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

Comparing JSON-XS/XS.pm (file contents):
Revision 1.115 by root, Tue Feb 17 23:29:38 2009 UTC vs.
Revision 1.150 by root, Tue Oct 29 00:48:07 2013 UTC

…		…
64	so, and even documents what "correct" means.	64	so, and even documents what "correct" means.
65		65
66	=item * round-trip integrity	66	=item * round-trip integrity
67		67
68	When you serialise a perl data structure using only data types supported	68	When you serialise a perl data structure using only data types supported
69	by JSON, the deserialised data structure is identical on the Perl level.	69	by JSON and Perl, the deserialised data structure is identical on the Perl
70	(e.g. the string "2.0" doesn't suddenly become "2" just because it looks	70	level. (e.g. the string "2.0" doesn't suddenly become "2" just because
71	like a number). There minor I<are> exceptions to this, read the MAPPING	71	it looks like a number). There I<are> minor exceptions to this, read the
72	section below to learn about those.	72	MAPPING section below to learn about those.
73		73
74	=item * strict checking of JSON correctness	74	=item * strict checking of JSON correctness
75		75
76	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,
77	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
…		…
83	this module usually compares favourably in terms of speed, too.	83	this module usually compares favourably in terms of speed, too.
84		84
85	=item * simple to use	85	=item * simple to use
86		86
87	This module has both a simple functional interface as well as an object	87	This module has both a simple functional interface as well as an object
88	oriented interface interface.	88	oriented interface.
89		89
90	=item * reasonably versatile output formats	90	=item * reasonably versatile output formats
91		91
92	You can choose between the most compact guaranteed-single-line format	92	You can choose between the most compact guaranteed-single-line format
93	possible (nice for simple line-based protocols), a pure-ASCII format	93	possible (nice for simple line-based protocols), a pure-ASCII format
…		…
99		99
100	=cut	100	=cut
101		101
102	package JSON::XS;	102	package JSON::XS;
103		103
104	no warnings;	104	use common::sense;
105	use strict;
106		105
107	our $VERSION = '2.232';	106	our $VERSION = '3.0';
108	our @ISA = qw(Exporter);	107	our @ISA = qw(Exporter);
109		108
110	our @EXPORT = qw(encode_json decode_json to_json from_json);	109	our @EXPORT = qw(encode_json decode_json);
111
112	sub to_json($) {
113	require Carp;
114	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");
115	}
116
117	sub from_json($) {
118	require Carp;
119	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");
120	}
121		110
122	use Exporter;	111	use Exporter;
123	use XSLoader;	112	use XSLoader;
		113
		114	use Types::Serialiser ();
124		115
125	=head1 FUNCTIONAL INTERFACE	116	=head1 FUNCTIONAL INTERFACE
126		117
127	The following convenience methods are provided by this module. They are	118	The following convenience methods are provided by this module. They are
128	exported by default:	119	exported by default:
…		…
149	This function call is functionally identical to:	140	This function call is functionally identical to:
150		141
151	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)	142	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)
152		143
153	Except being faster.	144	Except being faster.
154
155	=item $is_boolean = JSON::XS::is_bool $scalar
156
157	Returns true if the passed scalar represents either JSON::XS::true or
158	JSON::XS::false, two constants that act like C<1> and C<0>, respectively
159	and are used to represent JSON C<true> and C<false> values in Perl.
160
161	See MAPPING, below, for more information on how JSON values are mapped to
162	Perl.
163		145
164	=back	146	=back
165		147
166		148
167	=head1 A FEW NOTES ON UNICODE AND PERL	149	=head1 A FEW NOTES ON UNICODE AND PERL
…		…
433	If C<$enable> is true (or missing), then the C<encode> method will output JSON objects	415	If C<$enable> is true (or missing), then the C<encode> method will output JSON objects
434	by sorting their keys. This is adding a comparatively high overhead.	416	by sorting their keys. This is adding a comparatively high overhead.
435		417
436	If C<$enable> is false, then the C<encode> method will output key-value	418	If C<$enable> is false, then the C<encode> method will output key-value
437	pairs in the order Perl stores them (which will likely change between runs	419	pairs in the order Perl stores them (which will likely change between runs
438	of the same script).	420	of the same script, and can change even within the same run from 5.18
		421	onwards).
439		422
440	This option is useful if you want the same data structure to be encoded as	423	This option is useful if you want the same data structure to be encoded as
441	the same JSON text (given the same overall settings). If it is disabled,	424	the same JSON text (given the same overall settings). If it is disabled,
442	the same hash might be encoded differently even if contains the same data,	425	the same hash might be encoded differently even if contains the same data,
443	as key-value pairs have no inherent ordering in Perl.	426	as key-value pairs have no inherent ordering in Perl.
444		427
445	This setting has no effect when decoding JSON texts.	428	This setting has no effect when decoding JSON texts.
		429
		430	This setting has currently no effect on tied hashes.
446		431
447	=item $json = $json->allow_nonref ([$enable])	432	=item $json = $json->allow_nonref ([$enable])
448		433
449	=item $enabled = $json->get_allow_nonref	434	=item $enabled = $json->get_allow_nonref
450		435
…		…
482		467
483	=item $json = $json->allow_blessed ([$enable])	468	=item $json = $json->allow_blessed ([$enable])
484		469
485	=item $enabled = $json->get_allow_blessed	470	=item $enabled = $json->get_allow_blessed
486		471
		472	See L<OBJECT SERIALISATION> for details.
		473
487	If C<$enable> is true (or missing), then the C<encode> method will not	474	If C<$enable> is true (or missing), then the C<encode> method will not
488	barf when it encounters a blessed reference. Instead, the value of the	475	barf when it encounters a blessed reference that it cannot convert
489	B<convert_blessed> option will decide whether C<null> (C<convert_blessed>	476	otherwise. Instead, a JSON C<null> value is encoded instead of the object.
490	disabled or no C<TO_JSON> method found) or a representation of the
491	object (C<convert_blessed> enabled and C<TO_JSON> method found) is being
492	encoded. Has no effect on C<decode>.
493		477
494	If C<$enable> is false (the default), then C<encode> will throw an	478	If C<$enable> is false (the default), then C<encode> will throw an
495	exception when it encounters a blessed object.	479	exception when it encounters a blessed object that it cannot convert
		480	otherwise.
		481
		482	This setting has no effect on C<decode>.
496		483
497	=item $json = $json->convert_blessed ([$enable])	484	=item $json = $json->convert_blessed ([$enable])
498		485
499	=item $enabled = $json->get_convert_blessed	486	=item $enabled = $json->get_convert_blessed
		487
		488	See L<OBJECT SERIALISATION> for details.
500		489
501	If C<$enable> is true (or missing), then C<encode>, upon encountering a	490	If C<$enable> is true (or missing), then C<encode>, upon encountering a
502	blessed object, will check for the availability of the C<TO_JSON> method	491	blessed object, will check for the availability of the C<TO_JSON> method
503	on the object's class. If found, it will be called in scalar context	492	on the object's class. If found, it will be called in scalar context and
504	and the resulting scalar will be encoded instead of the object. If no	493	the resulting scalar will be encoded instead of the object.
505	C<TO_JSON> method is found, the value of C<allow_blessed> will decide what
506	to do.
507		494
508	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>	495	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
509	returns other blessed objects, those will be handled in the same	496	returns other blessed objects, those will be handled in the same
510	way. C<TO_JSON> must take care of not causing an endless recursion cycle	497	way. C<TO_JSON> must take care of not causing an endless recursion cycle
511	(== crash) in this case. The name of C<TO_JSON> was chosen because other	498	(== crash) in this case. The name of C<TO_JSON> was chosen because other
512	methods called by the Perl core (== not by the user of the object) are	499	methods called by the Perl core (== not by the user of the object) are
513	usually in upper case letters and to avoid collisions with any C<to_json>	500	usually in upper case letters and to avoid collisions with any C<to_json>
514	function or method.	501	function or method.
515		502
516	This setting does not yet influence C<decode> in any way, but in the	503	If C<$enable> is false (the default), then C<encode> will not consider
517	future, global hooks might get installed that influence C<decode> and are	504	this type of conversion.
518	enabled by this setting.
519		505
520	If C<$enable> is false, then the C<allow_blessed> setting will decide what	506	This setting has no effect on C<decode>.
521	to do when a blessed object is found.	507
		508	=item $json = $json->allow_tags ([$enable])
		509
		510	=item $enabled = $json->allow_tags
		511
		512	See L<OBJECT SERIALISATION> for details.
		513
		514	If C<$enable> is true (or missing), then C<encode>, upon encountering a
		515	blessed object, will check for the availability of the C<FREEZE> method on
		516	the object's class. If found, it will be used to serialise the object into
		517	a nonstandard tagged JSON value (that JSON decoders cannot decode).
		518
		519	It also causes C<decode> to parse such tagged JSON values and deserialise
		520	them via a call to the C<THAW> method.
		521
		522	If C<$enable> is false (the default), then C<encode> will not consider
		523	this type of conversion, and tagged JSON values will cause a parse error
		524	in C<decode>, as if tags were not part of the grammar.
522		525
523	=item $json = $json->filter_json_object ([$coderef->($hashref)])	526	=item $json = $json->filter_json_object ([$coderef->($hashref)])
524		527
525	When C<$coderef> is specified, it will be called from C<decode> each	528	When C<$coderef> is specified, it will be called from C<decode> each
526	time it decodes a JSON object. The only argument is a reference to the	529	time it decodes a JSON object. The only argument is a reference to the
…		…
665		668
666	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.	669	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
667		670
668	=item $json_text = $json->encode ($perl_scalar)	671	=item $json_text = $json->encode ($perl_scalar)
669		672
670	Converts the given Perl data structure (a simple scalar or a reference	673	Converts the given Perl value or data structure to its JSON
671	to a hash or array) to its JSON representation. Simple scalars will be	674	representation. Croaks on error.
672	converted into JSON string or number sequences, while references to arrays
673	become JSON arrays and references to hashes become JSON objects. Undefined
674	Perl values (e.g. C<undef>) become JSON C<null> values. Neither C<true>
675	nor C<false> values will be generated.
676		675
677	=item $perl_scalar = $json->decode ($json_text)	676	=item $perl_scalar = $json->decode ($json_text)
678		677
679	The opposite of C<encode>: expects a JSON text and tries to parse it,	678	The opposite of C<encode>: expects a JSON text and tries to parse it,
680	returning the resulting simple scalar or reference. Croaks on error.	679	returning the resulting simple scalar or reference. Croaks on error.
681
682	JSON numbers and strings become simple Perl scalars. JSON arrays become
683	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes
684	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.
685		680
686	=item ($perl_scalar, $characters) = $json->decode_prefix ($json_text)	681	=item ($perl_scalar, $characters) = $json->decode_prefix ($json_text)
687		682
688	This works like the C<decode> method, but instead of raising an exception	683	This works like the C<decode> method, but instead of raising an exception
689	when there is trailing garbage after the first JSON object, it will	684	when there is trailing garbage after the first JSON object, it will
690	silently stop parsing there and return the number of characters consumed	685	silently stop parsing there and return the number of characters consumed
691	so far.	686	so far.
692		687
693	This is useful if your JSON texts are not delimited by an outer protocol	688	This is useful if your JSON texts are not delimited by an outer protocol
694	(which is not the brightest thing to do in the first place) and you need
695	to know where the JSON text ends.	689	and you need to know where the JSON text ends.
696		690
697	JSON::XS->new->decode_prefix ("[1] the tail")	691	JSON::XS->new->decode_prefix ("[1] the tail")
698	=> ([], 3)	692	=> ([], 3)
699		693
700	=back	694	=back
…		…
712	calls).	706	calls).
713		707
714	JSON::XS will only attempt to parse the JSON text once it is sure it	708	JSON::XS will only attempt to parse the JSON text once it is sure it
715	has enough text to get a decisive result, using a very simple but	709	has enough text to get a decisive result, using a very simple but
716	truly incremental parser. This means that it sometimes won't stop as	710	truly incremental parser. This means that it sometimes won't stop as
717	early as the full parser, for example, it doesn't detect parenthese	711	early as the full parser, for example, it doesn't detect mismatched
718	mismatches. The only thing it guarantees is that it starts decoding as	712	parentheses. The only thing it guarantees is that it starts decoding as
719	soon as a syntactically valid JSON text has been seen. This means you need	713	soon as a syntactically valid JSON text has been seen. This means you need
720	to set resource limits (e.g. C<max_size>) to ensure the parser will stop	714	to set resource limits (e.g. C<max_size>) to ensure the parser will stop
721	parsing in the presence if syntax errors.	715	parsing in the presence if syntax errors.
722		716
723	The following methods implement this incremental parser.	717	The following methods implement this incremental parser.
…		…
739		733
740	If the method is called in scalar context, then it will try to extract	734	If the method is called in scalar context, then it will try to extract
741	exactly I<one> JSON object. If that is successful, it will return this	735	exactly I<one> JSON object. If that is successful, it will return this
742	object, otherwise it will return C<undef>. If there is a parse error,	736	object, otherwise it will return C<undef>. If there is a parse error,
743	this method will croak just as C<decode> would do (one can then use	737	this method will croak just as C<decode> would do (one can then use
744	C<incr_skip> to skip the errornous part). This is the most common way of	738	C<incr_skip> to skip the erroneous part). This is the most common way of
745	using the method.	739	using the method.
746		740
747	And finally, in list context, it will try to extract as many objects	741	And finally, in list context, it will try to extract as many objects
748	from the stream as it can find and return them, or the empty list	742	from the stream as it can find and return them, or the empty list
749	otherwise. For this to work, there must be no separators between the JSON	743	otherwise. For this to work, there must be no separators between the JSON
750	objects or arrays, instead they must be concatenated back-to-back. If	744	objects or arrays, instead they must be concatenated back-to-back. If
751	an error occurs, an exception will be raised as in the scalar context	745	an error occurs, an exception will be raised as in the scalar context
752	case. Note that in this case, any previously-parsed JSON texts will be	746	case. Note that in this case, any previously-parsed JSON texts will be
753	lost.	747	lost.
754		748
		749	Example: Parse some JSON arrays/objects in a given string and return
		750	them.
		751
		752	my @objs = JSON::XS->new->incr_parse ("[5][7][1,2]");
		753
755	=item $lvalue_string = $json->incr_text	754	=item $lvalue_string = $json->incr_text
756		755
757	This method returns the currently stored JSON fragment as an lvalue, that	756	This method returns the currently stored JSON fragment as an lvalue, that
758	is, you can manipulate it. This I<only> works when a preceding call to	757	is, you can manipulate it. This I<only> works when a preceding call to
759	C<incr_parse> in I<scalar context> successfully returned an object. Under	758	C<incr_parse> in I<scalar context> successfully returned an object. Under
…		…
773	C<incr_parse> died, in which case the input buffer and incremental parser	772	C<incr_parse> died, in which case the input buffer and incremental parser
774	state is left unchanged, to skip the text parsed so far and to reset the	773	state is left unchanged, to skip the text parsed so far and to reset the
775	parse state.	774	parse state.
776		775
777	The difference to C<incr_reset> is that only text until the parse error	776	The difference to C<incr_reset> is that only text until the parse error
778	occured is removed.	777	occurred is removed.
779		778
780	=item $json->incr_reset	779	=item $json->incr_reset
781		780
782	This completely resets the incremental parser, that is, after this call,	781	This completely resets the incremental parser, that is, after this call,
783	it will be as if the parser had never parsed anything.	782	it will be as if the parser had never parsed anything.
…		…
789	=back	788	=back
790		789
791	=head2 LIMITATIONS	790	=head2 LIMITATIONS
792		791
793	All options that affect decoding are supported, except	792	All options that affect decoding are supported, except
794	C<allow_nonref>. The reason for this is that it cannot be made to	793	C<allow_nonref>. The reason for this is that it cannot be made to work
795	work sensibly: JSON objects and arrays are self-delimited, i.e. you can concatenate	794	sensibly: JSON objects and arrays are self-delimited, i.e. you can
796	them back to back and still decode them perfectly. This does not hold true	795	concatenate them back to back and still decode them perfectly. This does
797	for JSON numbers, however.	796	not hold true for JSON numbers, however.
798		797
799	For example, is the string C<1> a single JSON number, or is it simply the	798	For example, is the string C<1> a single JSON number, or is it simply the
800	start of C<12>? Or is C<12> a single JSON number, or the concatenation	799	start of C<12>? Or is C<12> a single JSON number, or the concatenation
801	of C<1> and C<2>? In neither case you can tell, and this is why JSON::XS	800	of C<1> and C<2>? In neither case you can tell, and this is why JSON::XS
802	takes the conservative route and disallows this case.	801	takes the conservative route and disallows this case.
…		…
981	If the number consists of digits only, JSON::XS will try to represent	980	If the number consists of digits only, JSON::XS will try to represent
982	it as an integer value. If that fails, it will try to represent it as	981	it as an integer value. If that fails, it will try to represent it as
983	a numeric (floating point) value if that is possible without loss of	982	a numeric (floating point) value if that is possible without loss of
984	precision. Otherwise it will preserve the number as a string value (in	983	precision. Otherwise it will preserve the number as a string value (in
985	which case you lose roundtripping ability, as the JSON number will be	984	which case you lose roundtripping ability, as the JSON number will be
986	re-encoded toa JSON string).	985	re-encoded to a JSON string).
987		986
988	Numbers containing a fractional or exponential part will always be	987	Numbers containing a fractional or exponential part will always be
989	represented as numeric (floating point) values, possibly at a loss of	988	represented as numeric (floating point) values, possibly at a loss of
990	precision (in which case you might lose perfect roundtripping ability, but	989	precision (in which case you might lose perfect roundtripping ability, but
991	the JSON number will still be re-encoded as a JSON number).	990	the JSON number will still be re-encoded as a JSON number).
992		991
		992	Note that precision is not accuracy - binary floating point values cannot
		993	represent most decimal fractions exactly, and when converting from and to
		994	floating point, JSON::XS only guarantees precision up to but not including
		995	the least significant bit.
		996
993	=item true, false	997	=item true, false
994		998
995	These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,	999	These JSON atoms become C<Types::Serialiser::true> and
996	respectively. They are overloaded to act almost exactly like the numbers	1000	C<Types::Serialiser::false>, respectively. They are overloaded to act
997	C<1> and C<0>. You can check whether a scalar is a JSON boolean by using	1001	almost exactly like the numbers C<1> and C<0>. You can check whether
998	the C<JSON::XS::is_bool> function.	1002	a scalar is a JSON boolean by using the C<Types::Serialiser::is_bool>
		1003	function (after C<use Types::Serialier>, of course).
999		1004
1000	=item null	1005	=item null
1001		1006
1002	A JSON null atom becomes C<undef> in Perl.	1007	A JSON null atom becomes C<undef> in Perl.
		1008
		1009	=item shell-style comments (C<< # I<text> >>)
		1010
		1011	As a nonstandard extension to the JSON syntax that is enabled by the
		1012	C<relaxed> setting, shell-style comments are allowed. They can start
		1013	anywhere outside strings and go till the end of the line.
		1014
		1015	=item tagged values (C<< (I<tag>)I<value> >>).
		1016
		1017	Another nonstandard extension to the JSON syntax, enabled with the
		1018	C<allow_tags> setting, are tagged values. In this implementation, the
		1019	I<tag> must be a perl package/class name encoded as a JSON string, and the
		1020	I<value> must be a JSON array encoding optional constructor arguments.
		1021
		1022	See L<OBJECT SERIALISATION>, below, for details.
1003		1023
1004	=back	1024	=back
1005		1025
1006		1026
1007	=head2 PERL -> JSON	1027	=head2 PERL -> JSON
…		…
1012		1032
1013	=over 4	1033	=over 4
1014		1034
1015	=item hash references	1035	=item hash references
1016		1036
1017	Perl hash references become JSON objects. As there is no inherent ordering	1037	Perl hash references become JSON objects. As there is no inherent
1018	in hash keys (or JSON objects), they will usually be encoded in a	1038	ordering in hash keys (or JSON objects), they will usually be encoded
1019	pseudo-random order that can change between runs of the same program but	1039	in a pseudo-random order. JSON::XS can optionally sort the hash keys
1020	stays generally the same within a single run of a program. JSON::XS can	1040	(determined by the I<canonical> flag), so the same datastructure will
1021	optionally sort the hash keys (determined by the I<canonical> flag), so	1041	serialise to the same JSON text (given same settings and version of
1022	the same datastructure will serialise to the same JSON text (given same	1042	JSON::XS), but this incurs a runtime overhead and is only rarely useful,
1023	settings and version of JSON::XS), but this incurs a runtime overhead	1043	e.g. when you want to compare some JSON text against another for equality.
1024	and is only rarely useful, e.g. when you want to compare some JSON text
1025	against another for equality.
1026		1044
1027	=item array references	1045	=item array references
1028		1046
1029	Perl array references become JSON arrays.	1047	Perl array references become JSON arrays.
1030		1048
1031	=item other references	1049	=item other references
1032		1050
1033	Other unblessed references are generally not allowed and will cause an	1051	Other unblessed references are generally not allowed and will cause an
1034	exception to be thrown, except for references to the integers C<0> and	1052	exception to be thrown, except for references to the integers C<0> and
1035	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can	1053	C<1>, which get turned into C<false> and C<true> atoms in JSON.
1036	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
1037		1054
		1055	Since C<JSON::XS> uses the boolean model from L<Types::Serialiser>, you
		1056	can also C<use Types::Serialiser> and then use C<Types::Serialiser::false>
		1057	and C<Types::Serialiser::true> to improve readability.
		1058
		1059	use Types::Serialiser;
1038	encode_json [\0, JSON::XS::true] # yields [false,true]	1060	encode_json [\0, Types::Serialiser::true] # yields [false,true]
1039		1061
1040	=item JSON::XS::true, JSON::XS::false	1062	=item Types::Serialiser::true, Types::Serialiser::false
1041		1063
1042	These special values become JSON true and JSON false values,	1064	These special values from the L<Types::Serialiser> module become JSON true
1043	respectively. You can also use C<\1> and C<\0> directly if you want.	1065	and JSON false values, respectively. You can also use C<\1> and C<\0>
		1066	directly if you want.
1044		1067
1045	=item blessed objects	1068	=item blessed objects
1046		1069
1047	Blessed objects are not directly representable in JSON. See the	1070	Blessed objects are not directly representable in JSON, but C<JSON::XS>
1048	C<allow_blessed> and C<convert_blessed> methods on various options on	1071	allows various ways of handling objects. See L<OBJECT SERIALISATION>,
1049	how to deal with this: basically, you can choose between throwing an	1072	below, for details.
1050	exception, encoding the reference as if it weren't blessed, or provide
1051	your own serialiser method.
1052		1073
1053	=item simple scalars	1074	=item simple scalars
1054		1075
1055	Simple Perl scalars (any scalar that is not a reference) are the most	1076	Simple Perl scalars (any scalar that is not a reference) are the most
1056	difficult objects to encode: JSON::XS will encode undefined scalars as	1077	difficult objects to encode: JSON::XS will encode undefined scalars as
…		…
1084		1105
1085	You can not currently force the type in other, less obscure, ways. Tell me	1106	You can not currently force the type in other, less obscure, ways. Tell me
1086	if you need this capability (but don't forget to explain why it's needed	1107	if you need this capability (but don't forget to explain why it's needed
1087	:).	1108	:).
1088		1109
		1110	Note that numerical precision has the same meaning as under Perl (so
		1111	binary to decimal conversion follows the same rules as in Perl, which
		1112	can differ to other languages). Also, your perl interpreter might expose
		1113	extensions to the floating point numbers of your platform, such as
		1114	infinities or NaN's - these cannot be represented in JSON, and it is an
		1115	error to pass those in.
		1116
1089	=back	1117	=back
		1118
		1119	=head2 OBJECT SERIALISATION
		1120
		1121	As JSON cannot directly represent Perl objects, you have to choose between
		1122	a pure JSON representation (without the ability to deserialise the object
		1123	automatically again), and a nonstandard extension to the JSON syntax,
		1124	tagged values.
		1125
		1126	=head3 SERIALISATION
		1127
		1128	What happens when C<JSON::XS> encounters a Perl object depends on the
		1129	C<allow_blessed>, C<convert_blessed> and C<allow_tags> settings, which are
		1130	used in this order:
		1131
		1132	=over 4
		1133
		1134	=item 1. C<allow_tags> is enabled and the object has a C<FREEZE> method.
		1135
		1136	In this case, C<JSON::XS> uses the L<Types::Serialiser> object
		1137	serialisation protocol to create a tagged JSON value, using a nonstandard
		1138	extension to the JSON syntax.
		1139
		1140	This works by invoking the C<FREEZE> method on the object, with the first
		1141	argument being the object to serialise, and the second argument being the
		1142	constant string C<JSON> to distinguish it from other serialisers.
		1143
		1144	The C<FREEZE> method can return any number of values (i.e. zero or
		1145	more). These values and the paclkage/classname of the object will then be
		1146	encoded as a tagged JSON value in the following format:
		1147
		1148	("classname")[FREEZE return values...]
		1149
		1150	e.g.:
		1151
		1152	("URI")["http://www.google.com/"]
		1153	("MyDate")[2013,10,29]
		1154	("ImageData::JPEG")["Z3...VlCg=="]
		1155
		1156	For example, the hypothetical C<My::Object> C<FREEZE> method might use the
		1157	objects C<type> and C<id> members to encode the object:
		1158
		1159	sub My::Object::FREEZE {
		1160	my ($self, $serialiser) = @_;
		1161
		1162	($self->{type}, $self->{id})
		1163	}
		1164
		1165	=item 2. C<convert_blessed> is enabled and the object has a C<TO_JSON> method.
		1166
		1167	In this case, the C<TO_JSON> method of the object is invoked in scalar
		1168	context. It must return a single scalar that can be directly encoded into
		1169	JSON. This scalar replaces the object in the JSON text.
		1170
		1171	For example, the following C<TO_JSON> method will convert all L<URI>
		1172	objects to JSON strings when serialised. The fatc that these values
		1173	originally were L<URI> objects is lost.
		1174
		1175	sub URI::TO_JSON {
		1176	my ($uri) = @_;
		1177	$uri->as_string
		1178	}
		1179
		1180	=item 3. C<allow_blessed> is enabled.
		1181
		1182	The object will be serialised as a JSON null value.
		1183
		1184	=item 4. none of the above
		1185
		1186	If none of the settings are enabled or the respective methods are missing,
		1187	C<JSON::XS> throws an exception.
		1188
		1189	=back
		1190
		1191	=head3 DESERIALISATION
		1192
		1193	For deserialisation there are only two cases to consider: either
		1194	nonstandard tagging was used, in which case C<allow_tags> decides,
		1195	or objects cannot be automatically be deserialised, in which
		1196	case you can use postprocessing or the C<filter_json_object> or
		1197	C<filter_json_single_key_object> callbacks to get some real objects our of
		1198	your JSON.
		1199
		1200	This section only considers the tagged value case: I a tagged JSON object
		1201	is encountered during decoding and C<allow_tags> is disabled, a parse
		1202	error will result (as if tagged values were not part of the grammar).
		1203
		1204	If C<allow_tags> is enabled, C<JSON::XS> will look up the C<THAW> method
		1205	of the package/classname used during serialisation (it will not attempt
		1206	to load the package as a Perl module). If there is no such method, the
		1207	decoding will fail with an error.
		1208
		1209	Otherwise, the C<THAW> method is invoked with the classname as first
		1210	argument, the constant string C<JSON> as second argument, and all the
		1211	values from the JSON array (the values originally returned by the
		1212	C<FREEZE> method) as remaining arguments.
		1213
		1214	The method must then return the object. While technically you can return
		1215	any Perl scalar, you might have to enable the C<enable_nonref> setting to
		1216	make that work in all cases, so better return an actual blessed reference.
		1217
		1218	As an example, let's implement a C<THAW> function that regenerates the
		1219	C<My::Object> from the C<FREEZE> example earlier:
		1220
		1221	sub My::Object::THAW {
		1222	my ($class, $serialiser, $type, $id) = @_;
		1223
		1224	$class->new (type => $type, id => $id)
		1225	}
1090		1226
1091		1227
1092	=head1 ENCODING/CODESET FLAG NOTES	1228	=head1 ENCODING/CODESET FLAG NOTES
1093		1229
1094	The interested reader might have seen a number of flags that signify	1230	The interested reader might have seen a number of flags that signify
…		…
1119	=item C<utf8> flag disabled	1255	=item C<utf8> flag disabled
1120		1256
1121	When C<utf8> is disabled (the default), then C<encode>/C<decode> generate	1257	When C<utf8> is disabled (the default), then C<encode>/C<decode> generate
1122	and expect Unicode strings, that is, characters with high ordinal Unicode	1258	and expect Unicode strings, that is, characters with high ordinal Unicode
1123	values (> 255) will be encoded as such characters, and likewise such	1259	values (> 255) will be encoded as such characters, and likewise such
1124	characters are decoded as-is, no canges to them will be done, except	1260	characters are decoded as-is, no changes to them will be done, except
1125	"(re-)interpreting" them as Unicode codepoints or Unicode characters,	1261	"(re-)interpreting" them as Unicode codepoints or Unicode characters,
1126	respectively (to Perl, these are the same thing in strings unless you do	1262	respectively (to Perl, these are the same thing in strings unless you do
1127	funny/weird/dumb stuff).	1263	funny/weird/dumb stuff).
1128		1264
1129	This is useful when you want to do the encoding yourself (e.g. when you	1265	This is useful when you want to do the encoding yourself (e.g. when you
…		…
1209	use JSON::XS;	1345	use JSON::XS;
1210		1346
1211	print encode_json [chr 0x2028];	1347	print encode_json [chr 0x2028];
1212		1348
1213	The right fix for this is to use a proper JSON parser in your javascript	1349	The right fix for this is to use a proper JSON parser in your javascript
1214	programs, and not rely on C<eval>.	1350	programs, and not rely on C<eval> (see for example Douglas Crockford's
		1351	F<json2.js> parser).
1215		1352
1216	If this is not an option, you can, as a stop-gap measure, simply encode to	1353	If this is not an option, you can, as a stop-gap measure, simply encode to
1217	ASCII-only JSON:	1354	ASCII-only JSON:
1218		1355
1219	use JSON::XS;	1356	use JSON::XS;
1220		1357
1221	print JSON::XS->new->ascii->encode ([chr 0x2028]);	1358	print JSON::XS->new->ascii->encode ([chr 0x2028]);
1222		1359
1223	And if you are concerned about the size of the resulting JSON text, you	1360	Note that this will enlarge the resulting JSON text quite a bit if you
1224	can run some regexes to only escape U+2028 and U+2029:	1361	have many non-ASCII characters. You might be tempted to run some regexes
		1362	to only escape U+2028 and U+2029, e.g.:
1225		1363
1226	use JSON::XS;	1364	# DO NOT USE THIS!
1227
1228	my $json = JSON::XS->new->utf8->encode ([chr 0x2028]);	1365	my $json = JSON::XS->new->utf8->encode ([chr 0x2028]);
1229	$json =~ s/\xe2\x80\xa8/\\u2028/g; # escape U+2028	1366	$json =~ s/\xe2\x80\xa8/\\u2028/g; # escape U+2028
1230	$json =~ s/\xe2\x80\xa9/\\u2029/g; # escape U+2029	1367	$json =~ s/\xe2\x80\xa9/\\u2029/g; # escape U+2029
1231	print $json;	1368	print $json;
1232		1369
1233	This works because U+2028/U+2029 are not allowed outside of strings and	1370	Note that I<this is a bad idea>: the above only works for U+2028 and
1234	are not used for syntax, so replacing them unconditionally just works.	1371	U+2029 and thus only for fully ECMAscript-compliant parsers. Many existing
1235		1372	javascript implementations, however, have issues with other characters as
1236	Note, however, that fixing the broken JSON parser is better than working	1373	well - using C<eval> naively simply I<will> cause problems.
1237	around it in every other generator. The above regexes should work well in
1238	other languages, as long as they operate on UTF-8. It is equally valid to
1239	replace all occurences of U+2028/2029 directly by their \\u-escaped forms
1240	in unicode texts, so they can simply be used to fix any parsers relying on
1241	C<eval> by first applying the regexes on the encoded texts.
1242		1374
1243	Another problem is that some javascript implementations reserve	1375	Another problem is that some javascript implementations reserve
1244	some property names for their own purposes (which probably makes	1376	some property names for their own purposes (which probably makes
1245	them non-ECMAscript-compliant). For example, Iceweasel reserves the	1377	them non-ECMAscript-compliant). For example, Iceweasel reserves the
1246	C<__proto__> property name for it's own purposes.	1378	C<__proto__> property name for its own purposes.
1247		1379
1248	If that is a problem, you could parse try to filter the resulting JSON	1380	If that is a problem, you could parse try to filter the resulting JSON
1249	output for these property strings, e.g.:	1381	output for these property strings, e.g.:
1250		1382
1251	$json =~ s/"__proto__"\s*:/"__proto__renamed":/g;	1383	$json =~ s/"__proto__"\s*:/"__proto__renamed":/g;
1252		1384
1253	This works because C<__proto__> is not valid outside of strings, so every	1385	This works because C<__proto__> is not valid outside of strings, so every
1254	occurence of C<"__proto__"\s*:> must be a string used as property name.	1386	occurrence of C<"__proto__"\s*:> must be a string used as property name.
1255		1387
1256	If you know of other incompatibilities, please let me know.	1388	If you know of other incompatibilities, please let me know.
1257		1389
1258		1390
1259	=head2 JSON and YAML	1391	=head2 JSON and YAML
…		…
1271	my $yaml = $to_yaml->encode ($ref) . "\n";	1403	my $yaml = $to_yaml->encode ($ref) . "\n";
1272		1404
1273	This will I<usually> generate JSON texts that also parse as valid	1405	This will I<usually> generate JSON texts that also parse as valid
1274	YAML. Please note that YAML has hardcoded limits on (simple) object key	1406	YAML. Please note that YAML has hardcoded limits on (simple) object key
1275	lengths that JSON doesn't have and also has different and incompatible	1407	lengths that JSON doesn't have and also has different and incompatible
1276	unicode handling, so you should make sure that your hash keys are	1408	unicode character escape syntax, so you should make sure that your hash
1277	noticeably shorter than the 1024 "stream characters" YAML allows and that	1409	keys are noticeably shorter than the 1024 "stream characters" YAML allows
1278	you do not have characters with codepoint values outside the Unicode BMP	1410	and that you do not have characters with codepoint values outside the
1279	(basic multilingual page). YAML also does not allow C<\/> sequences in	1411	Unicode BMP (basic multilingual page). YAML also does not allow C<\/>
1280	strings (which JSON::XS does not I<currently> generate, but other JSON	1412	sequences in strings (which JSON::XS does not I<currently> generate, but
1281	generators might).	1413	other JSON generators might).
1282		1414
1283	There might be other incompatibilities that I am not aware of (or the YAML	1415	There might be other incompatibilities that I am not aware of (or the YAML
1284	specification has been changed yet again - it does so quite often). In	1416	specification has been changed yet again - it does so quite often). In
1285	general you should not try to generate YAML with a JSON generator or vice	1417	general you should not try to generate YAML with a JSON generator or vice
1286	versa, or try to parse JSON with a YAML parser or vice versa: chances are	1418	versa, or try to parse JSON with a YAML parser or vice versa: chances are
…		…
1305	that difficult or long) and finally make YAML compatible to it, and	1437	that difficult or long) and finally make YAML compatible to it, and
1306	educating users about the changes, instead of spreading lies about the	1438	educating users about the changes, instead of spreading lies about the
1307	real compatibility for many I<years> and trying to silence people who	1439	real compatibility for many I<years> and trying to silence people who
1308	point out that it isn't true.	1440	point out that it isn't true.
1309		1441
		1442	Addendum/2009: the YAML 1.2 spec is still incompatible with JSON, even
		1443	though the incompatibilities have been documented (and are known to Brian)
		1444	for many years and the spec makes explicit claims that YAML is a superset
		1445	of JSON. It would be so easy to fix, but apparently, bullying people and
		1446	corrupting userdata is so much easier.
		1447
1310	=back	1448	=back
1311		1449
1312		1450
1313	=head2 SPEED	1451	=head2 SPEED
1314		1452
…		…
1321	a very short single-line JSON string (also available at	1459	a very short single-line JSON string (also available at
1322	L<http://dist.schmorp.de/misc/json/short.json>).	1460	L<http://dist.schmorp.de/misc/json/short.json>).
1323		1461
1324	{"method": "handleMessage", "params": ["user1",	1462	{"method": "handleMessage", "params": ["user1",
1325	"we were just talking"], "id": null, "array":[1,11,234,-5,1e5,1e7,	1463	"we were just talking"], "id": null, "array":[1,11,234,-5,1e5,1e7,
1326	true, false]}	1464	1, 0]}
1327		1465
1328	It shows the number of encodes/decodes per second (JSON::XS uses	1466	It shows the number of encodes/decodes per second (JSON::XS uses
1329	the functional interface, while JSON::XS/2 uses the OO interface	1467	the functional interface, while JSON::XS/2 uses the OO interface
1330	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables	1468	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables
1331	shrink). Higher is better:	1469	shrink. JSON::DWIW/DS uses the deserialise function, while JSON::DWIW::FJ
		1470	uses the from_json method). Higher is better:
1332		1471
1333	module \| encode \| decode \|	1472	module \| encode \| decode \|
1334	-----------\|------------\|------------\|	1473	--------------\|------------\|------------\|
1335	JSON 1.x \| 4990.842 \| 4088.813 \|	1474	JSON::DWIW/DS \| 86302.551 \| 102300.098 \|
1336	JSON::DWIW \| 51653.990 \| 71575.154 \|	1475	JSON::DWIW/FJ \| 86302.551 \| 75983.768 \|
1337	JSON::PC \| 65948.176 \| 74631.744 \|	1476	JSON::PP \| 15827.562 \| 6638.658 \|
1338	JSON::PP \| 8931.652 \| 3817.168 \|	1477	JSON::Syck \| 63358.066 \| 47662.545 \|
1339	JSON::Syck \| 24877.248 \| 27776.848 \|	1478	JSON::XS \| 511500.488 \| 511500.488 \|
1340	JSON::XS \| 388361.481 \| 227951.304 \|	1479	JSON::XS/2 \| 291271.111 \| 388361.481 \|
1341	JSON::XS/2 \| 227951.304 \| 218453.333 \|	1480	JSON::XS/3 \| 361577.931 \| 361577.931 \|
1342	JSON::XS/3 \| 338250.323 \| 218453.333 \|	1481	Storable \| 66788.280 \| 265462.278 \|
1343	Storable \| 16500.016 \| 135300.129 \|
1344	-----------+------------+------------+	1482	--------------+------------+------------+
1345		1483
1346	That is, JSON::XS is about five times faster than JSON::DWIW on encoding,	1484	That is, JSON::XS is almost six times faster than JSON::DWIW on encoding,
1347	about three times faster on decoding, and over forty times faster	1485	about five times faster on decoding, and over thirty to seventy times
1348	than JSON, even with pretty-printing and key sorting. It also compares	1486	faster than JSON's pure perl implementation. It also compares favourably
1349	favourably to Storable for small amounts of data.	1487	to Storable for small amounts of data.
1350		1488
1351	Using a longer test string (roughly 18KB, generated from Yahoo! Locals	1489	Using a longer test string (roughly 18KB, generated from Yahoo! Locals
1352	search API (L<http://dist.schmorp.de/misc/json/long.json>).	1490	search API (L<http://dist.schmorp.de/misc/json/long.json>).
1353		1491
1354	module \| encode \| decode \|	1492	module \| encode \| decode \|
1355	-----------\|------------\|------------\|	1493	--------------\|------------\|------------\|
1356	JSON 1.x \| 55.260 \| 34.971 \|	1494	JSON::DWIW/DS \| 1647.927 \| 2673.916 \|
1357	JSON::DWIW \| 825.228 \| 1082.513 \|	1495	JSON::DWIW/FJ \| 1630.249 \| 2596.128 \|
1358	JSON::PC \| 3571.444 \| 2394.829 \|
1359	JSON::PP \| 210.987 \| 32.574 \|	1496	JSON::PP \| 400.640 \| 62.311 \|
1360	JSON::Syck \| 552.551 \| 787.544 \|	1497	JSON::Syck \| 1481.040 \| 1524.869 \|
1361	JSON::XS \| 5780.463 \| 4854.519 \|	1498	JSON::XS \| 20661.596 \| 9541.183 \|
1362	JSON::XS/2 \| 3869.998 \| 4798.975 \|	1499	JSON::XS/2 \| 10683.403 \| 9416.938 \|
1363	JSON::XS/3 \| 5862.880 \| 4798.975 \|	1500	JSON::XS/3 \| 20661.596 \| 9400.054 \|
1364	Storable \| 4445.002 \| 5235.027 \|	1501	Storable \| 19765.806 \| 10000.725 \|
1365	-----------+------------+------------+	1502	--------------+------------+------------+
1366		1503
1367	Again, JSON::XS leads by far (except for Storable which non-surprisingly	1504	Again, JSON::XS leads by far (except for Storable which non-surprisingly
1368	decodes faster).	1505	decodes a bit faster).
1369		1506
1370	On large strings containing lots of high Unicode characters, some modules	1507	On large strings containing lots of high Unicode characters, some modules
1371	(such as JSON::PC) seem to decode faster than JSON::XS, but the result	1508	(such as JSON::PC) seem to decode faster than JSON::XS, but the result
1372	will be broken due to missing (or wrong) Unicode handling. Others refuse	1509	will be broken due to missing (or wrong) Unicode handling. Others refuse
1373	to decode or encode properly, so it was impossible to prepare a fair	1510	to decode or encode properly, so it was impossible to prepare a fair
…		…
1409	information you might want to make sure that exceptions thrown by JSON::XS	1546	information you might want to make sure that exceptions thrown by JSON::XS
1410	will not end up in front of untrusted eyes.	1547	will not end up in front of untrusted eyes.
1411		1548
1412	If you are using JSON::XS to return packets to consumption	1549	If you are using JSON::XS to return packets to consumption
1413	by JavaScript scripts in a browser you should have a look at	1550	by JavaScript scripts in a browser you should have a look at
1414	L<http://jpsykes.com/47/practical-csrf-and-json-security> to see whether	1551	L<http://blog.archive.jpsykes.com/47/practical-csrf-and-json-security/> to
1415	you are vulnerable to some common attack vectors (which really are browser	1552	see whether you are vulnerable to some common attack vectors (which really
1416	design bugs, but it is still you who will have to deal with it, as major	1553	are browser design bugs, but it is still you who will have to deal with
1417	browser developers care only for features, not about getting security	1554	it, as major browser developers care only for features, not about getting
1418	right).	1555	security right).
		1556
		1557
		1558	=head1 INTEROPERABILITY WITH OTHER MODULES
		1559
		1560	C<JSON::XS> uses the L<Types::Serialiser> module to provide boolean
		1561	constants. That means that the JSON true and false values will be
		1562	comaptible to true and false values of iother modules that do the same,
		1563	such as L<JSON::PP> and L<CBOR::XS>.
1419		1564
1420		1565
1421	=head1 THREADS	1566	=head1 THREADS
1422		1567
1423	This module is I<not> guaranteed to be thread safe and there are no	1568	This module is I<not> guaranteed to be thread safe and there are no
…		…
1426	process simulations - use fork, it's I<much> faster, cheaper, better).	1571	process simulations - use fork, it's I<much> faster, cheaper, better).
1427		1572
1428	(It might actually work, but you have been warned).	1573	(It might actually work, but you have been warned).
1429		1574
1430		1575
		1576	=head1 THE PERILS OF SETLOCALE
		1577
		1578	Sometimes people avoid the Perl locale support and directly call the
		1579	system's setlocale function with C<LC_ALL>.
		1580
		1581	This breaks both perl and modules such as JSON::XS, as stringification of
		1582	numbers no longer works correctly (e.g. C<$x = 0.1; print "$x"+1> might
		1583	print C<1>, and JSON::XS might output illegal JSON as JSON::XS relies on
		1584	perl to stringify numbers).
		1585
		1586	The solution is simple: don't call C<setlocale>, or use it for only those
		1587	categories you need, such as C<LC_MESSAGES> or C<LC_CTYPE>.
		1588
		1589	If you need C<LC_NUMERIC>, you should enable it only around the code that
		1590	actually needs it (avoiding stringification of numbers), and restore it
		1591	afterwards.
		1592
		1593
1431	=head1 BUGS	1594	=head1 BUGS
1432		1595
1433	While the goal of this module is to be correct, that unfortunately does	1596	While the goal of this module is to be correct, that unfortunately does
1434	not mean it's bug-free, only that I think its design is bug-free. If you	1597	not mean it's bug-free, only that I think its design is bug-free. If you
1435	keep reporting bugs they will be fixed swiftly, though.	1598	keep reporting bugs they will be fixed swiftly, though.
…		…
1437	Please refrain from using rt.cpan.org or any other bug reporting	1600	Please refrain from using rt.cpan.org or any other bug reporting
1438	service. I put the contact address into my modules for a reason.	1601	service. I put the contact address into my modules for a reason.
1439		1602
1440	=cut	1603	=cut
1441		1604
1442	our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" };	1605	BEGIN {
1443	our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" };	1606	*true = \$Types::Serialiser::true;
		1607	*true = \&Types::Serialiser::true;
		1608	*false = \$Types::Serialiser::false;
		1609	*false = \&Types::Serialiser::false;
		1610	*is_bool = \&Types::Serialiser::is_bool;
1444		1611
1445	sub true() { $true }	1612	JSON::XS::Boolean:: = Types::Serialiser::Boolean::;
1446	sub false() { $false }
1447
1448	sub is_bool($) {
1449	UNIVERSAL::isa $_[0], "JSON::XS::Boolean"
1450	# or UNIVERSAL::isa $_[0], "JSON::Literal"
1451	}	1613	}
1452		1614
1453	XSLoader::load "JSON::XS", $VERSION;	1615	XSLoader::load "JSON::XS", $VERSION;
1454
1455	package JSON::XS::Boolean;
1456
1457	use overload
1458	"0+" => sub { ${$_[0]} },
1459	"++" => sub { $_[0] = ${$_[0]} + 1 },
1460	"--" => sub { $_[0] = ${$_[0]} - 1 },
1461	fallback => 1;
1462
1463	1;
1464		1616
1465	=head1 SEE ALSO	1617	=head1 SEE ALSO
1466		1618
1467	The F<json_xs> command line utility for quick experiments.	1619	The F<json_xs> command line utility for quick experiments.
1468		1620
…		…
1471	Marc Lehmann <schmorp@schmorp.de>	1623	Marc Lehmann <schmorp@schmorp.de>
1472	http://home.schmorp.de/	1624	http://home.schmorp.de/
1473		1625
1474	=cut	1626	=cut
1475		1627
		1628	1
		1629

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Comparing JSON-XS/XS.pm (file contents): Revision 1.115 by root, Tue Feb 17 23:29:38 2009 UTC vs. Revision 1.150 by root, Tue Oct 29 00:48:07 2013 UTC

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Comparing JSON-XS/XS.pm (file contents):
Revision 1.115 by root, Tue Feb 17 23:29:38 2009 UTC vs.
Revision 1.150 by root, Tue Oct 29 00:48:07 2013 UTC