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81 | |
81 | |
82 | package JSON::XS; |
82 | package JSON::XS; |
83 | |
83 | |
84 | use strict; |
84 | use strict; |
85 | |
85 | |
86 | our $VERSION = '1.4'; |
86 | our $VERSION = '1.5'; |
87 | our @ISA = qw(Exporter); |
87 | our @ISA = qw(Exporter); |
88 | |
88 | |
89 | our @EXPORT = qw(to_json from_json); |
89 | our @EXPORT = qw(to_json from_json); |
90 | |
90 | |
91 | use Exporter; |
91 | use Exporter; |
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278 | |
278 | |
279 | Example, space_before and indent disabled, space_after enabled: |
279 | Example, space_before and indent disabled, space_after enabled: |
280 | |
280 | |
281 | {"key": "value"} |
281 | {"key": "value"} |
282 | |
282 | |
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283 | =item $json = $json->relaxed ([$enable]) |
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284 | |
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285 | If C<$enable> is true (or missing), then C<decode> will accept some |
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286 | extensions to normal JSON syntax (see below). C<encode> will not be |
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287 | affected in anyway. I<Be aware that this option makes you accept invalid |
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288 | JSON texts as if they were valid!>. I suggest only to use this option to |
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289 | parse application-specific files written by humans (configuration files, |
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290 | resource files etc.) |
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291 | |
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292 | If C<$enable> is false (the default), then C<decode> will only accept |
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293 | valid JSON texts. |
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294 | |
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295 | Currently accepted extensions are: |
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296 | |
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297 | =over 4 |
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298 | |
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299 | =item * list items can have an end-comma |
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300 | |
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301 | JSON I<separates> array elements and key-value pairs with commas. This |
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302 | can be annoying if you write JSON texts manually and want to be able to |
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303 | quickly append elements, so this extension accepts comma at the end of |
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304 | such items not just between them: |
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305 | |
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306 | [ |
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307 | 1, |
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308 | 2, <- this comma not normally allowed |
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309 | ] |
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310 | { |
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311 | "k1": "v1", |
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312 | "k2": "v2", <- this comma not normally allowed |
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313 | } |
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314 | |
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315 | =back |
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316 | |
283 | =item $json = $json->canonical ([$enable]) |
317 | =item $json = $json->canonical ([$enable]) |
284 | |
318 | |
285 | If C<$enable> is true (or missing), then the C<encode> method will output JSON objects |
319 | If C<$enable> is true (or missing), then the C<encode> method will output JSON objects |
286 | by sorting their keys. This is adding a comparatively high overhead. |
320 | by sorting their keys. This is adding a comparatively high overhead. |
287 | |
321 | |
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347 | future, global hooks might get installed that influence C<decode> and are |
381 | future, global hooks might get installed that influence C<decode> and are |
348 | enabled by this setting. |
382 | enabled by this setting. |
349 | |
383 | |
350 | If C<$enable> is false, then the C<allow_blessed> setting will decide what |
384 | If C<$enable> is false, then the C<allow_blessed> setting will decide what |
351 | to do when a blessed object is found. |
385 | to do when a blessed object is found. |
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386 | |
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387 | =item $json = $json->filter_json_object ([$coderef->($hashref)]) |
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388 | |
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389 | When C<$coderef> is specified, it will be called from C<decode> each |
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390 | time it decodes a JSON object. The only argument is a reference to the |
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391 | newly-created hash. If the code references returns a single scalar (which |
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392 | need not be a reference), this value (i.e. a copy of that scalar to avoid |
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393 | aliasing) is inserted into the deserialised data structure. If it returns |
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394 | an empty list (NOTE: I<not> C<undef>, which is a valid scalar), the |
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395 | original deserialised hash will be inserted. This setting can slow down |
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396 | decoding considerably. |
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397 | |
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398 | When C<$coderef> is omitted or undefined, any existing callback will |
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399 | be removed and C<decode> will not change the deserialised hash in any |
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400 | way. |
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401 | |
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402 | Example, convert all JSON objects into the integer 5: |
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403 | |
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404 | my $js = JSON::XS->new->filter_json_object (sub { 5 }); |
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405 | # returns [5] |
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406 | $js->decode ('[{}]') |
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407 | # throw an exception because allow_nonref is not enabled |
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408 | # so a lone 5 is not allowed. |
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409 | $js->decode ('{"a":1, "b":2}'); |
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410 | |
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411 | =item $json = $json->filter_json_single_key_object ($key [=> $coderef->($value)]) |
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412 | |
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413 | Works remotely similar to C<filter_json_object>, but is only called for |
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414 | JSON objects having a single key named C<$key>. |
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415 | |
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416 | This C<$coderef> is called before the one specified via |
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417 | C<filter_json_object>, if any. It gets passed the single value in the JSON |
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418 | object. If it returns a single value, it will be inserted into the data |
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419 | structure. If it returns nothing (not even C<undef> but the empty list), |
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420 | the callback from C<filter_json_object> will be called next, as if no |
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421 | single-key callback were specified. |
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422 | |
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423 | If C<$coderef> is omitted or undefined, the corresponding callback will be |
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424 | disabled. There can only ever be one callback for a given key. |
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425 | |
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426 | As this callback gets called less often then the C<filter_json_object> |
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427 | one, decoding speed will not usually suffer as much. Therefore, single-key |
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428 | objects make excellent targets to serialise Perl objects into, especially |
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429 | as single-key JSON objects are as close to the type-tagged value concept |
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430 | as JSON gets (its basically an ID/VALUE tuple). Of course, JSON does not |
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431 | support this in any way, so you need to make sure your data never looks |
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432 | like a serialised Perl hash. |
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433 | |
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434 | Typical names for the single object key are C<__class_whatever__>, or |
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435 | C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even |
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436 | things like C<__class_md5sum(classname)__>, to reduce the risk of clashing |
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437 | with real hashes. |
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438 | |
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439 | Example, decode JSON objects of the form C<< { "__widget__" => <id> } >> |
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440 | into the corresponding C<< $WIDGET{<id>} >> object: |
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441 | |
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442 | # return whatever is in $WIDGET{5}: |
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443 | JSON::XS |
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444 | ->new |
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445 | ->filter_json_single_key_object (__widget__ => sub { |
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446 | $WIDGET{ $_[0] } |
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447 | }) |
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448 | ->decode ('{"__widget__": 5') |
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449 | |
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450 | # this can be used with a TO_JSON method in some "widget" class |
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451 | # for serialisation to json: |
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452 | sub WidgetBase::TO_JSON { |
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453 | my ($self) = @_; |
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454 | |
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455 | unless ($self->{id}) { |
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456 | $self->{id} = ..get..some..id..; |
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457 | $WIDGET{$self->{id}} = $self; |
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458 | } |
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459 | |
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460 | { __widget__ => $self->{id} } |
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461 | } |
352 | |
462 | |
353 | =item $json = $json->shrink ([$enable]) |
463 | =item $json = $json->shrink ([$enable]) |
354 | |
464 | |
355 | Perl usually over-allocates memory a bit when allocating space for |
465 | Perl usually over-allocates memory a bit when allocating space for |
356 | strings. This flag optionally resizes strings generated by either |
466 | strings. This flag optionally resizes strings generated by either |
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477 | are represented by the same codepoints in the Perl string, so no manual |
587 | are represented by the same codepoints in the Perl string, so no manual |
478 | decoding is necessary. |
588 | decoding is necessary. |
479 | |
589 | |
480 | =item number |
590 | =item number |
481 | |
591 | |
482 | A JSON number becomes either an integer or numeric (floating point) |
592 | A JSON number becomes either an integer, numeric (floating point) or |
483 | scalar in perl, depending on its range and any fractional parts. On the |
593 | string scalar in perl, depending on its range and any fractional parts. On |
484 | Perl level, there is no difference between those as Perl handles all the |
594 | the Perl level, there is no difference between those as Perl handles all |
485 | conversion details, but an integer may take slightly less memory and might |
595 | the conversion details, but an integer may take slightly less memory and |
486 | represent more values exactly than (floating point) numbers. |
596 | might represent more values exactly than (floating point) numbers. |
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597 | |
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598 | If the number consists of digits only, JSON::XS will try to represent |
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599 | it as an integer value. If that fails, it will try to represent it as |
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600 | a numeric (floating point) value if that is possible without loss of |
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601 | precision. Otherwise it will preserve the number as a string value. |
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602 | |
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603 | Numbers containing a fractional or exponential part will always be |
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604 | represented as numeric (floating point) values, possibly at a loss of |
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605 | precision. |
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606 | |
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607 | This might create round-tripping problems as numbers might become strings, |
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608 | but as Perl is typeless there is no other way to do it. |
487 | |
609 | |
488 | =item true, false |
610 | =item true, false |
489 | |
611 | |
490 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
612 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
491 | respectively. They are overloaded to act almost exactly like the numbers |
613 | respectively. They are overloaded to act almost exactly like the numbers |