… | |
… | |
85 | |
85 | |
86 | package JSON::XS; |
86 | package JSON::XS; |
87 | |
87 | |
88 | use strict; |
88 | use strict; |
89 | |
89 | |
90 | BEGIN { |
|
|
91 | our $VERSION = '1.01'; |
90 | our $VERSION = '1.4'; |
92 | our @ISA = qw(Exporter); |
91 | our @ISA = qw(Exporter); |
93 | |
92 | |
94 | our @EXPORT = qw(to_json from_json objToJson jsonToObj); |
93 | our @EXPORT = qw(to_json from_json objToJson jsonToObj); |
95 | require Exporter; |
|
|
96 | |
94 | |
97 | require XSLoader; |
95 | use Exporter; |
98 | XSLoader::load JSON::XS::, $VERSION; |
96 | use XSLoader; |
99 | } |
|
|
100 | |
97 | |
101 | =head1 FUNCTIONAL INTERFACE |
98 | =head1 FUNCTIONAL INTERFACE |
102 | |
99 | |
103 | The following convinience methods are provided by this module. They are |
100 | The following convinience methods are provided by this module. They are |
104 | exported by default: |
101 | exported by default: |
… | |
… | |
126 | This function call is functionally identical to: |
123 | This 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 | |
130 | except being faster. |
127 | except being faster. |
|
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128 | |
|
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129 | =item $is_boolean = JSON::XS::is_bool $scalar |
|
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130 | |
|
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131 | Returns true if the passed scalar represents either JSON::XS::true or |
|
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132 | JSON::XS::false, two constants that act like C<1> and C<0>, respectively |
|
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133 | and are used to represent JSON C<true> and C<false> values in Perl. |
|
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134 | |
|
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135 | See MAPPING, below, for more information on how JSON values are mapped to |
|
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136 | Perl. |
131 | |
137 | |
132 | =back |
138 | =back |
133 | |
139 | |
134 | |
140 | |
135 | =head1 OBJECT-ORIENTED INTERFACE |
141 | =head1 OBJECT-ORIENTED INTERFACE |
… | |
… | |
154 | |
160 | |
155 | If C<$enable> is true (or missing), then the C<encode> method will not |
161 | If C<$enable> is true (or missing), then the C<encode> method will not |
156 | generate characters outside the code range C<0..127> (which is ASCII). Any |
162 | generate characters outside the code range C<0..127> (which is ASCII). Any |
157 | unicode characters outside that range will be escaped using either a |
163 | unicode characters outside that range will be escaped using either a |
158 | single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, |
164 | single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, |
159 | as per RFC4627. |
165 | as per RFC4627. The resulting encoded JSON text can be treated as a native |
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166 | unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string, |
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167 | or any other superset of ASCII. |
160 | |
168 | |
161 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
169 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
162 | characters unless required by the JSON syntax. This results in a faster |
170 | characters unless required by the JSON syntax or other flags. This results |
163 | and more compact format. |
171 | in a faster and more compact format. |
|
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172 | |
|
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173 | The main use for this flag is to produce JSON texts that can be |
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174 | transmitted over a 7-bit channel, as the encoded JSON texts will not |
|
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175 | contain any 8 bit characters. |
164 | |
176 | |
165 | JSON::XS->new->ascii (1)->encode ([chr 0x10401]) |
177 | JSON::XS->new->ascii (1)->encode ([chr 0x10401]) |
166 | => ["\ud801\udc01"] |
178 | => ["\ud801\udc01"] |
|
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179 | |
|
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180 | =item $json = $json->latin1 ([$enable]) |
|
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181 | |
|
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182 | If C<$enable> is true (or missing), then the C<encode> method will encode |
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183 | the resulting JSON text as latin1 (or iso-8859-1), escaping any characters |
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184 | outside the code range C<0..255>. The resulting string can be treated as a |
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185 | latin1-encoded JSON text or a native unicode string. The C<decode> method |
|
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186 | will not be affected in any way by this flag, as C<decode> by default |
|
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187 | expects unicode, which is a strict superset of latin1. |
|
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188 | |
|
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189 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
|
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190 | characters unless required by the JSON syntax or other flags. |
|
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191 | |
|
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192 | The main use for this flag is efficiently encoding binary data as JSON |
|
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193 | text, as most octets will not be escaped, resulting in a smaller encoded |
|
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194 | size. The disadvantage is that the resulting JSON text is encoded |
|
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195 | in latin1 (and must correctly be treated as such when storing and |
|
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196 | transfering), a rare encoding for JSON. It is therefore most useful when |
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197 | you want to store data structures known to contain binary data efficiently |
|
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198 | in files or databases, not when talking to other JSON encoders/decoders. |
|
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199 | |
|
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200 | JSON::XS->new->latin1->encode (["\x{89}\x{abc}"] |
|
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201 | => ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not) |
167 | |
202 | |
168 | =item $json = $json->utf8 ([$enable]) |
203 | =item $json = $json->utf8 ([$enable]) |
169 | |
204 | |
170 | If C<$enable> is true (or missing), then the C<encode> method will encode |
205 | If C<$enable> is true (or missing), then the C<encode> method will encode |
171 | the JSON result into UTF-8, as required by many protocols, while the |
206 | the JSON result into UTF-8, as required by many protocols, while the |
… | |
… | |
280 | 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>, |
281 | resulting in an invalid JSON text: |
316 | resulting in an invalid JSON text: |
282 | |
317 | |
283 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
318 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
284 | => "Hello, World!" |
319 | => "Hello, World!" |
|
|
320 | |
|
|
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. |
285 | |
356 | |
286 | =item $json = $json->shrink ([$enable]) |
357 | =item $json = $json->shrink ([$enable]) |
287 | |
358 | |
288 | Perl usually over-allocates memory a bit when allocating space for |
359 | Perl usually over-allocates memory a bit when allocating space for |
289 | strings. This flag optionally resizes strings generated by either |
360 | strings. This flag optionally resizes strings generated by either |
… | |
… | |
309 | strings that look like integers or floats into integers or floats |
380 | strings that look like integers or floats into integers or floats |
310 | internally (there is no difference on the Perl level), saving space. |
381 | internally (there is no difference on the Perl level), saving space. |
311 | |
382 | |
312 | =item $json = $json->max_depth ([$maximum_nesting_depth]) |
383 | =item $json = $json->max_depth ([$maximum_nesting_depth]) |
313 | |
384 | |
314 | Sets the maximum nesting level (default C<4096>) accepted while encoding |
385 | Sets the maximum nesting level (default C<512>) accepted while encoding |
315 | or decoding. If the JSON text or Perl data structure has an equal or |
386 | or decoding. If the JSON text or Perl data structure has an equal or |
316 | higher nesting level then this limit, then the encoder and decoder will |
387 | higher nesting level then this limit, then the encoder and decoder will |
317 | stop and croak at that point. |
388 | stop and croak at that point. |
318 | |
389 | |
319 | Nesting level is defined by number of hash- or arrayrefs that the encoder |
390 | Nesting level is defined by number of hash- or arrayrefs that the encoder |
… | |
… | |
322 | given character in a string. |
393 | given character in a string. |
323 | |
394 | |
324 | 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 |
325 | that the object is only a single hash/object or array. |
396 | that the object is only a single hash/object or array. |
326 | |
397 | |
327 | 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 |
328 | 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. |
|
|
403 | |
|
|
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> |
|
|
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). |
329 | |
415 | |
330 | 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. |
331 | |
417 | |
332 | =item $json_text = $json->encode ($perl_scalar) |
418 | =item $json_text = $json->encode ($perl_scalar) |
333 | |
419 | |
… | |
… | |
345 | |
431 | |
346 | JSON numbers and strings become simple Perl scalars. JSON arrays become |
432 | JSON numbers and strings become simple Perl scalars. JSON arrays become |
347 | Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes |
433 | Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes |
348 | C<1>, C<false> becomes C<0> and C<null> becomes C<undef>. |
434 | C<1>, C<false> becomes C<0> and C<null> becomes C<undef>. |
349 | |
435 | |
|
|
436 | =item ($perl_scalar, $characters) = $json->decode_prefix ($json_text) |
|
|
437 | |
|
|
438 | This works like the C<decode> method, but instead of raising an exception |
|
|
439 | when there is trailing garbage after the first JSON object, it will |
|
|
440 | silently stop parsing there and return the number of characters consumed |
|
|
441 | so far. |
|
|
442 | |
|
|
443 | This is useful if your JSON texts are not delimited by an outer protocol |
|
|
444 | (which is not the brightest thing to do in the first place) and you need |
|
|
445 | to know where the JSON text ends. |
|
|
446 | |
|
|
447 | JSON::XS->new->decode_prefix ("[1] the tail") |
|
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448 | => ([], 3) |
|
|
449 | |
350 | =back |
450 | =back |
351 | |
451 | |
352 | |
452 | |
353 | =head1 MAPPING |
453 | =head1 MAPPING |
354 | |
454 | |
… | |
… | |
358 | (what you put in comes out as something equivalent). |
458 | (what you put in comes out as something equivalent). |
359 | |
459 | |
360 | For the more enlightened: note that in the following descriptions, |
460 | For the more enlightened: note that in the following descriptions, |
361 | lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl> |
461 | lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl> |
362 | refers to the abstract Perl language itself. |
462 | refers to the abstract Perl language itself. |
|
|
463 | |
363 | |
464 | |
364 | =head2 JSON -> PERL |
465 | =head2 JSON -> PERL |
365 | |
466 | |
366 | =over 4 |
467 | =over 4 |
367 | |
468 | |
… | |
… | |
388 | conversion details, but an integer may take slightly less memory and might |
489 | conversion details, but an integer may take slightly less memory and might |
389 | represent more values exactly than (floating point) numbers. |
490 | represent more values exactly than (floating point) numbers. |
390 | |
491 | |
391 | =item true, false |
492 | =item true, false |
392 | |
493 | |
393 | These JSON atoms become C<0>, C<1>, respectively. Information is lost in |
494 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
394 | this process. Future versions might represent those values differently, |
495 | respectively. They are overloaded to act almost exactly like the numbers |
395 | but they will be guarenteed to act like these integers would normally in |
496 | C<1> and C<0>. You can check wether a scalar is a JSON boolean by using |
396 | Perl. |
497 | the C<JSON::XS::is_bool> function. |
397 | |
498 | |
398 | =item null |
499 | =item null |
399 | |
500 | |
400 | A JSON null atom becomes C<undef> in Perl. |
501 | A JSON null atom becomes C<undef> in Perl. |
401 | |
502 | |
402 | =back |
503 | =back |
|
|
504 | |
403 | |
505 | |
404 | =head2 PERL -> JSON |
506 | =head2 PERL -> JSON |
405 | |
507 | |
406 | The mapping from Perl to JSON is slightly more difficult, as Perl is a |
508 | The mapping from Perl to JSON is slightly more difficult, as Perl is a |
407 | truly typeless language, so we can only guess which JSON type is meant by |
509 | truly typeless language, so we can only guess which JSON type is meant by |
… | |
… | |
432 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
534 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
433 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
535 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
434 | |
536 | |
435 | to_json [\0,JSON::XS::true] # yields [false,true] |
537 | to_json [\0,JSON::XS::true] # yields [false,true] |
436 | |
538 | |
|
|
539 | =item JSON::XS::true, JSON::XS::false |
|
|
540 | |
|
|
541 | These special values become JSON true and JSON false values, |
|
|
542 | respectively. You cna alos use C<\1> and C<\0> directly if you want. |
|
|
543 | |
437 | =item blessed objects |
544 | =item blessed objects |
438 | |
545 | |
439 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
546 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
440 | underlying representation (hash- or arrayref), but this behaviour might |
547 | underlying representation (hash- or arrayref), but this behaviour might |
441 | change in future versions. |
548 | change in future versions. |
… | |
… | |
472 | $x += 0; # numify it, ensuring it will be dumped as a number |
579 | $x += 0; # numify it, ensuring it will be dumped as a number |
473 | $x *= 1; # same thing, the choise is yours. |
580 | $x *= 1; # same thing, the choise is yours. |
474 | |
581 | |
475 | You can not currently output JSON booleans or force the type in other, |
582 | You can not currently output JSON booleans or force the type in other, |
476 | less obscure, ways. Tell me if you need this capability. |
583 | less obscure, ways. Tell me if you need this capability. |
477 | |
|
|
478 | =item circular data structures |
|
|
479 | |
|
|
480 | Those will be encoded until memory or stackspace runs out. |
|
|
481 | |
584 | |
482 | =back |
585 | =back |
483 | |
586 | |
484 | |
587 | |
485 | =head1 COMPARISON |
588 | =head1 COMPARISON |
… | |
… | |
566 | |
669 | |
567 | Does not check input for validity. |
670 | Does not check input for validity. |
568 | |
671 | |
569 | =back |
672 | =back |
570 | |
673 | |
|
|
674 | |
|
|
675 | =head2 JSON and YAML |
|
|
676 | |
|
|
677 | You often hear that JSON is a subset (or a close subset) of YAML. This is, |
|
|
678 | however, a mass hysteria and very far from the truth. In general, there is |
|
|
679 | no way to configure JSON::XS to output a data structure as valid YAML. |
|
|
680 | |
|
|
681 | If you really must use JSON::XS to generate YAML, you should use this |
|
|
682 | algorithm (subject to change in future versions): |
|
|
683 | |
|
|
684 | my $to_yaml = JSON::XS->new->utf8->space_after (1); |
|
|
685 | my $yaml = $to_yaml->encode ($ref) . "\n"; |
|
|
686 | |
|
|
687 | This will usually generate JSON texts that also parse as valid |
|
|
688 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
|
|
689 | lengths that JSON doesn't have, so you should make sure that your hash |
|
|
690 | keys are noticably shorter than the 1024 characters YAML allows. |
|
|
691 | |
|
|
692 | There might be other incompatibilities that I am not aware of. In general |
|
|
693 | you should not try to generate YAML with a JSON generator or vice versa, |
|
|
694 | or try to parse JSON with a YAML parser or vice versa: chances are high |
|
|
695 | that you will run into severe interoperability problems. |
|
|
696 | |
|
|
697 | |
571 | =head2 SPEED |
698 | =head2 SPEED |
572 | |
699 | |
573 | It seems that JSON::XS is surprisingly fast, as shown in the following |
700 | It seems that JSON::XS is surprisingly fast, as shown in the following |
574 | tables. They have been generated with the help of the C<eg/bench> program |
701 | tables. They have been generated with the help of the C<eg/bench> program |
575 | in the JSON::XS distribution, to make it easy to compare on your own |
702 | in the JSON::XS distribution, to make it easy to compare on your own |
576 | system. |
703 | system. |
577 | |
704 | |
578 | First comes a comparison between various modules using a very short JSON |
705 | First comes a comparison between various modules using a very short |
579 | string: |
706 | single-line JSON string: |
580 | |
707 | |
581 | {"method": "handleMessage", "params": ["user1", "we were just talking"], "id": null} |
708 | {"method": "handleMessage", "params": ["user1", "we were just talking"], \ |
|
|
709 | "id": null, "array":[1,11,234,-5,1e5,1e7, true, false]} |
582 | |
710 | |
583 | It shows the number of encodes/decodes per second (JSON::XS uses the |
711 | It shows the number of encodes/decodes per second (JSON::XS uses |
584 | functional interface, while JSON::XS/2 uses the OO interface with |
712 | the functional interface, while JSON::XS/2 uses the OO interface |
585 | pretty-printing and hashkey sorting enabled). Higher is better: |
713 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
|
|
714 | shrink). Higher is better: |
586 | |
715 | |
|
|
716 | Storable | 15779.925 | 14169.946 | |
|
|
717 | -----------+------------+------------+ |
587 | module | encode | decode | |
718 | module | encode | decode | |
588 | -----------|------------|------------| |
719 | -----------|------------|------------| |
589 | JSON | 11488.516 | 7823.035 | |
720 | JSON | 4990.842 | 4088.813 | |
590 | JSON::DWIW | 94708.054 | 129094.260 | |
721 | JSON::DWIW | 51653.990 | 71575.154 | |
591 | JSON::PC | 63884.157 | 128528.212 | |
722 | JSON::PC | 65948.176 | 74631.744 | |
592 | JSON::Syck | 34898.677 | 42096.911 | |
723 | JSON::PP | 8931.652 | 3817.168 | |
593 | JSON::XS | 654027.064 | 396423.669 | |
724 | JSON::Syck | 24877.248 | 27776.848 | |
594 | JSON::XS/2 | 371564.190 | 371725.613 | |
725 | JSON::XS | 388361.481 | 227951.304 | |
|
|
726 | JSON::XS/2 | 227951.304 | 218453.333 | |
|
|
727 | JSON::XS/3 | 338250.323 | 218453.333 | |
|
|
728 | Storable | 16500.016 | 135300.129 | |
595 | -----------+------------+------------+ |
729 | -----------+------------+------------+ |
596 | |
730 | |
597 | That is, JSON::XS is more than six times faster than JSON::DWIW on |
731 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
598 | encoding, more than three times faster on decoding, and about thirty times |
732 | about three times faster on decoding, and over fourty times faster |
599 | faster than JSON, even with pretty-printing and key sorting. |
733 | than JSON, even with pretty-printing and key sorting. It also compares |
|
|
734 | favourably to Storable for small amounts of data. |
600 | |
735 | |
601 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
736 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
602 | search API (http://nanoref.com/yahooapis/mgPdGg): |
737 | search API (http://nanoref.com/yahooapis/mgPdGg): |
603 | |
738 | |
604 | module | encode | decode | |
739 | module | encode | decode | |
605 | -----------|------------|------------| |
740 | -----------|------------|------------| |
606 | JSON | 273.023 | 44.674 | |
741 | JSON | 55.260 | 34.971 | |
607 | JSON::DWIW | 1089.383 | 1145.704 | |
742 | JSON::DWIW | 825.228 | 1082.513 | |
608 | JSON::PC | 3097.419 | 2393.921 | |
743 | JSON::PC | 3571.444 | 2394.829 | |
609 | JSON::Syck | 514.060 | 843.053 | |
744 | JSON::PP | 210.987 | 32.574 | |
610 | JSON::XS | 6479.668 | 3636.364 | |
745 | JSON::Syck | 552.551 | 787.544 | |
611 | JSON::XS/2 | 3774.221 | 3599.124 | |
746 | JSON::XS | 5780.463 | 4854.519 | |
|
|
747 | JSON::XS/2 | 3869.998 | 4798.975 | |
|
|
748 | JSON::XS/3 | 5862.880 | 4798.975 | |
|
|
749 | Storable | 4445.002 | 5235.027 | |
612 | -----------+------------+------------+ |
750 | -----------+------------+------------+ |
613 | |
751 | |
614 | Again, JSON::XS leads by far. |
752 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
|
|
753 | decodes faster). |
615 | |
754 | |
616 | On large strings containing lots of high unicode characters, some modules |
755 | On large strings containing lots of high unicode characters, some modules |
617 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
756 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
618 | will be broken due to missing (or wrong) unicode handling. Others refuse |
757 | will be broken due to missing (or wrong) unicode handling. Others refuse |
619 | to decode or encode properly, so it was impossible to prepare a fair |
758 | to decode or encode properly, so it was impossible to prepare a fair |
… | |
… | |
632 | 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 |
633 | 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 |
634 | 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 |
635 | 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 |
636 | 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 |
637 | it into a Perl structure. |
776 | it into a Perl structure. While JSON::XS can check the size of the JSON |
|
|
777 | text, it might be too late when you already have it in memory, so you |
|
|
778 | might want to check the size before you accept the string. |
638 | |
779 | |
639 | 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 |
640 | 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 |
641 | machine with 8MB of stack size I can decode around 180k nested arrays |
782 | machine with 8MB of stack size I can decode around 180k nested arrays but |
642 | but only 14k nested JSON objects. If that is exceeded, the program |
783 | only 14k nested JSON objects (due to perl itself recursing deeply on croak |
643 | crashes. Thats why the default nesting limit is set to 4096. If your |
784 | to free the temporary). If that is exceeded, the program crashes. to be |
|
|
785 | conservative, the default nesting limit is set to 512. If your process |
644 | process has a smaller stack, you should adjust this setting accordingly |
786 | has a smaller stack, you should adjust this setting accordingly with the |
645 | with the C<max_depth> method. |
787 | C<max_depth> method. |
646 | |
788 | |
647 | And last but least, something else could bomb you that I forgot to think |
789 | And last but least, something else could bomb you that I forgot to think |
648 | of. In that case, you get to keep the pieces. I am alway sopen for hints, |
790 | of. In that case, you get to keep the pieces. I am always open for hints, |
649 | though... |
791 | though... |
|
|
792 | |
|
|
793 | If you are using JSON::XS to return packets to consumption |
|
|
794 | by javascript scripts in a browser you should have a look at |
|
|
795 | L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether |
|
|
796 | you are vulnerable to some common attack vectors (which really are browser |
|
|
797 | design bugs, but it is still you who will have to deal with it, as major |
|
|
798 | browser developers care only for features, not about doing security |
|
|
799 | right). |
650 | |
800 | |
651 | |
801 | |
652 | =head1 BUGS |
802 | =head1 BUGS |
653 | |
803 | |
654 | While the goal of this module is to be correct, that unfortunately does |
804 | While the goal of this module is to be correct, that unfortunately does |
… | |
… | |
656 | still relatively early in its development. If you keep reporting bugs they |
806 | still relatively early in its development. If you keep reporting bugs they |
657 | will be fixed swiftly, though. |
807 | will be fixed swiftly, though. |
658 | |
808 | |
659 | =cut |
809 | =cut |
660 | |
810 | |
|
|
811 | our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" }; |
|
|
812 | our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" }; |
|
|
813 | |
661 | sub true() { \1 } |
814 | sub true() { $true } |
662 | sub false() { \0 } |
815 | sub false() { $false } |
|
|
816 | |
|
|
817 | sub is_bool($) { |
|
|
818 | UNIVERSAL::isa $_[0], "JSON::XS::Boolean" |
|
|
819 | # or UNIVERSAL::isa $_[0], "JSON::Literal" |
|
|
820 | } |
|
|
821 | |
|
|
822 | XSLoader::load "JSON::XS", $VERSION; |
|
|
823 | |
|
|
824 | package JSON::XS::Boolean; |
|
|
825 | |
|
|
826 | use overload |
|
|
827 | "0+" => sub { ${$_[0]} }, |
|
|
828 | "++" => sub { $_[0] = ${$_[0]} + 1 }, |
|
|
829 | "--" => sub { $_[0] = ${$_[0]} - 1 }, |
|
|
830 | fallback => 1; |
663 | |
831 | |
664 | 1; |
832 | 1; |
665 | |
833 | |
666 | =head1 AUTHOR |
834 | =head1 AUTHOR |
667 | |
835 | |