[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 1.155 by root, Mon Nov 24 18:42:51 2014 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 = 3.01;
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;
…		…
404	[	404	[
405	1, # this comment not allowed in JSON	405	1, # this comment not allowed in JSON
406	# neither this one...	406	# neither this one...
407	]	407	]
408		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
409	=back	419	=back
410		420
411	=item $json = $json->canonical ([$enable])	421	=item $json = $json->canonical ([$enable])
412		422
413	=item $enabled = $json->get_canonical	423	=item $enabled = $json->get_canonical
…		…
467		477
468	=item $json = $json->allow_blessed ([$enable])	478	=item $json = $json->allow_blessed ([$enable])
469		479
470	=item $enabled = $json->get_allow_blessed	480	=item $enabled = $json->get_allow_blessed
471		481
		482	See L<OBJECT SERIALISATION> for details.
		483
472	If C<$enable> is true (or missing), then the C<encode> method will not	484	If C<$enable> is true (or missing), then the C<encode> method will not
473	barf when it encounters a blessed reference. Instead, the value of the	485	barf when it encounters a blessed reference that it cannot convert
474	B<convert_blessed> option will decide whether C<null> (C<convert_blessed>	486	otherwise. Instead, a JSON C<null> value is encoded instead of the object.
475	disabled or no C<TO_JSON> method found) or a representation of the
476	object (C<convert_blessed> enabled and C<TO_JSON> method found) is being
477	encoded. Has no effect on C<decode>.
478		487
479	If C<$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
480	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>.
481		493
482	=item $json = $json->convert_blessed ([$enable])	494	=item $json = $json->convert_blessed ([$enable])
483		495
484	=item $enabled = $json->get_convert_blessed	496	=item $enabled = $json->get_convert_blessed
		497
		498	See L<OBJECT SERIALISATION> for details.
485		499
486	If C<$enable> is true (or missing), then C<encode>, upon encountering a	500	If C<$enable> is true (or missing), then C<encode>, upon encountering a
487	blessed object, will check for the availability of the C<TO_JSON> method	501	blessed object, will check for the availability of the C<TO_JSON> method
488	on the object's class. If found, it will be called in scalar context	502	on the object's class. If found, it will be called in scalar context and
489	and the resulting scalar will be encoded instead of the object. If no	503	the resulting scalar will be encoded instead of the object.
490	C<TO_JSON> method is found, the value of C<allow_blessed> will decide what
491	to do.
492		504
493	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>	505	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
494	returns other blessed objects, those will be handled in the same	506	returns other blessed objects, those will be handled in the same
495	way. C<TO_JSON> must take care of not causing an endless recursion cycle	507	way. C<TO_JSON> must take care of not causing an endless recursion cycle
496	(== crash) in this case. The name of C<TO_JSON> was chosen because other	508	(== crash) in this case. The name of C<TO_JSON> was chosen because other
497	methods called by the Perl core (== not by the user of the object) are	509	methods called by the Perl core (== not by the user of the object) are
498	usually in upper case letters and to avoid collisions with any C<to_json>	510	usually in upper case letters and to avoid collisions with any C<to_json>
499	function or method.	511	function or method.
500		512
501	This setting does not yet influence C<decode> in any way, but in the	513	If C<$enable> is false (the default), then C<encode> will not consider
502	future, global hooks might get installed that influence C<decode> and are	514	this type of conversion.
503	enabled by this setting.
504		515
505	If C<$enable> is false, then the C<allow_blessed> setting will decide what	516	This setting has no effect on C<decode>.
506	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.
507		535
508	=item $json = $json->filter_json_object ([$coderef->($hashref)])	536	=item $json = $json->filter_json_object ([$coderef->($hashref)])
509		537
510	When C<$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
511	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
…		…
986		1014
987	=item null	1015	=item null
988		1016
989	A JSON null atom becomes C<undef> in Perl.	1017	A JSON null atom becomes C<undef> in Perl.
990		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.
		1033
991	=back	1034	=back
992		1035
993		1036
994	=head2 PERL -> JSON	1037	=head2 PERL -> JSON
995		1038
…		…
1032	and JSON false values, respectively. You can also use C<\1> and C<\0>	1075	and JSON false values, respectively. You can also use C<\1> and C<\0>
1033	directly if you want.	1076	directly if you want.
1034		1077
1035	=item blessed objects	1078	=item blessed objects
1036		1079
1037	Blessed objects are not directly representable in JSON. See the	1080	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	1081	allows various ways of handling objects. See L<OBJECT SERIALISATION>,
1039	how to deal with this: basically, you can choose between throwing an	1082	below, for details.
1040	exception, encoding the reference as if it weren't blessed, or provide
1041	your own serialiser method.
1042		1083
1043	=item simple scalars	1084	=item simple scalars
1044		1085
1045	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
1046	difficult objects to encode: JSON::XS will encode undefined scalars as	1087	difficult objects to encode: JSON::XS will encode undefined scalars as
…		…
1082	extensions to the floating point numbers of your platform, such as	1123	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	1124	infinities or NaN's - these cannot be represented in JSON, and it is an
1084	error to pass those in.	1125	error to pass those in.
1085		1126
1086	=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	}
1087		1236
1088		1237
1089	=head1 ENCODING/CODESET FLAG NOTES	1238	=head1 ENCODING/CODESET FLAG NOTES
1090		1239
1091	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
…		…
1422	constants. That means that the JSON true and false values will be	1571	constants. That means that the JSON true and false values will be
1423	comaptible to true and false values of iother modules that do the same,	1572	comaptible to true and false values of iother modules that do the same,
1424	such as L<JSON::PP> and L<CBOR::XS>.	1573	such as L<JSON::PP> and L<CBOR::XS>.
1425		1574
1426		1575
		1576	=head1 INTEROPERABILITY WITH OTHER JSON DECODERS
		1577
		1578	As long as you only serialise data that can be directly expressed in JSON,
		1579	C<JSON::XS> is incapable of generating invalid JSON output (modulo bugs,
		1580	but C<JSON::XS> has found more bugs in the official JSON testsuite (1)
		1581	than the official JSON testsuite has found in C<JSON::XS> (0)).
		1582
		1583	When you have trouble decoding JSON generated by this module using other
		1584	decoders, then it is very likely that you have an encoding mismatch or the
		1585	other decoder is broken.
		1586
		1587	When decoding, C<JSON::XS> is strict by default and will likely catch all
		1588	errors. There are currently two settings that change this: C<relaxed>
		1589	makes C<JSON::XS> accept (but not generate) some non-standard extensions,
		1590	and C<allow_tags> will allow you to encode and decode Perl objects, at the
		1591	cost of not outputting valid JSON anymore.
		1592
		1593	=head2 TAGGED VALUE SYNTAX AND STANDARD JSON EN/DECODERS
		1594
		1595	When you use C<allow_tags> to use the extended (and also nonstandard and
		1596	invalid) JSON syntax for serialised objects, and you still want to decode
		1597	the generated When you want to serialise objects, you can run a regex
		1598	to replace the tagged syntax by standard JSON arrays (it only works for
		1599	"normal" packagesnames without comma, newlines or single colons). First,
		1600	the readable Perl version:
		1601
		1602	# if your FREEZE methods return no values, you need this replace first:
		1603	$json =~ s/$ \s* (" (?: [^\\":,]+\|\\.\|::)* ") \s* $ \s* \[\s*\]/[$1]/gx;
		1604
		1605	# this works for non-empty constructor arg lists:
		1606	$json =~ s/$ \s* (" (?: [^\\":,]+\|\\.\|::)* ") \s* $ \s* \[/[$1,/gx;
		1607
		1608	And here is a less readable version that is easy to adapt to other
		1609	languages:
		1610
		1611	$json =~ s/$\s("([^\\":,]+\|\\.\|::)")\s$\s\[/[$1,/g;
		1612
		1613	Here is an ECMAScript version (same regex):
		1614
		1615	json = json.replace (/$\s("([^\\":,]+\|\\.\|::)")\s$\s\[/g, "[$1,");
		1616
		1617	Since this syntax converts to standard JSON arrays, it might be hard to
		1618	distinguish serialised objects from normal arrays. You can prepend a
		1619	"magic number" as first array element to reduce chances of a collision:
		1620
		1621	$json =~ s/$\s("([^\\":,]+\|\\.\|::)")\s$\s\[/["XU1peReLzT4ggEllLanBYq4G9VzliwKF",$1,/g;
		1622
		1623	And after decoding the JSON text, you could walk the data
		1624	structure looking for arrays with a first element of
		1625	C<XU1peReLzT4ggEllLanBYq4G9VzliwKF>.
		1626
		1627	The same approach can be used to create the tagged format with another
		1628	encoder. First, you create an array with the magic string as first member,
		1629	the classname as second, and constructor arguments last, encode it as part
		1630	of your JSON structure, and then:
		1631
		1632	$json =~ s/\[\s"XU1peReLzT4ggEllLanBYq4G9VzliwKF"\s,\s("([^\\":,]+\|\\.\|::)")\s*,/($1)[/g;
		1633
		1634	Again, this has some limitations - the magic string must not be encoded
		1635	with character escapes, and the constructor arguments must be non-empty.
		1636
		1637
		1638	=head1 RFC7159
		1639
		1640	Since this module was written, Google has written a new JSON RFC, RFC 7159
		1641	(and RFC7158). Unfortunately, this RFC breaks compatibility with both the
		1642	original JSON specification on www.json.org and RFC4627.
		1643
		1644	As far as I can see, you can get partial compatibility when parsing by
		1645	using C<< ->allow_nonref >>. However, consider thew security implications
		1646	of doing so.
		1647
		1648	I haven't decided yet when to break compatibility with RFC4627 by default
		1649	(and potentially leave applications insecure) and change the default to
		1650	follow RFC7159, but application authors are well advised to call C<<
		1651	->allow_nonref(0) >> even if this is the current default, if they cannot
		1652	handle non-reference values, in preparation for the day when the4 default
		1653	will change.
		1654
		1655
1427	=head1 THREADS	1656	=head1 THREADS
1428		1657
1429	This module is I<not> guaranteed to be thread safe and there are no	1658	This module is I<not> guaranteed to be thread safe and there are no
1430	plans to change this until Perl gets thread support (as opposed to the	1659	plans to change this until Perl gets thread support (as opposed to the
1431	horribly slow so-called "threads" which are simply slow and bloated	1660	horribly slow so-called "threads" which are simply slow and bloated

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Comparing JSON-XS/XS.pm (file contents): Revision 1.144 by root, Mon Oct 28 23:19:54 2013 UTC vs. Revision 1.155 by root, Mon Nov 24 18:42:51 2014 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 1.155 by root, Mon Nov 24 18:42:51 2014 UTC