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

Comparing JSON-XS/XS.pm (file contents):
Revision 1.135 by root, Wed Jun 1 13:01:09 2011 UTC vs.
Revision 1.159 by root, Wed Sep 7 17:14:56 2016 UTC

…		…
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
…		…
101		101
102	package JSON::XS;	102	package JSON::XS;
103		103
104	use common::sense;	104	use common::sense;
105		105
106	our $VERSION = '2.3';	106	our $VERSION = 3.02;
107	our @ISA = qw(Exporter);	107	our @ISA = qw(Exporter);
108		108
109	our @EXPORT = qw(encode_json decode_json to_json from_json);	109	our @EXPORT = qw(encode_json decode_json);
110
111	sub to_json($) {
112	require Carp;
113	Carp::croak ("JSON::XS::to_json has been renamed to encode_json, either downgrade to pre-2.0 versions of JSON::XS or rename the call");
114	}
115
116	sub from_json($) {
117	require Carp;
118	Carp::croak ("JSON::XS::from_json has been renamed to decode_json, either downgrade to pre-2.0 versions of JSON::XS or rename the call");
119	}
120		110
121	use Exporter;	111	use Exporter;
122	use XSLoader;	112	use XSLoader;
		113
		114	use Types::Serialiser ();
123		115
124	=head1 FUNCTIONAL INTERFACE	116	=head1 FUNCTIONAL INTERFACE
125		117
126	The following convenience methods are provided by this module. They are	118	The following convenience methods are provided by this module. They are
127	exported by default:	119	exported by default:
…		…
148	This function call is functionally identical to:	140	This function call is functionally identical to:
149		141
150	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)	142	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)
151		143
152	Except being faster.	144	Except being faster.
153
154	=item $is_boolean = JSON::XS::is_bool $scalar
155
156	Returns true if the passed scalar represents either JSON::XS::true or
157	JSON::XS::false, two constants that act like C<1> and C<0>, respectively
158	and are used to represent JSON C<true> and C<false> values in Perl.
159
160	See MAPPING, below, for more information on how JSON values are mapped to
161	Perl.
162		145
163	=back	146	=back
164		147
165		148
166	=head1 A FEW NOTES ON UNICODE AND PERL	149	=head1 A FEW NOTES ON UNICODE AND PERL
…		…
421	[	404	[
422	1, # this comment not allowed in JSON	405	1, # this comment not allowed in JSON
423	# neither this one...	406	# neither this one...
424	]	407	]
425		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
426	=back	419	=back
427		420
428	=item $json = $json->canonical ([$enable])	421	=item $json = $json->canonical ([$enable])
429		422
430	=item $enabled = $json->get_canonical	423	=item $enabled = $json->get_canonical
…		…
432	If C<$enable> is true (or missing), then the C<encode> method will output JSON objects	425	If C<$enable> is true (or missing), then the C<encode> method will output JSON objects
433	by sorting their keys. This is adding a comparatively high overhead.	426	by sorting their keys. This is adding a comparatively high overhead.
434		427
435	If C<$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
436	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
437	of the same script).	430	of the same script, and can change even within the same run from 5.18
		431	onwards).
438		432
439	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
440	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,
441	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,
442	as key-value pairs have no inherent ordering in Perl.	436	as key-value pairs have no inherent ordering in Perl.
…		…
483		477
484	=item $json = $json->allow_blessed ([$enable])	478	=item $json = $json->allow_blessed ([$enable])
485		479
486	=item $enabled = $json->get_allow_blessed	480	=item $enabled = $json->get_allow_blessed
487		481
		482	See L<OBJECT SERIALISATION> for details.
		483
488	If C<$enable> is true (or missing), then the C<encode> method will not	484	If C<$enable> is true (or missing), then the C<encode> method will not
489	barf when it encounters a blessed reference. Instead, the value of the	485	barf when it encounters a blessed reference that it cannot convert
490	B<convert_blessed> option will decide whether C<null> (C<convert_blessed>	486	otherwise. Instead, a JSON C<null> value is encoded instead of the object.
491	disabled or no C<TO_JSON> method found) or a representation of the
492	object (C<convert_blessed> enabled and C<TO_JSON> method found) is being
493	encoded. Has no effect on C<decode>.
494		487
495	If C<$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
496	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>.
497		493
498	=item $json = $json->convert_blessed ([$enable])	494	=item $json = $json->convert_blessed ([$enable])
499		495
500	=item $enabled = $json->get_convert_blessed	496	=item $enabled = $json->get_convert_blessed
		497
		498	See L<OBJECT SERIALISATION> for details.
501		499
502	If C<$enable> is true (or missing), then C<encode>, upon encountering a	500	If C<$enable> is true (or missing), then C<encode>, upon encountering a
503	blessed object, will check for the availability of the C<TO_JSON> method	501	blessed object, will check for the availability of the C<TO_JSON> method
504	on the object's class. If found, it will be called in scalar context	502	on the object's class. If found, it will be called in scalar context and
505	and the resulting scalar will be encoded instead of the object. If no	503	the resulting scalar will be encoded instead of the object.
506	C<TO_JSON> method is found, the value of C<allow_blessed> will decide what
507	to do.
508		504
509	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>	505	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
510	returns other blessed objects, those will be handled in the same	506	returns other blessed objects, those will be handled in the same
511	way. C<TO_JSON> must take care of not causing an endless recursion cycle	507	way. C<TO_JSON> must take care of not causing an endless recursion cycle
512	(== crash) in this case. The name of C<TO_JSON> was chosen because other	508	(== crash) in this case. The name of C<TO_JSON> was chosen because other
513	methods called by the Perl core (== not by the user of the object) are	509	methods called by the Perl core (== not by the user of the object) are
514	usually in upper case letters and to avoid collisions with any C<to_json>	510	usually in upper case letters and to avoid collisions with any C<to_json>
515	function or method.	511	function or method.
516		512
517	This setting does not yet influence C<decode> in any way, but in the	513	If C<$enable> is false (the default), then C<encode> will not consider
518	future, global hooks might get installed that influence C<decode> and are	514	this type of conversion.
519	enabled by this setting.
520		515
521	If C<$enable> is false, then the C<allow_blessed> setting will decide what	516	This setting has no effect on C<decode>.
522	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.
523		535
524	=item $json = $json->filter_json_object ([$coderef->($hashref)])	536	=item $json = $json->filter_json_object ([$coderef->($hashref)])
525		537
526	When C<$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
527	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
…		…
666		678
667	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.
668		680
669	=item $json_text = $json->encode ($perl_scalar)	681	=item $json_text = $json->encode ($perl_scalar)
670		682
671	Converts the given Perl data structure (a simple scalar or a reference	683	Converts the given Perl value or data structure to its JSON
672	to a hash or array) to its JSON representation. Simple scalars will be	684	representation. Croaks on error.
673	converted into JSON string or number sequences, while references to arrays
674	become JSON arrays and references to hashes become JSON objects. Undefined
675	Perl values (e.g. C<undef>) become JSON C<null> values. Neither C<true>
676	nor C<false> values will be generated.
677		685
678	=item $perl_scalar = $json->decode ($json_text)	686	=item $perl_scalar = $json->decode ($json_text)
679		687
680	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,
681	returning the resulting simple scalar or reference. Croaks on error.	689	returning the resulting simple scalar or reference. Croaks on error.
682
683	JSON numbers and strings become simple Perl scalars. JSON arrays become
684	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes
685	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.
686		690
687	=item ($perl_scalar, $characters) = $json->decode_prefix ($json_text)	691	=item ($perl_scalar, $characters) = $json->decode_prefix ($json_text)
688		692
689	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
690	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
691	silently stop parsing there and return the number of characters consumed	695	silently stop parsing there and return the number of characters consumed
692	so far.	696	so far.
693		697
694	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
695	(which is not the brightest thing to do in the first place) and you need
696	to know where the JSON text ends.	699	and you need to know where the JSON text ends.
697		700
698	JSON::XS->new->decode_prefix ("[1] the tail")	701	JSON::XS->new->decode_prefix ("[1] the tail")
699	=> ([], 3)	702	=> ([1], 3)
700		703
701	=back	704	=back
702		705
703		706
704	=head1 INCREMENTAL PARSING	707	=head1 INCREMENTAL PARSING
…		…
740		743
741	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
742	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
743	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,
744	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
745	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
746	using the method.	749	using the method.
747		750
748	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
749	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
750	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
751	objects or arrays, instead they must be concatenated back-to-back. If	754	whitespace) between the JSON objects or arrays, instead they must be
752	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
753	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
754	lost.	757	previously-parsed JSON texts will be lost.
755		758
756	Example: Parse some JSON arrays/objects in a given string and return	759	Example: Parse some JSON arrays/objects in a given string and return
757	them.	760	them.
758		761
759	my @objs = JSON::XS->new->incr_parse ("[5][7][1,2]");	762	my @objs = JSON::XS->new->incr_parse ("[5][7][1,2]");
…		…
779	C<incr_parse> died, in which case the input buffer and incremental parser	782	C<incr_parse> died, in which case the input buffer and incremental parser
780	state is left unchanged, to skip the text parsed so far and to reset the	783	state is left unchanged, to skip the text parsed so far and to reset the
781	parse state.	784	parse state.
782		785
783	The difference to C<incr_reset> is that only text until the parse error	786	The difference to C<incr_reset> is that only text until the parse error
784	occured is removed.	787	occurred is removed.
785		788
786	=item $json->incr_reset	789	=item $json->incr_reset
787		790
788	This completely resets the incremental parser, that is, after this call,	791	This completely resets the incremental parser, that is, after this call,
789	it will be as if the parser had never parsed anything.	792	it will be as if the parser had never parsed anything.
…		…
795	=back	798	=back
796		799
797	=head2 LIMITATIONS	800	=head2 LIMITATIONS
798		801
799	All options that affect decoding are supported, except	802	All options that affect decoding are supported, except
800	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
801	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
802	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
803	for JSON numbers, however.	806	not hold true for JSON numbers, however.
804		807
805	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
806	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
807	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
808	takes the conservative route and disallows this case.	811	takes the conservative route and disallows this case.
…		…
987	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
988	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
989	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
990	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
991	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
992	re-encoded toa JSON string).	995	re-encoded to a JSON string).
993		996
994	Numbers containing a fractional or exponential part will always be	997	Numbers containing a fractional or exponential part will always be
995	represented as numeric (floating point) values, possibly at a loss of	998	represented as numeric (floating point) values, possibly at a loss of
996	precision (in which case you might lose perfect roundtripping ability, but	999	precision (in which case you might lose perfect roundtripping ability, but
997	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).
998		1001
999	Note that precision is not accuracy - binary floating point values cannot	1002	Note that precision is not accuracy - binary floating point values cannot
1000	represent most decimal fractions exactly, and when converting from and to	1003	represent most decimal fractions exactly, and when converting from and to
1001	floating point, JSON::XS only guarantees precision up to but not including	1004	floating point, JSON::XS only guarantees precision up to but not including
1002	the leats significant bit.	1005	the least significant bit.
1003		1006
1004	=item true, false	1007	=item true, false
1005		1008
1006	These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,	1009	These JSON atoms become C<Types::Serialiser::true> and
1007	respectively. They are overloaded to act almost exactly like the numbers	1010	C<Types::Serialiser::false>, respectively. They are overloaded to act
1008	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
1009	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).
1010		1014
1011	=item null	1015	=item null
1012		1016
1013	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.
1014		1033
1015	=back	1034	=back
1016		1035
1017		1036
1018	=head2 PERL -> JSON	1037	=head2 PERL -> JSON
…		…
1023		1042
1024	=over 4	1043	=over 4
1025		1044
1026	=item hash references	1045	=item hash references
1027		1046
1028	Perl hash references become JSON objects. As there is no inherent ordering	1047	Perl hash references become JSON objects. As there is no inherent
1029	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
1030	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
1031	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
1032	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
1033	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,
1034	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.
1035	and is only rarely useful, e.g. when you want to compare some JSON text
1036	against another for equality.
1037		1054
1038	=item array references	1055	=item array references
1039		1056
1040	Perl array references become JSON arrays.	1057	Perl array references become JSON arrays.
1041		1058
1042	=item other references	1059	=item other references
1043		1060
1044	Other unblessed references are generally not allowed and will cause an	1061	Other unblessed references are generally not allowed and will cause an
1045	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
1046	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.
1047	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
1048		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;
1049	encode_json [\0, JSON::XS::true] # yields [false,true]	1070	encode_json [\0, Types::Serialiser::true] # yields [false,true]
1050		1071
1051	=item JSON::XS::true, JSON::XS::false	1072	=item Types::Serialiser::true, Types::Serialiser::false
1052		1073
1053	These special values become JSON true and JSON false values,	1074	These special values from the L<Types::Serialiser> module become JSON true
1054	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.
1055		1077
1056	=item blessed objects	1078	=item blessed objects
1057		1079
1058	Blessed objects are not directly representable in JSON. See the	1080	Blessed objects are not directly representable in JSON, but C<JSON::XS>
1059	C<allow_blessed> and C<convert_blessed> methods on various options on	1081	allows various ways of handling objects. See L<OBJECT SERIALISATION>,
1060	how to deal with this: basically, you can choose between throwing an	1082	below, for details.
1061	exception, encoding the reference as if it weren't blessed, or provide
1062	your own serialiser method.
1063		1083
1064	=item simple scalars	1084	=item simple scalars
1065		1085
1066	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
1067	difficult objects to encode: JSON::XS will encode undefined scalars as	1087	difficult objects to encode: JSON::XS will encode undefined scalars as
…		…
1104	infinities or NaN's - these cannot be represented in JSON, and it is an	1124	infinities or NaN's - these cannot be represented in JSON, and it is an
1105	error to pass those in.	1125	error to pass those in.
1106		1126
1107	=back	1127	=back
1108		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	}
		1236
1109		1237
1110	=head1 ENCODING/CODESET FLAG NOTES	1238	=head1 ENCODING/CODESET FLAG NOTES
1111		1239
1112	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
1113	encodings or codesets - C<utf8>, C<latin1> and C<ascii>. There seems to be	1241	encodings or codesets - C<utf8>, C<latin1> and C<ascii>. There seems to be
…		…
1137	=item C<utf8> flag disabled	1265	=item C<utf8> flag disabled
1138		1266
1139	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
1140	and expect Unicode strings, that is, characters with high ordinal Unicode	1268	and expect Unicode strings, that is, characters with high ordinal Unicode
1141	values (> 255) will be encoded as such characters, and likewise such	1269	values (> 255) will be encoded as such characters, and likewise such
1142	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
1143	"(re-)interpreting" them as Unicode codepoints or Unicode characters,	1271	"(re-)interpreting" them as Unicode codepoints or Unicode characters,
1144	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
1145	funny/weird/dumb stuff).	1273	funny/weird/dumb stuff).
1146		1274
1147	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
…		…
1263	output for these property strings, e.g.:	1391	output for these property strings, e.g.:
1264		1392
1265	$json =~ s/"__proto__"\s*:/"__proto__renamed":/g;	1393	$json =~ s/"__proto__"\s*:/"__proto__renamed":/g;
1266		1394
1267	This works because C<__proto__> is not valid outside of strings, so every	1395	This works because C<__proto__> is not valid outside of strings, so every
1268	occurence of C<"__proto__"\s*:> must be a string used as property name.	1396	occurrence of C<"__proto__"\s*:> must be a string used as property name.
1269		1397
1270	If you know of other incompatibilities, please let me know.	1398	If you know of other incompatibilities, please let me know.
1271		1399
1272		1400
1273	=head2 JSON and YAML	1401	=head2 JSON and YAML
…		…
1435	are browser design bugs, but it is still you who will have to deal with	1563	are browser design bugs, but it is still you who will have to deal with
1436	it, as major browser developers care only for features, not about getting	1564	it, as major browser developers care only for features, not about getting
1437	security right).	1565	security right).
1438		1566
1439		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.
		1695
		1696
1440	=head1 THREADS	1697	=head1 THREADS
1441		1698
1442	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
1443	plans to change this until Perl gets thread support (as opposed to the	1700	plans to change this until Perl gets thread support (as opposed to the
1444	horribly slow so-called "threads" which are simply slow and bloated	1701	horribly slow so-called "threads" which are simply slow and bloated
1445	process simulations - use fork, it's I<much> faster, cheaper, better).	1702	process simulations - use fork, it's I<much> faster, cheaper, better).
1446		1703
1447	(It might actually work, but you have been warned).	1704	(It might actually work, but you have been warned).
1448		1705
1449		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
1450	=head1 BUGS	1725	=head1 BUGS
1451		1726
1452	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
1453	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
1454	keep reporting bugs they will be fixed swiftly, though.	1729	keep reporting bugs they will be fixed swiftly, though.
…		…
1456	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
1457	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.
1458		1733
1459	=cut	1734	=cut
1460		1735
1461	our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" };	1736	BEGIN {
1462	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;
1463		1742
1464	sub true() { $true }	1743	JSON::XS::Boolean:: = Types::Serialiser::Boolean::;
1465	sub false() { $false }
1466
1467	sub is_bool($) {
1468	UNIVERSAL::isa $_[0], "JSON::XS::Boolean"
1469	# or UNIVERSAL::isa $_[0], "JSON::Literal"
1470	}	1744	}
1471		1745
1472	XSLoader::load "JSON::XS", $VERSION;	1746	XSLoader::load "JSON::XS", $VERSION;
1473
1474	package JSON::XS::Boolean;
1475
1476	use overload
1477	"0+" => sub { ${$_[0]} },
1478	"++" => sub { $_[0] = ${$_[0]} + 1 },
1479	"--" => sub { $_[0] = ${$_[0]} - 1 },
1480	fallback => 1;
1481
1482	1;
1483		1747
1484	=head1 SEE ALSO	1748	=head1 SEE ALSO
1485		1749
1486	The F<json_xs> command line utility for quick experiments.	1750	The F<json_xs> command line utility for quick experiments.
1487		1751
…		…
1490	Marc Lehmann <schmorp@schmorp.de>	1754	Marc Lehmann <schmorp@schmorp.de>
1491	http://home.schmorp.de/	1755	http://home.schmorp.de/
1492		1756
1493	=cut	1757	=cut
1494		1758
		1759	1
		1760

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Comparing JSON-XS/XS.pm (file contents): Revision 1.135 by root, Wed Jun 1 13:01:09 2011 UTC vs. Revision 1.159 by root, Wed Sep 7 17:14:56 2016 UTC

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Comparing JSON-XS/XS.pm (file contents):
Revision 1.135 by root, Wed Jun 1 13:01:09 2011 UTC vs.
Revision 1.159 by root, Wed Sep 7 17:14:56 2016 UTC