803 | will be fixed swiftly, though. |
596 | |
804 | |
597 | =cut |
805 | =cut |
|
|
806 | |
|
|
807 | our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" }; |
|
|
808 | our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" }; |
|
|
809 | |
|
|
810 | sub true() { $true } |
|
|
811 | sub false() { $false } |
|
|
812 | |
|
|
813 | sub is_bool($) { |
|
|
814 | UNIVERSAL::isa $_[0], "JSON::XS::Boolean" |
|
|
815 | # or UNIVERSAL::isa $_[0], "JSON::Literal" |
|
|
816 | } |
|
|
817 | |
|
|
818 | XSLoader::load "JSON::XS", $VERSION; |
|
|
819 | |
|
|
820 | package JSON::XS::Boolean; |
|
|
821 | |
|
|
822 | use overload |
|
|
823 | "0+" => sub { ${$_[0]} }, |
|
|
824 | "++" => sub { $_[0] = ${$_[0]} + 1 }, |
|
|
825 | "--" => sub { $_[0] = ${$_[0]} - 1 }, |
|
|
826 | fallback => 1; |
598 | |
827 | |
599 | 1; |
828 | 1; |
600 | |
829 | |
601 | =head1 AUTHOR |
830 | =head1 AUTHOR |
602 | |
831 | |