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Revision 1.51 by root, Mon Jul 2 01:12:27 2007 UTC vs.
Revision 1.79 by root, Wed Dec 19 11:42:52 2007 UTC

1=head1 NAME 1=head1 NAME
2 2
3JSON::XS - JSON serialising/deserialising, done correctly and fast 3JSON::XS - JSON serialising/deserialising, done correctly and fast
4
5JSON::XS - 正しくて高速な JSON シリアライザ/デシリアライザ
6 (http://fleur.hio.jp/perldoc/mix/lib/JSON/XS.html)
4 7
5=head1 SYNOPSIS 8=head1 SYNOPSIS
6 9
7 use JSON::XS; 10 use JSON::XS;
8 11
9 # exported functions, they croak on error 12 # exported functions, they croak on error
10 # and expect/generate UTF-8 13 # and expect/generate UTF-8
11 14
12 $utf8_encoded_json_text = to_json $perl_hash_or_arrayref; 15 $utf8_encoded_json_text = encode_json $perl_hash_or_arrayref;
13 $perl_hash_or_arrayref = from_json $utf8_encoded_json_text; 16 $perl_hash_or_arrayref = decode_json $utf8_encoded_json_text;
14 17
15 # OO-interface 18 # OO-interface
16 19
17 $coder = JSON::XS->new->ascii->pretty->allow_nonref; 20 $coder = JSON::XS->new->ascii->pretty->allow_nonref;
18 $pretty_printed_unencoded = $coder->encode ($perl_scalar); 21 $pretty_printed_unencoded = $coder->encode ($perl_scalar);
19 $perl_scalar = $coder->decode ($unicode_json_text); 22 $perl_scalar = $coder->decode ($unicode_json_text);
20 23
24 # Note that JSON version 2.0 and above will automatically use JSON::XS
25 # if available, at virtually no speed overhead either, so you should
26 # be able to just:
27
28 use JSON;
29
30 # and do the same things, except that you have a pure-perl fallback now.
31
21=head1 DESCRIPTION 32=head1 DESCRIPTION
22 33
23This module converts Perl data structures to JSON and vice versa. Its 34This module converts Perl data structures to JSON and vice versa. Its
24primary goal is to be I<correct> and its secondary goal is to be 35primary goal is to be I<correct> and its secondary goal is to be
25I<fast>. To reach the latter goal it was written in C. 36I<fast>. To reach the latter goal it was written in C.
37
38Beginning with version 2.0 of the JSON module, when both JSON and
39JSON::XS are installed, then JSON will fall back on JSON::XS (this can be
40overriden) with no overhead due to emulation (by inheritign constructor
41and methods). If JSON::XS is not available, it will fall back to the
42compatible JSON::PP module as backend, so using JSON instead of JSON::XS
43gives you a portable JSON API that can be fast when you need and doesn't
44require a C compiler when that is a problem.
26 45
27As this is the n-th-something JSON module on CPAN, what was the reason 46As this is the n-th-something JSON module on CPAN, what was the reason
28to write yet another JSON module? While it seems there are many JSON 47to write yet another JSON module? While it seems there are many JSON
29modules, none of them correctly handle all corner cases, and in most cases 48modules, none of them correctly handle all corner cases, and in most cases
30their maintainers are unresponsive, gone missing, or not listening to bug 49their maintainers are unresponsive, gone missing, or not listening to bug
37 56
38=head2 FEATURES 57=head2 FEATURES
39 58
40=over 4 59=over 4
41 60
42=item * correct unicode handling 61=item * correct Unicode handling
43 62
44This module knows how to handle Unicode, and even documents how and when 63This module knows how to handle Unicode, and even documents how and when
45it does so. 64it does so.
46 65
47=item * round-trip integrity 66=item * round-trip integrity
67This module has both a simple functional interface as well as an OO 86This module has both a simple functional interface as well as an OO
68interface. 87interface.
69 88
70=item * reasonably versatile output formats 89=item * reasonably versatile output formats
71 90
72You can choose between the most compact guarenteed single-line format 91You can choose between the most compact guaranteed single-line format
73possible (nice for simple line-based protocols), a pure-ascii format 92possible (nice for simple line-based protocols), a pure-ascii format
74(for when your transport is not 8-bit clean, still supports the whole 93(for when your transport is not 8-bit clean, still supports the whole
75unicode range), or a pretty-printed format (for when you want to read that 94Unicode range), or a pretty-printed format (for when you want to read that
76stuff). Or you can combine those features in whatever way you like. 95stuff). Or you can combine those features in whatever way you like.
77 96
78=back 97=back
79 98
80=cut 99=cut
81 100
82package JSON::XS; 101package JSON::XS;
83 102
84use strict; 103use strict;
85 104
86our $VERSION = '1.4'; 105our $VERSION = '2.01';
87our @ISA = qw(Exporter); 106our @ISA = qw(Exporter);
88 107
89our @EXPORT = qw(to_json from_json); 108our @EXPORT = qw(encode_json decode_json to_json from_json);
109
110sub to_json($) {
111 require Carp;
112 Carp::croak ("JSON::XS::to_json has been renamed to encode_json, either downgrade to pre-2.0 versions of JSON::XS or rename the call");
113}
114
115sub from_json($) {
116 require Carp;
117 Carp::croak ("JSON::XS::from_json has been renamed to decode_json, either downgrade to pre-2.0 versions of JSON::XS or rename the call");
118}
90 119
91use Exporter; 120use Exporter;
92use XSLoader; 121use XSLoader;
93 122
94=head1 FUNCTIONAL INTERFACE 123=head1 FUNCTIONAL INTERFACE
95 124
96The following convinience methods are provided by this module. They are 125The following convenience methods are provided by this module. They are
97exported by default: 126exported by default:
98 127
99=over 4 128=over 4
100 129
101=item $json_text = to_json $perl_scalar 130=item $json_text = encode_json $perl_scalar
102 131
103Converts the given Perl data structure (a simple scalar or a reference to 132Converts the given Perl data structure to a UTF-8 encoded, binary string
104a hash or array) to a UTF-8 encoded, binary string (that is, the string contains 133(that is, the string contains octets only). Croaks on error.
105octets only). Croaks on error.
106 134
107This function call is functionally identical to: 135This function call is functionally identical to:
108 136
109 $json_text = JSON::XS->new->utf8->encode ($perl_scalar) 137 $json_text = JSON::XS->new->utf8->encode ($perl_scalar)
110 138
111except being faster. 139except being faster.
112 140
113=item $perl_scalar = from_json $json_text 141=item $perl_scalar = decode_json $json_text
114 142
115The opposite of C<to_json>: expects an UTF-8 (binary) string and tries to 143The opposite of C<encode_json>: expects an UTF-8 (binary) string and tries
116parse that as an UTF-8 encoded JSON text, returning the resulting simple 144to parse that as an UTF-8 encoded JSON text, returning the resulting
117scalar or reference. Croaks on error. 145reference. Croaks on error.
118 146
119This function call is functionally identical to: 147This function call is functionally identical to:
120 148
121 $perl_scalar = JSON::XS->new->utf8->decode ($json_text) 149 $perl_scalar = JSON::XS->new->utf8->decode ($json_text)
122 150
132Perl. 160Perl.
133 161
134=back 162=back
135 163
136 164
165=head1 A FEW NOTES ON UNICODE AND PERL
166
167Since this often leads to confusion, here are a few very clear words on
168how Unicode works in Perl, modulo bugs.
169
170=over 4
171
172=item 1. Perl strings can store characters with ordinal values > 255.
173
174This enables you to store Unicode characters as single characters in a
175Perl string - very natural.
176
177=item 2. Perl does I<not> associate an encoding with your strings.
178
179Unless you force it to, e.g. when matching it against a regex, or printing
180the scalar to a file, in which case Perl either interprets your string as
181locale-encoded text, octets/binary, or as Unicode, depending on various
182settings. In no case is an encoding stored together with your data, it is
183I<use> that decides encoding, not any magical metadata.
184
185=item 3. The internal utf-8 flag has no meaning with regards to the
186encoding of your string.
187
188Just ignore that flag unless you debug a Perl bug, a module written in
189XS or want to dive into the internals of perl. Otherwise it will only
190confuse you, as, despite the name, it says nothing about how your string
191is encoded. You can have Unicode strings with that flag set, with that
192flag clear, and you can have binary data with that flag set and that flag
193clear. Other possibilities exist, too.
194
195If you didn't know about that flag, just the better, pretend it doesn't
196exist.
197
198=item 4. A "Unicode String" is simply a string where each character can be
199validly interpreted as a Unicode codepoint.
200
201If you have UTF-8 encoded data, it is no longer a Unicode string, but a
202Unicode string encoded in UTF-8, giving you a binary string.
203
204=item 5. A string containing "high" (> 255) character values is I<not> a UTF-8 string.
205
206It's a fact. Learn to live with it.
207
208=back
209
210I hope this helps :)
211
212
137=head1 OBJECT-ORIENTED INTERFACE 213=head1 OBJECT-ORIENTED INTERFACE
138 214
139The object oriented interface lets you configure your own encoding or 215The object oriented interface lets you configure your own encoding or
140decoding style, within the limits of supported formats. 216decoding style, within the limits of supported formats.
141 217
152 my $json = JSON::XS->new->utf8->space_after->encode ({a => [1,2]}) 228 my $json = JSON::XS->new->utf8->space_after->encode ({a => [1,2]})
153 => {"a": [1, 2]} 229 => {"a": [1, 2]}
154 230
155=item $json = $json->ascii ([$enable]) 231=item $json = $json->ascii ([$enable])
156 232
233=item $enabled = $json->get_ascii
234
157If C<$enable> is true (or missing), then the C<encode> method will not 235If C<$enable> is true (or missing), then the C<encode> method will not
158generate characters outside the code range C<0..127> (which is ASCII). Any 236generate characters outside the code range C<0..127> (which is ASCII). Any
159unicode characters outside that range will be escaped using either a 237Unicode characters outside that range will be escaped using either a
160single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, 238single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,
161as per RFC4627. The resulting encoded JSON text can be treated as a native 239as per RFC4627. The resulting encoded JSON text can be treated as a native
162unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string, 240Unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string,
163or any other superset of ASCII. 241or any other superset of ASCII.
164 242
165If C<$enable> is false, then the C<encode> method will not escape Unicode 243If C<$enable> is false, then the C<encode> method will not escape Unicode
166characters unless required by the JSON syntax or other flags. This results 244characters unless required by the JSON syntax or other flags. This results
167in a faster and more compact format. 245in a faster and more compact format.
173 JSON::XS->new->ascii (1)->encode ([chr 0x10401]) 251 JSON::XS->new->ascii (1)->encode ([chr 0x10401])
174 => ["\ud801\udc01"] 252 => ["\ud801\udc01"]
175 253
176=item $json = $json->latin1 ([$enable]) 254=item $json = $json->latin1 ([$enable])
177 255
256=item $enabled = $json->get_latin1
257
178If C<$enable> is true (or missing), then the C<encode> method will encode 258If C<$enable> is true (or missing), then the C<encode> method will encode
179the resulting JSON text as latin1 (or iso-8859-1), escaping any characters 259the resulting JSON text as latin1 (or iso-8859-1), escaping any characters
180outside the code range C<0..255>. The resulting string can be treated as a 260outside the code range C<0..255>. The resulting string can be treated as a
181latin1-encoded JSON text or a native unicode string. The C<decode> method 261latin1-encoded JSON text or a native Unicode string. The C<decode> method
182will not be affected in any way by this flag, as C<decode> by default 262will not be affected in any way by this flag, as C<decode> by default
183expects unicode, which is a strict superset of latin1. 263expects Unicode, which is a strict superset of latin1.
184 264
185If C<$enable> is false, then the C<encode> method will not escape Unicode 265If C<$enable> is false, then the C<encode> method will not escape Unicode
186characters unless required by the JSON syntax or other flags. 266characters unless required by the JSON syntax or other flags.
187 267
188The main use for this flag is efficiently encoding binary data as JSON 268The main use for this flag is efficiently encoding binary data as JSON
189text, as most octets will not be escaped, resulting in a smaller encoded 269text, as most octets will not be escaped, resulting in a smaller encoded
190size. The disadvantage is that the resulting JSON text is encoded 270size. The disadvantage is that the resulting JSON text is encoded
191in latin1 (and must correctly be treated as such when storing and 271in latin1 (and must correctly be treated as such when storing and
192transfering), a rare encoding for JSON. It is therefore most useful when 272transferring), a rare encoding for JSON. It is therefore most useful when
193you want to store data structures known to contain binary data efficiently 273you want to store data structures known to contain binary data efficiently
194in files or databases, not when talking to other JSON encoders/decoders. 274in files or databases, not when talking to other JSON encoders/decoders.
195 275
196 JSON::XS->new->latin1->encode (["\x{89}\x{abc}"] 276 JSON::XS->new->latin1->encode (["\x{89}\x{abc}"]
197 => ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not) 277 => ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not)
198 278
199=item $json = $json->utf8 ([$enable]) 279=item $json = $json->utf8 ([$enable])
280
281=item $enabled = $json->get_utf8
200 282
201If C<$enable> is true (or missing), then the C<encode> method will encode 283If C<$enable> is true (or missing), then the C<encode> method will encode
202the JSON result into UTF-8, as required by many protocols, while the 284the JSON result into UTF-8, as required by many protocols, while the
203C<decode> method expects to be handled an UTF-8-encoded string. Please 285C<decode> method expects to be handled an UTF-8-encoded string. Please
204note that UTF-8-encoded strings do not contain any characters outside the 286note that UTF-8-encoded strings do not contain any characters outside the
205range C<0..255>, they are thus useful for bytewise/binary I/O. In future 287range C<0..255>, they are thus useful for bytewise/binary I/O. In future
206versions, enabling this option might enable autodetection of the UTF-16 288versions, enabling this option might enable autodetection of the UTF-16
207and UTF-32 encoding families, as described in RFC4627. 289and UTF-32 encoding families, as described in RFC4627.
208 290
209If C<$enable> is false, then the C<encode> method will return the JSON 291If C<$enable> is false, then the C<encode> method will return the JSON
210string as a (non-encoded) unicode string, while C<decode> expects thus a 292string as a (non-encoded) Unicode string, while C<decode> expects thus a
211unicode string. Any decoding or encoding (e.g. to UTF-8 or UTF-16) needs 293Unicode string. Any decoding or encoding (e.g. to UTF-8 or UTF-16) needs
212to be done yourself, e.g. using the Encode module. 294to be done yourself, e.g. using the Encode module.
213 295
214Example, output UTF-16BE-encoded JSON: 296Example, output UTF-16BE-encoded JSON:
215 297
216 use Encode; 298 use Encode;
238 ] 320 ]
239 } 321 }
240 322
241=item $json = $json->indent ([$enable]) 323=item $json = $json->indent ([$enable])
242 324
325=item $enabled = $json->get_indent
326
243If C<$enable> is true (or missing), then the C<encode> method will use a multiline 327If C<$enable> is true (or missing), then the C<encode> method will use a multiline
244format as output, putting every array member or object/hash key-value pair 328format as output, putting every array member or object/hash key-value pair
245into its own line, identing them properly. 329into its own line, indenting them properly.
246 330
247If C<$enable> is false, no newlines or indenting will be produced, and the 331If C<$enable> is false, no newlines or indenting will be produced, and the
248resulting JSON text is guarenteed not to contain any C<newlines>. 332resulting JSON text is guaranteed not to contain any C<newlines>.
249 333
250This setting has no effect when decoding JSON texts. 334This setting has no effect when decoding JSON texts.
251 335
252=item $json = $json->space_before ([$enable]) 336=item $json = $json->space_before ([$enable])
337
338=item $enabled = $json->get_space_before
253 339
254If C<$enable> is true (or missing), then the C<encode> method will add an extra 340If C<$enable> is true (or missing), then the C<encode> method will add an extra
255optional space before the C<:> separating keys from values in JSON objects. 341optional space before the C<:> separating keys from values in JSON objects.
256 342
257If C<$enable> is false, then the C<encode> method will not add any extra 343If C<$enable> is false, then the C<encode> method will not add any extra
263Example, space_before enabled, space_after and indent disabled: 349Example, space_before enabled, space_after and indent disabled:
264 350
265 {"key" :"value"} 351 {"key" :"value"}
266 352
267=item $json = $json->space_after ([$enable]) 353=item $json = $json->space_after ([$enable])
354
355=item $enabled = $json->get_space_after
268 356
269If C<$enable> is true (or missing), then the C<encode> method will add an extra 357If C<$enable> is true (or missing), then the C<encode> method will add an extra
270optional space after the C<:> separating keys from values in JSON objects 358optional space after the C<:> separating keys from values in JSON objects
271and extra whitespace after the C<,> separating key-value pairs and array 359and extra whitespace after the C<,> separating key-value pairs and array
272members. 360members.
278 366
279Example, space_before and indent disabled, space_after enabled: 367Example, space_before and indent disabled, space_after enabled:
280 368
281 {"key": "value"} 369 {"key": "value"}
282 370
371=item $json = $json->relaxed ([$enable])
372
373=item $enabled = $json->get_relaxed
374
375If C<$enable> is true (or missing), then C<decode> will accept some
376extensions to normal JSON syntax (see below). C<encode> will not be
377affected in anyway. I<Be aware that this option makes you accept invalid
378JSON texts as if they were valid!>. I suggest only to use this option to
379parse application-specific files written by humans (configuration files,
380resource files etc.)
381
382If C<$enable> is false (the default), then C<decode> will only accept
383valid JSON texts.
384
385Currently accepted extensions are:
386
387=over 4
388
389=item * list items can have an end-comma
390
391JSON I<separates> array elements and key-value pairs with commas. This
392can be annoying if you write JSON texts manually and want to be able to
393quickly append elements, so this extension accepts comma at the end of
394such items not just between them:
395
396 [
397 1,
398 2, <- this comma not normally allowed
399 ]
400 {
401 "k1": "v1",
402 "k2": "v2", <- this comma not normally allowed
403 }
404
405=item * shell-style '#'-comments
406
407Whenever JSON allows whitespace, shell-style comments are additionally
408allowed. They are terminated by the first carriage-return or line-feed
409character, after which more white-space and comments are allowed.
410
411 [
412 1, # this comment not allowed in JSON
413 # neither this one...
414 ]
415
416=back
417
283=item $json = $json->canonical ([$enable]) 418=item $json = $json->canonical ([$enable])
419
420=item $enabled = $json->get_canonical
284 421
285If C<$enable> is true (or missing), then the C<encode> method will output JSON objects 422If C<$enable> is true (or missing), then the C<encode> method will output JSON objects
286by sorting their keys. This is adding a comparatively high overhead. 423by sorting their keys. This is adding a comparatively high overhead.
287 424
288If C<$enable> is false, then the C<encode> method will output key-value 425If C<$enable> is false, then the C<encode> method will output key-value
289pairs in the order Perl stores them (which will likely change between runs 426pairs in the order Perl stores them (which will likely change between runs
290of the same script). 427of the same script).
291 428
292This option is useful if you want the same data structure to be encoded as 429This option is useful if you want the same data structure to be encoded as
293the same JSON text (given the same overall settings). If it is disabled, 430the same JSON text (given the same overall settings). If it is disabled,
294the same hash migh be encoded differently even if contains the same data, 431the same hash might be encoded differently even if contains the same data,
295as key-value pairs have no inherent ordering in Perl. 432as key-value pairs have no inherent ordering in Perl.
296 433
297This setting has no effect when decoding JSON texts. 434This setting has no effect when decoding JSON texts.
298 435
299=item $json = $json->allow_nonref ([$enable]) 436=item $json = $json->allow_nonref ([$enable])
437
438=item $enabled = $json->get_allow_nonref
300 439
301If C<$enable> is true (or missing), then the C<encode> method can convert a 440If C<$enable> is true (or missing), then the C<encode> method can convert a
302non-reference into its corresponding string, number or null JSON value, 441non-reference into its corresponding string, number or null JSON value,
303which is an extension to RFC4627. Likewise, C<decode> will accept those JSON 442which is an extension to RFC4627. Likewise, C<decode> will accept those JSON
304values instead of croaking. 443values instead of croaking.
314 JSON::XS->new->allow_nonref->encode ("Hello, World!") 453 JSON::XS->new->allow_nonref->encode ("Hello, World!")
315 => "Hello, World!" 454 => "Hello, World!"
316 455
317=item $json = $json->allow_blessed ([$enable]) 456=item $json = $json->allow_blessed ([$enable])
318 457
458=item $enabled = $json->get_allow_blessed
459
319If C<$enable> is true (or missing), then the C<encode> method will not 460If C<$enable> is true (or missing), then the C<encode> method will not
320barf when it encounters a blessed reference. Instead, the value of the 461barf when it encounters a blessed reference. Instead, the value of the
321B<convert_blessed> option will decide wether C<null> (C<convert_blessed> 462B<convert_blessed> option will decide whether C<null> (C<convert_blessed>
322disabled or no C<to_json> method found) or a representation of the 463disabled or no C<TO_JSON> method found) or a representation of the
323object (C<convert_blessed> enabled and C<to_json> method found) is being 464object (C<convert_blessed> enabled and C<TO_JSON> method found) is being
324encoded. Has no effect on C<decode>. 465encoded. Has no effect on C<decode>.
325 466
326If C<$enable> is false (the default), then C<encode> will throw an 467If C<$enable> is false (the default), then C<encode> will throw an
327exception when it encounters a blessed object. 468exception when it encounters a blessed object.
328 469
329=item $json = $json->convert_blessed ([$enable]) 470=item $json = $json->convert_blessed ([$enable])
471
472=item $enabled = $json->get_convert_blessed
330 473
331If C<$enable> is true (or missing), then C<encode>, upon encountering a 474If C<$enable> is true (or missing), then C<encode>, upon encountering a
332blessed object, will check for the availability of the C<TO_JSON> method 475blessed object, will check for the availability of the C<TO_JSON> method
333on the object's class. If found, it will be called in scalar context 476on the object's class. If found, it will be called in scalar context
334and the resulting scalar will be encoded instead of the object. If no 477and the resulting scalar will be encoded instead of the object. If no
338The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON> 481The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
339returns other blessed objects, those will be handled in the same 482returns other blessed objects, those will be handled in the same
340way. C<TO_JSON> must take care of not causing an endless recursion cycle 483way. C<TO_JSON> must take care of not causing an endless recursion cycle
341(== crash) in this case. The name of C<TO_JSON> was chosen because other 484(== crash) in this case. The name of C<TO_JSON> was chosen because other
342methods called by the Perl core (== not by the user of the object) are 485methods called by the Perl core (== not by the user of the object) are
343usually in upper case letters and to avoid collisions with the C<to_json> 486usually in upper case letters and to avoid collisions with any C<to_json>
344function. 487function or method.
345 488
346This setting does not yet influence C<decode> in any way, but in the 489This setting does not yet influence C<decode> in any way, but in the
347future, global hooks might get installed that influence C<decode> and are 490future, global hooks might get installed that influence C<decode> and are
348enabled by this setting. 491enabled by this setting.
349 492
350If C<$enable> is false, then the C<allow_blessed> setting will decide what 493If C<$enable> is false, then the C<allow_blessed> setting will decide what
351to do when a blessed object is found. 494to do when a blessed object is found.
352 495
353=item $json = $json->filter_json_object ([$coderef]) 496=item $json = $json->filter_json_object ([$coderef->($hashref)])
354 497
355When C<$coderef> is specified, it will be called from C<decode> each 498When C<$coderef> is specified, it will be called from C<decode> each
356time it decodes a JSON object. The only argument is a reference to the 499time it decodes a JSON object. The only argument is a reference to the
357newly-created hash. If the code references returns a single scalar (which 500newly-created hash. If the code references returns a single scalar (which
358need not be a reference), this value (i.e. a copy of that scalar to avoid 501need not be a reference), this value (i.e. a copy of that scalar to avoid
359aliasing) is inserted into the deserialised data structure. If it returns 502aliasing) is inserted into the deserialised data structure. If it returns
360an empty list (NOTE: I<not> C<undef>, which is a valid scalar), the 503an empty list (NOTE: I<not> C<undef>, which is a valid scalar), the
361original deserialised hash will be inserted. This setting can slow down 504original deserialised hash will be inserted. This setting can slow down
362decoding considerably. 505decoding considerably.
363 506
364When C<$coderef> is omitted or undefined, C<decode> will not change the 507When C<$coderef> is omitted or undefined, any existing callback will
365deserialised hash in any way. This is maximally fast. 508be removed and C<decode> will not change the deserialised hash in any
509way.
366 510
367Example, convert all JSON objects into the integer 5: 511Example, convert all JSON objects into the integer 5:
368 512
369 my $js = JSON::XS->new->filter_json_object (sub { 5 }); 513 my $js = JSON::XS->new->filter_json_object (sub { 5 });
370 # returns [5] 514 # returns [5]
371 $js->decode ('[{}]') 515 $js->decode ('[{}]')
372 # throw an exception because allow_nonref is not enabled: 516 # throw an exception because allow_nonref is not enabled
517 # so a lone 5 is not allowed.
373 $js->decode ('{"a":1, "b":2}'); 518 $js->decode ('{"a":1, "b":2}');
374 519
375=item $json = $json->filter_json_single_key_object ([$coderef]) 520=item $json = $json->filter_json_single_key_object ($key [=> $coderef->($value)])
376 521
377Works like C<filter_json_object>, but is only called for JSON objects 522Works remotely similar to C<filter_json_object>, but is only called for
378having only a single key. 523JSON objects having a single key named C<$key>.
379 524
380This C<$coderef> is called before the one specified via 525This C<$coderef> is called before the one specified via
381C<filter_json_object>, if any. If it returns something, that will be 526C<filter_json_object>, if any. It gets passed the single value in the JSON
382inserted into the data structure. If it returns nothing, the callback 527object. If it returns a single value, it will be inserted into the data
383from C<filter_json_object> will be called next. If you want to force 528structure. If it returns nothing (not even C<undef> but the empty list),
384insertion of single-key objects even in the presence of a mutating 529the callback from C<filter_json_object> will be called next, as if no
385C<filter_json_object> callback, simply return the passed hash. 530single-key callback were specified.
531
532If C<$coderef> is omitted or undefined, the corresponding callback will be
533disabled. There can only ever be one callback for a given key.
386 534
387As this callback gets called less often then the C<filter_json_object> 535As this callback gets called less often then the C<filter_json_object>
388one, decoding speed will not usually suffer as much. Therefore, single-key 536one, decoding speed will not usually suffer as much. Therefore, single-key
389objects make excellent targets to serialise Perl objects into, especially 537objects make excellent targets to serialise Perl objects into, especially
390as single-key JSON objects are as close to the type-tagged value concept 538as single-key JSON objects are as close to the type-tagged value concept
391as JSON gets (its basically an ID/VALUE tuple). Of course, JSON does not 539as JSON gets (it's basically an ID/VALUE tuple). Of course, JSON does not
392support this in any way, so you need to make sure your data never looks 540support this in any way, so you need to make sure your data never looks
393like a serialised Perl hash. 541like a serialised Perl hash.
394 542
395Typical names for the single object key are C<__class_whatever__>, or 543Typical names for the single object key are C<__class_whatever__>, or
396C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even 544C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even
401into the corresponding C<< $WIDGET{<id>} >> object: 549into the corresponding C<< $WIDGET{<id>} >> object:
402 550
403 # return whatever is in $WIDGET{5}: 551 # return whatever is in $WIDGET{5}:
404 JSON::XS 552 JSON::XS
405 ->new 553 ->new
406 ->filter_json_single_key_object (sub { 554 ->filter_json_single_key_object (__widget__ => sub {
407 exists $_[0]{__widget__}
408 ? $WIDGET{ $_[0]{__widget__} } 555 $WIDGET{ $_[0] }
409 : ()
410 }) 556 })
411 ->decode ('{"__widget__": 5') 557 ->decode ('{"__widget__": 5')
412 558
413 # this can be used with a TO_JSON method in some "widget" class 559 # this can be used with a TO_JSON method in some "widget" class
414 # for serialisation to json: 560 # for serialisation to json:
422 568
423 { __widget__ => $self->{id} } 569 { __widget__ => $self->{id} }
424 } 570 }
425 571
426=item $json = $json->shrink ([$enable]) 572=item $json = $json->shrink ([$enable])
573
574=item $enabled = $json->get_shrink
427 575
428Perl usually over-allocates memory a bit when allocating space for 576Perl usually over-allocates memory a bit when allocating space for
429strings. This flag optionally resizes strings generated by either 577strings. This flag optionally resizes strings generated by either
430C<encode> or C<decode> to their minimum size possible. This can save 578C<encode> or C<decode> to their minimum size possible. This can save
431memory when your JSON texts are either very very long or you have many 579memory when your JSON texts are either very very long or you have many
449strings that look like integers or floats into integers or floats 597strings that look like integers or floats into integers or floats
450internally (there is no difference on the Perl level), saving space. 598internally (there is no difference on the Perl level), saving space.
451 599
452=item $json = $json->max_depth ([$maximum_nesting_depth]) 600=item $json = $json->max_depth ([$maximum_nesting_depth])
453 601
602=item $max_depth = $json->get_max_depth
603
454Sets the maximum nesting level (default C<512>) accepted while encoding 604Sets the maximum nesting level (default C<512>) accepted while encoding
455or decoding. If the JSON text or Perl data structure has an equal or 605or decoding. If the JSON text or Perl data structure has an equal or
456higher nesting level then this limit, then the encoder and decoder will 606higher nesting level then this limit, then the encoder and decoder will
457stop and croak at that point. 607stop and croak at that point.
458 608
469used, which is rarely useful. 619used, which is rarely useful.
470 620
471See SECURITY CONSIDERATIONS, below, for more info on why this is useful. 621See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
472 622
473=item $json = $json->max_size ([$maximum_string_size]) 623=item $json = $json->max_size ([$maximum_string_size])
624
625=item $max_size = $json->get_max_size
474 626
475Set the maximum length a JSON text may have (in bytes) where decoding is 627Set the maximum length a JSON text may have (in bytes) where decoding is
476being attempted. The default is C<0>, meaning no limit. When C<decode> 628being attempted. The default is C<0>, meaning no limit. When C<decode>
477is called on a string longer then this number of characters it will not 629is called on a string longer then this number of characters it will not
478attempt to decode the string but throw an exception. This setting has no 630attempt to decode the string but throw an exception. This setting has no
525vice versa. These mappings are designed to "do the right thing" in most 677vice versa. These mappings are designed to "do the right thing" in most
526circumstances automatically, preserving round-tripping characteristics 678circumstances automatically, preserving round-tripping characteristics
527(what you put in comes out as something equivalent). 679(what you put in comes out as something equivalent).
528 680
529For the more enlightened: note that in the following descriptions, 681For the more enlightened: note that in the following descriptions,
530lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl> 682lowercase I<perl> refers to the Perl interpreter, while uppercase I<Perl>
531refers to the abstract Perl language itself. 683refers to the abstract Perl language itself.
532 684
533 685
534=head2 JSON -> PERL 686=head2 JSON -> PERL
535 687
536=over 4 688=over 4
537 689
538=item object 690=item object
539 691
540A JSON object becomes a reference to a hash in Perl. No ordering of object 692A JSON object becomes a reference to a hash in Perl. No ordering of object
541keys is preserved (JSON does not preserver object key ordering itself). 693keys is preserved (JSON does not preserve object key ordering itself).
542 694
543=item array 695=item array
544 696
545A JSON array becomes a reference to an array in Perl. 697A JSON array becomes a reference to an array in Perl.
546 698
550are represented by the same codepoints in the Perl string, so no manual 702are represented by the same codepoints in the Perl string, so no manual
551decoding is necessary. 703decoding is necessary.
552 704
553=item number 705=item number
554 706
555A JSON number becomes either an integer or numeric (floating point) 707A JSON number becomes either an integer, numeric (floating point) or
556scalar in perl, depending on its range and any fractional parts. On the 708string scalar in perl, depending on its range and any fractional parts. On
557Perl level, there is no difference between those as Perl handles all the 709the Perl level, there is no difference between those as Perl handles all
558conversion details, but an integer may take slightly less memory and might 710the conversion details, but an integer may take slightly less memory and
559represent more values exactly than (floating point) numbers. 711might represent more values exactly than (floating point) numbers.
712
713If the number consists of digits only, JSON::XS will try to represent
714it as an integer value. If that fails, it will try to represent it as
715a numeric (floating point) value if that is possible without loss of
716precision. Otherwise it will preserve the number as a string value.
717
718Numbers containing a fractional or exponential part will always be
719represented as numeric (floating point) values, possibly at a loss of
720precision.
721
722This might create round-tripping problems as numbers might become strings,
723but as Perl is typeless there is no other way to do it.
560 724
561=item true, false 725=item true, false
562 726
563These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, 727These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,
564respectively. They are overloaded to act almost exactly like the numbers 728respectively. They are overloaded to act almost exactly like the numbers
565C<1> and C<0>. You can check wether a scalar is a JSON boolean by using 729C<1> and C<0>. You can check whether a scalar is a JSON boolean by using
566the C<JSON::XS::is_bool> function. 730the C<JSON::XS::is_bool> function.
567 731
568=item null 732=item null
569 733
570A JSON null atom becomes C<undef> in Perl. 734A JSON null atom becomes C<undef> in Perl.
601Other unblessed references are generally not allowed and will cause an 765Other unblessed references are generally not allowed and will cause an
602exception to be thrown, except for references to the integers C<0> and 766exception to be thrown, except for references to the integers C<0> and
603C<1>, which get turned into C<false> and C<true> atoms in JSON. You can 767C<1>, which get turned into C<false> and C<true> atoms in JSON. You can
604also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. 768also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
605 769
606 to_json [\0,JSON::XS::true] # yields [false,true] 770 encode_json [\0,JSON::XS::true] # yields [false,true]
607 771
608=item JSON::XS::true, JSON::XS::false 772=item JSON::XS::true, JSON::XS::false
609 773
610These special values become JSON true and JSON false values, 774These special values become JSON true and JSON false values,
611respectively. You cna alos use C<\1> and C<\0> directly if you want. 775respectively. You can also use C<\1> and C<\0> directly if you want.
612 776
613=item blessed objects 777=item blessed objects
614 778
615Blessed objects are not allowed. JSON::XS currently tries to encode their 779Blessed objects are not allowed. JSON::XS currently tries to encode their
616underlying representation (hash- or arrayref), but this behaviour might 780underlying representation (hash- or arrayref), but this behaviour might
622difficult objects to encode: JSON::XS will encode undefined scalars as 786difficult objects to encode: JSON::XS will encode undefined scalars as
623JSON null value, scalars that have last been used in a string context 787JSON null value, scalars that have last been used in a string context
624before encoding as JSON strings and anything else as number value: 788before encoding as JSON strings and anything else as number value:
625 789
626 # dump as number 790 # dump as number
627 to_json [2] # yields [2] 791 encode_json [2] # yields [2]
628 to_json [-3.0e17] # yields [-3e+17] 792 encode_json [-3.0e17] # yields [-3e+17]
629 my $value = 5; to_json [$value] # yields [5] 793 my $value = 5; encode_json [$value] # yields [5]
630 794
631 # used as string, so dump as string 795 # used as string, so dump as string
632 print $value; 796 print $value;
633 to_json [$value] # yields ["5"] 797 encode_json [$value] # yields ["5"]
634 798
635 # undef becomes null 799 # undef becomes null
636 to_json [undef] # yields [null] 800 encode_json [undef] # yields [null]
637 801
638You can force the type to be a string by stringifying it: 802You can force the type to be a JSON string by stringifying it:
639 803
640 my $x = 3.1; # some variable containing a number 804 my $x = 3.1; # some variable containing a number
641 "$x"; # stringified 805 "$x"; # stringified
642 $x .= ""; # another, more awkward way to stringify 806 $x .= ""; # another, more awkward way to stringify
643 print $x; # perl does it for you, too, quite often 807 print $x; # perl does it for you, too, quite often
644 808
645You can force the type to be a number by numifying it: 809You can force the type to be a JSON number by numifying it:
646 810
647 my $x = "3"; # some variable containing a string 811 my $x = "3"; # some variable containing a string
648 $x += 0; # numify it, ensuring it will be dumped as a number 812 $x += 0; # numify it, ensuring it will be dumped as a number
649 $x *= 1; # same thing, the choise is yours. 813 $x *= 1; # same thing, the choice is yours.
650 814
651You can not currently output JSON booleans or force the type in other, 815You can not currently force the type in other, less obscure, ways. Tell me
652less obscure, ways. Tell me if you need this capability. 816if you need this capability.
653 817
654=back 818=back
655 819
656 820
657=head1 COMPARISON 821=head1 COMPARISON
666 830
667=item JSON 1.07 831=item JSON 1.07
668 832
669Slow (but very portable, as it is written in pure Perl). 833Slow (but very portable, as it is written in pure Perl).
670 834
671Undocumented/buggy Unicode handling (how JSON handles unicode values is 835Undocumented/buggy Unicode handling (how JSON handles Unicode values is
672undocumented. One can get far by feeding it unicode strings and doing 836undocumented. One can get far by feeding it Unicode strings and doing
673en-/decoding oneself, but unicode escapes are not working properly). 837en-/decoding oneself, but Unicode escapes are not working properly).
674 838
675No roundtripping (strings get clobbered if they look like numbers, e.g. 839No round-tripping (strings get clobbered if they look like numbers, e.g.
676the string C<2.0> will encode to C<2.0> instead of C<"2.0">, and that will 840the string C<2.0> will encode to C<2.0> instead of C<"2.0">, and that will
677decode into the number 2. 841decode into the number 2.
678 842
679=item JSON::PC 0.01 843=item JSON::PC 0.01
680 844
681Very fast. 845Very fast.
682 846
683Undocumented/buggy Unicode handling. 847Undocumented/buggy Unicode handling.
684 848
685No roundtripping. 849No round-tripping.
686 850
687Has problems handling many Perl values (e.g. regex results and other magic 851Has problems handling many Perl values (e.g. regex results and other magic
688values will make it croak). 852values will make it croak).
689 853
690Does not even generate valid JSON (C<{1,2}> gets converted to C<{1:2}> 854Does not even generate valid JSON (C<{1,2}> gets converted to C<{1:2}>
700Very inflexible (no human-readable format supported, format pretty much 864Very inflexible (no human-readable format supported, format pretty much
701undocumented. I need at least a format for easy reading by humans and a 865undocumented. I need at least a format for easy reading by humans and a
702single-line compact format for use in a protocol, and preferably a way to 866single-line compact format for use in a protocol, and preferably a way to
703generate ASCII-only JSON texts). 867generate ASCII-only JSON texts).
704 868
705Completely broken (and confusingly documented) Unicode handling (unicode 869Completely broken (and confusingly documented) Unicode handling (Unicode
706escapes are not working properly, you need to set ImplicitUnicode to 870escapes are not working properly, you need to set ImplicitUnicode to
707I<different> values on en- and decoding to get symmetric behaviour). 871I<different> values on en- and decoding to get symmetric behaviour).
708 872
709No roundtripping (simple cases work, but this depends on wether the scalar 873No round-tripping (simple cases work, but this depends on whether the scalar
710value was used in a numeric context or not). 874value was used in a numeric context or not).
711 875
712Dumping hashes may skip hash values depending on iterator state. 876Dumping hashes may skip hash values depending on iterator state.
713 877
714Unmaintained (maintainer unresponsive for many months, bugs are not 878Unmaintained (maintainer unresponsive for many months, bugs are not
715getting fixed). 879getting fixed).
716 880
717Does not check input for validity (i.e. will accept non-JSON input and 881Does not check input for validity (i.e. will accept non-JSON input and
718return "something" instead of raising an exception. This is a security 882return "something" instead of raising an exception. This is a security
719issue: imagine two banks transfering money between each other using 883issue: imagine two banks transferring money between each other using
720JSON. One bank might parse a given non-JSON request and deduct money, 884JSON. One bank might parse a given non-JSON request and deduct money,
721while the other might reject the transaction with a syntax error. While a 885while the other might reject the transaction with a syntax error. While a
722good protocol will at least recover, that is extra unnecessary work and 886good protocol will at least recover, that is extra unnecessary work and
723the transaction will still not succeed). 887the transaction will still not succeed).
724 888
725=item JSON::DWIW 0.04 889=item JSON::DWIW 0.04
726 890
727Very fast. Very natural. Very nice. 891Very fast. Very natural. Very nice.
728 892
729Undocumented unicode handling (but the best of the pack. Unicode escapes 893Undocumented Unicode handling (but the best of the pack. Unicode escapes
730still don't get parsed properly). 894still don't get parsed properly).
731 895
732Very inflexible. 896Very inflexible.
733 897
734No roundtripping. 898No round-tripping.
735 899
736Does not generate valid JSON texts (key strings are often unquoted, empty keys 900Does not generate valid JSON texts (key strings are often unquoted, empty keys
737result in nothing being output) 901result in nothing being output)
738 902
739Does not check input for validity. 903Does not check input for validity.
754 my $yaml = $to_yaml->encode ($ref) . "\n"; 918 my $yaml = $to_yaml->encode ($ref) . "\n";
755 919
756This will usually generate JSON texts that also parse as valid 920This will usually generate JSON texts that also parse as valid
757YAML. Please note that YAML has hardcoded limits on (simple) object key 921YAML. Please note that YAML has hardcoded limits on (simple) object key
758lengths that JSON doesn't have, so you should make sure that your hash 922lengths that JSON doesn't have, so you should make sure that your hash
759keys are noticably shorter than the 1024 characters YAML allows. 923keys are noticeably shorter than the 1024 characters YAML allows.
760 924
761There might be other incompatibilities that I am not aware of. In general 925There might be other incompatibilities that I am not aware of. In general
762you should not try to generate YAML with a JSON generator or vice versa, 926you should not try to generate YAML with a JSON generator or vice versa,
763or try to parse JSON with a YAML parser or vice versa: chances are high 927or try to parse JSON with a YAML parser or vice versa: chances are high
764that you will run into severe interoperability problems. 928that you will run into severe interoperability problems.
780It shows the number of encodes/decodes per second (JSON::XS uses 944It shows the number of encodes/decodes per second (JSON::XS uses
781the functional interface, while JSON::XS/2 uses the OO interface 945the functional interface, while JSON::XS/2 uses the OO interface
782with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables 946with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables
783shrink). Higher is better: 947shrink). Higher is better:
784 948
785 Storable | 15779.925 | 14169.946 |
786 -----------+------------+------------+
787 module | encode | decode | 949 module | encode | decode |
788 -----------|------------|------------| 950 -----------|------------|------------|
789 JSON | 4990.842 | 4088.813 | 951 JSON 1.x | 4990.842 | 4088.813 |
790 JSON::DWIW | 51653.990 | 71575.154 | 952 JSON::DWIW | 51653.990 | 71575.154 |
791 JSON::PC | 65948.176 | 74631.744 | 953 JSON::PC | 65948.176 | 74631.744 |
792 JSON::PP | 8931.652 | 3817.168 | 954 JSON::PP | 8931.652 | 3817.168 |
793 JSON::Syck | 24877.248 | 27776.848 | 955 JSON::Syck | 24877.248 | 27776.848 |
794 JSON::XS | 388361.481 | 227951.304 | 956 JSON::XS | 388361.481 | 227951.304 |
796 JSON::XS/3 | 338250.323 | 218453.333 | 958 JSON::XS/3 | 338250.323 | 218453.333 |
797 Storable | 16500.016 | 135300.129 | 959 Storable | 16500.016 | 135300.129 |
798 -----------+------------+------------+ 960 -----------+------------+------------+
799 961
800That is, JSON::XS is about five times faster than JSON::DWIW on encoding, 962That is, JSON::XS is about five times faster than JSON::DWIW on encoding,
801about three times faster on decoding, and over fourty times faster 963about three times faster on decoding, and over forty times faster
802than JSON, even with pretty-printing and key sorting. It also compares 964than JSON, even with pretty-printing and key sorting. It also compares
803favourably to Storable for small amounts of data. 965favourably to Storable for small amounts of data.
804 966
805Using a longer test string (roughly 18KB, generated from Yahoo! Locals 967Using a longer test string (roughly 18KB, generated from Yahoo! Locals
806search API (http://nanoref.com/yahooapis/mgPdGg): 968search API (http://nanoref.com/yahooapis/mgPdGg):
807 969
808 module | encode | decode | 970 module | encode | decode |
809 -----------|------------|------------| 971 -----------|------------|------------|
810 JSON | 55.260 | 34.971 | 972 JSON 1.x | 55.260 | 34.971 |
811 JSON::DWIW | 825.228 | 1082.513 | 973 JSON::DWIW | 825.228 | 1082.513 |
812 JSON::PC | 3571.444 | 2394.829 | 974 JSON::PC | 3571.444 | 2394.829 |
813 JSON::PP | 210.987 | 32.574 | 975 JSON::PP | 210.987 | 32.574 |
814 JSON::Syck | 552.551 | 787.544 | 976 JSON::Syck | 552.551 | 787.544 |
815 JSON::XS | 5780.463 | 4854.519 | 977 JSON::XS | 5780.463 | 4854.519 |
819 -----------+------------+------------+ 981 -----------+------------+------------+
820 982
821Again, JSON::XS leads by far (except for Storable which non-surprisingly 983Again, JSON::XS leads by far (except for Storable which non-surprisingly
822decodes faster). 984decodes faster).
823 985
824On large strings containing lots of high unicode characters, some modules 986On large strings containing lots of high Unicode characters, some modules
825(such as JSON::PC) seem to decode faster than JSON::XS, but the result 987(such as JSON::PC) seem to decode faster than JSON::XS, but the result
826will be broken due to missing (or wrong) unicode handling. Others refuse 988will be broken due to missing (or wrong) Unicode handling. Others refuse
827to decode or encode properly, so it was impossible to prepare a fair 989to decode or encode properly, so it was impossible to prepare a fair
828comparison table for that case. 990comparison table for that case.
829 991
830 992
831=head1 SECURITY CONSIDERATIONS 993=head1 SECURITY CONSIDERATIONS
837any buffer overflows. Obviously, this module should ensure that and I am 999any buffer overflows. Obviously, this module should ensure that and I am
838trying hard on making that true, but you never know. 1000trying hard on making that true, but you never know.
839 1001
840Second, you need to avoid resource-starving attacks. That means you should 1002Second, you need to avoid resource-starving attacks. That means you should
841limit the size of JSON texts you accept, or make sure then when your 1003limit the size of JSON texts you accept, or make sure then when your
842resources run out, thats just fine (e.g. by using a separate process that 1004resources run out, that's just fine (e.g. by using a separate process that
843can crash safely). The size of a JSON text in octets or characters is 1005can crash safely). The size of a JSON text in octets or characters is
844usually a good indication of the size of the resources required to decode 1006usually a good indication of the size of the resources required to decode
845it into a Perl structure. While JSON::XS can check the size of the JSON 1007it into a Perl structure. While JSON::XS can check the size of the JSON
846text, it might be too late when you already have it in memory, so you 1008text, it might be too late when you already have it in memory, so you
847might want to check the size before you accept the string. 1009might want to check the size before you accept the string.
848 1010
849Third, JSON::XS recurses using the C stack when decoding objects and 1011Third, JSON::XS recurses using the C stack when decoding objects and
850arrays. The C stack is a limited resource: for instance, on my amd64 1012arrays. The C stack is a limited resource: for instance, on my amd64
851machine with 8MB of stack size I can decode around 180k nested arrays but 1013machine with 8MB of stack size I can decode around 180k nested arrays but
852only 14k nested JSON objects (due to perl itself recursing deeply on croak 1014only 14k nested JSON objects (due to perl itself recursing deeply on croak
853to free the temporary). If that is exceeded, the program crashes. to be 1015to free the temporary). If that is exceeded, the program crashes. To be
854conservative, the default nesting limit is set to 512. If your process 1016conservative, the default nesting limit is set to 512. If your process
855has a smaller stack, you should adjust this setting accordingly with the 1017has a smaller stack, you should adjust this setting accordingly with the
856C<max_depth> method. 1018C<max_depth> method.
857 1019
858And last but least, something else could bomb you that I forgot to think 1020And last but least, something else could bomb you that I forgot to think
859of. In that case, you get to keep the pieces. I am always open for hints, 1021of. In that case, you get to keep the pieces. I am always open for hints,
860though... 1022though...
861 1023
862If you are using JSON::XS to return packets to consumption 1024If you are using JSON::XS to return packets to consumption
863by javascript scripts in a browser you should have a look at 1025by JavaScript scripts in a browser you should have a look at
864L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether 1026L<http://jpsykes.com/47/practical-csrf-and-json-security> to see whether
865you are vulnerable to some common attack vectors (which really are browser 1027you are vulnerable to some common attack vectors (which really are browser
866design bugs, but it is still you who will have to deal with it, as major 1028design bugs, but it is still you who will have to deal with it, as major
867browser developers care only for features, not about doing security 1029browser developers care only for features, not about getting security
868right). 1030right).
1031
1032
1033=head1 THREADS
1034
1035This module is I<not> guaranteed to be thread safe and there are no
1036plans to change this until Perl gets thread support (as opposed to the
1037horribly slow so-called "threads" which are simply slow and bloated
1038process simulations - use fork, its I<much> faster, cheaper, better).
1039
1040(It might actually work, but you have been warned).
869 1041
870 1042
871=head1 BUGS 1043=head1 BUGS
872 1044
873While the goal of this module is to be correct, that unfortunately does 1045While the goal of this module is to be correct, that unfortunately does
874not mean its bug-free, only that I think its design is bug-free. It is 1046not mean its bug-free, only that I think its design is bug-free. It is
875still relatively early in its development. If you keep reporting bugs they 1047still relatively early in its development. If you keep reporting bugs they
876will be fixed swiftly, though. 1048will be fixed swiftly, though.
877 1049
1050Please refrain from using rt.cpan.org or any other bug reporting
1051service. I put the contact address into my modules for a reason.
1052
878=cut 1053=cut
879 1054
880our $true = do { bless \(my $dummy = "1"), "JSON::XS::Boolean" }; 1055our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" };
881our $false = do { bless \(my $dummy = "0"), "JSON::XS::Boolean" }; 1056our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" };
882 1057
883sub true() { $true } 1058sub true() { $true }
884sub false() { $false } 1059sub false() { $false }
885 1060
886sub is_bool($) { 1061sub is_bool($) {

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