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

Comparing JSON-XS/XS.pm (file contents):
Revision 1.105 by root, Sat May 24 21:55:43 2008 UTC vs.
Revision 1.123 by root, Sat Aug 8 10:06:02 2009 UTC

…		…
49	to write yet another JSON module? While it seems there are many JSON	49	to write yet another JSON module? While it seems there are many JSON
50	modules, none of them correctly handle all corner cases, and in most cases	50	modules, none of them correctly handle all corner cases, and in most cases
51	their maintainers are unresponsive, gone missing, or not listening to bug	51	their maintainers are unresponsive, gone missing, or not listening to bug
52	reports for other reasons.	52	reports for other reasons.
53		53
54	See COMPARISON, below, for a comparison to some other JSON modules.
55
56	See MAPPING, below, on how JSON::XS maps perl values to JSON values and	54	See MAPPING, below, on how JSON::XS maps perl values to JSON values and
57	vice versa.	55	vice versa.
58		56
59	=head2 FEATURES	57	=head2 FEATURES
60		58
…		…
101		99
102	=cut	100	=cut
103		101
104	package JSON::XS;	102	package JSON::XS;
105		103
106	use strict;	104	use common::sense;
107		105
108	our $VERSION = '2.2';	106	our $VERSION = '2.25';
109	our @ISA = qw(Exporter);	107	our @ISA = qw(Exporter);
110		108
111	our @EXPORT = qw(encode_json decode_json to_json from_json);	109	our @EXPORT = qw(encode_json decode_json to_json from_json);
112		110
113	sub to_json($) {	111	sub to_json($) {
…		…
442	the same JSON text (given the same overall settings). If it is disabled,	440	the same JSON text (given the same overall settings). If it is disabled,
443	the same hash might be encoded differently even if contains the same data,	441	the same hash might be encoded differently even if contains the same data,
444	as key-value pairs have no inherent ordering in Perl.	442	as key-value pairs have no inherent ordering in Perl.
445		443
446	This setting has no effect when decoding JSON texts.	444	This setting has no effect when decoding JSON texts.
		445
		446	This setting has currently no effect on tied hashes.
447		447
448	=item $json = $json->allow_nonref ([$enable])	448	=item $json = $json->allow_nonref ([$enable])
449		449
450	=item $enabled = $json->get_allow_nonref	450	=item $enabled = $json->get_allow_nonref
451		451
…		…
706	In some cases, there is the need for incremental parsing of JSON	706	In some cases, there is the need for incremental parsing of JSON
707	texts. While this module always has to keep both JSON text and resulting	707	texts. While this module always has to keep both JSON text and resulting
708	Perl data structure in memory at one time, it does allow you to parse a	708	Perl data structure in memory at one time, it does allow you to parse a
709	JSON stream incrementally. It does so by accumulating text until it has	709	JSON stream incrementally. It does so by accumulating text until it has
710	a full JSON object, which it then can decode. This process is similar to	710	a full JSON object, which it then can decode. This process is similar to
711	using C<decode_prefix> to see if a full JSON object is available, but is	711	using C<decode_prefix> to see if a full JSON object is available, but
712	much more efficient (JSON::XS will only attempt to parse the JSON text	712	is much more efficient (and can be implemented with a minimum of method
		713	calls).
		714
		715	JSON::XS will only attempt to parse the JSON text once it is sure it
713	once it is sure it has enough text to get a decisive result, using a very	716	has enough text to get a decisive result, using a very simple but
714	simple but truly incremental parser).	717	truly incremental parser. This means that it sometimes won't stop as
		718	early as the full parser, for example, it doesn't detect parenthese
		719	mismatches. The only thing it guarantees is that it starts decoding as
		720	soon as a syntactically valid JSON text has been seen. This means you need
		721	to set resource limits (e.g. C<max_size>) to ensure the parser will stop
		722	parsing in the presence if syntax errors.
715		723
716	The following two methods deal with this.	724	The following methods implement this incremental parser.
717		725
718	=over 4	726	=over 4
719		727
720	=item [void, scalar or list context] = $json->incr_parse ([$string])	728	=item [void, scalar or list context] = $json->incr_parse ([$string])
721		729
…		…
759	JSON object or b) parsing multiple JSON objects separated by non-JSON text	767	JSON object or b) parsing multiple JSON objects separated by non-JSON text
760	(such as commas).	768	(such as commas).
761		769
762	=item $json->incr_skip	770	=item $json->incr_skip
763		771
764	This will reset the state of the incremental parser and will remove the	772	This will reset the state of the incremental parser and will remove
765	parsed text from the input buffer. This is useful after C<incr_parse>	773	the parsed text from the input buffer so far. This is useful after
766	died, in which case the input buffer and incremental parser state is left	774	C<incr_parse> died, in which case the input buffer and incremental parser
767	unchanged, to skip the text parsed so far and to reset the parse state.	775	state is left unchanged, to skip the text parsed so far and to reset the
		776	parse state.
		777
		778	The difference to C<incr_reset> is that only text until the parse error
		779	occured is removed.
		780
		781	=item $json->incr_reset
		782
		783	This completely resets the incremental parser, that is, after this call,
		784	it will be as if the parser had never parsed anything.
		785
		786	This is useful if you want to repeatedly parse JSON objects and want to
		787	ignore any trailing data, which means you have to reset the parser after
		788	each successful decode.
768		789
769	=back	790	=back
770		791
771	=head2 LIMITATIONS	792	=head2 LIMITATIONS
772		793
…		…
1163	when your channel for JSON transfer is not 8-bit clean or the encoding	1184	when your channel for JSON transfer is not 8-bit clean or the encoding
1164	might be mangled in between (e.g. in mail), and works because ASCII is a	1185	might be mangled in between (e.g. in mail), and works because ASCII is a
1165	proper subset of most 8-bit and multibyte encodings in use in the world.	1186	proper subset of most 8-bit and multibyte encodings in use in the world.
1166		1187
1167	=back	1188	=back
		1189
		1190
		1191	=head2 JSON and ECMAscript
		1192
		1193	JSON syntax is based on how literals are represented in javascript (the
		1194	not-standardised predecessor of ECMAscript) which is presumably why it is
		1195	called "JavaScript Object Notation".
		1196
		1197	However, JSON is not a subset (and also not a superset of course) of
		1198	ECMAscript (the standard) or javascript (whatever browsers actually
		1199	implement).
		1200
		1201	If you want to use javascript's C<eval> function to "parse" JSON, you
		1202	might run into parse errors for valid JSON texts, or the resulting data
		1203	structure might not be queryable:
		1204
		1205	One of the problems is that U+2028 and U+2029 are valid characters inside
		1206	JSON strings, but are not allowed in ECMAscript string literals, so the
		1207	following Perl fragment will not output something that can be guaranteed
		1208	to be parsable by javascript's C<eval>:
		1209
		1210	use JSON::XS;
		1211
		1212	print encode_json [chr 0x2028];
		1213
		1214	The right fix for this is to use a proper JSON parser in your javascript
		1215	programs, and not rely on C<eval> (see for example Douglas Crockford's
		1216	F<json2.js> parser).
		1217
		1218	If this is not an option, you can, as a stop-gap measure, simply encode to
		1219	ASCII-only JSON:
		1220
		1221	use JSON::XS;
		1222
		1223	print JSON::XS->new->ascii->encode ([chr 0x2028]);
		1224
		1225	Note that this will enlarge the resulting JSON text quite a bit if you
		1226	have many non-ASCII characters. You might be tempted to run some regexes
		1227	to only escape U+2028 and U+2029, e.g.:
		1228
		1229	# DO NOT USE THIS!
		1230	my $json = JSON::XS->new->utf8->encode ([chr 0x2028]);
		1231	$json =~ s/\xe2\x80\xa8/\\u2028/g; # escape U+2028
		1232	$json =~ s/\xe2\x80\xa9/\\u2029/g; # escape U+2029
		1233	print $json;
		1234
		1235	Note that I<this is a bad idea>: the above only works for U+2028 and
		1236	U+2029 and thus only for fully ECMAscript-compliant parsers. Many existing
		1237	javascript implementations, however, have issues with other characters as
		1238	well - using C<eval> naively simply I<will> cause problems.
		1239
		1240	Another problem is that some javascript implementations reserve
		1241	some property names for their own purposes (which probably makes
		1242	them non-ECMAscript-compliant). For example, Iceweasel reserves the
		1243	C<__proto__> property name for it's own purposes.
		1244
		1245	If that is a problem, you could parse try to filter the resulting JSON
		1246	output for these property strings, e.g.:
		1247
		1248	$json =~ s/"__proto__"\s*:/"__proto__renamed":/g;
		1249
		1250	This works because C<__proto__> is not valid outside of strings, so every
		1251	occurence of C<"__proto__"\s*:> must be a string used as property name.
		1252
		1253	If you know of other incompatibilities, please let me know.
1168		1254
1169		1255
1170	=head2 JSON and YAML	1256	=head2 JSON and YAML
1171		1257
1172	You often hear that JSON is a subset of YAML. This is, however, a mass	1258	You often hear that JSON is a subset of YAML. This is, however, a mass

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Comparing JSON-XS/XS.pm (file contents): Revision 1.105 by root, Sat May 24 21:55:43 2008 UTC vs. Revision 1.123 by root, Sat Aug 8 10:06:02 2009 UTC

Diff Legend

Comparing JSON-XS/XS.pm (file contents):
Revision 1.105 by root, Sat May 24 21:55:43 2008 UTC vs.
Revision 1.123 by root, Sat Aug 8 10:06:02 2009 UTC