[ViewVC] Diff of: cvs/JSON-XS/XS.pm

Comparing JSON-XS/XS.pm (file contents):
Revision 1.65 by root, Sat Oct 13 01:55:31 2007 UTC vs.
Revision 1.130 by root, Thu Mar 11 17:36:09 2010 UTC

…		…
		1	=head1 NAME
		2
		3	JSON::XS - JSON serialising/deserialising, done correctly and fast
		4
1	=encoding utf-8	5	=encoding utf-8
2
3	=head1 NAME
4
5	JSON::XS - JSON serialising/deserialising, done correctly and fast
6		6
7	JSON::XS - 正しくて高速な JSON シリアライザ/デシリアライザ	7	JSON::XS - 正しくて高速な JSON シリアライザ/デシリアライザ
8	(http://fleur.hio.jp/perldoc/mix/lib/JSON/XS.html)	8	(http://fleur.hio.jp/perldoc/mix/lib/JSON/XS.html)
9		9
10	=head1 SYNOPSIS	10	=head1 SYNOPSIS
12	use JSON::XS;	12	use JSON::XS;
13		13
14	# exported functions, they croak on error	14	# exported functions, they croak on error
15	# and expect/generate UTF-8	15	# and expect/generate UTF-8
16		16
17	$utf8_encoded_json_text = to_json $perl_hash_or_arrayref;	17	$utf8_encoded_json_text = encode_json $perl_hash_or_arrayref;
18	$perl_hash_or_arrayref = from_json $utf8_encoded_json_text;	18	$perl_hash_or_arrayref = decode_json $utf8_encoded_json_text;
19		19
20	# OO-interface	20	# OO-interface
21		21
22	$coder = JSON::XS->new->ascii->pretty->allow_nonref;	22	$coder = JSON::XS->new->ascii->pretty->allow_nonref;
23	$pretty_printed_unencoded = $coder->encode ($perl_scalar);	23	$pretty_printed_unencoded = $coder->encode ($perl_scalar);
24	$perl_scalar = $coder->decode ($unicode_json_text);	24	$perl_scalar = $coder->decode ($unicode_json_text);
25		25
		26	# Note that JSON version 2.0 and above will automatically use JSON::XS
		27	# if available, at virtually no speed overhead either, so you should
		28	# be able to just:
		29
		30	use JSON;
		31
		32	# and do the same things, except that you have a pure-perl fallback now.
		33
26	=head1 DESCRIPTION	34	=head1 DESCRIPTION
27		35
28	This module converts Perl data structures to JSON and vice versa. Its	36	This module converts Perl data structures to JSON and vice versa. Its
29	primary goal is to be I<correct> and its secondary goal is to be	37	primary goal is to be I<correct> and its secondary goal is to be
30	I<fast>. To reach the latter goal it was written in C.	38	I<fast>. To reach the latter goal it was written in C.
		39
		40	Beginning with version 2.0 of the JSON module, when both JSON and
		41	JSON::XS are installed, then JSON will fall back on JSON::XS (this can be
		42	overridden) with no overhead due to emulation (by inheriting constructor
		43	and methods). If JSON::XS is not available, it will fall back to the
		44	compatible JSON::PP module as backend, so using JSON instead of JSON::XS
		45	gives you a portable JSON API that can be fast when you need and doesn't
		46	require a C compiler when that is a problem.
31		47
32	As this is the n-th-something JSON module on CPAN, what was the reason	48	As this is the n-th-something JSON module on CPAN, what was the reason
33	to write yet another JSON module? While it seems there are many JSON	49	to write yet another JSON module? While it seems there are many JSON
34	modules, none of them correctly handle all corner cases, and in most cases	50	modules, none of them correctly handle all corner cases, and in most cases
35	their maintainers are unresponsive, gone missing, or not listening to bug	51	their maintainers are unresponsive, gone missing, or not listening to bug
36	reports for other reasons.	52	reports for other reasons.
37		53
38	See COMPARISON, below, for a comparison to some other JSON modules.
39
40	See MAPPING, below, on how JSON::XS maps perl values to JSON values and	54	See MAPPING, below, on how JSON::XS maps perl values to JSON values and
41	vice versa.	55	vice versa.
42		56
43	=head2 FEATURES	57	=head2 FEATURES
44		58
45	=over 4	59	=over 4
46		60
47	=item * correct unicode handling	61	=item * correct Unicode handling
48		62
49	This module knows how to handle Unicode, and even documents how and when	63	This module knows how to handle Unicode, documents how and when it does
50	it does so.	64	so, and even documents what "correct" means.
51		65
52	=item * round-trip integrity	66	=item * round-trip integrity
53		67
54	When you serialise a perl data structure using only datatypes supported	68	When you serialise a perl data structure using only data types supported
55	by JSON, the deserialised data structure is identical on the Perl level.	69	by JSON, the deserialised data structure is identical on the Perl level.
56	(e.g. the string "2.0" doesn't suddenly become "2" just because it looks	70	(e.g. the string "2.0" doesn't suddenly become "2" just because it looks
57	like a number).	71	like a number). There minor I<are> exceptions to this, read the MAPPING
		72	section below to learn about those.
58		73
59	=item * strict checking of JSON correctness	74	=item * strict checking of JSON correctness
60		75
61	There is no guessing, no generating of illegal JSON texts by default,	76	There is no guessing, no generating of illegal JSON texts by default,
62	and only JSON is accepted as input by default (the latter is a security	77	and only JSON is accepted as input by default (the latter is a security
63	feature).	78	feature).
64		79
65	=item * fast	80	=item * fast
66		81
67	Compared to other JSON modules, this module compares favourably in terms	82	Compared to other JSON modules and other serialisers such as Storable,
68	of speed, too.	83	this module usually compares favourably in terms of speed, too.
69		84
70	=item * simple to use	85	=item * simple to use
71		86
72	This module has both a simple functional interface as well as an OO	87	This module has both a simple functional interface as well as an object
73	interface.	88	oriented interface interface.
74		89
75	=item * reasonably versatile output formats	90	=item * reasonably versatile output formats
76		91
77	You can choose between the most compact guarenteed single-line format	92	You can choose between the most compact guaranteed-single-line format
78	possible (nice for simple line-based protocols), a pure-ascii format	93	possible (nice for simple line-based protocols), a pure-ASCII format
79	(for when your transport is not 8-bit clean, still supports the whole	94	(for when your transport is not 8-bit clean, still supports the whole
80	unicode range), or a pretty-printed format (for when you want to read that	95	Unicode range), or a pretty-printed format (for when you want to read that
81	stuff). Or you can combine those features in whatever way you like.	96	stuff). Or you can combine those features in whatever way you like.
82		97
83	=back	98	=back
84		99
85	=cut	100	=cut
86		101
87	package JSON::XS;	102	package JSON::XS;
88		103
89	use strict;	104	use common::sense;
90		105
91	our $VERSION = '1.51';	106	our $VERSION = '2.28';
92	our @ISA = qw(Exporter);	107	our @ISA = qw(Exporter);
93		108
94	our @EXPORT = qw(to_json from_json);	109	our @EXPORT = qw(encode_json decode_json to_json from_json);
		110
		111	sub to_json($) {
		112	require Carp;
		113	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");
		114	}
		115
		116	sub from_json($) {
		117	require Carp;
		118	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");
		119	}
95		120
96	use Exporter;	121	use Exporter;
97	use XSLoader;	122	use XSLoader;
98		123
99	=head1 FUNCTIONAL INTERFACE	124	=head1 FUNCTIONAL INTERFACE
100		125
101	The following convinience methods are provided by this module. They are	126	The following convenience methods are provided by this module. They are
102	exported by default:	127	exported by default:
103		128
104	=over 4	129	=over 4
105		130
106	=item $json_text = to_json $perl_scalar	131	=item $json_text = encode_json $perl_scalar
107		132
108	Converts the given Perl data structure to a UTF-8 encoded, binary string	133	Converts the given Perl data structure to a UTF-8 encoded, binary string
109	(that is, the string contains octets only). Croaks on error.	134	(that is, the string contains octets only). Croaks on error.
110		135
111	This function call is functionally identical to:	136	This function call is functionally identical to:
112		137
113	$json_text = JSON::XS->new->utf8->encode ($perl_scalar)	138	$json_text = JSON::XS->new->utf8->encode ($perl_scalar)
114		139
115	except being faster.	140	Except being faster.
116		141
117	=item $perl_scalar = from_json $json_text	142	=item $perl_scalar = decode_json $json_text
118		143
119	The opposite of C<to_json>: expects an UTF-8 (binary) string and tries	144	The opposite of C<encode_json>: expects an UTF-8 (binary) string and tries
120	to parse that as an UTF-8 encoded JSON text, returning the resulting	145	to parse that as an UTF-8 encoded JSON text, returning the resulting
121	reference. Croaks on error.	146	reference. Croaks on error.
122		147
123	This function call is functionally identical to:	148	This function call is functionally identical to:
124		149
125	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)	150	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)
126		151
127	except being faster.	152	Except being faster.
128		153
129	=item $is_boolean = JSON::XS::is_bool $scalar	154	=item $is_boolean = JSON::XS::is_bool $scalar
130		155
131	Returns true if the passed scalar represents either JSON::XS::true or	156	Returns true if the passed scalar represents either JSON::XS::true or
132	JSON::XS::false, two constants that act like C<1> and C<0>, respectively	157	JSON::XS::false, two constants that act like C<1> and C<0>, respectively
…		…
145		170
146	=over 4	171	=over 4
147		172
148	=item 1. Perl strings can store characters with ordinal values > 255.	173	=item 1. Perl strings can store characters with ordinal values > 255.
149		174
150	This enables you to store unicode characters as single characters in a	175	This enables you to store Unicode characters as single characters in a
151	Perl string - very natural.	176	Perl string - very natural.
152		177
153	=item 2. Perl does I<not> associate an encoding with your strings.	178	=item 2. Perl does I<not> associate an encoding with your strings.
154		179
155	Unless you force it to, e.g. when matching it against a regex, or printing	180	... until you force it to, e.g. when matching it against a regex, or
156	the scalar to a file, in which case Perl either interprets your string as	181	printing the scalar to a file, in which case Perl either interprets your
157	locale-encoded text, octets/binary, or as Unicode, depending on various	182	string as locale-encoded text, octets/binary, or as Unicode, depending
158	settings. In no case is an encoding stored together with your data, it is	183	on various settings. In no case is an encoding stored together with your
159	I<use> that decides encoding, not any magical metadata.	184	data, it is I<use> that decides encoding, not any magical meta data.
160		185
161	=item 3. The internal utf-8 flag has no meaning with regards to the	186	=item 3. The internal utf-8 flag has no meaning with regards to the
162	encoding of your string.	187	encoding of your string.
163		188
164	Just ignore that flag unless you debug a Perl bug, a module written in	189	Just ignore that flag unless you debug a Perl bug, a module written in
165	XS or want to dive into the internals of perl. Otherwise it will only	190	XS or want to dive into the internals of perl. Otherwise it will only
166	confuse you, as, despite the name, it says nothing about how your string	191	confuse you, as, despite the name, it says nothing about how your string
167	is encoded. You can have unicode strings with that flag set, with that	192	is encoded. You can have Unicode strings with that flag set, with that
168	flag clear, and you can have binary data with that flag set and that flag	193	flag clear, and you can have binary data with that flag set and that flag
169	clear. Other possibilities exist, too.	194	clear. Other possibilities exist, too.
170		195
171	If you didn't know about that flag, just the better, pretend it doesn't	196	If you didn't know about that flag, just the better, pretend it doesn't
172	exist.	197	exist.
173		198
174	=item 4. A "Unicode String" is simply a string where each character can be	199	=item 4. A "Unicode String" is simply a string where each character can be
175	validly interpreted as a Unicode codepoint.	200	validly interpreted as a Unicode code point.
176		201
177	If you have UTF-8 encoded data, it is no longer a Unicode string, but a	202	If you have UTF-8 encoded data, it is no longer a Unicode string, but a
178	Unicode string encoded in UTF-8, giving you a binary string.	203	Unicode string encoded in UTF-8, giving you a binary string.
179		204
180	=item 5. A string containing "high" (> 255) character values is I<not> a UTF-8 string.	205	=item 5. A string containing "high" (> 255) character values is I<not> a UTF-8 string.
181		206
182	Its a fact. Learn to live with it.	207	It's a fact. Learn to live with it.
183		208
184	=back	209	=back
185		210
186	I hope this helps :)	211	I hope this helps :)
187		212
…		…
204	my $json = JSON::XS->new->utf8->space_after->encode ({a => [1,2]})	229	my $json = JSON::XS->new->utf8->space_after->encode ({a => [1,2]})
205	=> {"a": [1, 2]}	230	=> {"a": [1, 2]}
206		231
207	=item $json = $json->ascii ([$enable])	232	=item $json = $json->ascii ([$enable])
208		233
		234	=item $enabled = $json->get_ascii
		235
209	If C<$enable> is true (or missing), then the C<encode> method will not	236	If C<$enable> is true (or missing), then the C<encode> method will not
210	generate characters outside the code range C<0..127> (which is ASCII). Any	237	generate characters outside the code range C<0..127> (which is ASCII). Any
211	unicode characters outside that range will be escaped using either a	238	Unicode characters outside that range will be escaped using either a
212	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,	239	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,
213	as per RFC4627. The resulting encoded JSON text can be treated as a native	240	as per RFC4627. The resulting encoded JSON text can be treated as a native
214	unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string,	241	Unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string,
215	or any other superset of ASCII.	242	or any other superset of ASCII.
216		243
217	If C<$enable> is false, then the C<encode> method will not escape Unicode	244	If C<$enable> is false, then the C<encode> method will not escape Unicode
218	characters unless required by the JSON syntax or other flags. This results	245	characters unless required by the JSON syntax or other flags. This results
219	in a faster and more compact format.	246	in a faster and more compact format.
220		247
		248	See also the section I<ENCODING/CODESET FLAG NOTES> later in this
		249	document.
		250
221	The main use for this flag is to produce JSON texts that can be	251	The main use for this flag is to produce JSON texts that can be
222	transmitted over a 7-bit channel, as the encoded JSON texts will not	252	transmitted over a 7-bit channel, as the encoded JSON texts will not
223	contain any 8 bit characters.	253	contain any 8 bit characters.
224		254
225	JSON::XS->new->ascii (1)->encode ([chr 0x10401])	255	JSON::XS->new->ascii (1)->encode ([chr 0x10401])
226	=> ["\ud801\udc01"]	256	=> ["\ud801\udc01"]
227		257
228	=item $json = $json->latin1 ([$enable])	258	=item $json = $json->latin1 ([$enable])
229		259
		260	=item $enabled = $json->get_latin1
		261
230	If C<$enable> is true (or missing), then the C<encode> method will encode	262	If C<$enable> is true (or missing), then the C<encode> method will encode
231	the resulting JSON text as latin1 (or iso-8859-1), escaping any characters	263	the resulting JSON text as latin1 (or iso-8859-1), escaping any characters
232	outside the code range C<0..255>. The resulting string can be treated as a	264	outside the code range C<0..255>. The resulting string can be treated as a
233	latin1-encoded JSON text or a native unicode string. The C<decode> method	265	latin1-encoded JSON text or a native Unicode string. The C<decode> method
234	will not be affected in any way by this flag, as C<decode> by default	266	will not be affected in any way by this flag, as C<decode> by default
235	expects unicode, which is a strict superset of latin1.	267	expects Unicode, which is a strict superset of latin1.
236		268
237	If C<$enable> is false, then the C<encode> method will not escape Unicode	269	If C<$enable> is false, then the C<encode> method will not escape Unicode
238	characters unless required by the JSON syntax or other flags.	270	characters unless required by the JSON syntax or other flags.
		271
		272	See also the section I<ENCODING/CODESET FLAG NOTES> later in this
		273	document.
239		274
240	The main use for this flag is efficiently encoding binary data as JSON	275	The main use for this flag is efficiently encoding binary data as JSON
241	text, as most octets will not be escaped, resulting in a smaller encoded	276	text, as most octets will not be escaped, resulting in a smaller encoded
242	size. The disadvantage is that the resulting JSON text is encoded	277	size. The disadvantage is that the resulting JSON text is encoded
243	in latin1 (and must correctly be treated as such when storing and	278	in latin1 (and must correctly be treated as such when storing and
244	transfering), a rare encoding for JSON. It is therefore most useful when	279	transferring), a rare encoding for JSON. It is therefore most useful when
245	you want to store data structures known to contain binary data efficiently	280	you want to store data structures known to contain binary data efficiently
246	in files or databases, not when talking to other JSON encoders/decoders.	281	in files or databases, not when talking to other JSON encoders/decoders.
247		282
248	JSON::XS->new->latin1->encode (["\x{89}\x{abc}"]	283	JSON::XS->new->latin1->encode (["\x{89}\x{abc}"]
249	=> ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not)	284	=> ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not)
250		285
251	=item $json = $json->utf8 ([$enable])	286	=item $json = $json->utf8 ([$enable])
		287
		288	=item $enabled = $json->get_utf8
252		289
253	If C<$enable> is true (or missing), then the C<encode> method will encode	290	If C<$enable> is true (or missing), then the C<encode> method will encode
254	the JSON result into UTF-8, as required by many protocols, while the	291	the JSON result into UTF-8, as required by many protocols, while the
255	C<decode> method expects to be handled an UTF-8-encoded string. Please	292	C<decode> method expects to be handled an UTF-8-encoded string. Please
256	note that UTF-8-encoded strings do not contain any characters outside the	293	note that UTF-8-encoded strings do not contain any characters outside the
257	range C<0..255>, they are thus useful for bytewise/binary I/O. In future	294	range C<0..255>, they are thus useful for bytewise/binary I/O. In future
258	versions, enabling this option might enable autodetection of the UTF-16	295	versions, enabling this option might enable autodetection of the UTF-16
259	and UTF-32 encoding families, as described in RFC4627.	296	and UTF-32 encoding families, as described in RFC4627.
260		297
261	If C<$enable> is false, then the C<encode> method will return the JSON	298	If C<$enable> is false, then the C<encode> method will return the JSON
262	string as a (non-encoded) unicode string, while C<decode> expects thus a	299	string as a (non-encoded) Unicode string, while C<decode> expects thus a
263	unicode string. Any decoding or encoding (e.g. to UTF-8 or UTF-16) needs	300	Unicode string. Any decoding or encoding (e.g. to UTF-8 or UTF-16) needs
264	to be done yourself, e.g. using the Encode module.	301	to be done yourself, e.g. using the Encode module.
		302
		303	See also the section I<ENCODING/CODESET FLAG NOTES> later in this
		304	document.
265		305
266	Example, output UTF-16BE-encoded JSON:	306	Example, output UTF-16BE-encoded JSON:
267		307
268	use Encode;	308	use Encode;
269	$jsontext = encode "UTF-16BE", JSON::XS->new->encode ($object);	309	$jsontext = encode "UTF-16BE", JSON::XS->new->encode ($object);
…		…
290	]	330	]
291	}	331	}
292		332
293	=item $json = $json->indent ([$enable])	333	=item $json = $json->indent ([$enable])
294		334
		335	=item $enabled = $json->get_indent
		336
295	If C<$enable> is true (or missing), then the C<encode> method will use a multiline	337	If C<$enable> is true (or missing), then the C<encode> method will use a multiline
296	format as output, putting every array member or object/hash key-value pair	338	format as output, putting every array member or object/hash key-value pair
297	into its own line, identing them properly.	339	into its own line, indenting them properly.
298		340
299	If C<$enable> is false, no newlines or indenting will be produced, and the	341	If C<$enable> is false, no newlines or indenting will be produced, and the
300	resulting JSON text is guarenteed not to contain any C<newlines>.	342	resulting JSON text is guaranteed not to contain any C<newlines>.
301		343
302	This setting has no effect when decoding JSON texts.	344	This setting has no effect when decoding JSON texts.
303		345
304	=item $json = $json->space_before ([$enable])	346	=item $json = $json->space_before ([$enable])
		347
		348	=item $enabled = $json->get_space_before
305		349
306	If C<$enable> is true (or missing), then the C<encode> method will add an extra	350	If C<$enable> is true (or missing), then the C<encode> method will add an extra
307	optional space before the C<:> separating keys from values in JSON objects.	351	optional space before the C<:> separating keys from values in JSON objects.
308		352
309	If C<$enable> is false, then the C<encode> method will not add any extra	353	If C<$enable> is false, then the C<encode> method will not add any extra
…		…
315	Example, space_before enabled, space_after and indent disabled:	359	Example, space_before enabled, space_after and indent disabled:
316		360
317	{"key" :"value"}	361	{"key" :"value"}
318		362
319	=item $json = $json->space_after ([$enable])	363	=item $json = $json->space_after ([$enable])
		364
		365	=item $enabled = $json->get_space_after
320		366
321	If C<$enable> is true (or missing), then the C<encode> method will add an extra	367	If C<$enable> is true (or missing), then the C<encode> method will add an extra
322	optional space after the C<:> separating keys from values in JSON objects	368	optional space after the C<:> separating keys from values in JSON objects
323	and extra whitespace after the C<,> separating key-value pairs and array	369	and extra whitespace after the C<,> separating key-value pairs and array
324	members.	370	members.
…		…
331	Example, space_before and indent disabled, space_after enabled:	377	Example, space_before and indent disabled, space_after enabled:
332		378
333	{"key": "value"}	379	{"key": "value"}
334		380
335	=item $json = $json->relaxed ([$enable])	381	=item $json = $json->relaxed ([$enable])
		382
		383	=item $enabled = $json->get_relaxed
336		384
337	If C<$enable> is true (or missing), then C<decode> will accept some	385	If C<$enable> is true (or missing), then C<decode> will accept some
338	extensions to normal JSON syntax (see below). C<encode> will not be	386	extensions to normal JSON syntax (see below). C<encode> will not be
339	affected in anyway. I<Be aware that this option makes you accept invalid	387	affected in anyway. I<Be aware that this option makes you accept invalid
340	JSON texts as if they were valid!>. I suggest only to use this option to	388	JSON texts as if they were valid!>. I suggest only to use this option to
…		…
377		425
378	=back	426	=back
379		427
380	=item $json = $json->canonical ([$enable])	428	=item $json = $json->canonical ([$enable])
381		429
		430	=item $enabled = $json->get_canonical
		431
382	If C<$enable> is true (or missing), then the C<encode> method will output JSON objects	432	If C<$enable> is true (or missing), then the C<encode> method will output JSON objects
383	by sorting their keys. This is adding a comparatively high overhead.	433	by sorting their keys. This is adding a comparatively high overhead.
384		434
385	If C<$enable> is false, then the C<encode> method will output key-value	435	If C<$enable> is false, then the C<encode> method will output key-value
386	pairs in the order Perl stores them (which will likely change between runs	436	pairs in the order Perl stores them (which will likely change between runs
387	of the same script).	437	of the same script).
388		438
389	This option is useful if you want the same data structure to be encoded as	439	This option is useful if you want the same data structure to be encoded as
390	the same JSON text (given the same overall settings). If it is disabled,	440	the same JSON text (given the same overall settings). If it is disabled,
391	the same hash migh be encoded differently even if contains the same data,	441	the same hash might be encoded differently even if contains the same data,
392	as key-value pairs have no inherent ordering in Perl.	442	as key-value pairs have no inherent ordering in Perl.
393		443
394	This setting has no effect when decoding JSON texts.	444	This setting has no effect when decoding JSON texts.
395		445
		446	This setting has currently no effect on tied hashes.
		447
396	=item $json = $json->allow_nonref ([$enable])	448	=item $json = $json->allow_nonref ([$enable])
		449
		450	=item $enabled = $json->get_allow_nonref
397		451
398	If C<$enable> is true (or missing), then the C<encode> method can convert a	452	If C<$enable> is true (or missing), then the C<encode> method can convert a
399	non-reference into its corresponding string, number or null JSON value,	453	non-reference into its corresponding string, number or null JSON value,
400	which is an extension to RFC4627. Likewise, C<decode> will accept those JSON	454	which is an extension to RFC4627. Likewise, C<decode> will accept those JSON
401	values instead of croaking.	455	values instead of croaking.
…		…
409	resulting in an invalid JSON text:	463	resulting in an invalid JSON text:
410		464
411	JSON::XS->new->allow_nonref->encode ("Hello, World!")	465	JSON::XS->new->allow_nonref->encode ("Hello, World!")
412	=> "Hello, World!"	466	=> "Hello, World!"
413		467
		468	=item $json = $json->allow_unknown ([$enable])
		469
		470	=item $enabled = $json->get_allow_unknown
		471
		472	If C<$enable> is true (or missing), then C<encode> will I<not> throw an
		473	exception when it encounters values it cannot represent in JSON (for
		474	example, filehandles) but instead will encode a JSON C<null> value. Note
		475	that blessed objects are not included here and are handled separately by
		476	c<allow_nonref>.
		477
		478	If C<$enable> is false (the default), then C<encode> will throw an
		479	exception when it encounters anything it cannot encode as JSON.
		480
		481	This option does not affect C<decode> in any way, and it is recommended to
		482	leave it off unless you know your communications partner.
		483
414	=item $json = $json->allow_blessed ([$enable])	484	=item $json = $json->allow_blessed ([$enable])
		485
		486	=item $enabled = $json->get_allow_blessed
415		487
416	If C<$enable> is true (or missing), then the C<encode> method will not	488	If C<$enable> is true (or missing), then the C<encode> method will not
417	barf when it encounters a blessed reference. Instead, the value of the	489	barf when it encounters a blessed reference. Instead, the value of the
418	B<convert_blessed> option will decide wether C<null> (C<convert_blessed>	490	B<convert_blessed> option will decide whether C<null> (C<convert_blessed>
419	disabled or no C<to_json> method found) or a representation of the	491	disabled or no C<TO_JSON> method found) or a representation of the
420	object (C<convert_blessed> enabled and C<to_json> method found) is being	492	object (C<convert_blessed> enabled and C<TO_JSON> method found) is being
421	encoded. Has no effect on C<decode>.	493	encoded. Has no effect on C<decode>.
422		494
423	If C<$enable> is false (the default), then C<encode> will throw an	495	If C<$enable> is false (the default), then C<encode> will throw an
424	exception when it encounters a blessed object.	496	exception when it encounters a blessed object.
425		497
426	=item $json = $json->convert_blessed ([$enable])	498	=item $json = $json->convert_blessed ([$enable])
		499
		500	=item $enabled = $json->get_convert_blessed
427		501
428	If C<$enable> is true (or missing), then C<encode>, upon encountering a	502	If C<$enable> is true (or missing), then C<encode>, upon encountering a
429	blessed object, will check for the availability of the C<TO_JSON> method	503	blessed object, will check for the availability of the C<TO_JSON> method
430	on the object's class. If found, it will be called in scalar context	504	on the object's class. If found, it will be called in scalar context
431	and the resulting scalar will be encoded instead of the object. If no	505	and the resulting scalar will be encoded instead of the object. If no
…		…
435	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>	509	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
436	returns other blessed objects, those will be handled in the same	510	returns other blessed objects, those will be handled in the same
437	way. C<TO_JSON> must take care of not causing an endless recursion cycle	511	way. C<TO_JSON> must take care of not causing an endless recursion cycle
438	(== crash) in this case. The name of C<TO_JSON> was chosen because other	512	(== crash) in this case. The name of C<TO_JSON> was chosen because other
439	methods called by the Perl core (== not by the user of the object) are	513	methods called by the Perl core (== not by the user of the object) are
440	usually in upper case letters and to avoid collisions with the C<to_json>	514	usually in upper case letters and to avoid collisions with any C<to_json>
441	function.	515	function or method.
442		516
443	This setting does not yet influence C<decode> in any way, but in the	517	This setting does not yet influence C<decode> in any way, but in the
444	future, global hooks might get installed that influence C<decode> and are	518	future, global hooks might get installed that influence C<decode> and are
445	enabled by this setting.	519	enabled by this setting.
446		520
…		…
488		562
489	As this callback gets called less often then the C<filter_json_object>	563	As this callback gets called less often then the C<filter_json_object>
490	one, decoding speed will not usually suffer as much. Therefore, single-key	564	one, decoding speed will not usually suffer as much. Therefore, single-key
491	objects make excellent targets to serialise Perl objects into, especially	565	objects make excellent targets to serialise Perl objects into, especially
492	as single-key JSON objects are as close to the type-tagged value concept	566	as single-key JSON objects are as close to the type-tagged value concept
493	as JSON gets (its basically an ID/VALUE tuple). Of course, JSON does not	567	as JSON gets (it's basically an ID/VALUE tuple). Of course, JSON does not
494	support this in any way, so you need to make sure your data never looks	568	support this in any way, so you need to make sure your data never looks
495	like a serialised Perl hash.	569	like a serialised Perl hash.
496		570
497	Typical names for the single object key are C<__class_whatever__>, or	571	Typical names for the single object key are C<__class_whatever__>, or
498	C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even	572	C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even
…		…
522		596
523	{ __widget__ => $self->{id} }	597	{ __widget__ => $self->{id} }
524	}	598	}
525		599
526	=item $json = $json->shrink ([$enable])	600	=item $json = $json->shrink ([$enable])
		601
		602	=item $enabled = $json->get_shrink
527		603
528	Perl usually over-allocates memory a bit when allocating space for	604	Perl usually over-allocates memory a bit when allocating space for
529	strings. This flag optionally resizes strings generated by either	605	strings. This flag optionally resizes strings generated by either
530	C<encode> or C<decode> to their minimum size possible. This can save	606	C<encode> or C<decode> to their minimum size possible. This can save
531	memory when your JSON texts are either very very long or you have many	607	memory when your JSON texts are either very very long or you have many
…		…
549	strings that look like integers or floats into integers or floats	625	strings that look like integers or floats into integers or floats
550	internally (there is no difference on the Perl level), saving space.	626	internally (there is no difference on the Perl level), saving space.
551		627
552	=item $json = $json->max_depth ([$maximum_nesting_depth])	628	=item $json = $json->max_depth ([$maximum_nesting_depth])
553		629
		630	=item $max_depth = $json->get_max_depth
		631
554	Sets the maximum nesting level (default C<512>) accepted while encoding	632	Sets the maximum nesting level (default C<512>) accepted while encoding
555	or decoding. If the JSON text or Perl data structure has an equal or	633	or decoding. If a higher nesting level is detected in JSON text or a Perl
556	higher nesting level then this limit, then the encoder and decoder will	634	data structure, then the encoder and decoder will stop and croak at that
557	stop and croak at that point.	635	point.
558		636
559	Nesting level is defined by number of hash- or arrayrefs that the encoder	637	Nesting level is defined by number of hash- or arrayrefs that the encoder
560	needs to traverse to reach a given point or the number of C<{> or C<[>	638	needs to traverse to reach a given point or the number of C<{> or C<[>
561	characters without their matching closing parenthesis crossed to reach a	639	characters without their matching closing parenthesis crossed to reach a
562	given character in a string.	640	given character in a string.
563		641
564	Setting the maximum depth to one disallows any nesting, so that ensures	642	Setting the maximum depth to one disallows any nesting, so that ensures
565	that the object is only a single hash/object or array.	643	that the object is only a single hash/object or array.
566		644
567	The argument to C<max_depth> will be rounded up to the next highest power
568	of two. If no argument is given, the highest possible setting will be	645	If no argument is given, the highest possible setting will be used, which
569	used, which is rarely useful.	646	is rarely useful.
		647
		648	Note that nesting is implemented by recursion in C. The default value has
		649	been chosen to be as large as typical operating systems allow without
		650	crashing.
570		651
571	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.	652	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
572		653
573	=item $json = $json->max_size ([$maximum_string_size])	654	=item $json = $json->max_size ([$maximum_string_size])
		655
		656	=item $max_size = $json->get_max_size
574		657
575	Set the maximum length a JSON text may have (in bytes) where decoding is	658	Set the maximum length a JSON text may have (in bytes) where decoding is
576	being attempted. The default is C<0>, meaning no limit. When C<decode>	659	being attempted. The default is C<0>, meaning no limit. When C<decode>
577	is called on a string longer then this number of characters it will not	660	is called on a string that is longer then this many bytes, it will not
578	attempt to decode the string but throw an exception. This setting has no	661	attempt to decode the string but throw an exception. This setting has no
579	effect on C<encode> (yet).	662	effect on C<encode> (yet).
580		663
581	The argument to C<max_size> will be rounded up to the next B<highest>	664	If no argument is given, the limit check will be deactivated (same as when
582	power of two (so may be more than requested). If no argument is given, the	665	C<0> is specified).
583	limit check will be deactivated (same as when C<0> is specified).
584		666
585	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.	667	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
586		668
587	=item $json_text = $json->encode ($perl_scalar)	669	=item $json_text = $json->encode ($perl_scalar)
588		670
…		…
617	=> ([], 3)	699	=> ([], 3)
618		700
619	=back	701	=back
620		702
621		703
		704	=head1 INCREMENTAL PARSING
		705
		706	In some cases, there is the need for incremental parsing of JSON
		707	texts. While this module always has to keep both JSON text and resulting
		708	Perl data structure in memory at one time, it does allow you to parse a
		709	JSON stream incrementally. It does so by accumulating text until it has
		710	a full JSON object, which it then can decode. This process is similar to
		711	using C<decode_prefix> to see if a full JSON object is available, but
		712	is much more efficient (and can be implemented with a minimum of method
		713	calls).
		714
		715	JSON::XS will only attempt to parse the JSON text once it is sure it
		716	has enough text to get a decisive result, using a very simple but
		717	truly incremental parser. This means that it sometimes won't stop as
		718	early as the full parser, for example, it doesn't detect parenthese
		719	mismatches. The only thing it guarantees is that it starts decoding as
		720	soon as a syntactically valid JSON text has been seen. This means you need
		721	to set resource limits (e.g. C<max_size>) to ensure the parser will stop
		722	parsing in the presence if syntax errors.
		723
		724	The following methods implement this incremental parser.
		725
		726	=over 4
		727
		728	=item [void, scalar or list context] = $json->incr_parse ([$string])
		729
		730	This is the central parsing function. It can both append new text and
		731	extract objects from the stream accumulated so far (both of these
		732	functions are optional).
		733
		734	If C<$string> is given, then this string is appended to the already
		735	existing JSON fragment stored in the C<$json> object.
		736
		737	After that, if the function is called in void context, it will simply
		738	return without doing anything further. This can be used to add more text
		739	in as many chunks as you want.
		740
		741	If the method is called in scalar context, then it will try to extract
		742	exactly I<one> JSON object. If that is successful, it will return this
		743	object, otherwise it will return C<undef>. If there is a parse error,
		744	this method will croak just as C<decode> would do (one can then use
		745	C<incr_skip> to skip the errornous part). This is the most common way of
		746	using the method.
		747
		748	And finally, in list context, it will try to extract as many objects
		749	from the stream as it can find and return them, or the empty list
		750	otherwise. For this to work, there must be no separators between the JSON
		751	objects or arrays, instead they must be concatenated back-to-back. If
		752	an error occurs, an exception will be raised as in the scalar context
		753	case. Note that in this case, any previously-parsed JSON texts will be
		754	lost.
		755
		756	Example: Parse some JSON arrays/objects in a given string and return
		757	them.
		758
		759	my @objs = JSON::XS->new->incr_parse ("[5][7][1,2]");
		760
		761	=item $lvalue_string = $json->incr_text
		762
		763	This method returns the currently stored JSON fragment as an lvalue, that
		764	is, you can manipulate it. This I<only> works when a preceding call to
		765	C<incr_parse> in I<scalar context> successfully returned an object. Under
		766	all other circumstances you must not call this function (I mean it.
		767	although in simple tests it might actually work, it I<will> fail under
		768	real world conditions). As a special exception, you can also call this
		769	method before having parsed anything.
		770
		771	This function is useful in two cases: a) finding the trailing text after a
		772	JSON object or b) parsing multiple JSON objects separated by non-JSON text
		773	(such as commas).
		774
		775	=item $json->incr_skip
		776
		777	This will reset the state of the incremental parser and will remove
		778	the parsed text from the input buffer so far. This is useful after
		779	C<incr_parse> died, in which case the input buffer and incremental parser
		780	state is left unchanged, to skip the text parsed so far and to reset the
		781	parse state.
		782
		783	The difference to C<incr_reset> is that only text until the parse error
		784	occured is removed.
		785
		786	=item $json->incr_reset
		787
		788	This completely resets the incremental parser, that is, after this call,
		789	it will be as if the parser had never parsed anything.
		790
		791	This is useful if you want to repeatedly parse JSON objects and want to
		792	ignore any trailing data, which means you have to reset the parser after
		793	each successful decode.
		794
		795	=back
		796
		797	=head2 LIMITATIONS
		798
		799	All options that affect decoding are supported, except
		800	C<allow_nonref>. The reason for this is that it cannot be made to
		801	work sensibly: JSON objects and arrays are self-delimited, i.e. you can concatenate
		802	them back to back and still decode them perfectly. This does not hold true
		803	for JSON numbers, however.
		804
		805	For example, is the string C<1> a single JSON number, or is it simply the
		806	start of C<12>? Or is C<12> a single JSON number, or the concatenation
		807	of C<1> and C<2>? In neither case you can tell, and this is why JSON::XS
		808	takes the conservative route and disallows this case.
		809
		810	=head2 EXAMPLES
		811
		812	Some examples will make all this clearer. First, a simple example that
		813	works similarly to C<decode_prefix>: We want to decode the JSON object at
		814	the start of a string and identify the portion after the JSON object:
		815
		816	my $text = "[1,2,3] hello";
		817
		818	my $json = new JSON::XS;
		819
		820	my $obj = $json->incr_parse ($text)
		821	or die "expected JSON object or array at beginning of string";
		822
		823	my $tail = $json->incr_text;
		824	# $tail now contains " hello"
		825
		826	Easy, isn't it?
		827
		828	Now for a more complicated example: Imagine a hypothetical protocol where
		829	you read some requests from a TCP stream, and each request is a JSON
		830	array, without any separation between them (in fact, it is often useful to
		831	use newlines as "separators", as these get interpreted as whitespace at
		832	the start of the JSON text, which makes it possible to test said protocol
		833	with C<telnet>...).
		834
		835	Here is how you'd do it (it is trivial to write this in an event-based
		836	manner):
		837
		838	my $json = new JSON::XS;
		839
		840	# read some data from the socket
		841	while (sysread $socket, my $buf, 4096) {
		842
		843	# split and decode as many requests as possible
		844	for my $request ($json->incr_parse ($buf)) {
		845	# act on the $request
		846	}
		847	}
		848
		849	Another complicated example: Assume you have a string with JSON objects
		850	or arrays, all separated by (optional) comma characters (e.g. C<[1],[2],
		851	[3]>). To parse them, we have to skip the commas between the JSON texts,
		852	and here is where the lvalue-ness of C<incr_text> comes in useful:
		853
		854	my $text = "[1],[2], [3]";
		855	my $json = new JSON::XS;
		856
		857	# void context, so no parsing done
		858	$json->incr_parse ($text);
		859
		860	# now extract as many objects as possible. note the
		861	# use of scalar context so incr_text can be called.
		862	while (my $obj = $json->incr_parse) {
		863	# do something with $obj
		864
		865	# now skip the optional comma
		866	$json->incr_text =~ s/^ \s* , //x;
		867	}
		868
		869	Now lets go for a very complex example: Assume that you have a gigantic
		870	JSON array-of-objects, many gigabytes in size, and you want to parse it,
		871	but you cannot load it into memory fully (this has actually happened in
		872	the real world :).
		873
		874	Well, you lost, you have to implement your own JSON parser. But JSON::XS
		875	can still help you: You implement a (very simple) array parser and let
		876	JSON decode the array elements, which are all full JSON objects on their
		877	own (this wouldn't work if the array elements could be JSON numbers, for
		878	example):
		879
		880	my $json = new JSON::XS;
		881
		882	# open the monster
		883	open my $fh, "<bigfile.json"
		884	or die "bigfile: $!";
		885
		886	# first parse the initial "["
		887	for (;;) {
		888	sysread $fh, my $buf, 65536
		889	or die "read error: $!";
		890	$json->incr_parse ($buf); # void context, so no parsing
		891
		892	# Exit the loop once we found and removed(!) the initial "[".
		893	# In essence, we are (ab-)using the $json object as a simple scalar
		894	# we append data to.
		895	last if $json->incr_text =~ s/^ \s* \[ //x;
		896	}
		897
		898	# now we have the skipped the initial "[", so continue
		899	# parsing all the elements.
		900	for (;;) {
		901	# in this loop we read data until we got a single JSON object
		902	for (;;) {
		903	if (my $obj = $json->incr_parse) {
		904	# do something with $obj
		905	last;
		906	}
		907
		908	# add more data
		909	sysread $fh, my $buf, 65536
		910	or die "read error: $!";
		911	$json->incr_parse ($buf); # void context, so no parsing
		912	}
		913
		914	# in this loop we read data until we either found and parsed the
		915	# separating "," between elements, or the final "]"
		916	for (;;) {
		917	# first skip whitespace
		918	$json->incr_text =~ s/^\s*//;
		919
		920	# if we find "]", we are done
		921	if ($json->incr_text =~ s/^\]//) {
		922	print "finished.\n";
		923	exit;
		924	}
		925
		926	# if we find ",", we can continue with the next element
		927	if ($json->incr_text =~ s/^,//) {
		928	last;
		929	}
		930
		931	# if we find anything else, we have a parse error!
		932	if (length $json->incr_text) {
		933	die "parse error near ", $json->incr_text;
		934	}
		935
		936	# else add more data
		937	sysread $fh, my $buf, 65536
		938	or die "read error: $!";
		939	$json->incr_parse ($buf); # void context, so no parsing
		940	}
		941
		942	This is a complex example, but most of the complexity comes from the fact
		943	that we are trying to be correct (bear with me if I am wrong, I never ran
		944	the above example :).
		945
		946
		947
622	=head1 MAPPING	948	=head1 MAPPING
623		949
624	This section describes how JSON::XS maps Perl values to JSON values and	950	This section describes how JSON::XS maps Perl values to JSON values and
625	vice versa. These mappings are designed to "do the right thing" in most	951	vice versa. These mappings are designed to "do the right thing" in most
626	circumstances automatically, preserving round-tripping characteristics	952	circumstances automatically, preserving round-tripping characteristics
627	(what you put in comes out as something equivalent).	953	(what you put in comes out as something equivalent).
628		954
629	For the more enlightened: note that in the following descriptions,	955	For the more enlightened: note that in the following descriptions,
630	lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl>	956	lowercase I<perl> refers to the Perl interpreter, while uppercase I<Perl>
631	refers to the abstract Perl language itself.	957	refers to the abstract Perl language itself.
632		958
633		959
634	=head2 JSON -> PERL	960	=head2 JSON -> PERL
635		961
636	=over 4	962	=over 4
637		963
638	=item object	964	=item object
639		965
640	A JSON object becomes a reference to a hash in Perl. No ordering of object	966	A JSON object becomes a reference to a hash in Perl. No ordering of object
641	keys is preserved (JSON does not preserver object key ordering itself).	967	keys is preserved (JSON does not preserve object key ordering itself).
642		968
643	=item array	969	=item array
644		970
645	A JSON array becomes a reference to an array in Perl.	971	A JSON array becomes a reference to an array in Perl.
646		972
…		…
654		980
655	A JSON number becomes either an integer, numeric (floating point) or	981	A JSON number becomes either an integer, numeric (floating point) or
656	string scalar in perl, depending on its range and any fractional parts. On	982	string scalar in perl, depending on its range and any fractional parts. On
657	the Perl level, there is no difference between those as Perl handles all	983	the Perl level, there is no difference between those as Perl handles all
658	the conversion details, but an integer may take slightly less memory and	984	the conversion details, but an integer may take slightly less memory and
659	might represent more values exactly than (floating point) numbers.	985	might represent more values exactly than floating point numbers.
660		986
661	If the number consists of digits only, JSON::XS will try to represent	987	If the number consists of digits only, JSON::XS will try to represent
662	it as an integer value. If that fails, it will try to represent it as	988	it as an integer value. If that fails, it will try to represent it as
663	a numeric (floating point) value if that is possible without loss of	989	a numeric (floating point) value if that is possible without loss of
664	precision. Otherwise it will preserve the number as a string value.	990	precision. Otherwise it will preserve the number as a string value (in
		991	which case you lose roundtripping ability, as the JSON number will be
		992	re-encoded toa JSON string).
665		993
666	Numbers containing a fractional or exponential part will always be	994	Numbers containing a fractional or exponential part will always be
667	represented as numeric (floating point) values, possibly at a loss of	995	represented as numeric (floating point) values, possibly at a loss of
668	precision.	996	precision (in which case you might lose perfect roundtripping ability, but
669		997	the JSON number will still be re-encoded as a JSON number).
670	This might create round-tripping problems as numbers might become strings,
671	but as Perl is typeless there is no other way to do it.
672		998
673	=item true, false	999	=item true, false
674		1000
675	These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,	1001	These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,
676	respectively. They are overloaded to act almost exactly like the numbers	1002	respectively. They are overloaded to act almost exactly like the numbers
677	C<1> and C<0>. You can check wether a scalar is a JSON boolean by using	1003	C<1> and C<0>. You can check whether a scalar is a JSON boolean by using
678	the C<JSON::XS::is_bool> function.	1004	the C<JSON::XS::is_bool> function.
679		1005
680	=item null	1006	=item null
681		1007
682	A JSON null atom becomes C<undef> in Perl.	1008	A JSON null atom becomes C<undef> in Perl.
…		…
713	Other unblessed references are generally not allowed and will cause an	1039	Other unblessed references are generally not allowed and will cause an
714	exception to be thrown, except for references to the integers C<0> and	1040	exception to be thrown, except for references to the integers C<0> and
715	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can	1041	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can
716	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.	1042	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
717		1043
718	to_json [\0,JSON::XS::true] # yields [false,true]	1044	encode_json [\0, JSON::XS::true] # yields [false,true]
719		1045
720	=item JSON::XS::true, JSON::XS::false	1046	=item JSON::XS::true, JSON::XS::false
721		1047
722	These special values become JSON true and JSON false values,	1048	These special values become JSON true and JSON false values,
723	respectively. You can also use C<\1> and C<\0> directly if you want.	1049	respectively. You can also use C<\1> and C<\0> directly if you want.
724		1050
725	=item blessed objects	1051	=item blessed objects
726		1052
727	Blessed objects are not allowed. JSON::XS currently tries to encode their	1053	Blessed objects are not directly representable in JSON. See the
728	underlying representation (hash- or arrayref), but this behaviour might	1054	C<allow_blessed> and C<convert_blessed> methods on various options on
729	change in future versions.	1055	how to deal with this: basically, you can choose between throwing an
		1056	exception, encoding the reference as if it weren't blessed, or provide
		1057	your own serialiser method.
730		1058
731	=item simple scalars	1059	=item simple scalars
732		1060
733	Simple Perl scalars (any scalar that is not a reference) are the most	1061	Simple Perl scalars (any scalar that is not a reference) are the most
734	difficult objects to encode: JSON::XS will encode undefined scalars as	1062	difficult objects to encode: JSON::XS will encode undefined scalars as
735	JSON null value, scalars that have last been used in a string context	1063	JSON C<null> values, scalars that have last been used in a string context
736	before encoding as JSON strings and anything else as number value:	1064	before encoding as JSON strings, and anything else as number value:
737		1065
738	# dump as number	1066	# dump as number
739	to_json [2] # yields [2]	1067	encode_json [2] # yields [2]
740	to_json [-3.0e17] # yields [-3e+17]	1068	encode_json [-3.0e17] # yields [-3e+17]
741	my $value = 5; to_json [$value] # yields [5]	1069	my $value = 5; encode_json [$value] # yields [5]
742		1070
743	# used as string, so dump as string	1071	# used as string, so dump as string
744	print $value;	1072	print $value;
745	to_json [$value] # yields ["5"]	1073	encode_json [$value] # yields ["5"]
746		1074
747	# undef becomes null	1075	# undef becomes null
748	to_json [undef] # yields [null]	1076	encode_json [undef] # yields [null]
749		1077
750	You can force the type to be a string by stringifying it:	1078	You can force the type to be a JSON string by stringifying it:
751		1079
752	my $x = 3.1; # some variable containing a number	1080	my $x = 3.1; # some variable containing a number
753	"$x"; # stringified	1081	"$x"; # stringified
754	$x .= ""; # another, more awkward way to stringify	1082	$x .= ""; # another, more awkward way to stringify
755	print $x; # perl does it for you, too, quite often	1083	print $x; # perl does it for you, too, quite often
756		1084
757	You can force the type to be a number by numifying it:	1085	You can force the type to be a JSON number by numifying it:
758		1086
759	my $x = "3"; # some variable containing a string	1087	my $x = "3"; # some variable containing a string
760	$x += 0; # numify it, ensuring it will be dumped as a number	1088	$x += 0; # numify it, ensuring it will be dumped as a number
761	$x *= 1; # same thing, the choise is yours.	1089	$x *= 1; # same thing, the choice is yours.
762		1090
763	You can not currently output JSON booleans or force the type in other,	1091	You can not currently force the type in other, less obscure, ways. Tell me
764	less obscure, ways. Tell me if you need this capability.	1092	if you need this capability (but don't forget to explain why it's needed
		1093	:).
765		1094
766	=back	1095	=back
767		1096
768		1097
769	=head1 COMPARISON	1098	=head1 ENCODING/CODESET FLAG NOTES
770		1099
771	As already mentioned, this module was created because none of the existing	1100	The interested reader might have seen a number of flags that signify
772	JSON modules could be made to work correctly. First I will describe the	1101	encodings or codesets - C<utf8>, C<latin1> and C<ascii>. There seems to be
773	problems (or pleasures) I encountered with various existing JSON modules,	1102	some confusion on what these do, so here is a short comparison:
774	followed by some benchmark values. JSON::XS was designed not to suffer	1103
775	from any of these problems or limitations.	1104	C<utf8> controls whether the JSON text created by C<encode> (and expected
		1105	by C<decode>) is UTF-8 encoded or not, while C<latin1> and C<ascii> only
		1106	control whether C<encode> escapes character values outside their respective
		1107	codeset range. Neither of these flags conflict with each other, although
		1108	some combinations make less sense than others.
		1109
		1110	Care has been taken to make all flags symmetrical with respect to
		1111	C<encode> and C<decode>, that is, texts encoded with any combination of
		1112	these flag values will be correctly decoded when the same flags are used
		1113	- in general, if you use different flag settings while encoding vs. when
		1114	decoding you likely have a bug somewhere.
		1115
		1116	Below comes a verbose discussion of these flags. Note that a "codeset" is
		1117	simply an abstract set of character-codepoint pairs, while an encoding
		1118	takes those codepoint numbers and I<encodes> them, in our case into
		1119	octets. Unicode is (among other things) a codeset, UTF-8 is an encoding,
		1120	and ISO-8859-1 (= latin 1) and ASCII are both codesets I<and> encodings at
		1121	the same time, which can be confusing.
776		1122
777	=over 4	1123	=over 4
778		1124
779	=item JSON 1.07	1125	=item C<utf8> flag disabled
780		1126
781	Slow (but very portable, as it is written in pure Perl).	1127	When C<utf8> is disabled (the default), then C<encode>/C<decode> generate
		1128	and expect Unicode strings, that is, characters with high ordinal Unicode
		1129	values (> 255) will be encoded as such characters, and likewise such
		1130	characters are decoded as-is, no canges to them will be done, except
		1131	"(re-)interpreting" them as Unicode codepoints or Unicode characters,
		1132	respectively (to Perl, these are the same thing in strings unless you do
		1133	funny/weird/dumb stuff).
782		1134
783	Undocumented/buggy Unicode handling (how JSON handles unicode values is	1135	This is useful when you want to do the encoding yourself (e.g. when you
784	undocumented. One can get far by feeding it unicode strings and doing	1136	want to have UTF-16 encoded JSON texts) or when some other layer does
785	en-/decoding oneself, but unicode escapes are not working properly).	1137	the encoding for you (for example, when printing to a terminal using a
		1138	filehandle that transparently encodes to UTF-8 you certainly do NOT want
		1139	to UTF-8 encode your data first and have Perl encode it another time).
786		1140
787	No roundtripping (strings get clobbered if they look like numbers, e.g.	1141	=item C<utf8> flag enabled
788	the string C<2.0> will encode to C<2.0> instead of C<"2.0">, and that will
789	decode into the number 2.
790		1142
791	=item JSON::PC 0.01	1143	If the C<utf8>-flag is enabled, C<encode>/C<decode> will encode all
		1144	characters using the corresponding UTF-8 multi-byte sequence, and will
		1145	expect your input strings to be encoded as UTF-8, that is, no "character"
		1146	of the input string must have any value > 255, as UTF-8 does not allow
		1147	that.
792		1148
793	Very fast.	1149	The C<utf8> flag therefore switches between two modes: disabled means you
		1150	will get a Unicode string in Perl, enabled means you get an UTF-8 encoded
		1151	octet/binary string in Perl.
794		1152
795	Undocumented/buggy Unicode handling.	1153	=item C<latin1> or C<ascii> flags enabled
796		1154
797	No roundtripping.	1155	With C<latin1> (or C<ascii>) enabled, C<encode> will escape characters
		1156	with ordinal values > 255 (> 127 with C<ascii>) and encode the remaining
		1157	characters as specified by the C<utf8> flag.
798		1158
799	Has problems handling many Perl values (e.g. regex results and other magic	1159	If C<utf8> is disabled, then the result is also correctly encoded in those
800	values will make it croak).	1160	character sets (as both are proper subsets of Unicode, meaning that a
		1161	Unicode string with all character values < 256 is the same thing as a
		1162	ISO-8859-1 string, and a Unicode string with all character values < 128 is
		1163	the same thing as an ASCII string in Perl).
801		1164
802	Does not even generate valid JSON (C<{1,2}> gets converted to C<{1:2}>	1165	If C<utf8> is enabled, you still get a correct UTF-8-encoded string,
803	which is not a valid JSON text.	1166	regardless of these flags, just some more characters will be escaped using
		1167	C<\uXXXX> then before.
804		1168
805	Unmaintained (maintainer unresponsive for many months, bugs are not	1169	Note that ISO-8859-1-I<encoded> strings are not compatible with UTF-8
806	getting fixed).	1170	encoding, while ASCII-encoded strings are. That is because the ISO-8859-1
		1171	encoding is NOT a subset of UTF-8 (despite the ISO-8859-1 I<codeset> being
		1172	a subset of Unicode), while ASCII is.
807		1173
808	=item JSON::Syck 0.21	1174	Surprisingly, C<decode> will ignore these flags and so treat all input
		1175	values as governed by the C<utf8> flag. If it is disabled, this allows you
		1176	to decode ISO-8859-1- and ASCII-encoded strings, as both strict subsets of
		1177	Unicode. If it is enabled, you can correctly decode UTF-8 encoded strings.
809		1178
810	Very buggy (often crashes).	1179	So neither C<latin1> nor C<ascii> are incompatible with the C<utf8> flag -
		1180	they only govern when the JSON output engine escapes a character or not.
811		1181
812	Very inflexible (no human-readable format supported, format pretty much	1182	The main use for C<latin1> is to relatively efficiently store binary data
813	undocumented. I need at least a format for easy reading by humans and a	1183	as JSON, at the expense of breaking compatibility with most JSON decoders.
814	single-line compact format for use in a protocol, and preferably a way to
815	generate ASCII-only JSON texts).
816		1184
817	Completely broken (and confusingly documented) Unicode handling (unicode	1185	The main use for C<ascii> is to force the output to not contain characters
818	escapes are not working properly, you need to set ImplicitUnicode to	1186	with values > 127, which means you can interpret the resulting string
819	I<different> values on en- and decoding to get symmetric behaviour).	1187	as UTF-8, ISO-8859-1, ASCII, KOI8-R or most about any character set and
820		1188	8-bit-encoding, and still get the same data structure back. This is useful
821	No roundtripping (simple cases work, but this depends on wether the scalar	1189	when your channel for JSON transfer is not 8-bit clean or the encoding
822	value was used in a numeric context or not).	1190	might be mangled in between (e.g. in mail), and works because ASCII is a
823		1191	proper subset of most 8-bit and multibyte encodings in use in the world.
824	Dumping hashes may skip hash values depending on iterator state.
825
826	Unmaintained (maintainer unresponsive for many months, bugs are not
827	getting fixed).
828
829	Does not check input for validity (i.e. will accept non-JSON input and
830	return "something" instead of raising an exception. This is a security
831	issue: imagine two banks transfering money between each other using
832	JSON. One bank might parse a given non-JSON request and deduct money,
833	while the other might reject the transaction with a syntax error. While a
834	good protocol will at least recover, that is extra unnecessary work and
835	the transaction will still not succeed).
836
837	=item JSON::DWIW 0.04
838
839	Very fast. Very natural. Very nice.
840
841	Undocumented unicode handling (but the best of the pack. Unicode escapes
842	still don't get parsed properly).
843
844	Very inflexible.
845
846	No roundtripping.
847
848	Does not generate valid JSON texts (key strings are often unquoted, empty keys
849	result in nothing being output)
850
851	Does not check input for validity.
852		1192
853	=back	1193	=back
854		1194
855		1195
		1196	=head2 JSON and ECMAscript
		1197
		1198	JSON syntax is based on how literals are represented in javascript (the
		1199	not-standardised predecessor of ECMAscript) which is presumably why it is
		1200	called "JavaScript Object Notation".
		1201
		1202	However, JSON is not a subset (and also not a superset of course) of
		1203	ECMAscript (the standard) or javascript (whatever browsers actually
		1204	implement).
		1205
		1206	If you want to use javascript's C<eval> function to "parse" JSON, you
		1207	might run into parse errors for valid JSON texts, or the resulting data
		1208	structure might not be queryable:
		1209
		1210	One of the problems is that U+2028 and U+2029 are valid characters inside
		1211	JSON strings, but are not allowed in ECMAscript string literals, so the
		1212	following Perl fragment will not output something that can be guaranteed
		1213	to be parsable by javascript's C<eval>:
		1214
		1215	use JSON::XS;
		1216
		1217	print encode_json [chr 0x2028];
		1218
		1219	The right fix for this is to use a proper JSON parser in your javascript
		1220	programs, and not rely on C<eval> (see for example Douglas Crockford's
		1221	F<json2.js> parser).
		1222
		1223	If this is not an option, you can, as a stop-gap measure, simply encode to
		1224	ASCII-only JSON:
		1225
		1226	use JSON::XS;
		1227
		1228	print JSON::XS->new->ascii->encode ([chr 0x2028]);
		1229
		1230	Note that this will enlarge the resulting JSON text quite a bit if you
		1231	have many non-ASCII characters. You might be tempted to run some regexes
		1232	to only escape U+2028 and U+2029, e.g.:
		1233
		1234	# DO NOT USE THIS!
		1235	my $json = JSON::XS->new->utf8->encode ([chr 0x2028]);
		1236	$json =~ s/\xe2\x80\xa8/\\u2028/g; # escape U+2028
		1237	$json =~ s/\xe2\x80\xa9/\\u2029/g; # escape U+2029
		1238	print $json;
		1239
		1240	Note that I<this is a bad idea>: the above only works for U+2028 and
		1241	U+2029 and thus only for fully ECMAscript-compliant parsers. Many existing
		1242	javascript implementations, however, have issues with other characters as
		1243	well - using C<eval> naively simply I<will> cause problems.
		1244
		1245	Another problem is that some javascript implementations reserve
		1246	some property names for their own purposes (which probably makes
		1247	them non-ECMAscript-compliant). For example, Iceweasel reserves the
		1248	C<__proto__> property name for it's own purposes.
		1249
		1250	If that is a problem, you could parse try to filter the resulting JSON
		1251	output for these property strings, e.g.:
		1252
		1253	$json =~ s/"__proto__"\s*:/"__proto__renamed":/g;
		1254
		1255	This works because C<__proto__> is not valid outside of strings, so every
		1256	occurence of C<"__proto__"\s*:> must be a string used as property name.
		1257
		1258	If you know of other incompatibilities, please let me know.
		1259
		1260
856	=head2 JSON and YAML	1261	=head2 JSON and YAML
857		1262
858	You often hear that JSON is a subset (or a close subset) of YAML. This is,	1263	You often hear that JSON is a subset of YAML. This is, however, a mass
859	however, a mass hysteria and very far from the truth. In general, there is	1264	hysteria(*) and very far from the truth (as of the time of this writing),
860	no way to configure JSON::XS to output a data structure as valid YAML.	1265	so let me state it clearly: I<in general, there is no way to configure
		1266	JSON::XS to output a data structure as valid YAML> that works in all
		1267	cases.
861		1268
862	If you really must use JSON::XS to generate YAML, you should use this	1269	If you really must use JSON::XS to generate YAML, you should use this
863	algorithm (subject to change in future versions):	1270	algorithm (subject to change in future versions):
864		1271
865	my $to_yaml = JSON::XS->new->utf8->space_after (1);	1272	my $to_yaml = JSON::XS->new->utf8->space_after (1);
866	my $yaml = $to_yaml->encode ($ref) . "\n";	1273	my $yaml = $to_yaml->encode ($ref) . "\n";
867		1274
868	This will usually generate JSON texts that also parse as valid	1275	This will I<usually> generate JSON texts that also parse as valid
869	YAML. Please note that YAML has hardcoded limits on (simple) object key	1276	YAML. Please note that YAML has hardcoded limits on (simple) object key
870	lengths that JSON doesn't have, so you should make sure that your hash	1277	lengths that JSON doesn't have and also has different and incompatible
		1278	unicode character escape syntax, so you should make sure that your hash
871	keys are noticably shorter than the 1024 characters YAML allows.	1279	keys are noticeably shorter than the 1024 "stream characters" YAML allows
		1280	and that you do not have characters with codepoint values outside the
		1281	Unicode BMP (basic multilingual page). YAML also does not allow C<\/>
		1282	sequences in strings (which JSON::XS does not I<currently> generate, but
		1283	other JSON generators might).
872		1284
873	There might be other incompatibilities that I am not aware of. In general	1285	There might be other incompatibilities that I am not aware of (or the YAML
		1286	specification has been changed yet again - it does so quite often). In
874	you should not try to generate YAML with a JSON generator or vice versa,	1287	general you should not try to generate YAML with a JSON generator or vice
875	or try to parse JSON with a YAML parser or vice versa: chances are high	1288	versa, or try to parse JSON with a YAML parser or vice versa: chances are
876	that you will run into severe interoperability problems.	1289	high that you will run into severe interoperability problems when you
		1290	least expect it.
		1291
		1292	=over 4
		1293
		1294	=item (*)
		1295
		1296	I have been pressured multiple times by Brian Ingerson (one of the
		1297	authors of the YAML specification) to remove this paragraph, despite him
		1298	acknowledging that the actual incompatibilities exist. As I was personally
		1299	bitten by this "JSON is YAML" lie, I refused and said I will continue to
		1300	educate people about these issues, so others do not run into the same
		1301	problem again and again. After this, Brian called me a (quote)I<complete
		1302	and worthless idiot>(unquote).
		1303
		1304	In my opinion, instead of pressuring and insulting people who actually
		1305	clarify issues with YAML and the wrong statements of some of its
		1306	proponents, I would kindly suggest reading the JSON spec (which is not
		1307	that difficult or long) and finally make YAML compatible to it, and
		1308	educating users about the changes, instead of spreading lies about the
		1309	real compatibility for many I<years> and trying to silence people who
		1310	point out that it isn't true.
		1311
		1312	Addendum/2009: the YAML 1.2 spec is still incomaptible with JSON, even
		1313	though the incompatibilities have been documented (and are known to
		1314	Brian) for many years and the spec makes explicit claims that YAML is a
		1315	superset of JSON. It would be so easy to fix, but apparently, bullying and
		1316	corrupting userdata is so much easier.
		1317
		1318	=back
877		1319
878		1320
879	=head2 SPEED	1321	=head2 SPEED
880		1322
881	It seems that JSON::XS is surprisingly fast, as shown in the following	1323	It seems that JSON::XS is surprisingly fast, as shown in the following
882	tables. They have been generated with the help of the C<eg/bench> program	1324	tables. They have been generated with the help of the C<eg/bench> program
883	in the JSON::XS distribution, to make it easy to compare on your own	1325	in the JSON::XS distribution, to make it easy to compare on your own
884	system.	1326	system.
885		1327
886	First comes a comparison between various modules using a very short	1328	First comes a comparison between various modules using
887	single-line JSON string:	1329	a very short single-line JSON string (also available at
		1330	L<http://dist.schmorp.de/misc/json/short.json>).
888		1331
889	{"method": "handleMessage", "params": ["user1", "we were just talking"], \	1332	{"method": "handleMessage", "params": ["user1",
890	"id": null, "array":[1,11,234,-5,1e5,1e7, true, false]}	1333	"we were just talking"], "id": null, "array":[1,11,234,-5,1e5,1e7,
		1334	1, 0]}
891		1335
892	It shows the number of encodes/decodes per second (JSON::XS uses	1336	It shows the number of encodes/decodes per second (JSON::XS uses
893	the functional interface, while JSON::XS/2 uses the OO interface	1337	the functional interface, while JSON::XS/2 uses the OO interface
894	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables	1338	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables
895	shrink). Higher is better:	1339	shrink. JSON::DWIW/DS uses the deserialise function, while JSON::DWIW::FJ
		1340	uses the from_json method). Higher is better:
896		1341
897	Storable \| 15779.925 \| 14169.946 \|
898	-----------+------------+------------+
899	module \| encode \| decode \|	1342	module \| encode \| decode \|
900	-----------\|------------\|------------\|	1343	--------------\|------------\|------------\|
901	JSON \| 4990.842 \| 4088.813 \|	1344	JSON::DWIW/DS \| 86302.551 \| 102300.098 \|
902	JSON::DWIW \| 51653.990 \| 71575.154 \|	1345	JSON::DWIW/FJ \| 86302.551 \| 75983.768 \|
903	JSON::PC \| 65948.176 \| 74631.744 \|	1346	JSON::PP \| 15827.562 \| 6638.658 \|
904	JSON::PP \| 8931.652 \| 3817.168 \|	1347	JSON::Syck \| 63358.066 \| 47662.545 \|
905	JSON::Syck \| 24877.248 \| 27776.848 \|	1348	JSON::XS \| 511500.488 \| 511500.488 \|
906	JSON::XS \| 388361.481 \| 227951.304 \|	1349	JSON::XS/2 \| 291271.111 \| 388361.481 \|
907	JSON::XS/2 \| 227951.304 \| 218453.333 \|	1350	JSON::XS/3 \| 361577.931 \| 361577.931 \|
908	JSON::XS/3 \| 338250.323 \| 218453.333 \|	1351	Storable \| 66788.280 \| 265462.278 \|
909	Storable \| 16500.016 \| 135300.129 \|
910	-----------+------------+------------+	1352	--------------+------------+------------+
911		1353
912	That is, JSON::XS is about five times faster than JSON::DWIW on encoding,	1354	That is, JSON::XS is almost six times faster than JSON::DWIW on encoding,
913	about three times faster on decoding, and over fourty times faster	1355	about five times faster on decoding, and over thirty to seventy times
914	than JSON, even with pretty-printing and key sorting. It also compares	1356	faster than JSON's pure perl implementation. It also compares favourably
915	favourably to Storable for small amounts of data.	1357	to Storable for small amounts of data.
916		1358
917	Using a longer test string (roughly 18KB, generated from Yahoo! Locals	1359	Using a longer test string (roughly 18KB, generated from Yahoo! Locals
918	search API (http://nanoref.com/yahooapis/mgPdGg):	1360	search API (L<http://dist.schmorp.de/misc/json/long.json>).
919		1361
920	module \| encode \| decode \|	1362	module \| encode \| decode \|
921	-----------\|------------\|------------\|	1363	--------------\|------------\|------------\|
922	JSON \| 55.260 \| 34.971 \|	1364	JSON::DWIW/DS \| 1647.927 \| 2673.916 \|
923	JSON::DWIW \| 825.228 \| 1082.513 \|	1365	JSON::DWIW/FJ \| 1630.249 \| 2596.128 \|
924	JSON::PC \| 3571.444 \| 2394.829 \|
925	JSON::PP \| 210.987 \| 32.574 \|	1366	JSON::PP \| 400.640 \| 62.311 \|
926	JSON::Syck \| 552.551 \| 787.544 \|	1367	JSON::Syck \| 1481.040 \| 1524.869 \|
927	JSON::XS \| 5780.463 \| 4854.519 \|	1368	JSON::XS \| 20661.596 \| 9541.183 \|
928	JSON::XS/2 \| 3869.998 \| 4798.975 \|	1369	JSON::XS/2 \| 10683.403 \| 9416.938 \|
929	JSON::XS/3 \| 5862.880 \| 4798.975 \|	1370	JSON::XS/3 \| 20661.596 \| 9400.054 \|
930	Storable \| 4445.002 \| 5235.027 \|	1371	Storable \| 19765.806 \| 10000.725 \|
931	-----------+------------+------------+	1372	--------------+------------+------------+
932		1373
933	Again, JSON::XS leads by far (except for Storable which non-surprisingly	1374	Again, JSON::XS leads by far (except for Storable which non-surprisingly
934	decodes faster).	1375	decodes a bit faster).
935		1376
936	On large strings containing lots of high unicode characters, some modules	1377	On large strings containing lots of high Unicode characters, some modules
937	(such as JSON::PC) seem to decode faster than JSON::XS, but the result	1378	(such as JSON::PC) seem to decode faster than JSON::XS, but the result
938	will be broken due to missing (or wrong) unicode handling. Others refuse	1379	will be broken due to missing (or wrong) Unicode handling. Others refuse
939	to decode or encode properly, so it was impossible to prepare a fair	1380	to decode or encode properly, so it was impossible to prepare a fair
940	comparison table for that case.	1381	comparison table for that case.
941		1382
942		1383
943	=head1 SECURITY CONSIDERATIONS	1384	=head1 SECURITY CONSIDERATIONS
…		…
949	any buffer overflows. Obviously, this module should ensure that and I am	1390	any buffer overflows. Obviously, this module should ensure that and I am
950	trying hard on making that true, but you never know.	1391	trying hard on making that true, but you never know.
951		1392
952	Second, you need to avoid resource-starving attacks. That means you should	1393	Second, you need to avoid resource-starving attacks. That means you should
953	limit the size of JSON texts you accept, or make sure then when your	1394	limit the size of JSON texts you accept, or make sure then when your
954	resources run out, thats just fine (e.g. by using a separate process that	1395	resources run out, that's just fine (e.g. by using a separate process that
955	can crash safely). The size of a JSON text in octets or characters is	1396	can crash safely). The size of a JSON text in octets or characters is
956	usually a good indication of the size of the resources required to decode	1397	usually a good indication of the size of the resources required to decode
957	it into a Perl structure. While JSON::XS can check the size of the JSON	1398	it into a Perl structure. While JSON::XS can check the size of the JSON
958	text, it might be too late when you already have it in memory, so you	1399	text, it might be too late when you already have it in memory, so you
959	might want to check the size before you accept the string.	1400	might want to check the size before you accept the string.
960		1401
961	Third, JSON::XS recurses using the C stack when decoding objects and	1402	Third, JSON::XS recurses using the C stack when decoding objects and
962	arrays. The C stack is a limited resource: for instance, on my amd64	1403	arrays. The C stack is a limited resource: for instance, on my amd64
963	machine with 8MB of stack size I can decode around 180k nested arrays but	1404	machine with 8MB of stack size I can decode around 180k nested arrays but
964	only 14k nested JSON objects (due to perl itself recursing deeply on croak	1405	only 14k nested JSON objects (due to perl itself recursing deeply on croak
965	to free the temporary). If that is exceeded, the program crashes. to be	1406	to free the temporary). If that is exceeded, the program crashes. To be
966	conservative, the default nesting limit is set to 512. If your process	1407	conservative, the default nesting limit is set to 512. If your process
967	has a smaller stack, you should adjust this setting accordingly with the	1408	has a smaller stack, you should adjust this setting accordingly with the
968	C<max_depth> method.	1409	C<max_depth> method.
969		1410
970	And last but least, something else could bomb you that I forgot to think	1411	Something else could bomb you, too, that I forgot to think of. In that
971	of. In that case, you get to keep the pieces. I am always open for hints,	1412	case, you get to keep the pieces. I am always open for hints, though...
972	though...	1413
		1414	Also keep in mind that JSON::XS might leak contents of your Perl data
		1415	structures in its error messages, so when you serialise sensitive
		1416	information you might want to make sure that exceptions thrown by JSON::XS
		1417	will not end up in front of untrusted eyes.
973		1418
974	If you are using JSON::XS to return packets to consumption	1419	If you are using JSON::XS to return packets to consumption
975	by javascript scripts in a browser you should have a look at	1420	by JavaScript scripts in a browser you should have a look at
976	L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether	1421	L<http://blog.archive.jpsykes.com/47/practical-csrf-and-json-security/> to
977	you are vulnerable to some common attack vectors (which really are browser	1422	see whether you are vulnerable to some common attack vectors (which really
978	design bugs, but it is still you who will have to deal with it, as major	1423	are browser design bugs, but it is still you who will have to deal with
979	browser developers care only for features, not about doing security	1424	it, as major browser developers care only for features, not about getting
980	right).	1425	security right).
981		1426
982		1427
983	=head1 THREADS	1428	=head1 THREADS
984		1429
985	This module is I<not> guarenteed to be thread safe and there are no	1430	This module is I<not> guaranteed to be thread safe and there are no
986	plans to change this until Perl gets thread support (as opposed to the	1431	plans to change this until Perl gets thread support (as opposed to the
987	horribly slow so-called "threads" which are simply slow and bloated	1432	horribly slow so-called "threads" which are simply slow and bloated
988	process simulations - use fork, its I<much> faster, cheaper, better).	1433	process simulations - use fork, it's I<much> faster, cheaper, better).
989		1434
990	(It might actually work, but you ahve ben warned).	1435	(It might actually work, but you have been warned).
991		1436
992		1437
993	=head1 BUGS	1438	=head1 BUGS
994		1439
995	While the goal of this module is to be correct, that unfortunately does	1440	While the goal of this module is to be correct, that unfortunately does
996	not mean its bug-free, only that I think its design is bug-free. It is	1441	not mean it's bug-free, only that I think its design is bug-free. If you
997	still relatively early in its development. If you keep reporting bugs they	1442	keep reporting bugs they will be fixed swiftly, though.
998	will be fixed swiftly, though.
999		1443
1000	Please refrain from using rt.cpan.org or any other bug reporting	1444	Please refrain from using rt.cpan.org or any other bug reporting
1001	service. I put the contact address into my modules for a reason.	1445	service. I put the contact address into my modules for a reason.
1002		1446
1003	=cut	1447	=cut
…		…
1023	"--" => sub { $_[0] = ${$_[0]} - 1 },	1467	"--" => sub { $_[0] = ${$_[0]} - 1 },
1024	fallback => 1;	1468	fallback => 1;
1025		1469
1026	1;	1470	1;
1027		1471
		1472	=head1 SEE ALSO
		1473
		1474	The F<json_xs> command line utility for quick experiments.
		1475
1028	=head1 AUTHOR	1476	=head1 AUTHOR
1029		1477
1030	Marc Lehmann <schmorp@schmorp.de>	1478	Marc Lehmann <schmorp@schmorp.de>
1031	http://home.schmorp.de/	1479	http://home.schmorp.de/
1032		1480

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Comparing JSON-XS/XS.pm (file contents): Revision 1.65 by root, Sat Oct 13 01:55:31 2007 UTC vs. Revision 1.130 by root, Thu Mar 11 17:36:09 2010 UTC

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Revision 1.65 by root, Sat Oct 13 01:55:31 2007 UTC vs.
Revision 1.130 by root, Thu Mar 11 17:36:09 2010 UTC