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

Comparing JSON-XS/XS.pm (file contents):
Revision 1.144 by root, Mon Oct 28 23:19:54 2013 UTC vs.
Revision 1.147 by root, Tue Oct 29 00:19:08 2013 UTC

…		…
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 = 2.34;	106	our $VERSION = '3.0';
107	our @ISA = qw(Exporter);	107	our @ISA = qw(Exporter);
108		108
109	our @EXPORT = qw(encode_json decode_json);	109	our @EXPORT = qw(encode_json decode_json);
110		110
111	use Exporter;	111	use Exporter;
…		…
467		467
468	=item $json = $json->allow_blessed ([$enable])	468	=item $json = $json->allow_blessed ([$enable])
469		469
470	=item $enabled = $json->get_allow_blessed	470	=item $enabled = $json->get_allow_blessed
471		471
		472	See L<OBJECT SERIALISATION> for details.
		473
472	If C<$enable> is true (or missing), then the C<encode> method will not	474	If C<$enable> is true (or missing), then the C<encode> method will not
473	barf when it encounters a blessed reference. Instead, the value of the	475	barf when it encounters a blessed reference that it cannot convert
474	B<convert_blessed> option will decide whether C<null> (C<convert_blessed>	476	otherwise. Instead, a JSON C<null> value is encoded instead of the object.
475	disabled or no C<TO_JSON> method found) or a representation of the
476	object (C<convert_blessed> enabled and C<TO_JSON> method found) is being
477	encoded. Has no effect on C<decode>.
478		477
479	If C<$enable> is false (the default), then C<encode> will throw an	478	If C<$enable> is false (the default), then C<encode> will throw an
480	exception when it encounters a blessed object.	479	exception when it encounters a blessed object that it cannot convert
		480	otherwise.
		481
		482	This setting has no effect on C<decode>.
481		483
482	=item $json = $json->convert_blessed ([$enable])	484	=item $json = $json->convert_blessed ([$enable])
483		485
484	=item $enabled = $json->get_convert_blessed	486	=item $enabled = $json->get_convert_blessed
		487
		488	See "OBJECT SERIALISATION" for details.
485		489
486	If C<$enable> is true (or missing), then C<encode>, upon encountering a	490	If C<$enable> is true (or missing), then C<encode>, upon encountering a
487	blessed object, will check for the availability of the C<TO_JSON> method	491	blessed object, will check for the availability of the C<TO_JSON> method
488	on the object's class. If found, it will be called in scalar context	492	on the object's class. If found, it will be called in scalar context and
489	and the resulting scalar will be encoded instead of the object. If no	493	the resulting scalar will be encoded instead of the object.
490	C<TO_JSON> method is found, the value of C<allow_blessed> will decide what
491	to do.
492		494
493	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>	495	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
494	returns other blessed objects, those will be handled in the same	496	returns other blessed objects, those will be handled in the same
495	way. C<TO_JSON> must take care of not causing an endless recursion cycle	497	way. C<TO_JSON> must take care of not causing an endless recursion cycle
496	(== crash) in this case. The name of C<TO_JSON> was chosen because other	498	(== crash) in this case. The name of C<TO_JSON> was chosen because other
497	methods called by the Perl core (== not by the user of the object) are	499	methods called by the Perl core (== not by the user of the object) are
498	usually in upper case letters and to avoid collisions with any C<to_json>	500	usually in upper case letters and to avoid collisions with any C<to_json>
499	function or method.	501	function or method.
500		502
501	This setting does not yet influence C<decode> in any way, but in the	503	If C<$enable> is false (the default), then C<encode> will not consider
502	future, global hooks might get installed that influence C<decode> and are	504	this type of conversion.
503	enabled by this setting.
504		505
505	If C<$enable> is false, then the C<allow_blessed> setting will decide what	506	This setting has no effect on C<decode>.
506	to do when a blessed object is found.	507
		508	=item $json = $json->allow_tags ([$enable])
		509
		510	=item $enabled = $json->allow_tags
		511
		512	See "OBJECT SERIALISATION" for details.
		513
		514	If C<$enable> is true (or missing), then C<encode>, upon encountering a
		515	blessed object, will check for the availability of the C<FREEZE> method on
		516	the object's class. If found, it will be used to serialise the object into
		517	a nonstandard tagged JSON value (that JSON decoders cannot decode).
		518
		519	It also causes C<decode> to parse such tagged JSON values and deserialise
		520	them via a call to the C<THAW> method.
		521
		522	If C<$enable> is false (the default), then C<encode> will not consider
		523	this type of conversion, and tagged JSON values will cause a parse error
		524	in C<decode>, as if tags were not part of the grammar.
507		525
508	=item $json = $json->filter_json_object ([$coderef->($hashref)])	526	=item $json = $json->filter_json_object ([$coderef->($hashref)])
509		527
510	When C<$coderef> is specified, it will be called from C<decode> each	528	When C<$coderef> is specified, it will be called from C<decode> each
511	time it decodes a JSON object. The only argument is a reference to the	529	time it decodes a JSON object. The only argument is a reference to the
…		…
986		1004
987	=item null	1005	=item null
988		1006
989	A JSON null atom becomes C<undef> in Perl.	1007	A JSON null atom becomes C<undef> in Perl.
990		1008
		1009	=item shell-style comments (C<< # I<text> >>)
		1010
		1011	As a nonstandard extension to the JSON syntax that is enabled by the
		1012	C<relaxed> setting, shell-style comments are allowed. They can start
		1013	anywhere outside strings and go till the end of the line.
		1014
		1015	=item tagged values (C<< (I<tag>)I<value> >>).
		1016
		1017	Another nonstandard extension to the JSON syntax, enabled with the
		1018	C<allow_tags> setting, are tagged values. In this implementation, the
		1019	I<tag> must be a perl package/class name encoded as a JSON string, and the
		1020	I<value> must be a JSON array encoding optional constructor arguments.
		1021
		1022	See "OBJECT SERIALISATION", below, for details.
		1023
991	=back	1024	=back
992		1025
993		1026
994	=head2 PERL -> JSON	1027	=head2 PERL -> JSON
995		1028
…		…
1032	and JSON false values, respectively. You can also use C<\1> and C<\0>	1065	and JSON false values, respectively. You can also use C<\1> and C<\0>
1033	directly if you want.	1066	directly if you want.
1034		1067
1035	=item blessed objects	1068	=item blessed objects
1036		1069
1037	Blessed objects are not directly representable in JSON. See the	1070	Blessed objects are not directly representable in JSON, but C<JSON::XS>
1038	C<allow_blessed> and C<convert_blessed> methods on various options on	1071	allows various ways of handling objects. See "OBJECT SERIALISATION",
1039	how to deal with this: basically, you can choose between throwing an	1072	below, for details.
1040	exception, encoding the reference as if it weren't blessed, or provide
1041	your own serialiser method.
1042		1073
1043	=item simple scalars	1074	=item simple scalars
1044		1075
1045	Simple Perl scalars (any scalar that is not a reference) are the most	1076	Simple Perl scalars (any scalar that is not a reference) are the most
1046	difficult objects to encode: JSON::XS will encode undefined scalars as	1077	difficult objects to encode: JSON::XS will encode undefined scalars as
…		…
1082	extensions to the floating point numbers of your platform, such as	1113	extensions to the floating point numbers of your platform, such as
1083	infinities or NaN's - these cannot be represented in JSON, and it is an	1114	infinities or NaN's - these cannot be represented in JSON, and it is an
1084	error to pass those in.	1115	error to pass those in.
1085		1116
1086	=back	1117	=back
		1118
		1119	=head2 OBJECT SERIALISATION
		1120
		1121	As JSON cannot directly represent Perl objects, you have to choose between
		1122	a pure JSON representation (without the ability to deserialise the object
		1123	automatically again), and a nonstandard extension to the JSON syntax,
		1124	tagged values.
		1125
		1126	=head3 SERIALISATION
		1127
		1128	What happens when C<JSON::XS> encounters a Perl object depends on the
		1129	C<allow_blessed>, C<convert_blessed> and C<allow_tags> settings, which are
		1130	used in this order:
		1131
		1132	=over 4
		1133
		1134	=item 1. C<allow_tags> is enabled and object has a C<FREEZE> method.
		1135
		1136	In this case, C<JSON::XS> uses the L<Types::Serialiser> object
		1137	serialisation protocol to create a tagged JSON value, using a nonstandard
		1138	extension to the JSON syntax.
		1139
		1140	This works by invoking the C<FREEZE> method on the object, with the first
		1141	argument being the object to serialise, and the second argument being the
		1142	constant string C<JSON> to distinguish it from other serialisers.
		1143
		1144	The C<FREEZE> method can return any number of values (i.e. zero or
		1145	more). These values and the paclkage/classname of the object will then be
		1146	encoded as a tagged JSON value in the following format:
		1147
		1148	("classname")[FREEZE return values...]
		1149
		1150	For example, the hypothetical C<My::Object> C<FREEZE> method might use the
		1151	objects C<type> and C<id> members to encode the object:
		1152
		1153	sub My::Object::FREEZE {
		1154	my ($self, $serialiser) = @_;
		1155
		1156	($self->{type}, $self->{id})
		1157	}
		1158
		1159	=item 2. C<convert_blessed> is enabled and object has a C<TO_JSON> method.
		1160
		1161	In this case, the C<TO_JSON> method of the object is invoked in scalar
		1162	context. It must return a single scalar that can be directly encoded into
		1163	JSON. This scalar replaces the object in the JSON text.
		1164
		1165	For example, the following C<TO_JSON> method will convert all L<URI>
		1166	objects to JSON strings when serialised. The fatc that these values
		1167	originally were L<URI> objects is lost.
		1168
		1169	sub URI::TO_JSON {
		1170	my ($uri) = @_;
		1171	$uri->as_string
		1172	}
		1173
		1174	=item 3. C<allow_blessed> is enabled.
		1175
		1176	The object will be serialised as a JSON null value.
		1177
		1178	=item 4. none of the above
		1179
		1180	If none of the settings are enabled or the respective methods are missing,
		1181	C<JSON::XS> throws an exception.
		1182
		1183	=back
		1184
		1185	=head3 DESERIALISATION
		1186
		1187	For deserialisation there are only two cases to consider: either
		1188	nonstandard tagging was used, in which case C<allow_tags> decides,
		1189	or objects cannot be automatically be deserialised, in which
		1190	case you can use postprocessing or the C<filter_json_object> or
		1191	C<filter_json_single_key_object> callbacks to get some real objects our of
		1192	your JSON.
		1193
		1194	This section only considers the tagged value case: I a tagged JSON object
		1195	is encountered during decoding and C<allow_tags> is disabled, a parse
		1196	error will result (as if tagged values were not part of the grammar).
		1197
		1198	If C<allow_tags> is enabled, C<JSON::XS> will look up the C<THAW> method
		1199	of the package/classname used during serialisation (it will not attempt
		1200	to load the package as a Perl module). If there is no such method, the
		1201	decoding will fail with an error.
		1202
		1203	Otherwise, the C<THAW> method is invoked with the classname as first
		1204	argument, the constant string C<JSON> as second argument, and all the
		1205	values from the JSON array (the values originally returned by the
		1206	C<FREEZE> method) as remaining arguments.
		1207
		1208	The method must then return the object. While technically you can return
		1209	any Perl scalar, you might have to enable the C<enable_nonref> setting to
		1210	make that work in all cases, so better return an actual blessed reference.
		1211
		1212	As an example, let's implement a C<THAW> function that regenerates the
		1213	C<My::Object> from the C<FREEZE> example earlier:
		1214
		1215	sub My::Object::THAW {
		1216	my ($class, $serialiser, $type, $id) = @_;
		1217
		1218	$class->new (type => $type, id => $id)
		1219	}
1087		1220
1088		1221
1089	=head1 ENCODING/CODESET FLAG NOTES	1222	=head1 ENCODING/CODESET FLAG NOTES
1090		1223
1091	The interested reader might have seen a number of flags that signify	1224	The interested reader might have seen a number of flags that signify

Diff Legend

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

Comparing JSON-XS/XS.pm (file contents): Revision 1.144 by root, Mon Oct 28 23:19:54 2013 UTC vs. Revision 1.147 by root, Tue Oct 29 00:19:08 2013 UTC

Diff Legend

Comparing JSON-XS/XS.pm (file contents):
Revision 1.144 by root, Mon Oct 28 23:19:54 2013 UTC vs.
Revision 1.147 by root, Tue Oct 29 00:19:08 2013 UTC