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

Comparing JSON-XS/XS.pm (file contents):
Revision 1.112 by root, Mon Sep 29 03:09:27 2008 UTC vs.
Revision 1.159 by root, Wed Sep 7 17:14:56 2016 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 = '2.23';	106	our $VERSION = 3.02;
108	our @ISA = qw(Exporter);	107	our @ISA = qw(Exporter);
109		108
110	our @EXPORT = qw(encode_json decode_json to_json from_json);	109	our @EXPORT = qw(encode_json decode_json);
111
112	sub to_json($) {
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
…		…
422	[	404	[
423	1, # this comment not allowed in JSON	405	1, # this comment not allowed in JSON
424	# neither this one...	406	# neither this one...
425	]	407	]
426		408
		409	=item * literal ASCII TAB characters in strings
		410
		411	Literal ASCII TAB characters are now allowed in strings (and treated as
		412	C<\t>).
		413
		414	[
		415	"Hello\tWorld",
		416	"Hello<TAB>World", # literal <TAB> would not normally be allowed
		417	]
		418
427	=back	419	=back
428		420
429	=item $json = $json->canonical ([$enable])	421	=item $json = $json->canonical ([$enable])
430		422
431	=item $enabled = $json->get_canonical	423	=item $enabled = $json->get_canonical
…		…
433	If C<$enable> is true (or missing), then the C<encode> method will output JSON objects	425	If C<$enable> is true (or missing), then the C<encode> method will output JSON objects
434	by sorting their keys. This is adding a comparatively high overhead.	426	by sorting their keys. This is adding a comparatively high overhead.
435		427
436	If C<$enable> is false, then the C<encode> method will output key-value	428	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	429	pairs in the order Perl stores them (which will likely change between runs
438	of the same script).	430	of the same script, and can change even within the same run from 5.18
		431	onwards).
439		432
440	This option is useful if you want the same data structure to be encoded as	433	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,	434	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,	435	the same hash might be encoded differently even if contains the same data,
443	as key-value pairs have no inherent ordering in Perl.	436	as key-value pairs have no inherent ordering in Perl.
444		437
445	This setting has no effect when decoding JSON texts.	438	This setting has no effect when decoding JSON texts.
		439
		440	This setting has currently no effect on tied hashes.
446		441
447	=item $json = $json->allow_nonref ([$enable])	442	=item $json = $json->allow_nonref ([$enable])
448		443
449	=item $enabled = $json->get_allow_nonref	444	=item $enabled = $json->get_allow_nonref
450		445
…		…
482		477
483	=item $json = $json->allow_blessed ([$enable])	478	=item $json = $json->allow_blessed ([$enable])
484		479
485	=item $enabled = $json->get_allow_blessed	480	=item $enabled = $json->get_allow_blessed
486		481
		482	See L<OBJECT SERIALISATION> for details.
		483
487	If C<$enable> is true (or missing), then the C<encode> method will not	484	If C<$enable> is true (or missing), then the C<encode> method will not
488	barf when it encounters a blessed reference. Instead, the value of the	485	barf when it encounters a blessed reference that it cannot convert
489	B<convert_blessed> option will decide whether C<null> (C<convert_blessed>	486	otherwise. Instead, a JSON C<null> value is encoded instead of the object.
490	disabled or no C<TO_JSON> method found) or a representation of the
491	object (C<convert_blessed> enabled and C<TO_JSON> method found) is being
492	encoded. Has no effect on C<decode>.
493		487
494	If C<$enable> is false (the default), then C<encode> will throw an	488	If C<$enable> is false (the default), then C<encode> will throw an
495	exception when it encounters a blessed object.	489	exception when it encounters a blessed object that it cannot convert
		490	otherwise.
		491
		492	This setting has no effect on C<decode>.
496		493
497	=item $json = $json->convert_blessed ([$enable])	494	=item $json = $json->convert_blessed ([$enable])
498		495
499	=item $enabled = $json->get_convert_blessed	496	=item $enabled = $json->get_convert_blessed
		497
		498	See L<OBJECT SERIALISATION> for details.
500		499
501	If C<$enable> is true (or missing), then C<encode>, upon encountering a	500	If C<$enable> is true (or missing), then C<encode>, upon encountering a
502	blessed object, will check for the availability of the C<TO_JSON> method	501	blessed object, will check for the availability of the C<TO_JSON> method
503	on the object's class. If found, it will be called in scalar context	502	on the object's class. If found, it will be called in scalar context and
504	and the resulting scalar will be encoded instead of the object. If no	503	the resulting scalar will be encoded instead of the object.
505	C<TO_JSON> method is found, the value of C<allow_blessed> will decide what
506	to do.
507		504
508	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>	505	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
509	returns other blessed objects, those will be handled in the same	506	returns other blessed objects, those will be handled in the same
510	way. C<TO_JSON> must take care of not causing an endless recursion cycle	507	way. C<TO_JSON> must take care of not causing an endless recursion cycle
511	(== crash) in this case. The name of C<TO_JSON> was chosen because other	508	(== crash) in this case. The name of C<TO_JSON> was chosen because other
512	methods called by the Perl core (== not by the user of the object) are	509	methods called by the Perl core (== not by the user of the object) are
513	usually in upper case letters and to avoid collisions with any C<to_json>	510	usually in upper case letters and to avoid collisions with any C<to_json>
514	function or method.	511	function or method.
515		512
516	This setting does not yet influence C<decode> in any way, but in the	513	If C<$enable> is false (the default), then C<encode> will not consider
517	future, global hooks might get installed that influence C<decode> and are	514	this type of conversion.
518	enabled by this setting.
519		515
520	If C<$enable> is false, then the C<allow_blessed> setting will decide what	516	This setting has no effect on C<decode>.
521	to do when a blessed object is found.	517
		518	=item $json = $json->allow_tags ([$enable])
		519
		520	=item $enabled = $json->allow_tags
		521
		522	See L<OBJECT SERIALISATION> for details.
		523
		524	If C<$enable> is true (or missing), then C<encode>, upon encountering a
		525	blessed object, will check for the availability of the C<FREEZE> method on
		526	the object's class. If found, it will be used to serialise the object into
		527	a nonstandard tagged JSON value (that JSON decoders cannot decode).
		528
		529	It also causes C<decode> to parse such tagged JSON values and deserialise
		530	them via a call to the C<THAW> method.
		531
		532	If C<$enable> is false (the default), then C<encode> will not consider
		533	this type of conversion, and tagged JSON values will cause a parse error
		534	in C<decode>, as if tags were not part of the grammar.
522		535
523	=item $json = $json->filter_json_object ([$coderef->($hashref)])	536	=item $json = $json->filter_json_object ([$coderef->($hashref)])
524		537
525	When C<$coderef> is specified, it will be called from C<decode> each	538	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	539	time it decodes a JSON object. The only argument is a reference to the
…		…
665		678
666	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.	679	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
667		680
668	=item $json_text = $json->encode ($perl_scalar)	681	=item $json_text = $json->encode ($perl_scalar)
669		682
670	Converts the given Perl data structure (a simple scalar or a reference	683	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	684	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		685
677	=item $perl_scalar = $json->decode ($json_text)	686	=item $perl_scalar = $json->decode ($json_text)
678		687
679	The opposite of C<encode>: expects a JSON text and tries to parse it,	688	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.	689	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		690
686	=item ($perl_scalar, $characters) = $json->decode_prefix ($json_text)	691	=item ($perl_scalar, $characters) = $json->decode_prefix ($json_text)
687		692
688	This works like the C<decode> method, but instead of raising an exception	693	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	694	when there is trailing garbage after the first JSON object, it will
690	silently stop parsing there and return the number of characters consumed	695	silently stop parsing there and return the number of characters consumed
691	so far.	696	so far.
692		697
693	This is useful if your JSON texts are not delimited by an outer protocol	698	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.	699	and you need to know where the JSON text ends.
696		700
697	JSON::XS->new->decode_prefix ("[1] the tail")	701	JSON::XS->new->decode_prefix ("[1] the tail")
698	=> ([], 3)	702	=> ([1], 3)
699		703
700	=back	704	=back
701		705
702		706
703	=head1 INCREMENTAL PARSING	707	=head1 INCREMENTAL PARSING
…		…
712	calls).	716	calls).
713		717
714	JSON::XS will only attempt to parse the JSON text once it is sure it	718	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	719	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	720	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	721	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	722	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	723	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	724	to set resource limits (e.g. C<max_size>) to ensure the parser will stop
721	parsing in the presence if syntax errors.	725	parsing in the presence if syntax errors.
722		726
723	The following methods implement this incremental parser.	727	The following methods implement this incremental parser.
…		…
739		743
740	If the method is called in scalar context, then it will try to extract	744	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	745	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,	746	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	747	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	748	C<incr_skip> to skip the erroneous part). This is the most common way of
745	using the method.	749	using the method.
746		750
747	And finally, in list context, it will try to extract as many objects	751	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	752	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	753	otherwise. For this to work, there must be no separators (other than
750	objects or arrays, instead they must be concatenated back-to-back. If	754	whitespace) between the JSON objects or arrays, instead they must be
751	an error occurs, an exception will be raised as in the scalar context	755	concatenated back-to-back. If an error occurs, an exception will be
752	case. Note that in this case, any previously-parsed JSON texts will be	756	raised as in the scalar context case. Note that in this case, any
753	lost.	757	previously-parsed JSON texts will be lost.
		758
		759	Example: Parse some JSON arrays/objects in a given string and return
		760	them.
		761
		762	my @objs = JSON::XS->new->incr_parse ("[5][7][1,2]");
754		763
755	=item $lvalue_string = $json->incr_text	764	=item $lvalue_string = $json->incr_text
756		765
757	This method returns the currently stored JSON fragment as an lvalue, that	766	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	767	is, you can manipulate it. This I<only> works when a preceding call to
…		…
766	JSON object or b) parsing multiple JSON objects separated by non-JSON text	775	JSON object or b) parsing multiple JSON objects separated by non-JSON text
767	(such as commas).	776	(such as commas).
768		777
769	=item $json->incr_skip	778	=item $json->incr_skip
770		779
771	This will reset the state of the incremental parser and will remove the	780	This will reset the state of the incremental parser and will remove
772	parsed text from the input buffer. This is useful after C<incr_parse>	781	the parsed text from the input buffer so far. This is useful after
773	died, in which case the input buffer and incremental parser state is left	782	C<incr_parse> died, in which case the input buffer and incremental parser
774	unchanged, to skip the text parsed so far and to reset the parse state.	783	state is left unchanged, to skip the text parsed so far and to reset the
		784	parse state.
		785
		786	The difference to C<incr_reset> is that only text until the parse error
		787	occurred is removed.
775		788
776	=item $json->incr_reset	789	=item $json->incr_reset
777		790
778	This completely resets the incremental parser, that is, after this call,	791	This completely resets the incremental parser, that is, after this call,
779	it will be as if the parser had never parsed anything.	792	it will be as if the parser had never parsed anything.
780		793
781	This is useful if you want ot repeatedly parse JSON objects and want to	794	This is useful if you want to repeatedly parse JSON objects and want to
782	ignore any trailing data, which means you have to reset the parser after	795	ignore any trailing data, which means you have to reset the parser after
783	each successful decode.	796	each successful decode.
784		797
785	=back	798	=back
786		799
787	=head2 LIMITATIONS	800	=head2 LIMITATIONS
788		801
789	All options that affect decoding are supported, except	802	All options that affect decoding are supported, except
790	C<allow_nonref>. The reason for this is that it cannot be made to	803	C<allow_nonref>. The reason for this is that it cannot be made to work
791	work sensibly: JSON objects and arrays are self-delimited, i.e. you can concatenate	804	sensibly: JSON objects and arrays are self-delimited, i.e. you can
792	them back to back and still decode them perfectly. This does not hold true	805	concatenate them back to back and still decode them perfectly. This does
793	for JSON numbers, however.	806	not hold true for JSON numbers, however.
794		807
795	For example, is the string C<1> a single JSON number, or is it simply the	808	For example, is the string C<1> a single JSON number, or is it simply the
796	start of C<12>? Or is C<12> a single JSON number, or the concatenation	809	start of C<12>? Or is C<12> a single JSON number, or the concatenation
797	of C<1> and C<2>? In neither case you can tell, and this is why JSON::XS	810	of C<1> and C<2>? In neither case you can tell, and this is why JSON::XS
798	takes the conservative route and disallows this case.	811	takes the conservative route and disallows this case.
…		…
977	If the number consists of digits only, JSON::XS will try to represent	990	If the number consists of digits only, JSON::XS will try to represent
978	it as an integer value. If that fails, it will try to represent it as	991	it as an integer value. If that fails, it will try to represent it as
979	a numeric (floating point) value if that is possible without loss of	992	a numeric (floating point) value if that is possible without loss of
980	precision. Otherwise it will preserve the number as a string value (in	993	precision. Otherwise it will preserve the number as a string value (in
981	which case you lose roundtripping ability, as the JSON number will be	994	which case you lose roundtripping ability, as the JSON number will be
982	re-encoded toa JSON string).	995	re-encoded to a JSON string).
983		996
984	Numbers containing a fractional or exponential part will always be	997	Numbers containing a fractional or exponential part will always be
985	represented as numeric (floating point) values, possibly at a loss of	998	represented as numeric (floating point) values, possibly at a loss of
986	precision (in which case you might lose perfect roundtripping ability, but	999	precision (in which case you might lose perfect roundtripping ability, but
987	the JSON number will still be re-encoded as a JSON number).	1000	the JSON number will still be re-encoded as a JSON number).
988		1001
		1002	Note that precision is not accuracy - binary floating point values cannot
		1003	represent most decimal fractions exactly, and when converting from and to
		1004	floating point, JSON::XS only guarantees precision up to but not including
		1005	the least significant bit.
		1006
989	=item true, false	1007	=item true, false
990		1008
991	These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,	1009	These JSON atoms become C<Types::Serialiser::true> and
992	respectively. They are overloaded to act almost exactly like the numbers	1010	C<Types::Serialiser::false>, respectively. They are overloaded to act
993	C<1> and C<0>. You can check whether a scalar is a JSON boolean by using	1011	almost exactly like the numbers C<1> and C<0>. You can check whether
994	the C<JSON::XS::is_bool> function.	1012	a scalar is a JSON boolean by using the C<Types::Serialiser::is_bool>
		1013	function (after C<use Types::Serialier>, of course).
995		1014
996	=item null	1015	=item null
997		1016
998	A JSON null atom becomes C<undef> in Perl.	1017	A JSON null atom becomes C<undef> in Perl.
		1018
		1019	=item shell-style comments (C<< # I<text> >>)
		1020
		1021	As a nonstandard extension to the JSON syntax that is enabled by the
		1022	C<relaxed> setting, shell-style comments are allowed. They can start
		1023	anywhere outside strings and go till the end of the line.
		1024
		1025	=item tagged values (C<< (I<tag>)I<value> >>).
		1026
		1027	Another nonstandard extension to the JSON syntax, enabled with the
		1028	C<allow_tags> setting, are tagged values. In this implementation, the
		1029	I<tag> must be a perl package/class name encoded as a JSON string, and the
		1030	I<value> must be a JSON array encoding optional constructor arguments.
		1031
		1032	See L<OBJECT SERIALISATION>, below, for details.
999		1033
1000	=back	1034	=back
1001		1035
1002		1036
1003	=head2 PERL -> JSON	1037	=head2 PERL -> JSON
…		…
1008		1042
1009	=over 4	1043	=over 4
1010		1044
1011	=item hash references	1045	=item hash references
1012		1046
1013	Perl hash references become JSON objects. As there is no inherent ordering	1047	Perl hash references become JSON objects. As there is no inherent
1014	in hash keys (or JSON objects), they will usually be encoded in a	1048	ordering in hash keys (or JSON objects), they will usually be encoded
1015	pseudo-random order that can change between runs of the same program but	1049	in a pseudo-random order. JSON::XS can optionally sort the hash keys
1016	stays generally the same within a single run of a program. JSON::XS can	1050	(determined by the I<canonical> flag), so the same datastructure will
1017	optionally sort the hash keys (determined by the I<canonical> flag), so	1051	serialise to the same JSON text (given same settings and version of
1018	the same datastructure will serialise to the same JSON text (given same	1052	JSON::XS), but this incurs a runtime overhead and is only rarely useful,
1019	settings and version of JSON::XS), but this incurs a runtime overhead	1053	e.g. when you want to compare some JSON text against another for equality.
1020	and is only rarely useful, e.g. when you want to compare some JSON text
1021	against another for equality.
1022		1054
1023	=item array references	1055	=item array references
1024		1056
1025	Perl array references become JSON arrays.	1057	Perl array references become JSON arrays.
1026		1058
1027	=item other references	1059	=item other references
1028		1060
1029	Other unblessed references are generally not allowed and will cause an	1061	Other unblessed references are generally not allowed and will cause an
1030	exception to be thrown, except for references to the integers C<0> and	1062	exception to be thrown, except for references to the integers C<0> and
1031	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can	1063	C<1>, which get turned into C<false> and C<true> atoms in JSON.
1032	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
1033		1064
		1065	Since C<JSON::XS> uses the boolean model from L<Types::Serialiser>, you
		1066	can also C<use Types::Serialiser> and then use C<Types::Serialiser::false>
		1067	and C<Types::Serialiser::true> to improve readability.
		1068
		1069	use Types::Serialiser;
1034	encode_json [\0, JSON::XS::true] # yields [false,true]	1070	encode_json [\0, Types::Serialiser::true] # yields [false,true]
1035		1071
1036	=item JSON::XS::true, JSON::XS::false	1072	=item Types::Serialiser::true, Types::Serialiser::false
1037		1073
1038	These special values become JSON true and JSON false values,	1074	These special values from the L<Types::Serialiser> module become JSON true
1039	respectively. You can also use C<\1> and C<\0> directly if you want.	1075	and JSON false values, respectively. You can also use C<\1> and C<\0>
		1076	directly if you want.
1040		1077
1041	=item blessed objects	1078	=item blessed objects
1042		1079
1043	Blessed objects are not directly representable in JSON. See the	1080	Blessed objects are not directly representable in JSON, but C<JSON::XS>
1044	C<allow_blessed> and C<convert_blessed> methods on various options on	1081	allows various ways of handling objects. See L<OBJECT SERIALISATION>,
1045	how to deal with this: basically, you can choose between throwing an	1082	below, for details.
1046	exception, encoding the reference as if it weren't blessed, or provide
1047	your own serialiser method.
1048		1083
1049	=item simple scalars	1084	=item simple scalars
1050		1085
1051	Simple Perl scalars (any scalar that is not a reference) are the most	1086	Simple Perl scalars (any scalar that is not a reference) are the most
1052	difficult objects to encode: JSON::XS will encode undefined scalars as	1087	difficult objects to encode: JSON::XS will encode undefined scalars as
…		…
1080		1115
1081	You can not currently force the type in other, less obscure, ways. Tell me	1116	You can not currently force the type in other, less obscure, ways. Tell me
1082	if you need this capability (but don't forget to explain why it's needed	1117	if you need this capability (but don't forget to explain why it's needed
1083	:).	1118	:).
1084		1119
		1120	Note that numerical precision has the same meaning as under Perl (so
		1121	binary to decimal conversion follows the same rules as in Perl, which
		1122	can differ to other languages). Also, your perl interpreter might expose
		1123	extensions to the floating point numbers of your platform, such as
		1124	infinities or NaN's - these cannot be represented in JSON, and it is an
		1125	error to pass those in.
		1126
1085	=back	1127	=back
		1128
		1129	=head2 OBJECT SERIALISATION
		1130
		1131	As JSON cannot directly represent Perl objects, you have to choose between
		1132	a pure JSON representation (without the ability to deserialise the object
		1133	automatically again), and a nonstandard extension to the JSON syntax,
		1134	tagged values.
		1135
		1136	=head3 SERIALISATION
		1137
		1138	What happens when C<JSON::XS> encounters a Perl object depends on the
		1139	C<allow_blessed>, C<convert_blessed> and C<allow_tags> settings, which are
		1140	used in this order:
		1141
		1142	=over 4
		1143
		1144	=item 1. C<allow_tags> is enabled and the object has a C<FREEZE> method.
		1145
		1146	In this case, C<JSON::XS> uses the L<Types::Serialiser> object
		1147	serialisation protocol to create a tagged JSON value, using a nonstandard
		1148	extension to the JSON syntax.
		1149
		1150	This works by invoking the C<FREEZE> method on the object, with the first
		1151	argument being the object to serialise, and the second argument being the
		1152	constant string C<JSON> to distinguish it from other serialisers.
		1153
		1154	The C<FREEZE> method can return any number of values (i.e. zero or
		1155	more). These values and the paclkage/classname of the object will then be
		1156	encoded as a tagged JSON value in the following format:
		1157
		1158	("classname")[FREEZE return values...]
		1159
		1160	e.g.:
		1161
		1162	("URI")["http://www.google.com/"]
		1163	("MyDate")[2013,10,29]
		1164	("ImageData::JPEG")["Z3...VlCg=="]
		1165
		1166	For example, the hypothetical C<My::Object> C<FREEZE> method might use the
		1167	objects C<type> and C<id> members to encode the object:
		1168
		1169	sub My::Object::FREEZE {
		1170	my ($self, $serialiser) = @_;
		1171
		1172	($self->{type}, $self->{id})
		1173	}
		1174
		1175	=item 2. C<convert_blessed> is enabled and the object has a C<TO_JSON> method.
		1176
		1177	In this case, the C<TO_JSON> method of the object is invoked in scalar
		1178	context. It must return a single scalar that can be directly encoded into
		1179	JSON. This scalar replaces the object in the JSON text.
		1180
		1181	For example, the following C<TO_JSON> method will convert all L<URI>
		1182	objects to JSON strings when serialised. The fatc that these values
		1183	originally were L<URI> objects is lost.
		1184
		1185	sub URI::TO_JSON {
		1186	my ($uri) = @_;
		1187	$uri->as_string
		1188	}
		1189
		1190	=item 3. C<allow_blessed> is enabled.
		1191
		1192	The object will be serialised as a JSON null value.
		1193
		1194	=item 4. none of the above
		1195
		1196	If none of the settings are enabled or the respective methods are missing,
		1197	C<JSON::XS> throws an exception.
		1198
		1199	=back
		1200
		1201	=head3 DESERIALISATION
		1202
		1203	For deserialisation there are only two cases to consider: either
		1204	nonstandard tagging was used, in which case C<allow_tags> decides,
		1205	or objects cannot be automatically be deserialised, in which
		1206	case you can use postprocessing or the C<filter_json_object> or
		1207	C<filter_json_single_key_object> callbacks to get some real objects our of
		1208	your JSON.
		1209
		1210	This section only considers the tagged value case: I a tagged JSON object
		1211	is encountered during decoding and C<allow_tags> is disabled, a parse
		1212	error will result (as if tagged values were not part of the grammar).
		1213
		1214	If C<allow_tags> is enabled, C<JSON::XS> will look up the C<THAW> method
		1215	of the package/classname used during serialisation (it will not attempt
		1216	to load the package as a Perl module). If there is no such method, the
		1217	decoding will fail with an error.
		1218
		1219	Otherwise, the C<THAW> method is invoked with the classname as first
		1220	argument, the constant string C<JSON> as second argument, and all the
		1221	values from the JSON array (the values originally returned by the
		1222	C<FREEZE> method) as remaining arguments.
		1223
		1224	The method must then return the object. While technically you can return
		1225	any Perl scalar, you might have to enable the C<enable_nonref> setting to
		1226	make that work in all cases, so better return an actual blessed reference.
		1227
		1228	As an example, let's implement a C<THAW> function that regenerates the
		1229	C<My::Object> from the C<FREEZE> example earlier:
		1230
		1231	sub My::Object::THAW {
		1232	my ($class, $serialiser, $type, $id) = @_;
		1233
		1234	$class->new (type => $type, id => $id)
		1235	}
1086		1236
1087		1237
1088	=head1 ENCODING/CODESET FLAG NOTES	1238	=head1 ENCODING/CODESET FLAG NOTES
1089		1239
1090	The interested reader might have seen a number of flags that signify	1240	The interested reader might have seen a number of flags that signify
…		…
1115	=item C<utf8> flag disabled	1265	=item C<utf8> flag disabled
1116		1266
1117	When C<utf8> is disabled (the default), then C<encode>/C<decode> generate	1267	When C<utf8> is disabled (the default), then C<encode>/C<decode> generate
1118	and expect Unicode strings, that is, characters with high ordinal Unicode	1268	and expect Unicode strings, that is, characters with high ordinal Unicode
1119	values (> 255) will be encoded as such characters, and likewise such	1269	values (> 255) will be encoded as such characters, and likewise such
1120	characters are decoded as-is, no canges to them will be done, except	1270	characters are decoded as-is, no changes to them will be done, except
1121	"(re-)interpreting" them as Unicode codepoints or Unicode characters,	1271	"(re-)interpreting" them as Unicode codepoints or Unicode characters,
1122	respectively (to Perl, these are the same thing in strings unless you do	1272	respectively (to Perl, these are the same thing in strings unless you do
1123	funny/weird/dumb stuff).	1273	funny/weird/dumb stuff).
1124		1274
1125	This is useful when you want to do the encoding yourself (e.g. when you	1275	This is useful when you want to do the encoding yourself (e.g. when you
…		…
1181	proper subset of most 8-bit and multibyte encodings in use in the world.	1331	proper subset of most 8-bit and multibyte encodings in use in the world.
1182		1332
1183	=back	1333	=back
1184		1334
1185		1335
		1336	=head2 JSON and ECMAscript
		1337
		1338	JSON syntax is based on how literals are represented in javascript (the
		1339	not-standardised predecessor of ECMAscript) which is presumably why it is
		1340	called "JavaScript Object Notation".
		1341
		1342	However, JSON is not a subset (and also not a superset of course) of
		1343	ECMAscript (the standard) or javascript (whatever browsers actually
		1344	implement).
		1345
		1346	If you want to use javascript's C<eval> function to "parse" JSON, you
		1347	might run into parse errors for valid JSON texts, or the resulting data
		1348	structure might not be queryable:
		1349
		1350	One of the problems is that U+2028 and U+2029 are valid characters inside
		1351	JSON strings, but are not allowed in ECMAscript string literals, so the
		1352	following Perl fragment will not output something that can be guaranteed
		1353	to be parsable by javascript's C<eval>:
		1354
		1355	use JSON::XS;
		1356
		1357	print encode_json [chr 0x2028];
		1358
		1359	The right fix for this is to use a proper JSON parser in your javascript
		1360	programs, and not rely on C<eval> (see for example Douglas Crockford's
		1361	F<json2.js> parser).
		1362
		1363	If this is not an option, you can, as a stop-gap measure, simply encode to
		1364	ASCII-only JSON:
		1365
		1366	use JSON::XS;
		1367
		1368	print JSON::XS->new->ascii->encode ([chr 0x2028]);
		1369
		1370	Note that this will enlarge the resulting JSON text quite a bit if you
		1371	have many non-ASCII characters. You might be tempted to run some regexes
		1372	to only escape U+2028 and U+2029, e.g.:
		1373
		1374	# DO NOT USE THIS!
		1375	my $json = JSON::XS->new->utf8->encode ([chr 0x2028]);
		1376	$json =~ s/\xe2\x80\xa8/\\u2028/g; # escape U+2028
		1377	$json =~ s/\xe2\x80\xa9/\\u2029/g; # escape U+2029
		1378	print $json;
		1379
		1380	Note that I<this is a bad idea>: the above only works for U+2028 and
		1381	U+2029 and thus only for fully ECMAscript-compliant parsers. Many existing
		1382	javascript implementations, however, have issues with other characters as
		1383	well - using C<eval> naively simply I<will> cause problems.
		1384
		1385	Another problem is that some javascript implementations reserve
		1386	some property names for their own purposes (which probably makes
		1387	them non-ECMAscript-compliant). For example, Iceweasel reserves the
		1388	C<__proto__> property name for its own purposes.
		1389
		1390	If that is a problem, you could parse try to filter the resulting JSON
		1391	output for these property strings, e.g.:
		1392
		1393	$json =~ s/"__proto__"\s*:/"__proto__renamed":/g;
		1394
		1395	This works because C<__proto__> is not valid outside of strings, so every
		1396	occurrence of C<"__proto__"\s*:> must be a string used as property name.
		1397
		1398	If you know of other incompatibilities, please let me know.
		1399
		1400
1186	=head2 JSON and YAML	1401	=head2 JSON and YAML
1187		1402
1188	You often hear that JSON is a subset of YAML. This is, however, a mass	1403	You often hear that JSON is a subset of YAML. This is, however, a mass
1189	hysteria(*) and very far from the truth (as of the time of this writing),	1404	hysteria(*) and very far from the truth (as of the time of this writing),
1190	so let me state it clearly: I<in general, there is no way to configure	1405	so let me state it clearly: I<in general, there is no way to configure
…		…
1198	my $yaml = $to_yaml->encode ($ref) . "\n";	1413	my $yaml = $to_yaml->encode ($ref) . "\n";
1199		1414
1200	This will I<usually> generate JSON texts that also parse as valid	1415	This will I<usually> generate JSON texts that also parse as valid
1201	YAML. Please note that YAML has hardcoded limits on (simple) object key	1416	YAML. Please note that YAML has hardcoded limits on (simple) object key
1202	lengths that JSON doesn't have and also has different and incompatible	1417	lengths that JSON doesn't have and also has different and incompatible
1203	unicode handling, so you should make sure that your hash keys are	1418	unicode character escape syntax, so you should make sure that your hash
1204	noticeably shorter than the 1024 "stream characters" YAML allows and that	1419	keys are noticeably shorter than the 1024 "stream characters" YAML allows
1205	you do not have characters with codepoint values outside the Unicode BMP	1420	and that you do not have characters with codepoint values outside the
1206	(basic multilingual page). YAML also does not allow C<\/> sequences in	1421	Unicode BMP (basic multilingual page). YAML also does not allow C<\/>
1207	strings (which JSON::XS does not I<currently> generate, but other JSON	1422	sequences in strings (which JSON::XS does not I<currently> generate, but
1208	generators might).	1423	other JSON generators might).
1209		1424
1210	There might be other incompatibilities that I am not aware of (or the YAML	1425	There might be other incompatibilities that I am not aware of (or the YAML
1211	specification has been changed yet again - it does so quite often). In	1426	specification has been changed yet again - it does so quite often). In
1212	general you should not try to generate YAML with a JSON generator or vice	1427	general you should not try to generate YAML with a JSON generator or vice
1213	versa, or try to parse JSON with a YAML parser or vice versa: chances are	1428	versa, or try to parse JSON with a YAML parser or vice versa: chances are
…		…
1232	that difficult or long) and finally make YAML compatible to it, and	1447	that difficult or long) and finally make YAML compatible to it, and
1233	educating users about the changes, instead of spreading lies about the	1448	educating users about the changes, instead of spreading lies about the
1234	real compatibility for many I<years> and trying to silence people who	1449	real compatibility for many I<years> and trying to silence people who
1235	point out that it isn't true.	1450	point out that it isn't true.
1236		1451
		1452	Addendum/2009: the YAML 1.2 spec is still incompatible with JSON, even
		1453	though the incompatibilities have been documented (and are known to Brian)
		1454	for many years and the spec makes explicit claims that YAML is a superset
		1455	of JSON. It would be so easy to fix, but apparently, bullying people and
		1456	corrupting userdata is so much easier.
		1457
1237	=back	1458	=back
1238		1459
1239		1460
1240	=head2 SPEED	1461	=head2 SPEED
1241		1462
…		…
1248	a very short single-line JSON string (also available at	1469	a very short single-line JSON string (also available at
1249	L<http://dist.schmorp.de/misc/json/short.json>).	1470	L<http://dist.schmorp.de/misc/json/short.json>).
1250		1471
1251	{"method": "handleMessage", "params": ["user1",	1472	{"method": "handleMessage", "params": ["user1",
1252	"we were just talking"], "id": null, "array":[1,11,234,-5,1e5,1e7,	1473	"we were just talking"], "id": null, "array":[1,11,234,-5,1e5,1e7,
1253	true, false]}	1474	1, 0]}
1254		1475
1255	It shows the number of encodes/decodes per second (JSON::XS uses	1476	It shows the number of encodes/decodes per second (JSON::XS uses
1256	the functional interface, while JSON::XS/2 uses the OO interface	1477	the functional interface, while JSON::XS/2 uses the OO interface
1257	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables	1478	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables
1258	shrink). Higher is better:	1479	shrink. JSON::DWIW/DS uses the deserialise function, while JSON::DWIW::FJ
		1480	uses the from_json method). Higher is better:
1259		1481
1260	module \| encode \| decode \|	1482	module \| encode \| decode \|
1261	-----------\|------------\|------------\|	1483	--------------\|------------\|------------\|
1262	JSON 1.x \| 4990.842 \| 4088.813 \|	1484	JSON::DWIW/DS \| 86302.551 \| 102300.098 \|
1263	JSON::DWIW \| 51653.990 \| 71575.154 \|	1485	JSON::DWIW/FJ \| 86302.551 \| 75983.768 \|
1264	JSON::PC \| 65948.176 \| 74631.744 \|	1486	JSON::PP \| 15827.562 \| 6638.658 \|
1265	JSON::PP \| 8931.652 \| 3817.168 \|	1487	JSON::Syck \| 63358.066 \| 47662.545 \|
1266	JSON::Syck \| 24877.248 \| 27776.848 \|	1488	JSON::XS \| 511500.488 \| 511500.488 \|
1267	JSON::XS \| 388361.481 \| 227951.304 \|	1489	JSON::XS/2 \| 291271.111 \| 388361.481 \|
1268	JSON::XS/2 \| 227951.304 \| 218453.333 \|	1490	JSON::XS/3 \| 361577.931 \| 361577.931 \|
1269	JSON::XS/3 \| 338250.323 \| 218453.333 \|	1491	Storable \| 66788.280 \| 265462.278 \|
1270	Storable \| 16500.016 \| 135300.129 \|
1271	-----------+------------+------------+	1492	--------------+------------+------------+
1272		1493
1273	That is, JSON::XS is about five times faster than JSON::DWIW on encoding,	1494	That is, JSON::XS is almost six times faster than JSON::DWIW on encoding,
1274	about three times faster on decoding, and over forty times faster	1495	about five times faster on decoding, and over thirty to seventy times
1275	than JSON, even with pretty-printing and key sorting. It also compares	1496	faster than JSON's pure perl implementation. It also compares favourably
1276	favourably to Storable for small amounts of data.	1497	to Storable for small amounts of data.
1277		1498
1278	Using a longer test string (roughly 18KB, generated from Yahoo! Locals	1499	Using a longer test string (roughly 18KB, generated from Yahoo! Locals
1279	search API (L<http://dist.schmorp.de/misc/json/long.json>).	1500	search API (L<http://dist.schmorp.de/misc/json/long.json>).
1280		1501
1281	module \| encode \| decode \|	1502	module \| encode \| decode \|
1282	-----------\|------------\|------------\|	1503	--------------\|------------\|------------\|
1283	JSON 1.x \| 55.260 \| 34.971 \|	1504	JSON::DWIW/DS \| 1647.927 \| 2673.916 \|
1284	JSON::DWIW \| 825.228 \| 1082.513 \|	1505	JSON::DWIW/FJ \| 1630.249 \| 2596.128 \|
1285	JSON::PC \| 3571.444 \| 2394.829 \|
1286	JSON::PP \| 210.987 \| 32.574 \|	1506	JSON::PP \| 400.640 \| 62.311 \|
1287	JSON::Syck \| 552.551 \| 787.544 \|	1507	JSON::Syck \| 1481.040 \| 1524.869 \|
1288	JSON::XS \| 5780.463 \| 4854.519 \|	1508	JSON::XS \| 20661.596 \| 9541.183 \|
1289	JSON::XS/2 \| 3869.998 \| 4798.975 \|	1509	JSON::XS/2 \| 10683.403 \| 9416.938 \|
1290	JSON::XS/3 \| 5862.880 \| 4798.975 \|	1510	JSON::XS/3 \| 20661.596 \| 9400.054 \|
1291	Storable \| 4445.002 \| 5235.027 \|	1511	Storable \| 19765.806 \| 10000.725 \|
1292	-----------+------------+------------+	1512	--------------+------------+------------+
1293		1513
1294	Again, JSON::XS leads by far (except for Storable which non-surprisingly	1514	Again, JSON::XS leads by far (except for Storable which non-surprisingly
1295	decodes faster).	1515	decodes a bit faster).
1296		1516
1297	On large strings containing lots of high Unicode characters, some modules	1517	On large strings containing lots of high Unicode characters, some modules
1298	(such as JSON::PC) seem to decode faster than JSON::XS, but the result	1518	(such as JSON::PC) seem to decode faster than JSON::XS, but the result
1299	will be broken due to missing (or wrong) Unicode handling. Others refuse	1519	will be broken due to missing (or wrong) Unicode handling. Others refuse
1300	to decode or encode properly, so it was impossible to prepare a fair	1520	to decode or encode properly, so it was impossible to prepare a fair
…		…
1336	information you might want to make sure that exceptions thrown by JSON::XS	1556	information you might want to make sure that exceptions thrown by JSON::XS
1337	will not end up in front of untrusted eyes.	1557	will not end up in front of untrusted eyes.
1338		1558
1339	If you are using JSON::XS to return packets to consumption	1559	If you are using JSON::XS to return packets to consumption
1340	by JavaScript scripts in a browser you should have a look at	1560	by JavaScript scripts in a browser you should have a look at
1341	L<http://jpsykes.com/47/practical-csrf-and-json-security> to see whether	1561	L<http://blog.archive.jpsykes.com/47/practical-csrf-and-json-security/> to
1342	you are vulnerable to some common attack vectors (which really are browser	1562	see whether you are vulnerable to some common attack vectors (which really
1343	design bugs, but it is still you who will have to deal with it, as major	1563	are browser design bugs, but it is still you who will have to deal with
1344	browser developers care only for features, not about getting security	1564	it, as major browser developers care only for features, not about getting
1345	right).	1565	security right).
		1566
		1567
		1568	=head1 "OLD" VS. "NEW" JSON (RFC 4627 VS. RFC 7159)
		1569
		1570	TL;DR: Due to security concerns, JSON::XS will not allow scalar data in
		1571	JSON texts by default - you need to create your own JSON::XS object and
		1572	enable C<allow_nonref>:
		1573
		1574
		1575	my $json = JSON::XS->new->allow_nonref;
		1576
		1577	$text = $json->encode ($data);
		1578	$data = $json->decode ($text);
		1579
		1580	The long version: JSON being an important and supposedly stable format,
		1581	the IETF standardised it as RFC 4627 in 2006. Unfortunately, the inventor
		1582	of JSON, Dougles Crockford, unilaterally changed the definition of JSON in
		1583	javascript. Rather than create a fork, the IETF decided to standardise the
		1584	new syntax (apparently, so Iw as told, without finding it very amusing).
		1585
		1586	The biggest difference between thed original JSON and the new JSON is that
		1587	the new JSON supports scalars (anything other than arrays and objects) at
		1588	the toplevel of a JSON text. While this is strictly backwards compatible
		1589	to older versions, it breaks a number of protocols that relied on sending
		1590	JSON back-to-back, and is a minor security concern.
		1591
		1592	For example, imagine you have two banks communicating, and on one side,
		1593	trhe JSON coder gets upgraded. Two messages, such as C<10> and C<1000>
		1594	might then be confused to mean C<101000>, something that couldn't happen
		1595	in the original JSON, because niether of these messages would be valid
		1596	JSON.
		1597
		1598	If one side accepts these messages, then an upgrade in the coder on either
		1599	side could result in this becoming exploitable.
		1600
		1601	This module has always allowed these messages as an optional extension, by
		1602	default disabled. The security concerns are the reason why the default is
		1603	still disabled, but future versions might/will likely upgrade to the newer
		1604	RFC as default format, so you are advised to check your implementation
		1605	and/or override the default with C<< ->allow_nonref (0) >> to ensure that
		1606	future versions are safe.
		1607
		1608
		1609	=head1 INTEROPERABILITY WITH OTHER MODULES
		1610
		1611	C<JSON::XS> uses the L<Types::Serialiser> module to provide boolean
		1612	constants. That means that the JSON true and false values will be
		1613	comaptible to true and false values of other modules that do the same,
		1614	such as L<JSON::PP> and L<CBOR::XS>.
		1615
		1616
		1617	=head1 INTEROPERABILITY WITH OTHER JSON DECODERS
		1618
		1619	As long as you only serialise data that can be directly expressed in JSON,
		1620	C<JSON::XS> is incapable of generating invalid JSON output (modulo bugs,
		1621	but C<JSON::XS> has found more bugs in the official JSON testsuite (1)
		1622	than the official JSON testsuite has found in C<JSON::XS> (0)).
		1623
		1624	When you have trouble decoding JSON generated by this module using other
		1625	decoders, then it is very likely that you have an encoding mismatch or the
		1626	other decoder is broken.
		1627
		1628	When decoding, C<JSON::XS> is strict by default and will likely catch all
		1629	errors. There are currently two settings that change this: C<relaxed>
		1630	makes C<JSON::XS> accept (but not generate) some non-standard extensions,
		1631	and C<allow_tags> will allow you to encode and decode Perl objects, at the
		1632	cost of not outputting valid JSON anymore.
		1633
		1634	=head2 TAGGED VALUE SYNTAX AND STANDARD JSON EN/DECODERS
		1635
		1636	When you use C<allow_tags> to use the extended (and also nonstandard and
		1637	invalid) JSON syntax for serialised objects, and you still want to decode
		1638	the generated When you want to serialise objects, you can run a regex
		1639	to replace the tagged syntax by standard JSON arrays (it only works for
		1640	"normal" package names without comma, newlines or single colons). First,
		1641	the readable Perl version:
		1642
		1643	# if your FREEZE methods return no values, you need this replace first:
		1644	$json =~ s/$ \s* (" (?: [^\\":,]+\|\\.\|::)* ") \s* $ \s* \[\s*\]/[$1]/gx;
		1645
		1646	# this works for non-empty constructor arg lists:
		1647	$json =~ s/$ \s* (" (?: [^\\":,]+\|\\.\|::)* ") \s* $ \s* \[/[$1,/gx;
		1648
		1649	And here is a less readable version that is easy to adapt to other
		1650	languages:
		1651
		1652	$json =~ s/$\s("([^\\":,]+\|\\.\|::)")\s$\s\[/[$1,/g;
		1653
		1654	Here is an ECMAScript version (same regex):
		1655
		1656	json = json.replace (/$\s("([^\\":,]+\|\\.\|::)")\s$\s\[/g, "[$1,");
		1657
		1658	Since this syntax converts to standard JSON arrays, it might be hard to
		1659	distinguish serialised objects from normal arrays. You can prepend a
		1660	"magic number" as first array element to reduce chances of a collision:
		1661
		1662	$json =~ s/$\s("([^\\":,]+\|\\.\|::)")\s$\s\[/["XU1peReLzT4ggEllLanBYq4G9VzliwKF",$1,/g;
		1663
		1664	And after decoding the JSON text, you could walk the data
		1665	structure looking for arrays with a first element of
		1666	C<XU1peReLzT4ggEllLanBYq4G9VzliwKF>.
		1667
		1668	The same approach can be used to create the tagged format with another
		1669	encoder. First, you create an array with the magic string as first member,
		1670	the classname as second, and constructor arguments last, encode it as part
		1671	of your JSON structure, and then:
		1672
		1673	$json =~ s/\[\s"XU1peReLzT4ggEllLanBYq4G9VzliwKF"\s,\s("([^\\":,]+\|\\.\|::)")\s*,/($1)[/g;
		1674
		1675	Again, this has some limitations - the magic string must not be encoded
		1676	with character escapes, and the constructor arguments must be non-empty.
		1677
		1678
		1679	=head1 RFC7159
		1680
		1681	Since this module was written, Google has written a new JSON RFC, RFC 7159
		1682	(and RFC7158). Unfortunately, this RFC breaks compatibility with both the
		1683	original JSON specification on www.json.org and RFC4627.
		1684
		1685	As far as I can see, you can get partial compatibility when parsing by
		1686	using C<< ->allow_nonref >>. However, consider the security implications
		1687	of doing so.
		1688
		1689	I haven't decided yet when to break compatibility with RFC4627 by default
		1690	(and potentially leave applications insecure) and change the default to
		1691	follow RFC7159, but application authors are well advised to call C<<
		1692	->allow_nonref(0) >> even if this is the current default, if they cannot
		1693	handle non-reference values, in preparation for the day when the default
		1694	will change.
1346		1695
1347		1696
1348	=head1 THREADS	1697	=head1 THREADS
1349		1698
1350	This module is I<not> guaranteed to be thread safe and there are no	1699	This module is I<not> guaranteed to be thread safe and there are no
…		…
1353	process simulations - use fork, it's I<much> faster, cheaper, better).	1702	process simulations - use fork, it's I<much> faster, cheaper, better).
1354		1703
1355	(It might actually work, but you have been warned).	1704	(It might actually work, but you have been warned).
1356		1705
1357		1706
		1707	=head1 THE PERILS OF SETLOCALE
		1708
		1709	Sometimes people avoid the Perl locale support and directly call the
		1710	system's setlocale function with C<LC_ALL>.
		1711
		1712	This breaks both perl and modules such as JSON::XS, as stringification of
		1713	numbers no longer works correctly (e.g. C<$x = 0.1; print "$x"+1> might
		1714	print C<1>, and JSON::XS might output illegal JSON as JSON::XS relies on
		1715	perl to stringify numbers).
		1716
		1717	The solution is simple: don't call C<setlocale>, or use it for only those
		1718	categories you need, such as C<LC_MESSAGES> or C<LC_CTYPE>.
		1719
		1720	If you need C<LC_NUMERIC>, you should enable it only around the code that
		1721	actually needs it (avoiding stringification of numbers), and restore it
		1722	afterwards.
		1723
		1724
1358	=head1 BUGS	1725	=head1 BUGS
1359		1726
1360	While the goal of this module is to be correct, that unfortunately does	1727	While the goal of this module is to be correct, that unfortunately does
1361	not mean it's bug-free, only that I think its design is bug-free. If you	1728	not mean it's bug-free, only that I think its design is bug-free. If you
1362	keep reporting bugs they will be fixed swiftly, though.	1729	keep reporting bugs they will be fixed swiftly, though.
…		…
1364	Please refrain from using rt.cpan.org or any other bug reporting	1731	Please refrain from using rt.cpan.org or any other bug reporting
1365	service. I put the contact address into my modules for a reason.	1732	service. I put the contact address into my modules for a reason.
1366		1733
1367	=cut	1734	=cut
1368		1735
1369	our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" };	1736	BEGIN {
1370	our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" };	1737	*true = \$Types::Serialiser::true;
		1738	*true = \&Types::Serialiser::true;
		1739	*false = \$Types::Serialiser::false;
		1740	*false = \&Types::Serialiser::false;
		1741	*is_bool = \&Types::Serialiser::is_bool;
1371		1742
1372	sub true() { $true }	1743	JSON::XS::Boolean:: = Types::Serialiser::Boolean::;
1373	sub false() { $false }
1374
1375	sub is_bool($) {
1376	UNIVERSAL::isa $_[0], "JSON::XS::Boolean"
1377	# or UNIVERSAL::isa $_[0], "JSON::Literal"
1378	}	1744	}
1379		1745
1380	XSLoader::load "JSON::XS", $VERSION;	1746	XSLoader::load "JSON::XS", $VERSION;
1381
1382	package JSON::XS::Boolean;
1383
1384	use overload
1385	"0+" => sub { ${$_[0]} },
1386	"++" => sub { $_[0] = ${$_[0]} + 1 },
1387	"--" => sub { $_[0] = ${$_[0]} - 1 },
1388	fallback => 1;
1389
1390	1;
1391		1747
1392	=head1 SEE ALSO	1748	=head1 SEE ALSO
1393		1749
1394	The F<json_xs> command line utility for quick experiments.	1750	The F<json_xs> command line utility for quick experiments.
1395		1751
…		…
1398	Marc Lehmann <schmorp@schmorp.de>	1754	Marc Lehmann <schmorp@schmorp.de>
1399	http://home.schmorp.de/	1755	http://home.schmorp.de/
1400		1756
1401	=cut	1757	=cut
1402		1758
		1759	1
		1760

Diff Legend

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

Comparing JSON-XS/XS.pm (file contents): Revision 1.112 by root, Mon Sep 29 03:09:27 2008 UTC vs. Revision 1.159 by root, Wed Sep 7 17:14:56 2016 UTC

Diff Legend

Comparing JSON-XS/XS.pm (file contents):
Revision 1.112 by root, Mon Sep 29 03:09:27 2008 UTC vs.
Revision 1.159 by root, Wed Sep 7 17:14:56 2016 UTC