… | |
… | |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use JSON::XS; |
7 | use JSON::XS; |
8 | |
8 | |
9 | # exported functions, croak on error |
9 | # exported functions, they croak on error |
|
|
10 | # and expect/generate UTF-8 |
10 | |
11 | |
11 | $utf8_encoded_json_text = to_json $perl_hash_or_arrayref; |
12 | $utf8_encoded_json_text = to_json $perl_hash_or_arrayref; |
12 | $perl_hash_or_arrayref = from_json $utf8_encoded_json_text; |
13 | $perl_hash_or_arrayref = from_json $utf8_encoded_json_text; |
13 | |
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 | # oo-interface |
19 | # OO-interface |
15 | |
20 | |
16 | $coder = JSON::XS->new->ascii->pretty->allow_nonref; |
21 | $coder = JSON::XS->new->ascii->pretty->allow_nonref; |
17 | $pretty_printed_unencoded = $coder->encode ($perl_scalar); |
22 | $pretty_printed_unencoded = $coder->encode ($perl_scalar); |
18 | $perl_scalar = $coder->decode ($unicode_json_text); |
23 | $perl_scalar = $coder->decode ($unicode_json_text); |
19 | |
24 | |
… | |
… | |
36 | |
41 | |
37 | =head2 FEATURES |
42 | =head2 FEATURES |
38 | |
43 | |
39 | =over 4 |
44 | =over 4 |
40 | |
45 | |
41 | =item * correct handling of unicode issues |
46 | =item * correct unicode handling |
42 | |
47 | |
43 | This module knows how to handle Unicode, and even documents how and when |
48 | This module knows how to handle Unicode, and even documents how and when |
44 | it does so. |
49 | it does so. |
45 | |
50 | |
46 | =item * round-trip integrity |
51 | =item * round-trip integrity |
47 | |
52 | |
48 | When you serialise a perl data structure using only datatypes supported |
53 | When you serialise a perl data structure using only datatypes supported |
49 | by JSON, the deserialised data structure is identical on the Perl level. |
54 | by JSON, the deserialised data structure is identical on the Perl level. |
50 | (e.g. the string "2.0" doesn't suddenly become "2"). |
55 | (e.g. the string "2.0" doesn't suddenly become "2" just because it looks |
|
|
56 | like a number). |
51 | |
57 | |
52 | =item * strict checking of JSON correctness |
58 | =item * strict checking of JSON correctness |
53 | |
59 | |
54 | There is no guessing, no generating of illegal JSON texts by default, |
60 | There is no guessing, no generating of illegal JSON texts by default, |
55 | and only JSON is accepted as input by default (the latter is a security |
61 | and only JSON is accepted as input by default (the latter is a security |
… | |
… | |
66 | interface. |
72 | interface. |
67 | |
73 | |
68 | =item * reasonably versatile output formats |
74 | =item * reasonably versatile output formats |
69 | |
75 | |
70 | You can choose between the most compact guarenteed single-line format |
76 | You can choose between the most compact guarenteed single-line format |
71 | possible (nice for simple line-based protocols), a pure-ascii format (for |
77 | possible (nice for simple line-based protocols), a pure-ascii format |
72 | when your transport is not 8-bit clean), or a pretty-printed format (for |
78 | (for when your transport is not 8-bit clean, still supports the whole |
73 | when you want to read that stuff). Or you can combine those features in |
79 | unicode range), or a pretty-printed format (for when you want to read that |
74 | whatever way you like. |
80 | stuff). Or you can combine those features in whatever way you like. |
75 | |
81 | |
76 | =back |
82 | =back |
77 | |
83 | |
78 | =cut |
84 | =cut |
79 | |
85 | |
80 | package JSON::XS; |
86 | package JSON::XS; |
81 | |
87 | |
82 | BEGIN { |
88 | use strict; |
|
|
89 | |
83 | $VERSION = '0.31'; |
90 | our $VERSION = '1.3'; |
84 | @ISA = qw(Exporter); |
91 | our @ISA = qw(Exporter); |
85 | |
92 | |
86 | @EXPORT = qw(to_json from_json); |
93 | our @EXPORT = qw(to_json from_json objToJson jsonToObj); |
87 | require Exporter; |
|
|
88 | |
94 | |
89 | require XSLoader; |
95 | use Exporter; |
90 | XSLoader::load JSON::XS::, $VERSION; |
96 | use XSLoader; |
91 | } |
|
|
92 | |
97 | |
93 | =head1 FUNCTIONAL INTERFACE |
98 | =head1 FUNCTIONAL INTERFACE |
94 | |
99 | |
95 | The following convinience methods are provided by this module. They are |
100 | The following convinience methods are provided by this module. They are |
96 | exported by default: |
101 | exported by default: |
… | |
… | |
119 | |
124 | |
120 | $perl_scalar = JSON::XS->new->utf8->decode ($json_text) |
125 | $perl_scalar = JSON::XS->new->utf8->decode ($json_text) |
121 | |
126 | |
122 | except being faster. |
127 | except being faster. |
123 | |
128 | |
|
|
129 | =item $is_boolean = JSON::XS::is_bool $scalar |
|
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130 | |
|
|
131 | Returns true if the passed scalar represents either JSON::XS::true or |
|
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132 | JSON::XS::false, two constants that act like C<1> and C<0>, respectively |
|
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133 | and are used to represent JSON C<true> and C<false> values in Perl. |
|
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134 | |
|
|
135 | See MAPPING, below, for more information on how JSON values are mapped to |
|
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136 | Perl. |
|
|
137 | |
124 | =back |
138 | =back |
|
|
139 | |
125 | |
140 | |
126 | =head1 OBJECT-ORIENTED INTERFACE |
141 | =head1 OBJECT-ORIENTED INTERFACE |
127 | |
142 | |
128 | The object oriented interface lets you configure your own encoding or |
143 | The object oriented interface lets you configure your own encoding or |
129 | decoding style, within the limits of supported formats. |
144 | decoding style, within the limits of supported formats. |
… | |
… | |
145 | |
160 | |
146 | If C<$enable> is true (or missing), then the C<encode> method will not |
161 | If C<$enable> is true (or missing), then the C<encode> method will not |
147 | generate characters outside the code range C<0..127> (which is ASCII). Any |
162 | generate characters outside the code range C<0..127> (which is ASCII). Any |
148 | unicode characters outside that range will be escaped using either a |
163 | unicode characters outside that range will be escaped using either a |
149 | single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, |
164 | single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, |
150 | as per RFC4627. |
165 | as per RFC4627. The resulting encoded JSON text can be treated as a native |
|
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166 | unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string, |
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167 | or any other superset of ASCII. |
151 | |
168 | |
152 | If C<$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 |
153 | 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 |
154 | and more compact format. |
171 | in a faster and more compact format. |
|
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172 | |
|
|
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. |
155 | |
176 | |
156 | JSON::XS->new->ascii (1)->encode ([chr 0x10401]) |
177 | JSON::XS->new->ascii (1)->encode ([chr 0x10401]) |
157 | => ["\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 | |
|
|
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 | |
|
|
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 | |
|
|
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) |
158 | |
202 | |
159 | =item $json = $json->utf8 ([$enable]) |
203 | =item $json = $json->utf8 ([$enable]) |
160 | |
204 | |
161 | 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 |
162 | 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 |
… | |
… | |
275 | => "Hello, World!" |
319 | => "Hello, World!" |
276 | |
320 | |
277 | =item $json = $json->shrink ([$enable]) |
321 | =item $json = $json->shrink ([$enable]) |
278 | |
322 | |
279 | Perl usually over-allocates memory a bit when allocating space for |
323 | Perl usually over-allocates memory a bit when allocating space for |
280 | strings. This flag optionally resizes strings generated by either |
324 | strings. This flag optionally resizes strings generated by either |
281 | C<encode> or C<decode> to their minimum size possible. This can save |
325 | C<encode> or C<decode> to their minimum size possible. This can save |
282 | memory when your JSON texts are either very very long or you have many |
326 | memory when your JSON texts are either very very long or you have many |
283 | short strings. It will also try to downgrade any strings to octet-form |
327 | short strings. It will also try to downgrade any strings to octet-form |
284 | if possible: perl stores strings internally either in an encoding called |
328 | if possible: perl stores strings internally either in an encoding called |
285 | UTF-X or in octet-form. The latter cannot store everything but uses less |
329 | UTF-X or in octet-form. The latter cannot store everything but uses less |
286 | space in general. |
330 | space in general (and some buggy Perl or C code might even rely on that |
|
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331 | internal representation being used). |
287 | |
332 | |
|
|
333 | The actual definition of what shrink does might change in future versions, |
|
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334 | but it will always try to save space at the expense of time. |
|
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335 | |
288 | If C<$enable> is true (or missing), the string returned by C<encode> will be shrunk-to-fit, |
336 | If C<$enable> is true (or missing), the string returned by C<encode> will |
289 | while all strings generated by C<decode> will also be shrunk-to-fit. |
337 | be shrunk-to-fit, while all strings generated by C<decode> will also be |
|
|
338 | shrunk-to-fit. |
290 | |
339 | |
291 | If C<$enable> is false, then the normal perl allocation algorithms are used. |
340 | If C<$enable> is false, then the normal perl allocation algorithms are used. |
292 | If you work with your data, then this is likely to be faster. |
341 | If you work with your data, then this is likely to be faster. |
293 | |
342 | |
294 | In the future, this setting might control other things, such as converting |
343 | In the future, this setting might control other things, such as converting |
295 | strings that look like integers or floats into integers or floats |
344 | strings that look like integers or floats into integers or floats |
296 | internally (there is no difference on the Perl level), saving space. |
345 | internally (there is no difference on the Perl level), saving space. |
|
|
346 | |
|
|
347 | =item $json = $json->max_depth ([$maximum_nesting_depth]) |
|
|
348 | |
|
|
349 | Sets the maximum nesting level (default C<512>) accepted while encoding |
|
|
350 | or decoding. If the JSON text or Perl data structure has an equal or |
|
|
351 | higher nesting level then this limit, then the encoder and decoder will |
|
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352 | stop and croak at that point. |
|
|
353 | |
|
|
354 | Nesting level is defined by number of hash- or arrayrefs that the encoder |
|
|
355 | needs to traverse to reach a given point or the number of C<{> or C<[> |
|
|
356 | characters without their matching closing parenthesis crossed to reach a |
|
|
357 | given character in a string. |
|
|
358 | |
|
|
359 | Setting the maximum depth to one disallows any nesting, so that ensures |
|
|
360 | that the object is only a single hash/object or array. |
|
|
361 | |
|
|
362 | The argument to C<max_depth> will be rounded up to the next nearest power |
|
|
363 | of two. |
|
|
364 | |
|
|
365 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
297 | |
366 | |
298 | =item $json_text = $json->encode ($perl_scalar) |
367 | =item $json_text = $json->encode ($perl_scalar) |
299 | |
368 | |
300 | Converts the given Perl data structure (a simple scalar or a reference |
369 | Converts the given Perl data structure (a simple scalar or a reference |
301 | to a hash or array) to its JSON representation. Simple scalars will be |
370 | to a hash or array) to its JSON representation. Simple scalars will be |
… | |
… | |
311 | |
380 | |
312 | JSON numbers and strings become simple Perl scalars. JSON arrays become |
381 | JSON numbers and strings become simple Perl scalars. JSON arrays become |
313 | Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes |
382 | Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes |
314 | C<1>, C<false> becomes C<0> and C<null> becomes C<undef>. |
383 | C<1>, C<false> becomes C<0> and C<null> becomes C<undef>. |
315 | |
384 | |
|
|
385 | =item ($perl_scalar, $characters) = $json->decode_prefix ($json_text) |
|
|
386 | |
|
|
387 | This works like the C<decode> method, but instead of raising an exception |
|
|
388 | when there is trailing garbage after the first JSON object, it will |
|
|
389 | silently stop parsing there and return the number of characters consumed |
|
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390 | so far. |
|
|
391 | |
|
|
392 | This is useful if your JSON texts are not delimited by an outer protocol |
|
|
393 | (which is not the brightest thing to do in the first place) and you need |
|
|
394 | to know where the JSON text ends. |
|
|
395 | |
|
|
396 | JSON::XS->new->decode_prefix ("[1] the tail") |
|
|
397 | => ([], 3) |
|
|
398 | |
316 | =back |
399 | =back |
|
|
400 | |
317 | |
401 | |
318 | =head1 MAPPING |
402 | =head1 MAPPING |
319 | |
403 | |
320 | This section describes how JSON::XS maps Perl values to JSON values and |
404 | This section describes how JSON::XS maps Perl values to JSON values and |
321 | vice versa. These mappings are designed to "do the right thing" in most |
405 | vice versa. These mappings are designed to "do the right thing" in most |
… | |
… | |
323 | (what you put in comes out as something equivalent). |
407 | (what you put in comes out as something equivalent). |
324 | |
408 | |
325 | For the more enlightened: note that in the following descriptions, |
409 | For the more enlightened: note that in the following descriptions, |
326 | lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl> |
410 | lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl> |
327 | refers to the abstract Perl language itself. |
411 | refers to the abstract Perl language itself. |
|
|
412 | |
328 | |
413 | |
329 | =head2 JSON -> PERL |
414 | =head2 JSON -> PERL |
330 | |
415 | |
331 | =over 4 |
416 | =over 4 |
332 | |
417 | |
… | |
… | |
353 | conversion details, but an integer may take slightly less memory and might |
438 | conversion details, but an integer may take slightly less memory and might |
354 | represent more values exactly than (floating point) numbers. |
439 | represent more values exactly than (floating point) numbers. |
355 | |
440 | |
356 | =item true, false |
441 | =item true, false |
357 | |
442 | |
358 | These JSON atoms become C<0>, C<1>, respectively. Information is lost in |
443 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
359 | this process. Future versions might represent those values differently, |
444 | respectively. They are overloaded to act almost exactly like the numbers |
360 | but they will be guarenteed to act like these integers would normally in |
445 | C<1> and C<0>. You can check wether a scalar is a JSON boolean by using |
361 | Perl. |
446 | the C<JSON::XS::is_bool> function. |
362 | |
447 | |
363 | =item null |
448 | =item null |
364 | |
449 | |
365 | A JSON null atom becomes C<undef> in Perl. |
450 | A JSON null atom becomes C<undef> in Perl. |
366 | |
451 | |
367 | =back |
452 | =back |
|
|
453 | |
368 | |
454 | |
369 | =head2 PERL -> JSON |
455 | =head2 PERL -> JSON |
370 | |
456 | |
371 | The mapping from Perl to JSON is slightly more difficult, as Perl is a |
457 | The mapping from Perl to JSON is slightly more difficult, as Perl is a |
372 | truly typeless language, so we can only guess which JSON type is meant by |
458 | truly typeless language, so we can only guess which JSON type is meant by |
… | |
… | |
375 | =over 4 |
461 | =over 4 |
376 | |
462 | |
377 | =item hash references |
463 | =item hash references |
378 | |
464 | |
379 | Perl hash references become JSON objects. As there is no inherent ordering |
465 | Perl hash references become JSON objects. As there is no inherent ordering |
380 | in hash keys, they will usually be encoded in a pseudo-random order that |
466 | in hash keys (or JSON objects), they will usually be encoded in a |
381 | can change between runs of the same program but stays generally the same |
467 | pseudo-random order that can change between runs of the same program but |
382 | within a single run of a program. JSON::XS can optionally sort the hash |
468 | stays generally the same within a single run of a program. JSON::XS can |
383 | keys (determined by the I<canonical> flag), so the same datastructure |
469 | optionally sort the hash keys (determined by the I<canonical> flag), so |
384 | will serialise to the same JSON text (given same settings and version of |
470 | the same datastructure will serialise to the same JSON text (given same |
385 | JSON::XS), but this incurs a runtime overhead. |
471 | settings and version of JSON::XS), but this incurs a runtime overhead |
|
|
472 | and is only rarely useful, e.g. when you want to compare some JSON text |
|
|
473 | against another for equality. |
386 | |
474 | |
387 | =item array references |
475 | =item array references |
388 | |
476 | |
389 | Perl array references become JSON arrays. |
477 | Perl array references become JSON arrays. |
|
|
478 | |
|
|
479 | =item other references |
|
|
480 | |
|
|
481 | Other unblessed references are generally not allowed and will cause an |
|
|
482 | exception to be thrown, except for references to the integers C<0> and |
|
|
483 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
|
|
484 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
|
|
485 | |
|
|
486 | to_json [\0,JSON::XS::true] # yields [false,true] |
|
|
487 | |
|
|
488 | =item JSON::XS::true, JSON::XS::false |
|
|
489 | |
|
|
490 | These special values become JSON true and JSON false values, |
|
|
491 | respectively. You cna alos use C<\1> and C<\0> directly if you want. |
390 | |
492 | |
391 | =item blessed objects |
493 | =item blessed objects |
392 | |
494 | |
393 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
495 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
394 | underlying representation (hash- or arrayref), but this behaviour might |
496 | underlying representation (hash- or arrayref), but this behaviour might |
… | |
… | |
427 | $x *= 1; # same thing, the choise is yours. |
529 | $x *= 1; # same thing, the choise is yours. |
428 | |
530 | |
429 | You can not currently output JSON booleans or force the type in other, |
531 | You can not currently output JSON booleans or force the type in other, |
430 | less obscure, ways. Tell me if you need this capability. |
532 | less obscure, ways. Tell me if you need this capability. |
431 | |
533 | |
432 | =item circular data structures |
|
|
433 | |
|
|
434 | Those will be encoded until memory or stackspace runs out. |
|
|
435 | |
|
|
436 | =back |
534 | =back |
|
|
535 | |
437 | |
536 | |
438 | =head1 COMPARISON |
537 | =head1 COMPARISON |
439 | |
538 | |
440 | As already mentioned, this module was created because none of the existing |
539 | As already mentioned, this module was created because none of the existing |
441 | JSON modules could be made to work correctly. First I will describe the |
540 | JSON modules could be made to work correctly. First I will describe the |
… | |
… | |
519 | |
618 | |
520 | Does not check input for validity. |
619 | Does not check input for validity. |
521 | |
620 | |
522 | =back |
621 | =back |
523 | |
622 | |
|
|
623 | |
|
|
624 | =head2 JSON and YAML |
|
|
625 | |
|
|
626 | You often hear that JSON is a subset (or a close subset) of YAML. This is, |
|
|
627 | however, a mass hysteria and very far from the truth. In general, there is |
|
|
628 | no way to configure JSON::XS to output a data structure as valid YAML. |
|
|
629 | |
|
|
630 | If you really must use JSON::XS to generate YAML, you should use this |
|
|
631 | algorithm (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 | |
|
|
636 | This will usually generate JSON texts that also parse as valid |
|
|
637 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
|
|
638 | lengths that JSON doesn't have, so you should make sure that your hash |
|
|
639 | keys are noticably shorter than the 1024 characters YAML allows. |
|
|
640 | |
|
|
641 | There might be other incompatibilities that I am not aware of. In general |
|
|
642 | you should not try to generate YAML with a JSON generator or vice versa, |
|
|
643 | or try to parse JSON with a YAML parser or vice versa: chances are high |
|
|
644 | that you will run into severe interoperability problems. |
|
|
645 | |
|
|
646 | |
524 | =head2 SPEED |
647 | =head2 SPEED |
525 | |
648 | |
526 | It seems that JSON::XS is surprisingly fast, as shown in the following |
649 | It seems that JSON::XS is surprisingly fast, as shown in the following |
527 | tables. They have been generated with the help of the C<eg/bench> program |
650 | tables. They have been generated with the help of the C<eg/bench> program |
528 | in the JSON::XS distribution, to make it easy to compare on your own |
651 | in the JSON::XS distribution, to make it easy to compare on your own |
529 | system. |
652 | system. |
530 | |
653 | |
531 | First comes a comparison between various modules using a very short JSON |
654 | First comes a comparison between various modules using a very short |
532 | string (83 bytes), showing the number of encodes/decodes per second |
655 | single-line JSON string: |
|
|
656 | |
|
|
657 | {"method": "handleMessage", "params": ["user1", "we were just talking"], \ |
|
|
658 | "id": null, "array":[1,11,234,-5,1e5,1e7, true, false]} |
|
|
659 | |
|
|
660 | It shows the number of encodes/decodes per second (JSON::XS uses |
533 | (JSON::XS is the functional interface, while JSON::XS/2 is the OO |
661 | the functional interface, while JSON::XS/2 uses the OO interface |
534 | interface with pretty-printing and hashkey sorting enabled). Higher is |
662 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
535 | better: |
663 | shrink). Higher is better: |
536 | |
664 | |
537 | module | encode | decode | |
665 | module | encode | decode | |
538 | -----------|------------|------------| |
666 | -----------|------------|------------| |
539 | JSON | 14006 | 6820 | |
667 | JSON | 7645.468 | 4208.613 | |
540 | JSON::DWIW | 200937 | 120386 | |
668 | JSON::DWIW | 40721.398 | 77101.176 | |
541 | JSON::PC | 85065 | 129366 | |
669 | JSON::PC | 65948.176 | 78251.940 | |
542 | JSON::Syck | 59898 | 44232 | |
670 | JSON::Syck | 22844.793 | 26479.192 | |
543 | JSON::XS | 1171478 | 342435 | |
671 | JSON::XS | 388361.481 | 199728.762 | |
544 | JSON::XS/2 | 730760 | 328714 | |
672 | JSON::XS/2 | 218453.333 | 192399.266 | |
|
|
673 | JSON::XS/3 | 338250.323 | 192399.266 | |
|
|
674 | Storable | 15779.925 | 14169.946 | |
545 | -----------+------------+------------+ |
675 | -----------+------------+------------+ |
546 | |
676 | |
547 | That is, JSON::XS is 6 times faster than than JSON::DWIW and about 80 |
677 | 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 |
548 | times faster than JSON, even with pretty-printing and key sorting. |
679 | than JSON, even with pretty-printing and key sorting. It also compares |
|
|
680 | favourably to Storable for small amounts of data. |
549 | |
681 | |
550 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
682 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
551 | search API (http://nanoref.com/yahooapis/mgPdGg): |
683 | search API (http://nanoref.com/yahooapis/mgPdGg): |
552 | |
684 | |
553 | module | encode | decode | |
685 | module | encode | decode | |
554 | -----------|------------|------------| |
686 | -----------|------------|------------| |
555 | JSON | 673 | 38 | |
687 | JSON | 254.685 | 37.665 | |
556 | JSON::DWIW | 5271 | 770 | |
688 | JSON::DWIW | 843.343 | 1049.731 | |
557 | JSON::PC | 9901 | 2491 | |
689 | JSON::PC | 3602.116 | 2307.352 | |
558 | JSON::Syck | 2360 | 786 | |
690 | JSON::Syck | 505.107 | 787.899 | |
559 | JSON::XS | 37398 | 3202 | |
691 | JSON::XS | 5747.196 | 3690.220 | |
560 | JSON::XS/2 | 13765 | 3153 | |
692 | JSON::XS/2 | 3968.121 | 3676.634 | |
|
|
693 | JSON::XS/3 | 6105.246 | 3662.508 | |
|
|
694 | Storable | 4417.337 | 5285.161 | |
561 | -----------+------------+------------+ |
695 | -----------+------------+------------+ |
562 | |
696 | |
563 | Again, JSON::XS leads by far in the encoding case, while still beating |
697 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
564 | every other module in the decoding case. |
698 | decodes faster). |
565 | |
699 | |
566 | On large strings containing lots of unicode characters, some modules |
700 | On large strings containing lots of high unicode characters, some modules |
567 | (such as JSON::PC) decode faster than JSON::XS, but the result will be |
701 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
568 | broken due to missing unicode handling. Others refuse to decode or encode |
702 | will be broken due to missing (or wrong) unicode handling. Others refuse |
569 | properly, so it was impossible to prepare a fair comparison table for that |
703 | to decode or encode properly, so it was impossible to prepare a fair |
570 | case. |
704 | comparison table for that case. |
571 | |
705 | |
572 | =head1 RESOURCE LIMITS |
|
|
573 | |
706 | |
574 | JSON::XS does not impose any limits on the size of JSON texts or Perl |
707 | =head1 SECURITY CONSIDERATIONS |
575 | values they represent - if your machine can handle it, JSON::XS will |
708 | |
576 | encode or decode it. Future versions might optionally impose structure |
709 | When you are using JSON in a protocol, talking to untrusted potentially |
577 | depth and memory use resource limits. |
710 | hostile creatures requires relatively few measures. |
|
|
711 | |
|
|
712 | First of all, your JSON decoder should be secure, that is, should not have |
|
|
713 | any buffer overflows. Obviously, this module should ensure that and I am |
|
|
714 | trying hard on making that true, but you never know. |
|
|
715 | |
|
|
716 | 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 |
|
|
718 | 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 |
|
|
720 | usually a good indication of the size of the resources required to decode |
|
|
721 | it into a Perl structure. |
|
|
722 | |
|
|
723 | 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 |
|
|
725 | 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 |
|
|
727 | to free the temporary). If that is exceeded, the program crashes. to be |
|
|
728 | conservative, the default nesting limit is set to 512. If your process |
|
|
729 | has a smaller stack, you should adjust this setting accordingly with the |
|
|
730 | C<max_depth> method. |
|
|
731 | |
|
|
732 | And last but least, something else could bomb you that I forgot to think |
|
|
733 | of. In that case, you get to keep the pieces. I am always open for hints, |
|
|
734 | though... |
|
|
735 | |
|
|
736 | If you are using JSON::XS to return packets to consumption |
|
|
737 | by javascript scripts in a browser you should have a look at |
|
|
738 | L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether |
|
|
739 | you are vulnerable to some common attack vectors (which really are browser |
|
|
740 | design bugs, but it is still you who will have to deal with it, as major |
|
|
741 | browser developers care only for features, not about doing security |
|
|
742 | right). |
|
|
743 | |
578 | |
744 | |
579 | =head1 BUGS |
745 | =head1 BUGS |
580 | |
746 | |
581 | While the goal of this module is to be correct, that unfortunately does |
747 | While the goal of this module is to be correct, that unfortunately does |
582 | not mean its bug-free, only that I think its design is bug-free. It is |
748 | not mean its bug-free, only that I think its design is bug-free. It is |
583 | still very young and not well-tested. If you keep reporting bugs they will |
749 | still relatively early in its development. If you keep reporting bugs they |
584 | be fixed swiftly, though. |
750 | will be fixed swiftly, though. |
585 | |
751 | |
586 | =cut |
752 | =cut |
|
|
753 | |
|
|
754 | our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" }; |
|
|
755 | our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" }; |
|
|
756 | |
|
|
757 | sub true() { $true } |
|
|
758 | sub false() { $false } |
|
|
759 | |
|
|
760 | sub is_bool($) { |
|
|
761 | UNIVERSAL::isa $_[0], "JSON::XS::Boolean" |
|
|
762 | or UNIVERSAL::isa $_[0], "JSON::Literal" |
|
|
763 | } |
|
|
764 | |
|
|
765 | XSLoader::load "JSON::XS", $VERSION; |
|
|
766 | |
|
|
767 | package JSON::XS::Boolean; |
|
|
768 | |
|
|
769 | use overload |
|
|
770 | "0+" => sub { ${$_[0]} }, |
|
|
771 | "++" => sub { $_[0] = ${$_[0]} + 1 }, |
|
|
772 | "--" => sub { $_[0] = ${$_[0]} - 1 }, |
|
|
773 | fallback => 1; |
587 | |
774 | |
588 | 1; |
775 | 1; |
589 | |
776 | |
590 | =head1 AUTHOR |
777 | =head1 AUTHOR |
591 | |
778 | |