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

Comparing JSON-XS/XS.pm (file contents):
Revision 1.12 by root, Fri Mar 23 18:33:50 2007 UTC vs.
Revision 1.32 by root, Thu Apr 12 07:25:29 2007 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use JSON::XS;	7	use JSON::XS;
8		8
9	# exported functions, croak on error	9	# exported functions, they croak on error
		10	# and expect/generate UTF-8
10		11
11	$utf8_encoded_json_text = to_json $perl_hash_or_arrayref;	12	$utf8_encoded_json_text = to_json $perl_hash_or_arrayref;
12	$perl_hash_or_arrayref = from_json $utf8_encoded_json_text;	13	$perl_hash_or_arrayref = from_json $utf8_encoded_json_text;
13		14
		15	# objToJson and jsonToObj aliases to to_json and from_json
		16	# are exported for compatibility to the JSON module,
		17	# but should not be used in new code.
		18
14	# oo-interface	19	# OO-interface
15		20
16	$coder = JSON::XS->new->ascii->pretty->allow_nonref;	21	$coder = JSON::XS->new->ascii->pretty->allow_nonref;
17	$pretty_printed_unencoded = $coder->encode ($perl_scalar);	22	$pretty_printed_unencoded = $coder->encode ($perl_scalar);
18	$perl_scalar = $coder->decode ($unicode_json_text);	23	$perl_scalar = $coder->decode ($unicode_json_text);
19		24
…		…
36		41
37	=head2 FEATURES	42	=head2 FEATURES
38		43
39	=over 4	44	=over 4
40		45
41	=item * correct handling of unicode issues	46	=item * correct unicode handling
42		47
43	This module knows how to handle Unicode, and even documents how and when	48	This module knows how to handle Unicode, and even documents how and when
44	it does so.	49	it does so.
45		50
46	=item * round-trip integrity	51	=item * round-trip integrity
47		52
48	When you serialise a perl data structure using only datatypes supported	53	When you serialise a perl data structure using only datatypes supported
49	by JSON, the deserialised data structure is identical on the Perl level.	54	by JSON, the deserialised data structure is identical on the Perl level.
50	(e.g. the string "2.0" doesn't suddenly become "2").	55	(e.g. the string "2.0" doesn't suddenly become "2" just because it looks
		56	like a number).
51		57
52	=item * strict checking of JSON correctness	58	=item * strict checking of JSON correctness
53		59
54	There is no guessing, no generating of illegal JSON strings by default,	60	There is no guessing, no generating of illegal JSON texts by default,
55	and only JSON is accepted as input by default (the latter is a security	61	and only JSON is accepted as input by default (the latter is a security
56	feature).	62	feature).
57		63
58	=item * fast	64	=item * fast
59		65
…		…
66	interface.	72	interface.
67		73
68	=item * reasonably versatile output formats	74	=item * reasonably versatile output formats
69		75
70	You can choose between the most compact guarenteed single-line format	76	You can choose between the most compact guarenteed single-line format
71	possible (nice for simple line-based protocols), a pure-ascii format (for	77	possible (nice for simple line-based protocols), a pure-ascii format
72	when your transport is not 8-bit clean), or a pretty-printed format (for	78	(for when your transport is not 8-bit clean, still supports the whole
73	when you want to read that stuff). Or you can combine those features in	79	unicode range), or a pretty-printed format (for when you want to read that
74	whatever way you like.	80	stuff). Or you can combine those features in whatever way you like.
75		81
76	=back	82	=back
77		83
78	=cut	84	=cut
79		85
80	package JSON::XS;	86	package JSON::XS;
81		87
		88	use strict;
		89
82	BEGIN {	90	BEGIN {
83	$VERSION = '0.3';	91	our $VERSION = '1.12';
84	@ISA = qw(Exporter);	92	our @ISA = qw(Exporter);
85		93
86	@EXPORT = qw(to_json from_json);	94	our @EXPORT = qw(to_json from_json objToJson jsonToObj);
87	require Exporter;	95	require Exporter;
88		96
89	require XSLoader;	97	require XSLoader;
90	XSLoader::load JSON::XS::, $VERSION;	98	XSLoader::load JSON::XS::, $VERSION;
91	}	99	}
…		…
95	The following convinience methods are provided by this module. They are	103	The following convinience methods are provided by this module. They are
96	exported by default:	104	exported by default:
97		105
98	=over 4	106	=over 4
99		107
100	=item $json_string = to_json $perl_scalar	108	=item $json_text = to_json $perl_scalar
101		109
102	Converts the given Perl data structure (a simple scalar or a reference to	110	Converts the given Perl data structure (a simple scalar or a reference to
103	a hash or array) to a UTF-8 encoded, binary string (that is, the string contains	111	a hash or array) to a UTF-8 encoded, binary string (that is, the string contains
104	octets only). Croaks on error.	112	octets only). Croaks on error.
105		113
106	This function call is functionally identical to C<< JSON::XS->new->utf8->encode ($perl_scalar) >>.	114	This function call is functionally identical to:
107		115
		116	$json_text = JSON::XS->new->utf8->encode ($perl_scalar)
		117
		118	except being faster.
		119
108	=item $perl_scalar = from_json $json_string	120	=item $perl_scalar = from_json $json_text
109		121
110	The opposite of C<to_json>: expects an UTF-8 (binary) string and tries to	122	The opposite of C<to_json>: expects an UTF-8 (binary) string and tries to
111	parse that as an UTF-8 encoded JSON string, returning the resulting simple	123	parse that as an UTF-8 encoded JSON text, returning the resulting simple
112	scalar or reference. Croaks on error.	124	scalar or reference. Croaks on error.
113		125
114	This function call is functionally identical to C<< JSON::XS->new->utf8->decode ($json_string) >>.	126	This function call is functionally identical to:
		127
		128	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)
		129
		130	except being faster.
115		131
116	=back	132	=back
		133
117		134
118	=head1 OBJECT-ORIENTED INTERFACE	135	=head1 OBJECT-ORIENTED INTERFACE
119		136
120	The object oriented interface lets you configure your own encoding or	137	The object oriented interface lets you configure your own encoding or
121	decoding style, within the limits of supported formats.	138	decoding style, within the limits of supported formats.
…		…
128	strings. All boolean flags described below are by default I<disabled>.	145	strings. All boolean flags described below are by default I<disabled>.
129		146
130	The mutators for flags all return the JSON object again and thus calls can	147	The mutators for flags all return the JSON object again and thus calls can
131	be chained:	148	be chained:
132		149
133	my $json = JSON::XS->new->utf8(1)->space_after(1)->encode ({a => [1,2]})	150	my $json = JSON::XS->new->utf8->space_after->encode ({a => [1,2]})
134	=> {"a": [1, 2]}	151	=> {"a": [1, 2]}
135		152
136	=item $json = $json->ascii ([$enable])	153	=item $json = $json->ascii ([$enable])
137		154
138	If C<$enable> is true (or missing), then the C<encode> method will	155	If C<$enable> is true (or missing), then the C<encode> method will not
139	not generate characters outside the code range C<0..127>. Any unicode	156	generate characters outside the code range C<0..127> (which is ASCII). Any
140	characters outside that range will be escaped using either a single	157	unicode characters outside that range will be escaped using either a
141	\uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, as per	158	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,
142	RFC4627.	159	as per RFC4627. The resulting encoded JSON text can be treated as a native
		160	unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string,
		161	or any other superset of ASCII.
143		162
144	If C<$enable> is false, then the C<encode> method will not escape Unicode	163	If C<$enable> is false, then the C<encode> method will not escape Unicode
145	characters unless necessary.	164	characters unless required by the JSON syntax. This results in a faster
		165	and more compact format.
146		166
147	JSON::XS->new->ascii (1)->encode (chr 0x10401)	167	JSON::XS->new->ascii (1)->encode ([chr 0x10401])
148	=> \ud801\udc01	168	=> ["\ud801\udc01"]
149		169
150	=item $json = $json->utf8 ([$enable])	170	=item $json = $json->utf8 ([$enable])
151		171
152	If C<$enable> is true (or missing), then the C<encode> method will encode	172	If C<$enable> is true (or missing), then the C<encode> method will encode
153	the JSON string into UTF-8, as required by many protocols, while the	173	the JSON result into UTF-8, as required by many protocols, while the
154	C<decode> method expects to be handled an UTF-8-encoded string. Please	174	C<decode> method expects to be handled an UTF-8-encoded string. Please
155	note that UTF-8-encoded strings do not contain any characters outside the	175	note that UTF-8-encoded strings do not contain any characters outside the
156	range C<0..255>, they are thus useful for bytewise/binary I/O.	176	range C<0..255>, they are thus useful for bytewise/binary I/O. In future
		177	versions, enabling this option might enable autodetection of the UTF-16
		178	and UTF-32 encoding families, as described in RFC4627.
157		179
158	If C<$enable> is false, then the C<encode> method will return the JSON	180	If C<$enable> is false, then the C<encode> method will return the JSON
159	string as a (non-encoded) unicode string, while C<decode> expects thus a	181	string as a (non-encoded) unicode string, while C<decode> expects thus a
160	unicode string. Any decoding or encoding (e.g. to UTF-8 or UTF-16) needs	182	unicode string. Any decoding or encoding (e.g. to UTF-8 or UTF-16) needs
161	to be done yourself, e.g. using the Encode module.	183	to be done yourself, e.g. using the Encode module.
162		184
163	Example, output UTF-16-encoded JSON:	185	Example, output UTF-16BE-encoded JSON:
		186
		187	use Encode;
		188	$jsontext = encode "UTF-16BE", JSON::XS->new->encode ($object);
		189
		190	Example, decode UTF-32LE-encoded JSON:
		191
		192	use Encode;
		193	$object = JSON::XS->new->decode (decode "UTF-32LE", $jsontext);
164		194
165	=item $json = $json->pretty ([$enable])	195	=item $json = $json->pretty ([$enable])
166		196
167	This enables (or disables) all of the C<indent>, C<space_before> and	197	This enables (or disables) all of the C<indent>, C<space_before> and
168	C<space_after> (and in the future possibly more) flags in one call to	198	C<space_after> (and in the future possibly more) flags in one call to
…		…
184	If C<$enable> is true (or missing), then the C<encode> method will use a multiline	214	If C<$enable> is true (or missing), then the C<encode> method will use a multiline
185	format as output, putting every array member or object/hash key-value pair	215	format as output, putting every array member or object/hash key-value pair
186	into its own line, identing them properly.	216	into its own line, identing them properly.
187		217
188	If C<$enable> is false, no newlines or indenting will be produced, and the	218	If C<$enable> is false, no newlines or indenting will be produced, and the
189	resulting JSON strings is guarenteed not to contain any C<newlines>.	219	resulting JSON text is guarenteed not to contain any C<newlines>.
190		220
191	This setting has no effect when decoding JSON strings.	221	This setting has no effect when decoding JSON texts.
192		222
193	=item $json = $json->space_before ([$enable])	223	=item $json = $json->space_before ([$enable])
194		224
195	If C<$enable> is true (or missing), then the C<encode> method will add an extra	225	If C<$enable> is true (or missing), then the C<encode> method will add an extra
196	optional space before the C<:> separating keys from values in JSON objects.	226	optional space before the C<:> separating keys from values in JSON objects.
197		227
198	If C<$enable> is false, then the C<encode> method will not add any extra	228	If C<$enable> is false, then the C<encode> method will not add any extra
199	space at those places.	229	space at those places.
200		230
201	This setting has no effect when decoding JSON strings. You will also most	231	This setting has no effect when decoding JSON texts. You will also
202	likely combine this setting with C<space_after>.	232	most likely combine this setting with C<space_after>.
203		233
204	Example, space_before enabled, space_after and indent disabled:	234	Example, space_before enabled, space_after and indent disabled:
205		235
206	{"key" :"value"}	236	{"key" :"value"}
207		237
…		…
213	members.	243	members.
214		244
215	If C<$enable> is false, then the C<encode> method will not add any extra	245	If C<$enable> is false, then the C<encode> method will not add any extra
216	space at those places.	246	space at those places.
217		247
218	This setting has no effect when decoding JSON strings.	248	This setting has no effect when decoding JSON texts.
219		249
220	Example, space_before and indent disabled, space_after enabled:	250	Example, space_before and indent disabled, space_after enabled:
221		251
222	{"key": "value"}	252	{"key": "value"}
223		253
…		…
229	If C<$enable> is false, then the C<encode> method will output key-value	259	If C<$enable> is false, then the C<encode> method will output key-value
230	pairs in the order Perl stores them (which will likely change between runs	260	pairs in the order Perl stores them (which will likely change between runs
231	of the same script).	261	of the same script).
232		262
233	This option is useful if you want the same data structure to be encoded as	263	This option is useful if you want the same data structure to be encoded as
234	the same JSON string (given the same overall settings). If it is disabled,	264	the same JSON text (given the same overall settings). If it is disabled,
235	the same hash migh be encoded differently even if contains the same data,	265	the same hash migh be encoded differently even if contains the same data,
236	as key-value pairs have no inherent ordering in Perl.	266	as key-value pairs have no inherent ordering in Perl.
237		267
238	This setting has no effect when decoding JSON strings.	268	This setting has no effect when decoding JSON texts.
239		269
240	=item $json = $json->allow_nonref ([$enable])	270	=item $json = $json->allow_nonref ([$enable])
241		271
242	If C<$enable> is true (or missing), then the C<encode> method can convert a	272	If C<$enable> is true (or missing), then the C<encode> method can convert a
243	non-reference into its corresponding string, number or null JSON value,	273	non-reference into its corresponding string, number or null JSON value,
244	which is an extension to RFC4627. Likewise, C<decode> will accept those JSON	274	which is an extension to RFC4627. Likewise, C<decode> will accept those JSON
245	values instead of croaking.	275	values instead of croaking.
246		276
247	If C<$enable> is false, then the C<encode> method will croak if it isn't	277	If C<$enable> is false, then the C<encode> method will croak if it isn't
248	passed an arrayref or hashref, as JSON strings must either be an object	278	passed an arrayref or hashref, as JSON texts must either be an object
249	or array. Likewise, C<decode> will croak if given something that is not a	279	or array. Likewise, C<decode> will croak if given something that is not a
250	JSON object or array.	280	JSON object or array.
251		281
252	Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>,	282	Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>,
253	resulting in an invalid JSON text:	283	resulting in an invalid JSON text:
…		…
256	=> "Hello, World!"	286	=> "Hello, World!"
257		287
258	=item $json = $json->shrink ([$enable])	288	=item $json = $json->shrink ([$enable])
259		289
260	Perl usually over-allocates memory a bit when allocating space for	290	Perl usually over-allocates memory a bit when allocating space for
261	strings. This flag optionally resizes strings generated by either	291	strings. This flag optionally resizes strings generated by either
262	C<encode> or C<decode> to their minimum size possible. This can save	292	C<encode> or C<decode> to their minimum size possible. This can save
263	memory when your JSON strings are either very very long or you have many	293	memory when your JSON texts are either very very long or you have many
264	short strings. It will also try to downgrade any strings to octet-form	294	short strings. It will also try to downgrade any strings to octet-form
265	if possible: perl stores strings internally either in an encoding called	295	if possible: perl stores strings internally either in an encoding called
266	UTF-X or in octet-form. The latter cannot store everything but uses less	296	UTF-X or in octet-form. The latter cannot store everything but uses less
267	space in general.	297	space in general (and some buggy Perl or C code might even rely on that
		298	internal representation being used).
268		299
		300	The actual definition of what shrink does might change in future versions,
		301	but it will always try to save space at the expense of time.
		302
269	If C<$enable> is true (or missing), the string returned by C<encode> will be shrunk-to-fit,	303	If C<$enable> is true (or missing), the string returned by C<encode> will
270	while all strings generated by C<decode> will also be shrunk-to-fit.	304	be shrunk-to-fit, while all strings generated by C<decode> will also be
		305	shrunk-to-fit.
271		306
272	If C<$enable> is false, then the normal perl allocation algorithms are used.	307	If C<$enable> is false, then the normal perl allocation algorithms are used.
273	If you work with your data, then this is likely to be faster.	308	If you work with your data, then this is likely to be faster.
274		309
275	In the future, this setting might control other things, such as converting	310	In the future, this setting might control other things, such as converting
276	strings that look like integers or floats into integers or floats	311	strings that look like integers or floats into integers or floats
277	internally (there is no difference on the Perl level), saving space.	312	internally (there is no difference on the Perl level), saving space.
278		313
		314	=item $json = $json->max_depth ([$maximum_nesting_depth])
		315
		316	Sets the maximum nesting level (default C<512>) accepted while encoding
		317	or decoding. If the JSON text or Perl data structure has an equal or
		318	higher nesting level then this limit, then the encoder and decoder will
		319	stop and croak at that point.
		320
		321	Nesting level is defined by number of hash- or arrayrefs that the encoder
		322	needs to traverse to reach a given point or the number of C<{> or C<[>
		323	characters without their matching closing parenthesis crossed to reach a
		324	given character in a string.
		325
		326	Setting the maximum depth to one disallows any nesting, so that ensures
		327	that the object is only a single hash/object or array.
		328
		329	The argument to C<max_depth> will be rounded up to the next nearest power
		330	of two.
		331
		332	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
		333
279	=item $json_string = $json->encode ($perl_scalar)	334	=item $json_text = $json->encode ($perl_scalar)
280		335
281	Converts the given Perl data structure (a simple scalar or a reference	336	Converts the given Perl data structure (a simple scalar or a reference
282	to a hash or array) to its JSON representation. Simple scalars will be	337	to a hash or array) to its JSON representation. Simple scalars will be
283	converted into JSON string or number sequences, while references to arrays	338	converted into JSON string or number sequences, while references to arrays
284	become JSON arrays and references to hashes become JSON objects. Undefined	339	become JSON arrays and references to hashes become JSON objects. Undefined
285	Perl values (e.g. C<undef>) become JSON C<null> values. Neither C<true>	340	Perl values (e.g. C<undef>) become JSON C<null> values. Neither C<true>
286	nor C<false> values will be generated.	341	nor C<false> values will be generated.
287		342
288	=item $perl_scalar = $json->decode ($json_string)	343	=item $perl_scalar = $json->decode ($json_text)
289		344
290	The opposite of C<encode>: expects a JSON string and tries to parse it,	345	The opposite of C<encode>: expects a JSON text and tries to parse it,
291	returning the resulting simple scalar or reference. Croaks on error.	346	returning the resulting simple scalar or reference. Croaks on error.
292		347
293	JSON numbers and strings become simple Perl scalars. JSON arrays become	348	JSON numbers and strings become simple Perl scalars. JSON arrays become
294	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes	349	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes
295	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.	350	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.
296		351
297	=back	352	=back
		353
298		354
299	=head1 MAPPING	355	=head1 MAPPING
300		356
301	This section describes how JSON::XS maps Perl values to JSON values and	357	This section describes how JSON::XS maps Perl values to JSON values and
302	vice versa. These mappings are designed to "do the right thing" in most	358	vice versa. These mappings are designed to "do the right thing" in most
…		…
312	=over 4	368	=over 4
313		369
314	=item object	370	=item object
315		371
316	A JSON object becomes a reference to a hash in Perl. No ordering of object	372	A JSON object becomes a reference to a hash in Perl. No ordering of object
317	keys is preserved.	373	keys is preserved (JSON does not preserver object key ordering itself).
318		374
319	=item array	375	=item array
320		376
321	A JSON array becomes a reference to an array in Perl.	377	A JSON array becomes a reference to an array in Perl.
322		378
…		…
356	=over 4	412	=over 4
357		413
358	=item hash references	414	=item hash references
359		415
360	Perl hash references become JSON objects. As there is no inherent ordering	416	Perl hash references become JSON objects. As there is no inherent ordering
361	in hash keys, they will usually be encoded in a pseudo-random order that	417	in hash keys (or JSON objects), they will usually be encoded in a
362	can change between runs of the same program but stays generally the same	418	pseudo-random order that can change between runs of the same program but
363	within the single run of a program. JSON::XS can optionally sort the hash	419	stays generally the same within a single run of a program. JSON::XS can
364	keys (determined by the I<canonical> flag), so the same datastructure	420	optionally sort the hash keys (determined by the I<canonical> flag), so
365	will serialise to the same JSON text (given same settings and version of	421	the same datastructure will serialise to the same JSON text (given same
366	JSON::XS), but this incurs a runtime overhead.	422	settings and version of JSON::XS), but this incurs a runtime overhead
		423	and is only rarely useful, e.g. when you want to compare some JSON text
		424	against another for equality.
367		425
368	=item array references	426	=item array references
369		427
370	Perl array references become JSON arrays.	428	Perl array references become JSON arrays.
		429
		430	=item other references
		431
		432	Other unblessed references are generally not allowed and will cause an
		433	exception to be thrown, except for references to the integers C<0> and
		434	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can
		435	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
		436
		437	to_json [\0,JSON::XS::true] # yields [false,true]
371		438
372	=item blessed objects	439	=item blessed objects
373		440
374	Blessed objects are not allowed. JSON::XS currently tries to encode their	441	Blessed objects are not allowed. JSON::XS currently tries to encode their
375	underlying representation (hash- or arrayref), but this behaviour might	442	underlying representation (hash- or arrayref), but this behaviour might
…		…
408	$x *= 1; # same thing, the choise is yours.	475	$x *= 1; # same thing, the choise is yours.
409		476
410	You can not currently output JSON booleans or force the type in other,	477	You can not currently output JSON booleans or force the type in other,
411	less obscure, ways. Tell me if you need this capability.	478	less obscure, ways. Tell me if you need this capability.
412		479
413	=item circular data structures
414
415	Those will be encoded until memory or stackspace runs out.
416
417	=back	480	=back
		481
418		482
419	=head1 COMPARISON	483	=head1 COMPARISON
420		484
421	As already mentioned, this module was created because none of the existing	485	As already mentioned, this module was created because none of the existing
422	JSON modules could be made to work correctly. First I will describe the	486	JSON modules could be made to work correctly. First I will describe the
…		…
448		512
449	Has problems handling many Perl values (e.g. regex results and other magic	513	Has problems handling many Perl values (e.g. regex results and other magic
450	values will make it croak).	514	values will make it croak).
451		515
452	Does not even generate valid JSON (C<{1,2}> gets converted to C<{1:2}>	516	Does not even generate valid JSON (C<{1,2}> gets converted to C<{1:2}>
453	which is not a valid JSON string.	517	which is not a valid JSON text.
454		518
455	Unmaintained (maintainer unresponsive for many months, bugs are not	519	Unmaintained (maintainer unresponsive for many months, bugs are not
456	getting fixed).	520	getting fixed).
457		521
458	=item JSON::Syck 0.21	522	=item JSON::Syck 0.21
…		…
460	Very buggy (often crashes).	524	Very buggy (often crashes).
461		525
462	Very inflexible (no human-readable format supported, format pretty much	526	Very inflexible (no human-readable format supported, format pretty much
463	undocumented. I need at least a format for easy reading by humans and a	527	undocumented. I need at least a format for easy reading by humans and a
464	single-line compact format for use in a protocol, and preferably a way to	528	single-line compact format for use in a protocol, and preferably a way to
465	generate ASCII-only JSON strings).	529	generate ASCII-only JSON texts).
466		530
467	Completely broken (and confusingly documented) Unicode handling (unicode	531	Completely broken (and confusingly documented) Unicode handling (unicode
468	escapes are not working properly, you need to set ImplicitUnicode to	532	escapes are not working properly, you need to set ImplicitUnicode to
469	I<different> values on en- and decoding to get symmetric behaviour).	533	I<different> values on en- and decoding to get symmetric behaviour).
470		534
…		…
493		557
494	Very inflexible.	558	Very inflexible.
495		559
496	No roundtripping.	560	No roundtripping.
497		561
498	Does not generate valid JSON (key strings are often unquoted, empty keys	562	Does not generate valid JSON texts (key strings are often unquoted, empty keys
499	result in nothing being output)	563	result in nothing being output)
500		564
501	Does not check input for validity.	565	Does not check input for validity.
502		566
503	=back	567	=back
…		…
507	It seems that JSON::XS is surprisingly fast, as shown in the following	571	It seems that JSON::XS is surprisingly fast, as shown in the following
508	tables. They have been generated with the help of the C<eg/bench> program	572	tables. They have been generated with the help of the C<eg/bench> program
509	in the JSON::XS distribution, to make it easy to compare on your own	573	in the JSON::XS distribution, to make it easy to compare on your own
510	system.	574	system.
511		575
512	First is a comparison between various modules using a very simple JSON	576	First comes a comparison between various modules using a very short JSON
		577	string:
		578
		579	{"method": "handleMessage", "params": ["user1", "we were just talking"], "id": null}
		580
513	string, showing the number of encodes/decodes per second (JSON::XS is	581	It shows the number of encodes/decodes per second (JSON::XS uses the
514	the functional interface, while JSON::XS/2 is the OO interface with	582	functional interface, while JSON::XS/2 uses the OO interface with
515	pretty-printing and hashkey sorting enabled).	583	pretty-printing and hashkey sorting enabled). Higher is better:
516		584
517	module \| encode \| decode \|	585	module \| encode \| decode \|
518	-----------\|------------\|------------\|	586	-----------\|------------\|------------\|
519	JSON \| 14006 \| 6820 \|	587	JSON \| 11488.516 \| 7823.035 \|
520	JSON::DWIW \| 200937 \| 120386 \|	588	JSON::DWIW \| 94708.054 \| 129094.260 \|
521	JSON::PC \| 85065 \| 129366 \|	589	JSON::PC \| 63884.157 \| 128528.212 \|
522	JSON::Syck \| 59898 \| 44232 \|	590	JSON::Syck \| 34898.677 \| 42096.911 \|
523	JSON::XS \| 1171478 \| 342435 \|	591	JSON::XS \| 654027.064 \| 396423.669 \|
524	JSON::XS/2 \| 730760 \| 328714 \|	592	JSON::XS/2 \| 371564.190 \| 371725.613 \|
525	-----------+------------+------------+	593	-----------+------------+------------+
526		594
527	That is, JSON::XS is 6 times faster than than JSON::DWIW and about 80	595	That is, JSON::XS is more than six times faster than JSON::DWIW on
		596	encoding, more than three times faster on decoding, and about thirty times
528	times faster than JSON, even with pretty-printing and key sorting.	597	faster than JSON, even with pretty-printing and key sorting.
529		598
530	Using a longer test string (roughly 8KB, generated from Yahoo! Locals	599	Using a longer test string (roughly 18KB, generated from Yahoo! Locals
531	search API (http://nanoref.com/yahooapis/mgPdGg):	600	search API (http://nanoref.com/yahooapis/mgPdGg):
532		601
533	module \| encode \| decode \|	602	module \| encode \| decode \|
534	-----------\|------------\|------------\|	603	-----------\|------------\|------------\|
535	JSON \| 673 \| 38 \|	604	JSON \| 273.023 \| 44.674 \|
536	JSON::DWIW \| 5271 \| 770 \|	605	JSON::DWIW \| 1089.383 \| 1145.704 \|
537	JSON::PC \| 9901 \| 2491 \|	606	JSON::PC \| 3097.419 \| 2393.921 \|
538	JSON::Syck \| 2360 \| 786 \|	607	JSON::Syck \| 514.060 \| 843.053 \|
539	JSON::XS \| 37398 \| 3202 \|	608	JSON::XS \| 6479.668 \| 3636.364 \|
540	JSON::XS/2 \| 13765 \| 3153 \|	609	JSON::XS/2 \| 3774.221 \| 3599.124 \|
541	-----------+------------+------------+	610	-----------+------------+------------+
542		611
543	Again, JSON::XS leads by far in the encoding case, while still beating	612	Again, JSON::XS leads by far.
544	every other module in the decoding case.
545		613
546	=head1 RESOURCE LIMITS	614	On large strings containing lots of high unicode characters, some modules
		615	(such as JSON::PC) seem to decode faster than JSON::XS, but the result
		616	will be broken due to missing (or wrong) unicode handling. Others refuse
		617	to decode or encode properly, so it was impossible to prepare a fair
		618	comparison table for that case.
547		619
548	JSON::XS does not impose any limits on the size of JSON texts or Perl	620
549	values they represent - if your machine can handle it, JSON::XS will	621	=head1 SECURITY CONSIDERATIONS
550	encode or decode it. Future versions might optionally impose structure	622
551	depth and memory use resource limits.	623	When you are using JSON in a protocol, talking to untrusted potentially
		624	hostile creatures requires relatively few measures.
		625
		626	First of all, your JSON decoder should be secure, that is, should not have
		627	any buffer overflows. Obviously, this module should ensure that and I am
		628	trying hard on making that true, but you never know.
		629
		630	Second, you need to avoid resource-starving attacks. That means you should
		631	limit the size of JSON texts you accept, or make sure then when your
		632	resources run out, thats just fine (e.g. by using a separate process that
		633	can crash safely). The size of a JSON text in octets or characters is
		634	usually a good indication of the size of the resources required to decode
		635	it into a Perl structure.
		636
		637	Third, JSON::XS recurses using the C stack when decoding objects and
		638	arrays. The C stack is a limited resource: for instance, on my amd64
		639	machine with 8MB of stack size I can decode around 180k nested arrays but
		640	only 14k nested JSON objects (due to perl itself recursing deeply on croak
		641	to free the temporary). If that is exceeded, the program crashes. to be
		642	conservative, the default nesting limit is set to 512. If your process
		643	has a smaller stack, you should adjust this setting accordingly with the
		644	C<max_depth> method.
		645
		646	And last but least, something else could bomb you that I forgot to think
		647	of. In that case, you get to keep the pieces. I am always open for hints,
		648	though...
		649
552		650
553	=head1 BUGS	651	=head1 BUGS
554		652
555	While the goal of this module is to be correct, that unfortunately does	653	While the goal of this module is to be correct, that unfortunately does
556	not mean its bug-free, only that I think its design is bug-free. It is	654	not mean its bug-free, only that I think its design is bug-free. It is
557	still very young and not well-tested. If you keep reporting bugs they will	655	still relatively early in its development. If you keep reporting bugs they
558	be fixed swiftly, though.	656	will be fixed swiftly, though.
559		657
560	=cut	658	=cut
		659
		660	sub true() { \1 }
		661	sub false() { \0 }
561		662
562	1;	663	1;
563		664
564	=head1 AUTHOR	665	=head1 AUTHOR
565		666

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing JSON-XS/XS.pm (file contents): Revision 1.12 by root, Fri Mar 23 18:33:50 2007 UTC vs. Revision 1.32 by root, Thu Apr 12 07:25:29 2007 UTC

Diff Legend

Comparing JSON-XS/XS.pm (file contents):
Revision 1.12 by root, Fri Mar 23 18:33:50 2007 UTC vs.
Revision 1.32 by root, Thu Apr 12 07:25:29 2007 UTC