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

Comparing JSON-XS/XS.pm (file contents):
Revision 1.110 by root, Sun Jul 20 17:55:19 2008 UTC vs.
Revision 1.115 by root, Tue Feb 17 23:29:38 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
…		…
104	package JSON::XS;	102	package JSON::XS;
105		103
106	no warnings;	104	no warnings;
107	use strict;	105	use strict;
108		106
109	our $VERSION = '2.2222';	107	our $VERSION = '2.232';
110	our @ISA = qw(Exporter);	108	our @ISA = qw(Exporter);
111		109
112	our @EXPORT = qw(encode_json decode_json to_json from_json);	110	our @EXPORT = qw(encode_json decode_json to_json from_json);
113		111
114	sub to_json($) {	112	sub to_json($) {
…		…
768	JSON object or b) parsing multiple JSON objects separated by non-JSON text	766	JSON object or b) parsing multiple JSON objects separated by non-JSON text
769	(such as commas).	767	(such as commas).
770		768
771	=item $json->incr_skip	769	=item $json->incr_skip
772		770
773	This will reset the state of the incremental parser and will remove the	771	This will reset the state of the incremental parser and will remove
774	parsed text from the input buffer. This is useful after C<incr_parse>	772	the parsed text from the input buffer so far. This is useful after
775	died, in which case the input buffer and incremental parser state is left	773	C<incr_parse> died, in which case the input buffer and incremental parser
776	unchanged, to skip the text parsed so far and to reset the parse state.	774	state is left unchanged, to skip the text parsed so far and to reset the
		775	parse state.
		776
		777	The difference to C<incr_reset> is that only text until the parse error
		778	occured is removed.
777		779
778	=item $json->incr_reset	780	=item $json->incr_reset
779		781
780	This completely resets the incremental parser, that is, after this call,	782	This completely resets the incremental parser, that is, after this call,
781	it will be as if the parser had never parsed anything.	783	it will be as if the parser had never parsed anything.
782		784
783	This is useful if you want ot repeatedly parse JSON objects and want to	785	This is useful if you want to repeatedly parse JSON objects and want to
784	ignore any trailing data, which means you have to reset the parser after	786	ignore any trailing data, which means you have to reset the parser after
785	each successful decode.	787	each successful decode.
786		788
787	=back	789	=back
788		790
…		…
1181	when your channel for JSON transfer is not 8-bit clean or the encoding	1183	when your channel for JSON transfer is not 8-bit clean or the encoding
1182	might be mangled in between (e.g. in mail), and works because ASCII is a	1184	might be mangled in between (e.g. in mail), and works because ASCII is a
1183	proper subset of most 8-bit and multibyte encodings in use in the world.	1185	proper subset of most 8-bit and multibyte encodings in use in the world.
1184		1186
1185	=back	1187	=back
		1188
		1189
		1190	=head2 JSON and ECMAscript
		1191
		1192	JSON syntax is based on how literals are represented in javascript (the
		1193	not-standardised predecessor of ECMAscript) which is presumably why it is
		1194	called "JavaScript Object Notation".
		1195
		1196	However, JSON is not a subset (and also not a superset of course) of
		1197	ECMAscript (the standard) or javascript (whatever browsers actually
		1198	implement).
		1199
		1200	If you want to use javascript's C<eval> function to "parse" JSON, you
		1201	might run into parse errors for valid JSON texts, or the resulting data
		1202	structure might not be queryable:
		1203
		1204	One of the problems is that U+2028 and U+2029 are valid characters inside
		1205	JSON strings, but are not allowed in ECMAscript string literals, so the
		1206	following Perl fragment will not output something that can be guaranteed
		1207	to be parsable by javascript's C<eval>:
		1208
		1209	use JSON::XS;
		1210
		1211	print encode_json [chr 0x2028];
		1212
		1213	The right fix for this is to use a proper JSON parser in your javascript
		1214	programs, and not rely on C<eval>.
		1215
		1216	If this is not an option, you can, as a stop-gap measure, simply encode to
		1217	ASCII-only JSON:
		1218
		1219	use JSON::XS;
		1220
		1221	print JSON::XS->new->ascii->encode ([chr 0x2028]);
		1222
		1223	And if you are concerned about the size of the resulting JSON text, you
		1224	can run some regexes to only escape U+2028 and U+2029:
		1225
		1226	use JSON::XS;
		1227
		1228	my $json = JSON::XS->new->utf8->encode ([chr 0x2028]);
		1229	$json =~ s/\xe2\x80\xa8/\\u2028/g; # escape U+2028
		1230	$json =~ s/\xe2\x80\xa9/\\u2029/g; # escape U+2029
		1231	print $json;
		1232
		1233	This works because U+2028/U+2029 are not allowed outside of strings and
		1234	are not used for syntax, so replacing them unconditionally just works.
		1235
		1236	Note, however, that fixing the broken JSON parser is better than working
		1237	around it in every other generator. The above regexes should work well in
		1238	other languages, as long as they operate on UTF-8. It is equally valid to
		1239	replace all occurences of U+2028/2029 directly by their \\u-escaped forms
		1240	in unicode texts, so they can simply be used to fix any parsers relying on
		1241	C<eval> by first applying the regexes on the encoded texts.
		1242
		1243	Another problem is that some javascript implementations reserve
		1244	some property names for their own purposes (which probably makes
		1245	them non-ECMAscript-compliant). For example, Iceweasel reserves the
		1246	C<__proto__> property name for it's own purposes.
		1247
		1248	If that is a problem, you could parse try to filter the resulting JSON
		1249	output for these property strings, e.g.:
		1250
		1251	$json =~ s/"__proto__"\s*:/"__proto__renamed":/g;
		1252
		1253	This works because C<__proto__> is not valid outside of strings, so every
		1254	occurence of C<"__proto__"\s*:> must be a string used as property name.
		1255
		1256	If you know of other incompatibilities, please let me know.
1186		1257
1187		1258
1188	=head2 JSON and YAML	1259	=head2 JSON and YAML
1189		1260
1190	You often hear that JSON is a subset of YAML. This is, however, a mass	1261	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 1.110 by root, Sun Jul 20 17:55:19 2008 UTC vs. Revision 1.115 by root, Tue Feb 17 23:29:38 2009 UTC

Diff Legend

Comparing JSON-XS/XS.pm (file contents):
Revision 1.110 by root, Sun Jul 20 17:55:19 2008 UTC vs.
Revision 1.115 by root, Tue Feb 17 23:29:38 2009 UTC