[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 1.59 by root, Mon Aug 27 01:49:01 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 = '1.5';
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
…		…
276		278
277	Example, space_before and indent disabled, space_after enabled:	279	Example, space_before and indent disabled, space_after enabled:
278		280
279	{"key": "value"}	281	{"key": "value"}
280		282
		283	=item $json = $json->relaxed ([$enable])
		284
		285	If C<$enable> is true (or missing), then C<decode> will accept some
		286	extensions to normal JSON syntax (see below). C<encode> will not be
		287	affected in anyway. I<Be aware that this option makes you accept invalid
		288	JSON texts as if they were valid!>. I suggest only to use this option to
		289	parse application-specific files written by humans (configuration files,
		290	resource files etc.)
		291
		292	If C<$enable> is false (the default), then C<decode> will only accept
		293	valid JSON texts.
		294
		295	Currently accepted extensions are:
		296
		297	=over 4
		298
		299	=item * list items can have an end-comma
		300
		301	JSON I<separates> array elements and key-value pairs with commas. This
		302	can be annoying if you write JSON texts manually and want to be able to
		303	quickly append elements, so this extension accepts comma at the end of
		304	such items not just between them:
		305
		306	[
		307	1,
		308	2, <- this comma not normally allowed
		309	]
		310	{
		311	"k1": "v1",
		312	"k2": "v2", <- this comma not normally allowed
		313	}
		314
		315	=back
		316
281	=item $json = $json->canonical ([$enable])	317	=item $json = $json->canonical ([$enable])
282		318
283	If C<$enable> is true (or missing), then the C<encode> method will output JSON objects	319	If C<$enable> is true (or missing), then the C<encode> method will output JSON objects
284	by sorting their keys. This is adding a comparatively high overhead.	320	by sorting their keys. This is adding a comparatively high overhead.
285		321
…		…
309	Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>,	345	Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>,
310	resulting in an invalid JSON text:	346	resulting in an invalid JSON text:
311		347
312	JSON::XS->new->allow_nonref->encode ("Hello, World!")	348	JSON::XS->new->allow_nonref->encode ("Hello, World!")
313	=> "Hello, World!"	349	=> "Hello, World!"
		350
		351	=item $json = $json->allow_blessed ([$enable])
		352
		353	If C<$enable> is true (or missing), then the C<encode> method will not
		354	barf when it encounters a blessed reference. Instead, the value of the
		355	B<convert_blessed> option will decide wether C<null> (C<convert_blessed>
		356	disabled or no C<to_json> method found) or a representation of the
		357	object (C<convert_blessed> enabled and C<to_json> method found) is being
		358	encoded. Has no effect on C<decode>.
		359
		360	If C<$enable> is false (the default), then C<encode> will throw an
		361	exception when it encounters a blessed object.
		362
		363	=item $json = $json->convert_blessed ([$enable])
		364
		365	If C<$enable> is true (or missing), then C<encode>, upon encountering a
		366	blessed object, will check for the availability of the C<TO_JSON> method
		367	on the object's class. If found, it will be called in scalar context
		368	and the resulting scalar will be encoded instead of the object. If no
		369	C<TO_JSON> method is found, the value of C<allow_blessed> will decide what
		370	to do.
		371
		372	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
		373	returns other blessed objects, those will be handled in the same
		374	way. C<TO_JSON> must take care of not causing an endless recursion cycle
		375	(== crash) in this case. The name of C<TO_JSON> was chosen because other
		376	methods called by the Perl core (== not by the user of the object) are
		377	usually in upper case letters and to avoid collisions with the C<to_json>
		378	function.
		379
		380	This setting does not yet influence C<decode> in any way, but in the
		381	future, global hooks might get installed that influence C<decode> and are
		382	enabled by this setting.
		383
		384	If C<$enable> is false, then the C<allow_blessed> setting will decide what
		385	to do when a blessed object is found.
		386
		387	=item $json = $json->filter_json_object ([$coderef->($hashref)])
		388
		389	When C<$coderef> is specified, it will be called from C<decode> each
		390	time it decodes a JSON object. The only argument is a reference to the
		391	newly-created hash. If the code references returns a single scalar (which
		392	need not be a reference), this value (i.e. a copy of that scalar to avoid
		393	aliasing) is inserted into the deserialised data structure. If it returns
		394	an empty list (NOTE: I<not> C<undef>, which is a valid scalar), the
		395	original deserialised hash will be inserted. This setting can slow down
		396	decoding considerably.
		397
		398	When C<$coderef> is omitted or undefined, any existing callback will
		399	be removed and C<decode> will not change the deserialised hash in any
		400	way.
		401
		402	Example, convert all JSON objects into the integer 5:
		403
		404	my $js = JSON::XS->new->filter_json_object (sub { 5 });
		405	# returns [5]
		406	$js->decode ('[{}]')
		407	# throw an exception because allow_nonref is not enabled
		408	# so a lone 5 is not allowed.
		409	$js->decode ('{"a":1, "b":2}');
		410
		411	=item $json = $json->filter_json_single_key_object ($key [=> $coderef->($value)])
		412
		413	Works remotely similar to C<filter_json_object>, but is only called for
		414	JSON objects having a single key named C<$key>.
		415
		416	This C<$coderef> is called before the one specified via
		417	C<filter_json_object>, if any. It gets passed the single value in the JSON
		418	object. If it returns a single value, it will be inserted into the data
		419	structure. If it returns nothing (not even C<undef> but the empty list),
		420	the callback from C<filter_json_object> will be called next, as if no
		421	single-key callback were specified.
		422
		423	If C<$coderef> is omitted or undefined, the corresponding callback will be
		424	disabled. There can only ever be one callback for a given key.
		425
		426	As this callback gets called less often then the C<filter_json_object>
		427	one, decoding speed will not usually suffer as much. Therefore, single-key
		428	objects make excellent targets to serialise Perl objects into, especially
		429	as single-key JSON objects are as close to the type-tagged value concept
		430	as JSON gets (its basically an ID/VALUE tuple). Of course, JSON does not
		431	support this in any way, so you need to make sure your data never looks
		432	like a serialised Perl hash.
		433
		434	Typical names for the single object key are C<__class_whatever__>, or
		435	C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even
		436	things like C<__class_md5sum(classname)__>, to reduce the risk of clashing
		437	with real hashes.
		438
		439	Example, decode JSON objects of the form C<< { "__widget__" => <id> } >>
		440	into the corresponding C<< $WIDGET{<id>} >> object:
		441
		442	# return whatever is in $WIDGET{5}:
		443	JSON::XS
		444	->new
		445	->filter_json_single_key_object (__widget__ => sub {
		446	$WIDGET{ $_[0] }
		447	})
		448	->decode ('{"__widget__": 5')
		449
		450	# this can be used with a TO_JSON method in some "widget" class
		451	# for serialisation to json:
		452	sub WidgetBase::TO_JSON {
		453	my ($self) = @_;
		454
		455	unless ($self->{id}) {
		456	$self->{id} = ..get..some..id..;
		457	$WIDGET{$self->{id}} = $self;
		458	}
		459
		460	{ __widget__ => $self->{id} }
		461	}
314		462
315	=item $json = $json->shrink ([$enable])	463	=item $json = $json->shrink ([$enable])
316		464
317	Perl usually over-allocates memory a bit when allocating space for	465	Perl usually over-allocates memory a bit when allocating space for
318	strings. This flag optionally resizes strings generated by either	466	strings. This flag optionally resizes strings generated by either
…		…
351	given character in a string.	499	given character in a string.
352		500
353	Setting the maximum depth to one disallows any nesting, so that ensures	501	Setting the maximum depth to one disallows any nesting, so that ensures
354	that the object is only a single hash/object or array.	502	that the object is only a single hash/object or array.
355		503
356	The argument to C<max_depth> will be rounded up to the next nearest power	504	The argument to C<max_depth> will be rounded up to the next highest power
357	of two.	505	of two. If no argument is given, the highest possible setting will be
		506	used, which is rarely useful.
		507
		508	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
		509
		510	=item $json = $json->max_size ([$maximum_string_size])
		511
		512	Set the maximum length a JSON text may have (in bytes) where decoding is
		513	being attempted. The default is C<0>, meaning no limit. When C<decode>
		514	is called on a string longer then this number of characters it will not
		515	attempt to decode the string but throw an exception. This setting has no
		516	effect on C<encode> (yet).
		517
		518	The argument to C<max_size> will be rounded up to the next B<highest>
		519	power of two (so may be more than requested). If no argument is given, the
		520	limit check will be deactivated (same as when C<0> is specified).
358		521
359	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.	522	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
360		523
361	=item $json_text = $json->encode ($perl_scalar)	524	=item $json_text = $json->encode ($perl_scalar)
362		525
…		…
424	are represented by the same codepoints in the Perl string, so no manual	587	are represented by the same codepoints in the Perl string, so no manual
425	decoding is necessary.	588	decoding is necessary.
426		589
427	=item number	590	=item number
428		591
429	A JSON number becomes either an integer or numeric (floating point)	592	A JSON number becomes either an integer, numeric (floating point) or
430	scalar in perl, depending on its range and any fractional parts. On the	593	string scalar in perl, depending on its range and any fractional parts. On
431	Perl level, there is no difference between those as Perl handles all the	594	the Perl level, there is no difference between those as Perl handles all
432	conversion details, but an integer may take slightly less memory and might	595	the conversion details, but an integer may take slightly less memory and
433	represent more values exactly than (floating point) numbers.	596	might represent more values exactly than (floating point) numbers.
		597
		598	If the number consists of digits only, JSON::XS will try to represent
		599	it as an integer value. If that fails, it will try to represent it as
		600	a numeric (floating point) value if that is possible without loss of
		601	precision. Otherwise it will preserve the number as a string value.
		602
		603	Numbers containing a fractional or exponential part will always be
		604	represented as numeric (floating point) values, possibly at a loss of
		605	precision.
		606
		607	This might create round-tripping problems as numbers might become strings,
		608	but as Perl is typeless there is no other way to do it.
434		609
435	=item true, false	610	=item true, false
436		611
437	These JSON atoms become C<0>, C<1>, respectively. Information is lost in	612	These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,
438	this process. Future versions might represent those values differently,	613	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	614	C<1> and C<0>. You can check wether a scalar is a JSON boolean by using
440	Perl.	615	the C<JSON::XS::is_bool> function.
441		616
442	=item null	617	=item null
443		618
444	A JSON null atom becomes C<undef> in Perl.	619	A JSON null atom becomes C<undef> in Perl.
445		620
…		…
477	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can	652	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.	653	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
479		654
480	to_json [\0,JSON::XS::true] # yields [false,true]	655	to_json [\0,JSON::XS::true] # yields [false,true]
481		656
		657	=item JSON::XS::true, JSON::XS::false
		658
		659	These special values become JSON true and JSON false values,
		660	respectively. You cna alos use C<\1> and C<\0> directly if you want.
		661
482	=item blessed objects	662	=item blessed objects
483		663
484	Blessed objects are not allowed. JSON::XS currently tries to encode their	664	Blessed objects are not allowed. JSON::XS currently tries to encode their
485	underlying representation (hash- or arrayref), but this behaviour might	665	underlying representation (hash- or arrayref), but this behaviour might
486	change in future versions.	666	change in future versions.
…		…
649	It shows the number of encodes/decodes per second (JSON::XS uses	829	It shows the number of encodes/decodes per second (JSON::XS uses
650	the functional interface, while JSON::XS/2 uses the OO interface	830	the functional interface, while JSON::XS/2 uses the OO interface
651	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables	831	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables
652	shrink). Higher is better:	832	shrink). Higher is better:
653		833
		834	Storable \| 15779.925 \| 14169.946 \|
		835	-----------+------------+------------+
654	module \| encode \| decode \|	836	module \| encode \| decode \|
655	-----------\|------------\|------------\|	837	-----------\|------------\|------------\|
656	JSON \| 7645.468 \| 4208.613 \|	838	JSON \| 4990.842 \| 4088.813 \|
657	JSON::DWIW \| 40721.398 \| 77101.176 \|	839	JSON::DWIW \| 51653.990 \| 71575.154 \|
658	JSON::PC \| 65948.176 \| 78251.940 \|	840	JSON::PC \| 65948.176 \| 74631.744 \|
659	JSON::Syck \| 22844.793 \| 26479.192 \|	841	JSON::PP \| 8931.652 \| 3817.168 \|
		842	JSON::Syck \| 24877.248 \| 27776.848 \|
660	JSON::XS \| 388361.481 \| 199728.762 \|	843	JSON::XS \| 388361.481 \| 227951.304 \|
661	JSON::XS/2 \| 218453.333 \| 192399.266 \|	844	JSON::XS/2 \| 227951.304 \| 218453.333 \|
662	JSON::XS/3 \| 338250.323 \| 192399.266 \|	845	JSON::XS/3 \| 338250.323 \| 218453.333 \|
663	Storable \| 15779.925 \| 14169.946 \|	846	Storable \| 16500.016 \| 135300.129 \|
664	-----------+------------+------------+	847	-----------+------------+------------+
665		848
666	That is, JSON::XS is about five times faster than JSON::DWIW on encoding,	849	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	850	about three times faster on decoding, and over fourty times faster
668	than JSON, even with pretty-printing and key sorting. It also compares	851	than JSON, even with pretty-printing and key sorting. It also compares
…		…
671	Using a longer test string (roughly 18KB, generated from Yahoo! Locals	854	Using a longer test string (roughly 18KB, generated from Yahoo! Locals
672	search API (http://nanoref.com/yahooapis/mgPdGg):	855	search API (http://nanoref.com/yahooapis/mgPdGg):
673		856
674	module \| encode \| decode \|	857	module \| encode \| decode \|
675	-----------\|------------\|------------\|	858	-----------\|------------\|------------\|
676	JSON \| 254.685 \| 37.665 \|	859	JSON \| 55.260 \| 34.971 \|
677	JSON::DWIW \| 843.343 \| 1049.731 \|	860	JSON::DWIW \| 825.228 \| 1082.513 \|
678	JSON::PC \| 3602.116 \| 2307.352 \|	861	JSON::PC \| 3571.444 \| 2394.829 \|
		862	JSON::PP \| 210.987 \| 32.574 \|
679	JSON::Syck \| 505.107 \| 787.899 \|	863	JSON::Syck \| 552.551 \| 787.544 \|
680	JSON::XS \| 5747.196 \| 3690.220 \|	864	JSON::XS \| 5780.463 \| 4854.519 \|
681	JSON::XS/2 \| 3968.121 \| 3676.634 \|	865	JSON::XS/2 \| 3869.998 \| 4798.975 \|
682	JSON::XS/3 \| 6105.246 \| 3662.508 \|	866	JSON::XS/3 \| 5862.880 \| 4798.975 \|
683	Storable \| 4417.337 \| 5285.161 \|	867	Storable \| 4445.002 \| 5235.027 \|
684	-----------+------------+------------+	868	-----------+------------+------------+
685		869
686	Again, JSON::XS leads by far (except for Storable which non-surprisingly	870	Again, JSON::XS leads by far (except for Storable which non-surprisingly
687	decodes faster).	871	decodes faster).
688		872
…		…
705	Second, you need to avoid resource-starving attacks. That means you should	889	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	890	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	891	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	892	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	893	usually a good indication of the size of the resources required to decode
710	it into a Perl structure.	894	it into a Perl structure. While JSON::XS can check the size of the JSON
		895	text, it might be too late when you already have it in memory, so you
		896	might want to check the size before you accept the string.
711		897
712	Third, JSON::XS recurses using the C stack when decoding objects and	898	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	899	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	900	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	901	only 14k nested JSON objects (due to perl itself recursing deeply on croak
…		…
720		906
721	And last but least, something else could bomb you that I forgot to think	907	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,	908	of. In that case, you get to keep the pieces. I am always open for hints,
723	though...	909	though...
724		910
		911	If you are using JSON::XS to return packets to consumption
		912	by javascript scripts in a browser you should have a look at
		913	L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether
		914	you are vulnerable to some common attack vectors (which really are browser
		915	design bugs, but it is still you who will have to deal with it, as major
		916	browser developers care only for features, not about doing security
		917	right).
		918
725		919
726	=head1 BUGS	920	=head1 BUGS
727		921
728	While the goal of this module is to be correct, that unfortunately does	922	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	923	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	924	still relatively early in its development. If you keep reporting bugs they
731	will be fixed swiftly, though.	925	will be fixed swiftly, though.
732		926
733	=cut	927	=cut
734		928
		929	our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" };
		930	our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" };
		931
735	sub true() { \1 }	932	sub true() { $true }
736	sub false() { \0 }	933	sub false() { $false }
		934
		935	sub is_bool($) {
		936	UNIVERSAL::isa $_[0], "JSON::XS::Boolean"
		937	# or UNIVERSAL::isa $_[0], "JSON::Literal"
		938	}
		939
		940	XSLoader::load "JSON::XS", $VERSION;
		941
		942	package JSON::XS::Boolean;
		943
		944	use overload
		945	"0+" => sub { ${$_[0]} },
		946	"++" => sub { $_[0] = ${$_[0]} + 1 },
		947	"--" => sub { $_[0] = ${$_[0]} - 1 },
		948	fallback => 1;
737		949
738	1;	950	1;
739		951
740	=head1 AUTHOR	952	=head1 AUTHOR
741		953

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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 1.59 by root, Mon Aug 27 01:49:01 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 1.59 by root, Mon Aug 27 01:49:01 2007 UTC