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

Comparing JSON-XS/XS.pm (file contents):
Revision 1.41 by root, Mon Jun 11 03:45:26 2007 UTC vs.
Revision 1.51 by root, Mon Jul 2 01:12:27 2007 UTC

…		…
9	# exported functions, they croak on error	9	# exported functions, they croak on error
10	# and expect/generate UTF-8	10	# and expect/generate UTF-8
11		11
12	$utf8_encoded_json_text = to_json $perl_hash_or_arrayref;	12	$utf8_encoded_json_text = to_json $perl_hash_or_arrayref;
13	$perl_hash_or_arrayref = from_json $utf8_encoded_json_text;	13	$perl_hash_or_arrayref = from_json $utf8_encoded_json_text;
14
15	# objToJson and jsonToObj aliases to to_json and from_json
16	# are exported for compatibility to the JSON module,
17	# but should not be used in new code.
18		14
19	# OO-interface	15	# OO-interface
20		16
21	$coder = JSON::XS->new->ascii->pretty->allow_nonref;	17	$coder = JSON::XS->new->ascii->pretty->allow_nonref;
22	$pretty_printed_unencoded = $coder->encode ($perl_scalar);	18	$pretty_printed_unencoded = $coder->encode ($perl_scalar);
…		…
85		81
86	package JSON::XS;	82	package JSON::XS;
87		83
88	use strict;	84	use strict;
89		85
90	BEGIN {
91	our $VERSION = '1.24';	86	our $VERSION = '1.4';
92	our @ISA = qw(Exporter);	87	our @ISA = qw(Exporter);
93		88
94	our @EXPORT = qw(to_json from_json objToJson jsonToObj);	89	our @EXPORT = qw(to_json from_json);
95	require Exporter;
96		90
97	require XSLoader;	91	use Exporter;
98	XSLoader::load JSON::XS::, $VERSION;	92	use XSLoader;
99	}
100		93
101	=head1 FUNCTIONAL INTERFACE	94	=head1 FUNCTIONAL INTERFACE
102		95
103	The following convinience methods are provided by this module. They are	96	The following convinience methods are provided by this module. They are
104	exported by default:	97	exported by default:
…		…
126	This function call is functionally identical to:	119	This function call is functionally identical to:
127		120
128	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)	121	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)
129		122
130	except being faster.	123	except being faster.
		124
		125	=item $is_boolean = JSON::XS::is_bool $scalar
		126
		127	Returns true if the passed scalar represents either JSON::XS::true or
		128	JSON::XS::false, two constants that act like C<1> and C<0>, respectively
		129	and are used to represent JSON C<true> and C<false> values in Perl.
		130
		131	See MAPPING, below, for more information on how JSON values are mapped to
		132	Perl.
131		133
132	=back	134	=back
133		135
134		136
135	=head1 OBJECT-ORIENTED INTERFACE	137	=head1 OBJECT-ORIENTED INTERFACE
…		…
309	Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>,	311	Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>,
310	resulting in an invalid JSON text:	312	resulting in an invalid JSON text:
311		313
312	JSON::XS->new->allow_nonref->encode ("Hello, World!")	314	JSON::XS->new->allow_nonref->encode ("Hello, World!")
313	=> "Hello, World!"	315	=> "Hello, World!"
		316
		317	=item $json = $json->allow_blessed ([$enable])
		318
		319	If C<$enable> is true (or missing), then the C<encode> method will not
		320	barf when it encounters a blessed reference. Instead, the value of the
		321	B<convert_blessed> option will decide wether C<null> (C<convert_blessed>
		322	disabled or no C<to_json> method found) or a representation of the
		323	object (C<convert_blessed> enabled and C<to_json> method found) is being
		324	encoded. Has no effect on C<decode>.
		325
		326	If C<$enable> is false (the default), then C<encode> will throw an
		327	exception when it encounters a blessed object.
		328
		329	=item $json = $json->convert_blessed ([$enable])
		330
		331	If C<$enable> is true (or missing), then C<encode>, upon encountering a
		332	blessed object, will check for the availability of the C<TO_JSON> method
		333	on the object's class. If found, it will be called in scalar context
		334	and the resulting scalar will be encoded instead of the object. If no
		335	C<TO_JSON> method is found, the value of C<allow_blessed> will decide what
		336	to do.
		337
		338	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
		339	returns other blessed objects, those will be handled in the same
		340	way. C<TO_JSON> must take care of not causing an endless recursion cycle
		341	(== crash) in this case. The name of C<TO_JSON> was chosen because other
		342	methods called by the Perl core (== not by the user of the object) are
		343	usually in upper case letters and to avoid collisions with the C<to_json>
		344	function.
		345
		346	This setting does not yet influence C<decode> in any way, but in the
		347	future, global hooks might get installed that influence C<decode> and are
		348	enabled by this setting.
		349
		350	If C<$enable> is false, then the C<allow_blessed> setting will decide what
		351	to do when a blessed object is found.
		352
		353	=item $json = $json->filter_json_object ([$coderef])
		354
		355	When C<$coderef> is specified, it will be called from C<decode> each
		356	time it decodes a JSON object. The only argument is a reference to the
		357	newly-created hash. If the code references returns a single scalar (which
		358	need not be a reference), this value (i.e. a copy of that scalar to avoid
		359	aliasing) is inserted into the deserialised data structure. If it returns
		360	an empty list (NOTE: I<not> C<undef>, which is a valid scalar), the
		361	original deserialised hash will be inserted. This setting can slow down
		362	decoding considerably.
		363
		364	When C<$coderef> is omitted or undefined, C<decode> will not change the
		365	deserialised hash in any way. This is maximally fast.
		366
		367	Example, convert all JSON objects into the integer 5:
		368
		369	my $js = JSON::XS->new->filter_json_object (sub { 5 });
		370	# returns [5]
		371	$js->decode ('[{}]')
		372	# throw an exception because allow_nonref is not enabled:
		373	$js->decode ('{"a":1, "b":2}');
		374
		375	=item $json = $json->filter_json_single_key_object ([$coderef])
		376
		377	Works like C<filter_json_object>, but is only called for JSON objects
		378	having only a single key.
		379
		380	This C<$coderef> is called before the one specified via
		381	C<filter_json_object>, if any. If it returns something, that will be
		382	inserted into the data structure. If it returns nothing, the callback
		383	from C<filter_json_object> will be called next. If you want to force
		384	insertion of single-key objects even in the presence of a mutating
		385	C<filter_json_object> callback, simply return the passed hash.
		386
		387	As this callback gets called less often then the C<filter_json_object>
		388	one, decoding speed will not usually suffer as much. Therefore, single-key
		389	objects make excellent targets to serialise Perl objects into, especially
		390	as single-key JSON objects are as close to the type-tagged value concept
		391	as JSON gets (its basically an ID/VALUE tuple). Of course, JSON does not
		392	support this in any way, so you need to make sure your data never looks
		393	like a serialised Perl hash.
		394
		395	Typical names for the single object key are C<__class_whatever__>, or
		396	C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even
		397	things like C<__class_md5sum(classname)__>, to reduce the risk of clashing
		398	with real hashes.
		399
		400	Example, decode JSON objects of the form C<< { "__widget__" => <id> } >>
		401	into the corresponding C<< $WIDGET{<id>} >> object:
		402
		403	# return whatever is in $WIDGET{5}:
		404	JSON::XS
		405	->new
		406	->filter_json_single_key_object (sub {
		407	exists $_[0]{__widget__}
		408	? $WIDGET{ $_[0]{__widget__} }
		409	: ()
		410	})
		411	->decode ('{"__widget__": 5')
		412
		413	# this can be used with a TO_JSON method in some "widget" class
		414	# for serialisation to json:
		415	sub WidgetBase::TO_JSON {
		416	my ($self) = @_;
		417
		418	unless ($self->{id}) {
		419	$self->{id} = ..get..some..id..;
		420	$WIDGET{$self->{id}} = $self;
		421	}
		422
		423	{ __widget__ => $self->{id} }
		424	}
314		425
315	=item $json = $json->shrink ([$enable])	426	=item $json = $json->shrink ([$enable])
316		427
317	Perl usually over-allocates memory a bit when allocating space for	428	Perl usually over-allocates memory a bit when allocating space for
318	strings. This flag optionally resizes strings generated by either	429	strings. This flag optionally resizes strings generated by either
…		…
351	given character in a string.	462	given character in a string.
352		463
353	Setting the maximum depth to one disallows any nesting, so that ensures	464	Setting the maximum depth to one disallows any nesting, so that ensures
354	that the object is only a single hash/object or array.	465	that the object is only a single hash/object or array.
355		466
356	The argument to C<max_depth> will be rounded up to the next nearest power	467	The argument to C<max_depth> will be rounded up to the next highest power
357	of two.	468	of two. If no argument is given, the highest possible setting will be
		469	used, which is rarely useful.
		470
		471	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
		472
		473	=item $json = $json->max_size ([$maximum_string_size])
		474
		475	Set the maximum length a JSON text may have (in bytes) where decoding is
		476	being attempted. The default is C<0>, meaning no limit. When C<decode>
		477	is called on a string longer then this number of characters it will not
		478	attempt to decode the string but throw an exception. This setting has no
		479	effect on C<encode> (yet).
		480
		481	The argument to C<max_size> will be rounded up to the next B<highest>
		482	power of two (so may be more than requested). If no argument is given, the
		483	limit check will be deactivated (same as when C<0> is specified).
358		484
359	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.	485	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
360		486
361	=item $json_text = $json->encode ($perl_scalar)	487	=item $json_text = $json->encode ($perl_scalar)
362		488
…		…
432	conversion details, but an integer may take slightly less memory and might	558	conversion details, but an integer may take slightly less memory and might
433	represent more values exactly than (floating point) numbers.	559	represent more values exactly than (floating point) numbers.
434		560
435	=item true, false	561	=item true, false
436		562
437	These JSON atoms become C<0>, C<1>, respectively. Information is lost in	563	These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,
438	this process. Future versions might represent those values differently,	564	respectively. They are overloaded to act almost exactly like the numbers
439	but they will be guarenteed to act like these integers would normally in	565	C<1> and C<0>. You can check wether a scalar is a JSON boolean by using
440	Perl.	566	the C<JSON::XS::is_bool> function.
441		567
442	=item null	568	=item null
443		569
444	A JSON null atom becomes C<undef> in Perl.	570	A JSON null atom becomes C<undef> in Perl.
445		571
…		…
477	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can	603	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can
478	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.	604	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
479		605
480	to_json [\0,JSON::XS::true] # yields [false,true]	606	to_json [\0,JSON::XS::true] # yields [false,true]
481		607
		608	=item JSON::XS::true, JSON::XS::false
		609
		610	These special values become JSON true and JSON false values,
		611	respectively. You cna alos use C<\1> and C<\0> directly if you want.
		612
482	=item blessed objects	613	=item blessed objects
483		614
484	Blessed objects are not allowed. JSON::XS currently tries to encode their	615	Blessed objects are not allowed. JSON::XS currently tries to encode their
485	underlying representation (hash- or arrayref), but this behaviour might	616	underlying representation (hash- or arrayref), but this behaviour might
486	change in future versions.	617	change in future versions.
…		…
649	It shows the number of encodes/decodes per second (JSON::XS uses	780	It shows the number of encodes/decodes per second (JSON::XS uses
650	the functional interface, while JSON::XS/2 uses the OO interface	781	the functional interface, while JSON::XS/2 uses the OO interface
651	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables	782	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables
652	shrink). Higher is better:	783	shrink). Higher is better:
653		784
		785	Storable \| 15779.925 \| 14169.946 \|
		786	-----------+------------+------------+
654	module \| encode \| decode \|	787	module \| encode \| decode \|
655	-----------\|------------\|------------\|	788	-----------\|------------\|------------\|
656	JSON \| 7645.468 \| 4208.613 \|	789	JSON \| 4990.842 \| 4088.813 \|
657	JSON::DWIW \| 40721.398 \| 77101.176 \|	790	JSON::DWIW \| 51653.990 \| 71575.154 \|
658	JSON::PC \| 65948.176 \| 78251.940 \|	791	JSON::PC \| 65948.176 \| 74631.744 \|
659	JSON::Syck \| 22844.793 \| 26479.192 \|	792	JSON::PP \| 8931.652 \| 3817.168 \|
		793	JSON::Syck \| 24877.248 \| 27776.848 \|
660	JSON::XS \| 388361.481 \| 199728.762 \|	794	JSON::XS \| 388361.481 \| 227951.304 \|
661	JSON::XS/2 \| 218453.333 \| 192399.266 \|	795	JSON::XS/2 \| 227951.304 \| 218453.333 \|
662	JSON::XS/3 \| 338250.323 \| 192399.266 \|	796	JSON::XS/3 \| 338250.323 \| 218453.333 \|
663	Storable \| 15779.925 \| 14169.946 \|	797	Storable \| 16500.016 \| 135300.129 \|
664	-----------+------------+------------+	798	-----------+------------+------------+
665		799
666	That is, JSON::XS is about five times faster than JSON::DWIW on encoding,	800	That is, JSON::XS is about five times faster than JSON::DWIW on encoding,
667	about three times faster on decoding, and over fourty times faster	801	about three times faster on decoding, and over fourty times faster
668	than JSON, even with pretty-printing and key sorting. It also compares	802	than JSON, even with pretty-printing and key sorting. It also compares
…		…
671	Using a longer test string (roughly 18KB, generated from Yahoo! Locals	805	Using a longer test string (roughly 18KB, generated from Yahoo! Locals
672	search API (http://nanoref.com/yahooapis/mgPdGg):	806	search API (http://nanoref.com/yahooapis/mgPdGg):
673		807
674	module \| encode \| decode \|	808	module \| encode \| decode \|
675	-----------\|------------\|------------\|	809	-----------\|------------\|------------\|
676	JSON \| 254.685 \| 37.665 \|	810	JSON \| 55.260 \| 34.971 \|
677	JSON::DWIW \| 843.343 \| 1049.731 \|	811	JSON::DWIW \| 825.228 \| 1082.513 \|
678	JSON::PC \| 3602.116 \| 2307.352 \|	812	JSON::PC \| 3571.444 \| 2394.829 \|
		813	JSON::PP \| 210.987 \| 32.574 \|
679	JSON::Syck \| 505.107 \| 787.899 \|	814	JSON::Syck \| 552.551 \| 787.544 \|
680	JSON::XS \| 5747.196 \| 3690.220 \|	815	JSON::XS \| 5780.463 \| 4854.519 \|
681	JSON::XS/2 \| 3968.121 \| 3676.634 \|	816	JSON::XS/2 \| 3869.998 \| 4798.975 \|
682	JSON::XS/3 \| 6105.246 \| 3662.508 \|	817	JSON::XS/3 \| 5862.880 \| 4798.975 \|
683	Storable \| 4417.337 \| 5285.161 \|	818	Storable \| 4445.002 \| 5235.027 \|
684	-----------+------------+------------+	819	-----------+------------+------------+
685		820
686	Again, JSON::XS leads by far (except for Storable which non-surprisingly	821	Again, JSON::XS leads by far (except for Storable which non-surprisingly
687	decodes faster).	822	decodes faster).
688		823
…		…
705	Second, you need to avoid resource-starving attacks. That means you should	840	Second, you need to avoid resource-starving attacks. That means you should
706	limit the size of JSON texts you accept, or make sure then when your	841	limit the size of JSON texts you accept, or make sure then when your
707	resources run out, thats just fine (e.g. by using a separate process that	842	resources run out, thats just fine (e.g. by using a separate process that
708	can crash safely). The size of a JSON text in octets or characters is	843	can crash safely). The size of a JSON text in octets or characters is
709	usually a good indication of the size of the resources required to decode	844	usually a good indication of the size of the resources required to decode
710	it into a Perl structure.	845	it into a Perl structure. While JSON::XS can check the size of the JSON
		846	text, it might be too late when you already have it in memory, so you
		847	might want to check the size before you accept the string.
711		848
712	Third, JSON::XS recurses using the C stack when decoding objects and	849	Third, JSON::XS recurses using the C stack when decoding objects and
713	arrays. The C stack is a limited resource: for instance, on my amd64	850	arrays. The C stack is a limited resource: for instance, on my amd64
714	machine with 8MB of stack size I can decode around 180k nested arrays but	851	machine with 8MB of stack size I can decode around 180k nested arrays but
715	only 14k nested JSON objects (due to perl itself recursing deeply on croak	852	only 14k nested JSON objects (due to perl itself recursing deeply on croak
…		…
720		857
721	And last but least, something else could bomb you that I forgot to think	858	And last but least, something else could bomb you that I forgot to think
722	of. In that case, you get to keep the pieces. I am always open for hints,	859	of. In that case, you get to keep the pieces. I am always open for hints,
723	though...	860	though...
724		861
		862	If you are using JSON::XS to return packets to consumption
		863	by javascript scripts in a browser you should have a look at
		864	L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether
		865	you are vulnerable to some common attack vectors (which really are browser
		866	design bugs, but it is still you who will have to deal with it, as major
		867	browser developers care only for features, not about doing security
		868	right).
		869
725		870
726	=head1 BUGS	871	=head1 BUGS
727		872
728	While the goal of this module is to be correct, that unfortunately does	873	While the goal of this module is to be correct, that unfortunately does
729	not mean its bug-free, only that I think its design is bug-free. It is	874	not mean its bug-free, only that I think its design is bug-free. It is
730	still relatively early in its development. If you keep reporting bugs they	875	still relatively early in its development. If you keep reporting bugs they
731	will be fixed swiftly, though.	876	will be fixed swiftly, though.
732		877
733	=cut	878	=cut
734		879
		880	our $true = do { bless \(my $dummy = "1"), "JSON::XS::Boolean" };
		881	our $false = do { bless \(my $dummy = "0"), "JSON::XS::Boolean" };
		882
735	sub true() { \1 }	883	sub true() { $true }
736	sub false() { \0 }	884	sub false() { $false }
		885
		886	sub is_bool($) {
		887	UNIVERSAL::isa $_[0], "JSON::XS::Boolean"
		888	# or UNIVERSAL::isa $_[0], "JSON::Literal"
		889	}
		890
		891	XSLoader::load "JSON::XS", $VERSION;
		892
		893	package JSON::XS::Boolean;
		894
		895	use overload
		896	"0+" => sub { ${$_[0]} },
		897	"++" => sub { $_[0] = ${$_[0]} + 1 },
		898	"--" => sub { $_[0] = ${$_[0]} - 1 },
		899	fallback => 1;
737		900
738	1;	901	1;
739		902
740	=head1 AUTHOR	903	=head1 AUTHOR
741		904

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Comparing JSON-XS/XS.pm (file contents): Revision 1.41 by root, Mon Jun 11 03:45:26 2007 UTC vs. Revision 1.51 by root, Mon Jul 2 01:12:27 2007 UTC

Diff Legend

Comparing JSON-XS/XS.pm (file contents):
Revision 1.41 by root, Mon Jun 11 03:45:26 2007 UTC vs.
Revision 1.51 by root, Mon Jul 2 01:12:27 2007 UTC