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1 | =encoding utf-8 |
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2 | |
1 | =head1 NAME |
3 | =head1 NAME |
2 | |
4 | |
3 | JSON::XS - JSON serialising/deserialising, done correctly and fast |
5 | JSON::XS - JSON serialising/deserialising, done correctly and fast |
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6 | |
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7 | JSON::XS - 正しくて高速な JSON シリアライザ/デシリアライザ |
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8 | (http://fleur.hio.jp/perldoc/mix/lib/JSON/XS.html) |
4 | |
9 | |
5 | =head1 SYNOPSIS |
10 | =head1 SYNOPSIS |
6 | |
11 | |
7 | use JSON::XS; |
12 | use JSON::XS; |
8 | |
13 | |
9 | # exported functions, they croak on error |
14 | # exported functions, they croak on error |
10 | # and expect/generate UTF-8 |
15 | # and expect/generate UTF-8 |
11 | |
16 | |
12 | $utf8_encoded_json_text = to_json $perl_hash_or_arrayref; |
17 | $utf8_encoded_json_text = to_json $perl_hash_or_arrayref; |
13 | $perl_hash_or_arrayref = from_json $utf8_encoded_json_text; |
18 | $perl_hash_or_arrayref = from_json $utf8_encoded_json_text; |
14 | |
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15 | # objToJson and jsonToObj aliases to to_json and from_json |
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16 | # are exported for compatibility to the JSON module, |
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17 | # but should not be used in new code. |
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18 | |
19 | |
19 | # OO-interface |
20 | # OO-interface |
20 | |
21 | |
21 | $coder = JSON::XS->new->ascii->pretty->allow_nonref; |
22 | $coder = JSON::XS->new->ascii->pretty->allow_nonref; |
22 | $pretty_printed_unencoded = $coder->encode ($perl_scalar); |
23 | $pretty_printed_unencoded = $coder->encode ($perl_scalar); |
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85 | |
86 | |
86 | package JSON::XS; |
87 | package JSON::XS; |
87 | |
88 | |
88 | use strict; |
89 | use strict; |
89 | |
90 | |
90 | BEGIN { |
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91 | our $VERSION = '1.12'; |
91 | our $VERSION = '1.5'; |
92 | our @ISA = qw(Exporter); |
92 | our @ISA = qw(Exporter); |
93 | |
93 | |
94 | our @EXPORT = qw(to_json from_json objToJson jsonToObj); |
94 | our @EXPORT = qw(to_json from_json); |
95 | require Exporter; |
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96 | |
95 | |
97 | require XSLoader; |
96 | use Exporter; |
98 | XSLoader::load JSON::XS::, $VERSION; |
97 | use XSLoader; |
99 | } |
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100 | |
98 | |
101 | =head1 FUNCTIONAL INTERFACE |
99 | =head1 FUNCTIONAL INTERFACE |
102 | |
100 | |
103 | The following convinience methods are provided by this module. They are |
101 | The following convinience methods are provided by this module. They are |
104 | exported by default: |
102 | exported by default: |
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126 | This function call is functionally identical to: |
124 | This function call is functionally identical to: |
127 | |
125 | |
128 | $perl_scalar = JSON::XS->new->utf8->decode ($json_text) |
126 | $perl_scalar = JSON::XS->new->utf8->decode ($json_text) |
129 | |
127 | |
130 | except being faster. |
128 | except being faster. |
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129 | |
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130 | =item $is_boolean = JSON::XS::is_bool $scalar |
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131 | |
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132 | Returns true if the passed scalar represents either JSON::XS::true or |
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133 | JSON::XS::false, two constants that act like C<1> and C<0>, respectively |
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134 | and are used to represent JSON C<true> and C<false> values in Perl. |
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135 | |
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136 | See MAPPING, below, for more information on how JSON values are mapped to |
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137 | Perl. |
131 | |
138 | |
132 | =back |
139 | =back |
133 | |
140 | |
134 | |
141 | |
135 | =head1 OBJECT-ORIENTED INTERFACE |
142 | =head1 OBJECT-ORIENTED INTERFACE |
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276 | |
283 | |
277 | Example, space_before and indent disabled, space_after enabled: |
284 | Example, space_before and indent disabled, space_after enabled: |
278 | |
285 | |
279 | {"key": "value"} |
286 | {"key": "value"} |
280 | |
287 | |
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288 | =item $json = $json->relaxed ([$enable]) |
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289 | |
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290 | If C<$enable> is true (or missing), then C<decode> will accept some |
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291 | extensions to normal JSON syntax (see below). C<encode> will not be |
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292 | affected in anyway. I<Be aware that this option makes you accept invalid |
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293 | JSON texts as if they were valid!>. I suggest only to use this option to |
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294 | parse application-specific files written by humans (configuration files, |
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295 | resource files etc.) |
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296 | |
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297 | If C<$enable> is false (the default), then C<decode> will only accept |
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298 | valid JSON texts. |
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299 | |
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300 | Currently accepted extensions are: |
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301 | |
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302 | =over 4 |
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303 | |
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304 | =item * list items can have an end-comma |
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305 | |
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306 | JSON I<separates> array elements and key-value pairs with commas. This |
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307 | can be annoying if you write JSON texts manually and want to be able to |
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308 | quickly append elements, so this extension accepts comma at the end of |
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309 | such items not just between them: |
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310 | |
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311 | [ |
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312 | 1, |
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313 | 2, <- this comma not normally allowed |
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314 | ] |
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315 | { |
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316 | "k1": "v1", |
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317 | "k2": "v2", <- this comma not normally allowed |
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318 | } |
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319 | |
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320 | =item * shell-style '#'-comments |
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321 | |
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322 | Whenever JSON allows whitespace, shell-style comments are additionally |
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323 | allowed. They are terminated by the first carriage-return or line-feed |
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324 | character, after which more white-space and comments are allowed. |
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325 | |
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326 | [ |
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327 | 1, # this comment not allowed in JSON |
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328 | # neither this one... |
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329 | ] |
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330 | |
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331 | =back |
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332 | |
281 | =item $json = $json->canonical ([$enable]) |
333 | =item $json = $json->canonical ([$enable]) |
282 | |
334 | |
283 | If C<$enable> is true (or missing), then the C<encode> method will output JSON objects |
335 | If C<$enable> is true (or missing), then the C<encode> method will output JSON objects |
284 | by sorting their keys. This is adding a comparatively high overhead. |
336 | by sorting their keys. This is adding a comparatively high overhead. |
285 | |
337 | |
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309 | Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>, |
361 | Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>, |
310 | resulting in an invalid JSON text: |
362 | resulting in an invalid JSON text: |
311 | |
363 | |
312 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
364 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
313 | => "Hello, World!" |
365 | => "Hello, World!" |
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366 | |
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367 | =item $json = $json->allow_blessed ([$enable]) |
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368 | |
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369 | If C<$enable> is true (or missing), then the C<encode> method will not |
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370 | barf when it encounters a blessed reference. Instead, the value of the |
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371 | B<convert_blessed> option will decide wether C<null> (C<convert_blessed> |
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372 | disabled or no C<to_json> method found) or a representation of the |
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373 | object (C<convert_blessed> enabled and C<to_json> method found) is being |
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374 | encoded. Has no effect on C<decode>. |
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375 | |
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376 | If C<$enable> is false (the default), then C<encode> will throw an |
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377 | exception when it encounters a blessed object. |
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378 | |
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379 | =item $json = $json->convert_blessed ([$enable]) |
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380 | |
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381 | If C<$enable> is true (or missing), then C<encode>, upon encountering a |
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382 | blessed object, will check for the availability of the C<TO_JSON> method |
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383 | on the object's class. If found, it will be called in scalar context |
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384 | and the resulting scalar will be encoded instead of the object. If no |
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385 | C<TO_JSON> method is found, the value of C<allow_blessed> will decide what |
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386 | to do. |
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387 | |
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388 | The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON> |
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389 | returns other blessed objects, those will be handled in the same |
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390 | way. C<TO_JSON> must take care of not causing an endless recursion cycle |
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391 | (== crash) in this case. The name of C<TO_JSON> was chosen because other |
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392 | methods called by the Perl core (== not by the user of the object) are |
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393 | usually in upper case letters and to avoid collisions with the C<to_json> |
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394 | function. |
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395 | |
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396 | This setting does not yet influence C<decode> in any way, but in the |
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397 | future, global hooks might get installed that influence C<decode> and are |
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398 | enabled by this setting. |
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399 | |
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400 | If C<$enable> is false, then the C<allow_blessed> setting will decide what |
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401 | to do when a blessed object is found. |
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402 | |
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403 | =item $json = $json->filter_json_object ([$coderef->($hashref)]) |
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404 | |
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405 | When C<$coderef> is specified, it will be called from C<decode> each |
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406 | time it decodes a JSON object. The only argument is a reference to the |
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407 | newly-created hash. If the code references returns a single scalar (which |
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408 | need not be a reference), this value (i.e. a copy of that scalar to avoid |
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409 | aliasing) is inserted into the deserialised data structure. If it returns |
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410 | an empty list (NOTE: I<not> C<undef>, which is a valid scalar), the |
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411 | original deserialised hash will be inserted. This setting can slow down |
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412 | decoding considerably. |
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413 | |
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414 | When C<$coderef> is omitted or undefined, any existing callback will |
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415 | be removed and C<decode> will not change the deserialised hash in any |
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416 | way. |
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417 | |
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418 | Example, convert all JSON objects into the integer 5: |
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419 | |
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420 | my $js = JSON::XS->new->filter_json_object (sub { 5 }); |
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421 | # returns [5] |
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422 | $js->decode ('[{}]') |
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423 | # throw an exception because allow_nonref is not enabled |
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424 | # so a lone 5 is not allowed. |
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425 | $js->decode ('{"a":1, "b":2}'); |
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426 | |
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427 | =item $json = $json->filter_json_single_key_object ($key [=> $coderef->($value)]) |
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428 | |
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429 | Works remotely similar to C<filter_json_object>, but is only called for |
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430 | JSON objects having a single key named C<$key>. |
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431 | |
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432 | This C<$coderef> is called before the one specified via |
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433 | C<filter_json_object>, if any. It gets passed the single value in the JSON |
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434 | object. If it returns a single value, it will be inserted into the data |
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435 | structure. If it returns nothing (not even C<undef> but the empty list), |
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436 | the callback from C<filter_json_object> will be called next, as if no |
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437 | single-key callback were specified. |
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438 | |
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439 | If C<$coderef> is omitted or undefined, the corresponding callback will be |
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440 | disabled. There can only ever be one callback for a given key. |
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441 | |
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442 | As this callback gets called less often then the C<filter_json_object> |
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443 | one, decoding speed will not usually suffer as much. Therefore, single-key |
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444 | objects make excellent targets to serialise Perl objects into, especially |
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445 | as single-key JSON objects are as close to the type-tagged value concept |
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446 | as JSON gets (its basically an ID/VALUE tuple). Of course, JSON does not |
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447 | support this in any way, so you need to make sure your data never looks |
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448 | like a serialised Perl hash. |
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449 | |
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450 | Typical names for the single object key are C<__class_whatever__>, or |
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451 | C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even |
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452 | things like C<__class_md5sum(classname)__>, to reduce the risk of clashing |
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453 | with real hashes. |
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454 | |
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455 | Example, decode JSON objects of the form C<< { "__widget__" => <id> } >> |
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456 | into the corresponding C<< $WIDGET{<id>} >> object: |
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457 | |
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458 | # return whatever is in $WIDGET{5}: |
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459 | JSON::XS |
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460 | ->new |
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461 | ->filter_json_single_key_object (__widget__ => sub { |
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462 | $WIDGET{ $_[0] } |
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463 | }) |
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464 | ->decode ('{"__widget__": 5') |
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465 | |
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466 | # this can be used with a TO_JSON method in some "widget" class |
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467 | # for serialisation to json: |
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468 | sub WidgetBase::TO_JSON { |
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469 | my ($self) = @_; |
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470 | |
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471 | unless ($self->{id}) { |
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472 | $self->{id} = ..get..some..id..; |
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473 | $WIDGET{$self->{id}} = $self; |
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474 | } |
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475 | |
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476 | { __widget__ => $self->{id} } |
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477 | } |
314 | |
478 | |
315 | =item $json = $json->shrink ([$enable]) |
479 | =item $json = $json->shrink ([$enable]) |
316 | |
480 | |
317 | Perl usually over-allocates memory a bit when allocating space for |
481 | Perl usually over-allocates memory a bit when allocating space for |
318 | strings. This flag optionally resizes strings generated by either |
482 | strings. This flag optionally resizes strings generated by either |
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351 | given character in a string. |
515 | given character in a string. |
352 | |
516 | |
353 | Setting the maximum depth to one disallows any nesting, so that ensures |
517 | Setting the maximum depth to one disallows any nesting, so that ensures |
354 | that the object is only a single hash/object or array. |
518 | that the object is only a single hash/object or array. |
355 | |
519 | |
356 | The argument to C<max_depth> will be rounded up to the next nearest power |
520 | The argument to C<max_depth> will be rounded up to the next highest power |
357 | of two. |
521 | of two. If no argument is given, the highest possible setting will be |
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522 | used, which is rarely useful. |
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523 | |
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524 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
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525 | |
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526 | =item $json = $json->max_size ([$maximum_string_size]) |
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527 | |
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528 | Set the maximum length a JSON text may have (in bytes) where decoding is |
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529 | being attempted. The default is C<0>, meaning no limit. When C<decode> |
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530 | is called on a string longer then this number of characters it will not |
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531 | attempt to decode the string but throw an exception. This setting has no |
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532 | effect on C<encode> (yet). |
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533 | |
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534 | The argument to C<max_size> will be rounded up to the next B<highest> |
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535 | power of two (so may be more than requested). If no argument is given, the |
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536 | limit check will be deactivated (same as when C<0> is specified). |
358 | |
537 | |
359 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
538 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
360 | |
539 | |
361 | =item $json_text = $json->encode ($perl_scalar) |
540 | =item $json_text = $json->encode ($perl_scalar) |
362 | |
541 | |
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374 | |
553 | |
375 | JSON numbers and strings become simple Perl scalars. JSON arrays become |
554 | JSON numbers and strings become simple Perl scalars. JSON arrays become |
376 | Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes |
555 | Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes |
377 | C<1>, C<false> becomes C<0> and C<null> becomes C<undef>. |
556 | C<1>, C<false> becomes C<0> and C<null> becomes C<undef>. |
378 | |
557 | |
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558 | =item ($perl_scalar, $characters) = $json->decode_prefix ($json_text) |
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559 | |
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560 | This works like the C<decode> method, but instead of raising an exception |
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561 | when there is trailing garbage after the first JSON object, it will |
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562 | silently stop parsing there and return the number of characters consumed |
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563 | so far. |
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564 | |
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565 | This is useful if your JSON texts are not delimited by an outer protocol |
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566 | (which is not the brightest thing to do in the first place) and you need |
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567 | to know where the JSON text ends. |
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568 | |
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569 | JSON::XS->new->decode_prefix ("[1] the tail") |
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570 | => ([], 3) |
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571 | |
379 | =back |
572 | =back |
380 | |
573 | |
381 | |
574 | |
382 | =head1 MAPPING |
575 | =head1 MAPPING |
383 | |
576 | |
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388 | |
581 | |
389 | For the more enlightened: note that in the following descriptions, |
582 | For the more enlightened: note that in the following descriptions, |
390 | lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl> |
583 | lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl> |
391 | refers to the abstract Perl language itself. |
584 | refers to the abstract Perl language itself. |
392 | |
585 | |
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586 | |
393 | =head2 JSON -> PERL |
587 | =head2 JSON -> PERL |
394 | |
588 | |
395 | =over 4 |
589 | =over 4 |
396 | |
590 | |
397 | =item object |
591 | =item object |
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409 | are represented by the same codepoints in the Perl string, so no manual |
603 | are represented by the same codepoints in the Perl string, so no manual |
410 | decoding is necessary. |
604 | decoding is necessary. |
411 | |
605 | |
412 | =item number |
606 | =item number |
413 | |
607 | |
414 | A JSON number becomes either an integer or numeric (floating point) |
608 | A JSON number becomes either an integer, numeric (floating point) or |
415 | scalar in perl, depending on its range and any fractional parts. On the |
609 | string scalar in perl, depending on its range and any fractional parts. On |
416 | Perl level, there is no difference between those as Perl handles all the |
610 | the Perl level, there is no difference between those as Perl handles all |
417 | conversion details, but an integer may take slightly less memory and might |
611 | the conversion details, but an integer may take slightly less memory and |
418 | represent more values exactly than (floating point) numbers. |
612 | might represent more values exactly than (floating point) numbers. |
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613 | |
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614 | If the number consists of digits only, JSON::XS will try to represent |
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615 | it as an integer value. If that fails, it will try to represent it as |
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616 | a numeric (floating point) value if that is possible without loss of |
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617 | precision. Otherwise it will preserve the number as a string value. |
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618 | |
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619 | Numbers containing a fractional or exponential part will always be |
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620 | represented as numeric (floating point) values, possibly at a loss of |
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621 | precision. |
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622 | |
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623 | This might create round-tripping problems as numbers might become strings, |
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624 | but as Perl is typeless there is no other way to do it. |
419 | |
625 | |
420 | =item true, false |
626 | =item true, false |
421 | |
627 | |
422 | These JSON atoms become C<0>, C<1>, respectively. Information is lost in |
628 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
423 | this process. Future versions might represent those values differently, |
629 | respectively. They are overloaded to act almost exactly like the numbers |
424 | but they will be guarenteed to act like these integers would normally in |
630 | C<1> and C<0>. You can check wether a scalar is a JSON boolean by using |
425 | Perl. |
631 | the C<JSON::XS::is_bool> function. |
426 | |
632 | |
427 | =item null |
633 | =item null |
428 | |
634 | |
429 | A JSON null atom becomes C<undef> in Perl. |
635 | A JSON null atom becomes C<undef> in Perl. |
430 | |
636 | |
431 | =back |
637 | =back |
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638 | |
432 | |
639 | |
433 | =head2 PERL -> JSON |
640 | =head2 PERL -> JSON |
434 | |
641 | |
435 | The mapping from Perl to JSON is slightly more difficult, as Perl is a |
642 | The mapping from Perl to JSON is slightly more difficult, as Perl is a |
436 | truly typeless language, so we can only guess which JSON type is meant by |
643 | truly typeless language, so we can only guess which JSON type is meant by |
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461 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
668 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
462 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
669 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
463 | |
670 | |
464 | to_json [\0,JSON::XS::true] # yields [false,true] |
671 | to_json [\0,JSON::XS::true] # yields [false,true] |
465 | |
672 | |
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673 | =item JSON::XS::true, JSON::XS::false |
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674 | |
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675 | These special values become JSON true and JSON false values, |
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676 | respectively. You can also use C<\1> and C<\0> directly if you want. |
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677 | |
466 | =item blessed objects |
678 | =item blessed objects |
467 | |
679 | |
468 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
680 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
469 | underlying representation (hash- or arrayref), but this behaviour might |
681 | underlying representation (hash- or arrayref), but this behaviour might |
470 | change in future versions. |
682 | change in future versions. |
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591 | |
803 | |
592 | Does not check input for validity. |
804 | Does not check input for validity. |
593 | |
805 | |
594 | =back |
806 | =back |
595 | |
807 | |
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808 | |
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809 | =head2 JSON and YAML |
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810 | |
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811 | You often hear that JSON is a subset (or a close subset) of YAML. This is, |
|
|
812 | however, a mass hysteria and very far from the truth. In general, there is |
|
|
813 | no way to configure JSON::XS to output a data structure as valid YAML. |
|
|
814 | |
|
|
815 | If you really must use JSON::XS to generate YAML, you should use this |
|
|
816 | algorithm (subject to change in future versions): |
|
|
817 | |
|
|
818 | my $to_yaml = JSON::XS->new->utf8->space_after (1); |
|
|
819 | my $yaml = $to_yaml->encode ($ref) . "\n"; |
|
|
820 | |
|
|
821 | This will usually generate JSON texts that also parse as valid |
|
|
822 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
|
|
823 | lengths that JSON doesn't have, so you should make sure that your hash |
|
|
824 | keys are noticably shorter than the 1024 characters YAML allows. |
|
|
825 | |
|
|
826 | There might be other incompatibilities that I am not aware of. In general |
|
|
827 | you should not try to generate YAML with a JSON generator or vice versa, |
|
|
828 | or try to parse JSON with a YAML parser or vice versa: chances are high |
|
|
829 | that you will run into severe interoperability problems. |
|
|
830 | |
|
|
831 | |
596 | =head2 SPEED |
832 | =head2 SPEED |
597 | |
833 | |
598 | It seems that JSON::XS is surprisingly fast, as shown in the following |
834 | It seems that JSON::XS is surprisingly fast, as shown in the following |
599 | tables. They have been generated with the help of the C<eg/bench> program |
835 | tables. They have been generated with the help of the C<eg/bench> program |
600 | in the JSON::XS distribution, to make it easy to compare on your own |
836 | in the JSON::XS distribution, to make it easy to compare on your own |
601 | system. |
837 | system. |
602 | |
838 | |
603 | First comes a comparison between various modules using a very short JSON |
839 | First comes a comparison between various modules using a very short |
604 | string: |
840 | single-line JSON string: |
605 | |
841 | |
606 | {"method": "handleMessage", "params": ["user1", "we were just talking"], "id": null} |
842 | {"method": "handleMessage", "params": ["user1", "we were just talking"], \ |
|
|
843 | "id": null, "array":[1,11,234,-5,1e5,1e7, true, false]} |
607 | |
844 | |
608 | It shows the number of encodes/decodes per second (JSON::XS uses the |
845 | It shows the number of encodes/decodes per second (JSON::XS uses |
609 | functional interface, while JSON::XS/2 uses the OO interface with |
846 | the functional interface, while JSON::XS/2 uses the OO interface |
610 | pretty-printing and hashkey sorting enabled). Higher is better: |
847 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
|
|
848 | shrink). Higher is better: |
611 | |
849 | |
|
|
850 | Storable | 15779.925 | 14169.946 | |
|
|
851 | -----------+------------+------------+ |
612 | module | encode | decode | |
852 | module | encode | decode | |
613 | -----------|------------|------------| |
853 | -----------|------------|------------| |
614 | JSON | 11488.516 | 7823.035 | |
854 | JSON | 4990.842 | 4088.813 | |
615 | JSON::DWIW | 94708.054 | 129094.260 | |
855 | JSON::DWIW | 51653.990 | 71575.154 | |
616 | JSON::PC | 63884.157 | 128528.212 | |
856 | JSON::PC | 65948.176 | 74631.744 | |
617 | JSON::Syck | 34898.677 | 42096.911 | |
857 | JSON::PP | 8931.652 | 3817.168 | |
618 | JSON::XS | 654027.064 | 396423.669 | |
858 | JSON::Syck | 24877.248 | 27776.848 | |
619 | JSON::XS/2 | 371564.190 | 371725.613 | |
859 | JSON::XS | 388361.481 | 227951.304 | |
|
|
860 | JSON::XS/2 | 227951.304 | 218453.333 | |
|
|
861 | JSON::XS/3 | 338250.323 | 218453.333 | |
|
|
862 | Storable | 16500.016 | 135300.129 | |
620 | -----------+------------+------------+ |
863 | -----------+------------+------------+ |
621 | |
864 | |
622 | That is, JSON::XS is more than six times faster than JSON::DWIW on |
865 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
623 | encoding, more than three times faster on decoding, and about thirty times |
866 | about three times faster on decoding, and over fourty times faster |
624 | faster than JSON, even with pretty-printing and key sorting. |
867 | than JSON, even with pretty-printing and key sorting. It also compares |
|
|
868 | favourably to Storable for small amounts of data. |
625 | |
869 | |
626 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
870 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
627 | search API (http://nanoref.com/yahooapis/mgPdGg): |
871 | search API (http://nanoref.com/yahooapis/mgPdGg): |
628 | |
872 | |
629 | module | encode | decode | |
873 | module | encode | decode | |
630 | -----------|------------|------------| |
874 | -----------|------------|------------| |
631 | JSON | 273.023 | 44.674 | |
875 | JSON | 55.260 | 34.971 | |
632 | JSON::DWIW | 1089.383 | 1145.704 | |
876 | JSON::DWIW | 825.228 | 1082.513 | |
633 | JSON::PC | 3097.419 | 2393.921 | |
877 | JSON::PC | 3571.444 | 2394.829 | |
634 | JSON::Syck | 514.060 | 843.053 | |
878 | JSON::PP | 210.987 | 32.574 | |
635 | JSON::XS | 6479.668 | 3636.364 | |
879 | JSON::Syck | 552.551 | 787.544 | |
636 | JSON::XS/2 | 3774.221 | 3599.124 | |
880 | JSON::XS | 5780.463 | 4854.519 | |
|
|
881 | JSON::XS/2 | 3869.998 | 4798.975 | |
|
|
882 | JSON::XS/3 | 5862.880 | 4798.975 | |
|
|
883 | Storable | 4445.002 | 5235.027 | |
637 | -----------+------------+------------+ |
884 | -----------+------------+------------+ |
638 | |
885 | |
639 | Again, JSON::XS leads by far. |
886 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
|
|
887 | decodes faster). |
640 | |
888 | |
641 | On large strings containing lots of high unicode characters, some modules |
889 | On large strings containing lots of high unicode characters, some modules |
642 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
890 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
643 | will be broken due to missing (or wrong) unicode handling. Others refuse |
891 | will be broken due to missing (or wrong) unicode handling. Others refuse |
644 | to decode or encode properly, so it was impossible to prepare a fair |
892 | to decode or encode properly, so it was impossible to prepare a fair |
… | |
… | |
657 | Second, you need to avoid resource-starving attacks. That means you should |
905 | Second, you need to avoid resource-starving attacks. That means you should |
658 | limit the size of JSON texts you accept, or make sure then when your |
906 | limit the size of JSON texts you accept, or make sure then when your |
659 | resources run out, thats just fine (e.g. by using a separate process that |
907 | resources run out, thats just fine (e.g. by using a separate process that |
660 | can crash safely). The size of a JSON text in octets or characters is |
908 | can crash safely). The size of a JSON text in octets or characters is |
661 | usually a good indication of the size of the resources required to decode |
909 | usually a good indication of the size of the resources required to decode |
662 | it into a Perl structure. |
910 | it into a Perl structure. While JSON::XS can check the size of the JSON |
|
|
911 | text, it might be too late when you already have it in memory, so you |
|
|
912 | might want to check the size before you accept the string. |
663 | |
913 | |
664 | Third, JSON::XS recurses using the C stack when decoding objects and |
914 | Third, JSON::XS recurses using the C stack when decoding objects and |
665 | arrays. The C stack is a limited resource: for instance, on my amd64 |
915 | arrays. The C stack is a limited resource: for instance, on my amd64 |
666 | machine with 8MB of stack size I can decode around 180k nested arrays but |
916 | machine with 8MB of stack size I can decode around 180k nested arrays but |
667 | only 14k nested JSON objects (due to perl itself recursing deeply on croak |
917 | only 14k nested JSON objects (due to perl itself recursing deeply on croak |
… | |
… | |
672 | |
922 | |
673 | And last but least, something else could bomb you that I forgot to think |
923 | And last but least, something else could bomb you that I forgot to think |
674 | of. In that case, you get to keep the pieces. I am always open for hints, |
924 | of. In that case, you get to keep the pieces. I am always open for hints, |
675 | though... |
925 | though... |
676 | |
926 | |
|
|
927 | If you are using JSON::XS to return packets to consumption |
|
|
928 | by javascript scripts in a browser you should have a look at |
|
|
929 | L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether |
|
|
930 | you are vulnerable to some common attack vectors (which really are browser |
|
|
931 | design bugs, but it is still you who will have to deal with it, as major |
|
|
932 | browser developers care only for features, not about doing security |
|
|
933 | right). |
|
|
934 | |
677 | |
935 | |
678 | =head1 BUGS |
936 | =head1 BUGS |
679 | |
937 | |
680 | While the goal of this module is to be correct, that unfortunately does |
938 | While the goal of this module is to be correct, that unfortunately does |
681 | not mean its bug-free, only that I think its design is bug-free. It is |
939 | not mean its bug-free, only that I think its design is bug-free. It is |
682 | still relatively early in its development. If you keep reporting bugs they |
940 | still relatively early in its development. If you keep reporting bugs they |
683 | will be fixed swiftly, though. |
941 | will be fixed swiftly, though. |
684 | |
942 | |
685 | =cut |
943 | =cut |
686 | |
944 | |
|
|
945 | our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" }; |
|
|
946 | our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" }; |
|
|
947 | |
687 | sub true() { \1 } |
948 | sub true() { $true } |
688 | sub false() { \0 } |
949 | sub false() { $false } |
|
|
950 | |
|
|
951 | sub is_bool($) { |
|
|
952 | UNIVERSAL::isa $_[0], "JSON::XS::Boolean" |
|
|
953 | # or UNIVERSAL::isa $_[0], "JSON::Literal" |
|
|
954 | } |
|
|
955 | |
|
|
956 | XSLoader::load "JSON::XS", $VERSION; |
|
|
957 | |
|
|
958 | package JSON::XS::Boolean; |
|
|
959 | |
|
|
960 | use overload |
|
|
961 | "0+" => sub { ${$_[0]} }, |
|
|
962 | "++" => sub { $_[0] = ${$_[0]} + 1 }, |
|
|
963 | "--" => sub { $_[0] = ${$_[0]} - 1 }, |
|
|
964 | fallback => 1; |
689 | |
965 | |
690 | 1; |
966 | 1; |
691 | |
967 | |
692 | =head1 AUTHOR |
968 | =head1 AUTHOR |
693 | |
969 | |