ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/JSON-XS/XS.pm
(Generate patch)

Comparing JSON-XS/XS.pm (file contents):
Revision 1.66 by root, Sun Oct 14 20:02:57 2007 UTC vs.
Revision 1.74 by root, Wed Nov 28 13:57:15 2007 UTC

40 40
41=head2 FEATURES 41=head2 FEATURES
42 42
43=over 4 43=over 4
44 44
45=item * correct unicode handling 45=item * correct Unicode handling
46 46
47This module knows how to handle Unicode, and even documents how and when 47This module knows how to handle Unicode, and even documents how and when
48it does so. 48it does so.
49 49
50=item * round-trip integrity 50=item * round-trip integrity
70This module has both a simple functional interface as well as an OO 70This module has both a simple functional interface as well as an OO
71interface. 71interface.
72 72
73=item * reasonably versatile output formats 73=item * reasonably versatile output formats
74 74
75You can choose between the most compact guarenteed single-line format 75You can choose between the most compact guaranteed single-line format
76possible (nice for simple line-based protocols), a pure-ascii format 76possible (nice for simple line-based protocols), a pure-ascii format
77(for when your transport is not 8-bit clean, still supports the whole 77(for when your transport is not 8-bit clean, still supports the whole
78unicode range), or a pretty-printed format (for when you want to read that 78Unicode range), or a pretty-printed format (for when you want to read that
79stuff). Or you can combine those features in whatever way you like. 79stuff). Or you can combine those features in whatever way you like.
80 80
81=back 81=back
82 82
83=cut 83=cut
84 84
85package JSON::XS; 85package JSON::XS;
86 86
87use strict; 87use strict;
88 88
89our $VERSION = '1.51'; 89our $VERSION = '2.0';
90our @ISA = qw(Exporter); 90our @ISA = qw(Exporter);
91 91
92our @EXPORT = qw(to_json from_json); 92our @EXPORT = qw(to_json from_json);
93 93
94use Exporter; 94use Exporter;
95use XSLoader; 95use XSLoader;
96 96
97=head1 FUNCTIONAL INTERFACE 97=head1 FUNCTIONAL INTERFACE
98 98
99The following convinience methods are provided by this module. They are 99The following convenience methods are provided by this module. They are
100exported by default: 100exported by default:
101 101
102=over 4 102=over 4
103 103
104=item $json_text = to_json $perl_scalar 104=item $json_text = to_json $perl_scalar
143 143
144=over 4 144=over 4
145 145
146=item 1. Perl strings can store characters with ordinal values > 255. 146=item 1. Perl strings can store characters with ordinal values > 255.
147 147
148This enables you to store unicode characters as single characters in a 148This enables you to store Unicode characters as single characters in a
149Perl string - very natural. 149Perl string - very natural.
150 150
151=item 2. Perl does I<not> associate an encoding with your strings. 151=item 2. Perl does I<not> associate an encoding with your strings.
152 152
153Unless you force it to, e.g. when matching it against a regex, or printing 153Unless you force it to, e.g. when matching it against a regex, or printing
160encoding of your string. 160encoding of your string.
161 161
162Just ignore that flag unless you debug a Perl bug, a module written in 162Just ignore that flag unless you debug a Perl bug, a module written in
163XS or want to dive into the internals of perl. Otherwise it will only 163XS or want to dive into the internals of perl. Otherwise it will only
164confuse you, as, despite the name, it says nothing about how your string 164confuse you, as, despite the name, it says nothing about how your string
165is encoded. You can have unicode strings with that flag set, with that 165is encoded. You can have Unicode strings with that flag set, with that
166flag clear, and you can have binary data with that flag set and that flag 166flag clear, and you can have binary data with that flag set and that flag
167clear. Other possibilities exist, too. 167clear. Other possibilities exist, too.
168 168
169If you didn't know about that flag, just the better, pretend it doesn't 169If you didn't know about that flag, just the better, pretend it doesn't
170exist. 170exist.
175If you have UTF-8 encoded data, it is no longer a Unicode string, but a 175If you have UTF-8 encoded data, it is no longer a Unicode string, but a
176Unicode string encoded in UTF-8, giving you a binary string. 176Unicode string encoded in UTF-8, giving you a binary string.
177 177
178=item 5. A string containing "high" (> 255) character values is I<not> a UTF-8 string. 178=item 5. A string containing "high" (> 255) character values is I<not> a UTF-8 string.
179 179
180Its a fact. Learn to live with it. 180It's a fact. Learn to live with it.
181 181
182=back 182=back
183 183
184I hope this helps :) 184I hope this helps :)
185 185
202 my $json = JSON::XS->new->utf8->space_after->encode ({a => [1,2]}) 202 my $json = JSON::XS->new->utf8->space_after->encode ({a => [1,2]})
203 => {"a": [1, 2]} 203 => {"a": [1, 2]}
204 204
205=item $json = $json->ascii ([$enable]) 205=item $json = $json->ascii ([$enable])
206 206
207=item $enabled = $json->get_ascii
208
207If C<$enable> is true (or missing), then the C<encode> method will not 209If C<$enable> is true (or missing), then the C<encode> method will not
208generate characters outside the code range C<0..127> (which is ASCII). Any 210generate characters outside the code range C<0..127> (which is ASCII). Any
209unicode characters outside that range will be escaped using either a 211Unicode characters outside that range will be escaped using either a
210single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, 212single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,
211as per RFC4627. The resulting encoded JSON text can be treated as a native 213as per RFC4627. The resulting encoded JSON text can be treated as a native
212unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string, 214Unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string,
213or any other superset of ASCII. 215or any other superset of ASCII.
214 216
215If C<$enable> is false, then the C<encode> method will not escape Unicode 217If C<$enable> is false, then the C<encode> method will not escape Unicode
216characters unless required by the JSON syntax or other flags. This results 218characters unless required by the JSON syntax or other flags. This results
217in a faster and more compact format. 219in a faster and more compact format.
223 JSON::XS->new->ascii (1)->encode ([chr 0x10401]) 225 JSON::XS->new->ascii (1)->encode ([chr 0x10401])
224 => ["\ud801\udc01"] 226 => ["\ud801\udc01"]
225 227
226=item $json = $json->latin1 ([$enable]) 228=item $json = $json->latin1 ([$enable])
227 229
230=item $enabled = $json->get_latin1
231
228If C<$enable> is true (or missing), then the C<encode> method will encode 232If C<$enable> is true (or missing), then the C<encode> method will encode
229the resulting JSON text as latin1 (or iso-8859-1), escaping any characters 233the resulting JSON text as latin1 (or iso-8859-1), escaping any characters
230outside the code range C<0..255>. The resulting string can be treated as a 234outside the code range C<0..255>. The resulting string can be treated as a
231latin1-encoded JSON text or a native unicode string. The C<decode> method 235latin1-encoded JSON text or a native Unicode string. The C<decode> method
232will not be affected in any way by this flag, as C<decode> by default 236will not be affected in any way by this flag, as C<decode> by default
233expects unicode, which is a strict superset of latin1. 237expects Unicode, which is a strict superset of latin1.
234 238
235If C<$enable> is false, then the C<encode> method will not escape Unicode 239If C<$enable> is false, then the C<encode> method will not escape Unicode
236characters unless required by the JSON syntax or other flags. 240characters unless required by the JSON syntax or other flags.
237 241
238The main use for this flag is efficiently encoding binary data as JSON 242The main use for this flag is efficiently encoding binary data as JSON
239text, as most octets will not be escaped, resulting in a smaller encoded 243text, as most octets will not be escaped, resulting in a smaller encoded
240size. The disadvantage is that the resulting JSON text is encoded 244size. The disadvantage is that the resulting JSON text is encoded
241in latin1 (and must correctly be treated as such when storing and 245in latin1 (and must correctly be treated as such when storing and
242transfering), a rare encoding for JSON. It is therefore most useful when 246transferring), a rare encoding for JSON. It is therefore most useful when
243you want to store data structures known to contain binary data efficiently 247you want to store data structures known to contain binary data efficiently
244in files or databases, not when talking to other JSON encoders/decoders. 248in files or databases, not when talking to other JSON encoders/decoders.
245 249
246 JSON::XS->new->latin1->encode (["\x{89}\x{abc}"] 250 JSON::XS->new->latin1->encode (["\x{89}\x{abc}"]
247 => ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not) 251 => ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not)
248 252
249=item $json = $json->utf8 ([$enable]) 253=item $json = $json->utf8 ([$enable])
254
255=item $enabled = $json->get_utf8
250 256
251If C<$enable> is true (or missing), then the C<encode> method will encode 257If C<$enable> is true (or missing), then the C<encode> method will encode
252the JSON result into UTF-8, as required by many protocols, while the 258the JSON result into UTF-8, as required by many protocols, while the
253C<decode> method expects to be handled an UTF-8-encoded string. Please 259C<decode> method expects to be handled an UTF-8-encoded string. Please
254note that UTF-8-encoded strings do not contain any characters outside the 260note that UTF-8-encoded strings do not contain any characters outside the
255range C<0..255>, they are thus useful for bytewise/binary I/O. In future 261range C<0..255>, they are thus useful for bytewise/binary I/O. In future
256versions, enabling this option might enable autodetection of the UTF-16 262versions, enabling this option might enable autodetection of the UTF-16
257and UTF-32 encoding families, as described in RFC4627. 263and UTF-32 encoding families, as described in RFC4627.
258 264
259If C<$enable> is false, then the C<encode> method will return the JSON 265If C<$enable> is false, then the C<encode> method will return the JSON
260string as a (non-encoded) unicode string, while C<decode> expects thus a 266string as a (non-encoded) Unicode string, while C<decode> expects thus a
261unicode string. Any decoding or encoding (e.g. to UTF-8 or UTF-16) needs 267Unicode string. Any decoding or encoding (e.g. to UTF-8 or UTF-16) needs
262to be done yourself, e.g. using the Encode module. 268to be done yourself, e.g. using the Encode module.
263 269
264Example, output UTF-16BE-encoded JSON: 270Example, output UTF-16BE-encoded JSON:
265 271
266 use Encode; 272 use Encode;
288 ] 294 ]
289 } 295 }
290 296
291=item $json = $json->indent ([$enable]) 297=item $json = $json->indent ([$enable])
292 298
299=item $enabled = $json->get_indent
300
293If C<$enable> is true (or missing), then the C<encode> method will use a multiline 301If C<$enable> is true (or missing), then the C<encode> method will use a multiline
294format as output, putting every array member or object/hash key-value pair 302format as output, putting every array member or object/hash key-value pair
295into its own line, identing them properly. 303into its own line, indenting them properly.
296 304
297If C<$enable> is false, no newlines or indenting will be produced, and the 305If C<$enable> is false, no newlines or indenting will be produced, and the
298resulting JSON text is guarenteed not to contain any C<newlines>. 306resulting JSON text is guaranteed not to contain any C<newlines>.
299 307
300This setting has no effect when decoding JSON texts. 308This setting has no effect when decoding JSON texts.
301 309
302=item $json = $json->space_before ([$enable]) 310=item $json = $json->space_before ([$enable])
311
312=item $enabled = $json->get_space_before
303 313
304If C<$enable> is true (or missing), then the C<encode> method will add an extra 314If C<$enable> is true (or missing), then the C<encode> method will add an extra
305optional space before the C<:> separating keys from values in JSON objects. 315optional space before the C<:> separating keys from values in JSON objects.
306 316
307If C<$enable> is false, then the C<encode> method will not add any extra 317If C<$enable> is false, then the C<encode> method will not add any extra
313Example, space_before enabled, space_after and indent disabled: 323Example, space_before enabled, space_after and indent disabled:
314 324
315 {"key" :"value"} 325 {"key" :"value"}
316 326
317=item $json = $json->space_after ([$enable]) 327=item $json = $json->space_after ([$enable])
328
329=item $enabled = $json->get_space_after
318 330
319If C<$enable> is true (or missing), then the C<encode> method will add an extra 331If C<$enable> is true (or missing), then the C<encode> method will add an extra
320optional space after the C<:> separating keys from values in JSON objects 332optional space after the C<:> separating keys from values in JSON objects
321and extra whitespace after the C<,> separating key-value pairs and array 333and extra whitespace after the C<,> separating key-value pairs and array
322members. 334members.
329Example, space_before and indent disabled, space_after enabled: 341Example, space_before and indent disabled, space_after enabled:
330 342
331 {"key": "value"} 343 {"key": "value"}
332 344
333=item $json = $json->relaxed ([$enable]) 345=item $json = $json->relaxed ([$enable])
346
347=item $enabled = $json->get_relaxed
334 348
335If C<$enable> is true (or missing), then C<decode> will accept some 349If C<$enable> is true (or missing), then C<decode> will accept some
336extensions to normal JSON syntax (see below). C<encode> will not be 350extensions to normal JSON syntax (see below). C<encode> will not be
337affected in anyway. I<Be aware that this option makes you accept invalid 351affected in anyway. I<Be aware that this option makes you accept invalid
338JSON texts as if they were valid!>. I suggest only to use this option to 352JSON texts as if they were valid!>. I suggest only to use this option to
375 389
376=back 390=back
377 391
378=item $json = $json->canonical ([$enable]) 392=item $json = $json->canonical ([$enable])
379 393
394=item $enabled = $json->get_canonical
395
380If C<$enable> is true (or missing), then the C<encode> method will output JSON objects 396If C<$enable> is true (or missing), then the C<encode> method will output JSON objects
381by sorting their keys. This is adding a comparatively high overhead. 397by sorting their keys. This is adding a comparatively high overhead.
382 398
383If C<$enable> is false, then the C<encode> method will output key-value 399If C<$enable> is false, then the C<encode> method will output key-value
384pairs in the order Perl stores them (which will likely change between runs 400pairs in the order Perl stores them (which will likely change between runs
385of the same script). 401of the same script).
386 402
387This option is useful if you want the same data structure to be encoded as 403This option is useful if you want the same data structure to be encoded as
388the same JSON text (given the same overall settings). If it is disabled, 404the same JSON text (given the same overall settings). If it is disabled,
389the same hash migh be encoded differently even if contains the same data, 405the same hash might be encoded differently even if contains the same data,
390as key-value pairs have no inherent ordering in Perl. 406as key-value pairs have no inherent ordering in Perl.
391 407
392This setting has no effect when decoding JSON texts. 408This setting has no effect when decoding JSON texts.
393 409
394=item $json = $json->allow_nonref ([$enable]) 410=item $json = $json->allow_nonref ([$enable])
411
412=item $enabled = $json->get_allow_nonref
395 413
396If C<$enable> is true (or missing), then the C<encode> method can convert a 414If C<$enable> is true (or missing), then the C<encode> method can convert a
397non-reference into its corresponding string, number or null JSON value, 415non-reference into its corresponding string, number or null JSON value,
398which is an extension to RFC4627. Likewise, C<decode> will accept those JSON 416which is an extension to RFC4627. Likewise, C<decode> will accept those JSON
399values instead of croaking. 417values instead of croaking.
409 JSON::XS->new->allow_nonref->encode ("Hello, World!") 427 JSON::XS->new->allow_nonref->encode ("Hello, World!")
410 => "Hello, World!" 428 => "Hello, World!"
411 429
412=item $json = $json->allow_blessed ([$enable]) 430=item $json = $json->allow_blessed ([$enable])
413 431
432=item $enabled = $json->get_allow_bless
433
414If C<$enable> is true (or missing), then the C<encode> method will not 434If C<$enable> is true (or missing), then the C<encode> method will not
415barf when it encounters a blessed reference. Instead, the value of the 435barf when it encounters a blessed reference. Instead, the value of the
416B<convert_blessed> option will decide wether C<null> (C<convert_blessed> 436B<convert_blessed> option will decide whether C<null> (C<convert_blessed>
417disabled or no C<to_json> method found) or a representation of the 437disabled or no C<to_json> method found) or a representation of the
418object (C<convert_blessed> enabled and C<to_json> method found) is being 438object (C<convert_blessed> enabled and C<to_json> method found) is being
419encoded. Has no effect on C<decode>. 439encoded. Has no effect on C<decode>.
420 440
421If C<$enable> is false (the default), then C<encode> will throw an 441If C<$enable> is false (the default), then C<encode> will throw an
422exception when it encounters a blessed object. 442exception when it encounters a blessed object.
423 443
424=item $json = $json->convert_blessed ([$enable]) 444=item $json = $json->convert_blessed ([$enable])
445
446=item $enabled = $json->get_convert_blessed
425 447
426If C<$enable> is true (or missing), then C<encode>, upon encountering a 448If C<$enable> is true (or missing), then C<encode>, upon encountering a
427blessed object, will check for the availability of the C<TO_JSON> method 449blessed object, will check for the availability of the C<TO_JSON> method
428on the object's class. If found, it will be called in scalar context 450on the object's class. If found, it will be called in scalar context
429and the resulting scalar will be encoded instead of the object. If no 451and the resulting scalar will be encoded instead of the object. If no
486 508
487As this callback gets called less often then the C<filter_json_object> 509As this callback gets called less often then the C<filter_json_object>
488one, decoding speed will not usually suffer as much. Therefore, single-key 510one, decoding speed will not usually suffer as much. Therefore, single-key
489objects make excellent targets to serialise Perl objects into, especially 511objects make excellent targets to serialise Perl objects into, especially
490as single-key JSON objects are as close to the type-tagged value concept 512as single-key JSON objects are as close to the type-tagged value concept
491as JSON gets (its basically an ID/VALUE tuple). Of course, JSON does not 513as JSON gets (it's basically an ID/VALUE tuple). Of course, JSON does not
492support this in any way, so you need to make sure your data never looks 514support this in any way, so you need to make sure your data never looks
493like a serialised Perl hash. 515like a serialised Perl hash.
494 516
495Typical names for the single object key are C<__class_whatever__>, or 517Typical names for the single object key are C<__class_whatever__>, or
496C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even 518C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even
520 542
521 { __widget__ => $self->{id} } 543 { __widget__ => $self->{id} }
522 } 544 }
523 545
524=item $json = $json->shrink ([$enable]) 546=item $json = $json->shrink ([$enable])
547
548=item $enabled = $json->get_shrink
525 549
526Perl usually over-allocates memory a bit when allocating space for 550Perl usually over-allocates memory a bit when allocating space for
527strings. This flag optionally resizes strings generated by either 551strings. This flag optionally resizes strings generated by either
528C<encode> or C<decode> to their minimum size possible. This can save 552C<encode> or C<decode> to their minimum size possible. This can save
529memory when your JSON texts are either very very long or you have many 553memory when your JSON texts are either very very long or you have many
547strings that look like integers or floats into integers or floats 571strings that look like integers or floats into integers or floats
548internally (there is no difference on the Perl level), saving space. 572internally (there is no difference on the Perl level), saving space.
549 573
550=item $json = $json->max_depth ([$maximum_nesting_depth]) 574=item $json = $json->max_depth ([$maximum_nesting_depth])
551 575
576=item $max_depth = $json->get_max_depth
577
552Sets the maximum nesting level (default C<512>) accepted while encoding 578Sets the maximum nesting level (default C<512>) accepted while encoding
553or decoding. If the JSON text or Perl data structure has an equal or 579or decoding. If the JSON text or Perl data structure has an equal or
554higher nesting level then this limit, then the encoder and decoder will 580higher nesting level then this limit, then the encoder and decoder will
555stop and croak at that point. 581stop and croak at that point.
556 582
567used, which is rarely useful. 593used, which is rarely useful.
568 594
569See SECURITY CONSIDERATIONS, below, for more info on why this is useful. 595See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
570 596
571=item $json = $json->max_size ([$maximum_string_size]) 597=item $json = $json->max_size ([$maximum_string_size])
598
599=item $max_size = $json->get_max_size
572 600
573Set the maximum length a JSON text may have (in bytes) where decoding is 601Set the maximum length a JSON text may have (in bytes) where decoding is
574being attempted. The default is C<0>, meaning no limit. When C<decode> 602being attempted. The default is C<0>, meaning no limit. When C<decode>
575is called on a string longer then this number of characters it will not 603is called on a string longer then this number of characters it will not
576attempt to decode the string but throw an exception. This setting has no 604attempt to decode the string but throw an exception. This setting has no
623vice versa. These mappings are designed to "do the right thing" in most 651vice versa. These mappings are designed to "do the right thing" in most
624circumstances automatically, preserving round-tripping characteristics 652circumstances automatically, preserving round-tripping characteristics
625(what you put in comes out as something equivalent). 653(what you put in comes out as something equivalent).
626 654
627For the more enlightened: note that in the following descriptions, 655For the more enlightened: note that in the following descriptions,
628lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl> 656lowercase I<perl> refers to the Perl interpreter, while uppercase I<Perl>
629refers to the abstract Perl language itself. 657refers to the abstract Perl language itself.
630 658
631 659
632=head2 JSON -> PERL 660=head2 JSON -> PERL
633 661
634=over 4 662=over 4
635 663
636=item object 664=item object
637 665
638A JSON object becomes a reference to a hash in Perl. No ordering of object 666A JSON object becomes a reference to a hash in Perl. No ordering of object
639keys is preserved (JSON does not preserver object key ordering itself). 667keys is preserved (JSON does not preserve object key ordering itself).
640 668
641=item array 669=item array
642 670
643A JSON array becomes a reference to an array in Perl. 671A JSON array becomes a reference to an array in Perl.
644 672
670 698
671=item true, false 699=item true, false
672 700
673These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, 701These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,
674respectively. They are overloaded to act almost exactly like the numbers 702respectively. They are overloaded to act almost exactly like the numbers
675C<1> and C<0>. You can check wether a scalar is a JSON boolean by using 703C<1> and C<0>. You can check whether a scalar is a JSON boolean by using
676the C<JSON::XS::is_bool> function. 704the C<JSON::XS::is_bool> function.
677 705
678=item null 706=item null
679 707
680A JSON null atom becomes C<undef> in Perl. 708A JSON null atom becomes C<undef> in Perl.
743 to_json [$value] # yields ["5"] 771 to_json [$value] # yields ["5"]
744 772
745 # undef becomes null 773 # undef becomes null
746 to_json [undef] # yields [null] 774 to_json [undef] # yields [null]
747 775
748You can force the type to be a string by stringifying it: 776You can force the type to be a JSON string by stringifying it:
749 777
750 my $x = 3.1; # some variable containing a number 778 my $x = 3.1; # some variable containing a number
751 "$x"; # stringified 779 "$x"; # stringified
752 $x .= ""; # another, more awkward way to stringify 780 $x .= ""; # another, more awkward way to stringify
753 print $x; # perl does it for you, too, quite often 781 print $x; # perl does it for you, too, quite often
754 782
755You can force the type to be a number by numifying it: 783You can force the type to be a JSON number by numifying it:
756 784
757 my $x = "3"; # some variable containing a string 785 my $x = "3"; # some variable containing a string
758 $x += 0; # numify it, ensuring it will be dumped as a number 786 $x += 0; # numify it, ensuring it will be dumped as a number
759 $x *= 1; # same thing, the choise is yours. 787 $x *= 1; # same thing, the choice is yours.
760 788
761You can not currently output JSON booleans or force the type in other, 789You can not currently force the type in other, less obscure, ways. Tell me
762less obscure, ways. Tell me if you need this capability. 790if you need this capability.
763 791
764=back 792=back
765 793
766 794
767=head1 COMPARISON 795=head1 COMPARISON
776 804
777=item JSON 1.07 805=item JSON 1.07
778 806
779Slow (but very portable, as it is written in pure Perl). 807Slow (but very portable, as it is written in pure Perl).
780 808
781Undocumented/buggy Unicode handling (how JSON handles unicode values is 809Undocumented/buggy Unicode handling (how JSON handles Unicode values is
782undocumented. One can get far by feeding it unicode strings and doing 810undocumented. One can get far by feeding it Unicode strings and doing
783en-/decoding oneself, but unicode escapes are not working properly). 811en-/decoding oneself, but Unicode escapes are not working properly).
784 812
785No roundtripping (strings get clobbered if they look like numbers, e.g. 813No round-tripping (strings get clobbered if they look like numbers, e.g.
786the string C<2.0> will encode to C<2.0> instead of C<"2.0">, and that will 814the string C<2.0> will encode to C<2.0> instead of C<"2.0">, and that will
787decode into the number 2. 815decode into the number 2.
788 816
789=item JSON::PC 0.01 817=item JSON::PC 0.01
790 818
791Very fast. 819Very fast.
792 820
793Undocumented/buggy Unicode handling. 821Undocumented/buggy Unicode handling.
794 822
795No roundtripping. 823No round-tripping.
796 824
797Has problems handling many Perl values (e.g. regex results and other magic 825Has problems handling many Perl values (e.g. regex results and other magic
798values will make it croak). 826values will make it croak).
799 827
800Does not even generate valid JSON (C<{1,2}> gets converted to C<{1:2}> 828Does not even generate valid JSON (C<{1,2}> gets converted to C<{1:2}>
810Very inflexible (no human-readable format supported, format pretty much 838Very inflexible (no human-readable format supported, format pretty much
811undocumented. I need at least a format for easy reading by humans and a 839undocumented. I need at least a format for easy reading by humans and a
812single-line compact format for use in a protocol, and preferably a way to 840single-line compact format for use in a protocol, and preferably a way to
813generate ASCII-only JSON texts). 841generate ASCII-only JSON texts).
814 842
815Completely broken (and confusingly documented) Unicode handling (unicode 843Completely broken (and confusingly documented) Unicode handling (Unicode
816escapes are not working properly, you need to set ImplicitUnicode to 844escapes are not working properly, you need to set ImplicitUnicode to
817I<different> values on en- and decoding to get symmetric behaviour). 845I<different> values on en- and decoding to get symmetric behaviour).
818 846
819No roundtripping (simple cases work, but this depends on wether the scalar 847No round-tripping (simple cases work, but this depends on whether the scalar
820value was used in a numeric context or not). 848value was used in a numeric context or not).
821 849
822Dumping hashes may skip hash values depending on iterator state. 850Dumping hashes may skip hash values depending on iterator state.
823 851
824Unmaintained (maintainer unresponsive for many months, bugs are not 852Unmaintained (maintainer unresponsive for many months, bugs are not
825getting fixed). 853getting fixed).
826 854
827Does not check input for validity (i.e. will accept non-JSON input and 855Does not check input for validity (i.e. will accept non-JSON input and
828return "something" instead of raising an exception. This is a security 856return "something" instead of raising an exception. This is a security
829issue: imagine two banks transfering money between each other using 857issue: imagine two banks transferring money between each other using
830JSON. One bank might parse a given non-JSON request and deduct money, 858JSON. One bank might parse a given non-JSON request and deduct money,
831while the other might reject the transaction with a syntax error. While a 859while the other might reject the transaction with a syntax error. While a
832good protocol will at least recover, that is extra unnecessary work and 860good protocol will at least recover, that is extra unnecessary work and
833the transaction will still not succeed). 861the transaction will still not succeed).
834 862
835=item JSON::DWIW 0.04 863=item JSON::DWIW 0.04
836 864
837Very fast. Very natural. Very nice. 865Very fast. Very natural. Very nice.
838 866
839Undocumented unicode handling (but the best of the pack. Unicode escapes 867Undocumented Unicode handling (but the best of the pack. Unicode escapes
840still don't get parsed properly). 868still don't get parsed properly).
841 869
842Very inflexible. 870Very inflexible.
843 871
844No roundtripping. 872No round-tripping.
845 873
846Does not generate valid JSON texts (key strings are often unquoted, empty keys 874Does not generate valid JSON texts (key strings are often unquoted, empty keys
847result in nothing being output) 875result in nothing being output)
848 876
849Does not check input for validity. 877Does not check input for validity.
864 my $yaml = $to_yaml->encode ($ref) . "\n"; 892 my $yaml = $to_yaml->encode ($ref) . "\n";
865 893
866This will usually generate JSON texts that also parse as valid 894This will usually generate JSON texts that also parse as valid
867YAML. Please note that YAML has hardcoded limits on (simple) object key 895YAML. Please note that YAML has hardcoded limits on (simple) object key
868lengths that JSON doesn't have, so you should make sure that your hash 896lengths that JSON doesn't have, so you should make sure that your hash
869keys are noticably shorter than the 1024 characters YAML allows. 897keys are noticeably shorter than the 1024 characters YAML allows.
870 898
871There might be other incompatibilities that I am not aware of. In general 899There might be other incompatibilities that I am not aware of. In general
872you should not try to generate YAML with a JSON generator or vice versa, 900you should not try to generate YAML with a JSON generator or vice versa,
873or try to parse JSON with a YAML parser or vice versa: chances are high 901or try to parse JSON with a YAML parser or vice versa: chances are high
874that you will run into severe interoperability problems. 902that you will run into severe interoperability problems.
890It shows the number of encodes/decodes per second (JSON::XS uses 918It shows the number of encodes/decodes per second (JSON::XS uses
891the functional interface, while JSON::XS/2 uses the OO interface 919the functional interface, while JSON::XS/2 uses the OO interface
892with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables 920with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables
893shrink). Higher is better: 921shrink). Higher is better:
894 922
895 Storable | 15779.925 | 14169.946 |
896 -----------+------------+------------+
897 module | encode | decode | 923 module | encode | decode |
898 -----------|------------|------------| 924 -----------|------------|------------|
899 JSON | 4990.842 | 4088.813 | 925 JSON 1.x | 4990.842 | 4088.813 |
900 JSON::DWIW | 51653.990 | 71575.154 | 926 JSON::DWIW | 51653.990 | 71575.154 |
901 JSON::PC | 65948.176 | 74631.744 | 927 JSON::PC | 65948.176 | 74631.744 |
902 JSON::PP | 8931.652 | 3817.168 | 928 JSON::PP | 8931.652 | 3817.168 |
903 JSON::Syck | 24877.248 | 27776.848 | 929 JSON::Syck | 24877.248 | 27776.848 |
904 JSON::XS | 388361.481 | 227951.304 | 930 JSON::XS | 388361.481 | 227951.304 |
906 JSON::XS/3 | 338250.323 | 218453.333 | 932 JSON::XS/3 | 338250.323 | 218453.333 |
907 Storable | 16500.016 | 135300.129 | 933 Storable | 16500.016 | 135300.129 |
908 -----------+------------+------------+ 934 -----------+------------+------------+
909 935
910That is, JSON::XS is about five times faster than JSON::DWIW on encoding, 936That is, JSON::XS is about five times faster than JSON::DWIW on encoding,
911about three times faster on decoding, and over fourty times faster 937about three times faster on decoding, and over forty times faster
912than JSON, even with pretty-printing and key sorting. It also compares 938than JSON, even with pretty-printing and key sorting. It also compares
913favourably to Storable for small amounts of data. 939favourably to Storable for small amounts of data.
914 940
915Using a longer test string (roughly 18KB, generated from Yahoo! Locals 941Using a longer test string (roughly 18KB, generated from Yahoo! Locals
916search API (http://nanoref.com/yahooapis/mgPdGg): 942search API (http://nanoref.com/yahooapis/mgPdGg):
917 943
918 module | encode | decode | 944 module | encode | decode |
919 -----------|------------|------------| 945 -----------|------------|------------|
920 JSON | 55.260 | 34.971 | 946 JSON 1.x | 55.260 | 34.971 |
921 JSON::DWIW | 825.228 | 1082.513 | 947 JSON::DWIW | 825.228 | 1082.513 |
922 JSON::PC | 3571.444 | 2394.829 | 948 JSON::PC | 3571.444 | 2394.829 |
923 JSON::PP | 210.987 | 32.574 | 949 JSON::PP | 210.987 | 32.574 |
924 JSON::Syck | 552.551 | 787.544 | 950 JSON::Syck | 552.551 | 787.544 |
925 JSON::XS | 5780.463 | 4854.519 | 951 JSON::XS | 5780.463 | 4854.519 |
929 -----------+------------+------------+ 955 -----------+------------+------------+
930 956
931Again, JSON::XS leads by far (except for Storable which non-surprisingly 957Again, JSON::XS leads by far (except for Storable which non-surprisingly
932decodes faster). 958decodes faster).
933 959
934On large strings containing lots of high unicode characters, some modules 960On large strings containing lots of high Unicode characters, some modules
935(such as JSON::PC) seem to decode faster than JSON::XS, but the result 961(such as JSON::PC) seem to decode faster than JSON::XS, but the result
936will be broken due to missing (or wrong) unicode handling. Others refuse 962will be broken due to missing (or wrong) Unicode handling. Others refuse
937to decode or encode properly, so it was impossible to prepare a fair 963to decode or encode properly, so it was impossible to prepare a fair
938comparison table for that case. 964comparison table for that case.
939 965
940 966
941=head1 SECURITY CONSIDERATIONS 967=head1 SECURITY CONSIDERATIONS
947any buffer overflows. Obviously, this module should ensure that and I am 973any buffer overflows. Obviously, this module should ensure that and I am
948trying hard on making that true, but you never know. 974trying hard on making that true, but you never know.
949 975
950Second, you need to avoid resource-starving attacks. That means you should 976Second, you need to avoid resource-starving attacks. That means you should
951limit the size of JSON texts you accept, or make sure then when your 977limit the size of JSON texts you accept, or make sure then when your
952resources run out, thats just fine (e.g. by using a separate process that 978resources run out, that's just fine (e.g. by using a separate process that
953can crash safely). The size of a JSON text in octets or characters is 979can crash safely). The size of a JSON text in octets or characters is
954usually a good indication of the size of the resources required to decode 980usually a good indication of the size of the resources required to decode
955it into a Perl structure. While JSON::XS can check the size of the JSON 981it into a Perl structure. While JSON::XS can check the size of the JSON
956text, it might be too late when you already have it in memory, so you 982text, it might be too late when you already have it in memory, so you
957might want to check the size before you accept the string. 983might want to check the size before you accept the string.
968And last but least, something else could bomb you that I forgot to think 994And last but least, something else could bomb you that I forgot to think
969of. In that case, you get to keep the pieces. I am always open for hints, 995of. In that case, you get to keep the pieces. I am always open for hints,
970though... 996though...
971 997
972If you are using JSON::XS to return packets to consumption 998If you are using JSON::XS to return packets to consumption
973by javascript scripts in a browser you should have a look at 999by JavaScript scripts in a browser you should have a look at
974L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether 1000L<http://jpsykes.com/47/practical-csrf-and-json-security> to see whether
975you are vulnerable to some common attack vectors (which really are browser 1001you are vulnerable to some common attack vectors (which really are browser
976design bugs, but it is still you who will have to deal with it, as major 1002design bugs, but it is still you who will have to deal with it, as major
977browser developers care only for features, not about doing security 1003browser developers care only for features, not about doing security
978right). 1004right).
979 1005
980 1006
981=head1 THREADS 1007=head1 THREADS
982 1008
983This module is I<not> guarenteed to be thread safe and there are no 1009This module is I<not> guaranteed to be thread safe and there are no
984plans to change this until Perl gets thread support (as opposed to the 1010plans to change this until Perl gets thread support (as opposed to the
985horribly slow so-called "threads" which are simply slow and bloated 1011horribly slow so-called "threads" which are simply slow and bloated
986process simulations - use fork, its I<much> faster, cheaper, better). 1012process simulations - use fork, its I<much> faster, cheaper, better).
987 1013
988(It might actually work, but you ahve ben warned). 1014(It might actually work, but you have been warned).
989 1015
990 1016
991=head1 BUGS 1017=head1 BUGS
992 1018
993While the goal of this module is to be correct, that unfortunately does 1019While the goal of this module is to be correct, that unfortunately does

Diff Legend

Removed lines
+ Added lines
< Changed lines
> Changed lines