… | |
… | |
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 | |
… | |
… | |
66 | so, and even documents what "correct" means. |
64 | so, and even documents what "correct" means. |
67 | |
65 | |
68 | =item * round-trip integrity |
66 | =item * round-trip integrity |
69 | |
67 | |
70 | When you serialise a perl data structure using only data types supported |
68 | When you serialise a perl data structure using only data types supported |
71 | by JSON, the deserialised data structure is identical on the Perl level. |
69 | by JSON and Perl, the deserialised data structure is identical on the Perl |
72 | (e.g. the string "2.0" doesn't suddenly become "2" just because it looks |
70 | level. (e.g. the string "2.0" doesn't suddenly become "2" just because |
73 | like a number). There minor I<are> exceptions to this, read the MAPPING |
71 | it looks like a number). There I<are> minor exceptions to this, read the |
74 | section below to learn about those. |
72 | MAPPING section below to learn about those. |
75 | |
73 | |
76 | =item * strict checking of JSON correctness |
74 | =item * strict checking of JSON correctness |
77 | |
75 | |
78 | There is no guessing, no generating of illegal JSON texts by default, |
76 | There is no guessing, no generating of illegal JSON texts by default, |
79 | and only JSON is accepted as input by default (the latter is a security |
77 | and only JSON is accepted as input by default (the latter is a security |
… | |
… | |
85 | this module usually compares favourably in terms of speed, too. |
83 | this module usually compares favourably in terms of speed, too. |
86 | |
84 | |
87 | =item * simple to use |
85 | =item * simple to use |
88 | |
86 | |
89 | This module has both a simple functional interface as well as an object |
87 | This module has both a simple functional interface as well as an object |
90 | oriented interface interface. |
88 | oriented interface. |
91 | |
89 | |
92 | =item * reasonably versatile output formats |
90 | =item * reasonably versatile output formats |
93 | |
91 | |
94 | You can choose between the most compact guaranteed-single-line format |
92 | You can choose between the most compact guaranteed-single-line format |
95 | possible (nice for simple line-based protocols), a pure-ASCII format |
93 | possible (nice for simple line-based protocols), a pure-ASCII format |
… | |
… | |
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 $VERSION = 2.34; |
109 | our @ISA = qw(Exporter); |
107 | our @ISA = qw(Exporter); |
110 | |
108 | |
111 | our @EXPORT = qw(encode_json decode_json to_json from_json); |
109 | our @EXPORT = qw(encode_json decode_json to_json from_json); |
112 | |
110 | |
113 | sub to_json($) { |
111 | sub to_json($) { |
… | |
… | |
434 | If C<$enable> is true (or missing), then the C<encode> method will output JSON objects |
432 | If C<$enable> is true (or missing), then the C<encode> method will output JSON objects |
435 | by sorting their keys. This is adding a comparatively high overhead. |
433 | by sorting their keys. This is adding a comparatively high overhead. |
436 | |
434 | |
437 | If C<$enable> is false, then the C<encode> method will output key-value |
435 | If C<$enable> is false, then the C<encode> method will output key-value |
438 | pairs in the order Perl stores them (which will likely change between runs |
436 | pairs in the order Perl stores them (which will likely change between runs |
439 | of the same script). |
437 | of the same script, and can change even within the same run from 5.18 |
|
|
438 | onwards). |
440 | |
439 | |
441 | This option is useful if you want the same data structure to be encoded as |
440 | This option is useful if you want the same data structure to be encoded as |
442 | the same JSON text (given the same overall settings). If it is disabled, |
441 | 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, |
442 | the same hash might be encoded differently even if contains the same data, |
444 | as key-value pairs have no inherent ordering in Perl. |
443 | as key-value pairs have no inherent ordering in Perl. |
445 | |
444 | |
446 | This setting has no effect when decoding JSON texts. |
445 | This setting has no effect when decoding JSON texts. |
|
|
446 | |
|
|
447 | This setting has currently no effect on tied hashes. |
447 | |
448 | |
448 | =item $json = $json->allow_nonref ([$enable]) |
449 | =item $json = $json->allow_nonref ([$enable]) |
449 | |
450 | |
450 | =item $enabled = $json->get_allow_nonref |
451 | =item $enabled = $json->get_allow_nonref |
451 | |
452 | |
… | |
… | |
706 | In some cases, there is the need for incremental parsing of JSON |
707 | 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 |
708 | 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 |
709 | 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 |
710 | 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 |
711 | 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 |
712 | 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 |
713 | is much more efficient (and can be implemented with a minimum of method |
|
|
714 | calls). |
|
|
715 | |
|
|
716 | 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 |
717 | has enough text to get a decisive result, using a very simple but |
714 | simple but truly incremental parser). |
718 | truly incremental parser. This means that it sometimes won't stop as |
|
|
719 | early as the full parser, for example, it doesn't detect mismatched |
|
|
720 | parentheses. The only thing it guarantees is that it starts decoding as |
|
|
721 | soon as a syntactically valid JSON text has been seen. This means you need |
|
|
722 | to set resource limits (e.g. C<max_size>) to ensure the parser will stop |
|
|
723 | parsing in the presence if syntax errors. |
715 | |
724 | |
716 | The following two methods deal with this. |
725 | The following methods implement this incremental parser. |
717 | |
726 | |
718 | =over 4 |
727 | =over 4 |
719 | |
728 | |
720 | =item [void, scalar or list context] = $json->incr_parse ([$string]) |
729 | =item [void, scalar or list context] = $json->incr_parse ([$string]) |
721 | |
730 | |
… | |
… | |
732 | |
741 | |
733 | If the method is called in scalar context, then it will try to extract |
742 | If the method is called in scalar context, then it will try to extract |
734 | exactly I<one> JSON object. If that is successful, it will return this |
743 | exactly I<one> JSON object. If that is successful, it will return this |
735 | object, otherwise it will return C<undef>. If there is a parse error, |
744 | object, otherwise it will return C<undef>. If there is a parse error, |
736 | this method will croak just as C<decode> would do (one can then use |
745 | this method will croak just as C<decode> would do (one can then use |
737 | C<incr_skip> to skip the errornous part). This is the most common way of |
746 | C<incr_skip> to skip the erroneous part). This is the most common way of |
738 | using the method. |
747 | using the method. |
739 | |
748 | |
740 | And finally, in list context, it will try to extract as many objects |
749 | And finally, in list context, it will try to extract as many objects |
741 | from the stream as it can find and return them, or the empty list |
750 | from the stream as it can find and return them, or the empty list |
742 | otherwise. For this to work, there must be no separators between the JSON |
751 | otherwise. For this to work, there must be no separators between the JSON |
743 | objects or arrays, instead they must be concatenated back-to-back. If |
752 | objects or arrays, instead they must be concatenated back-to-back. If |
744 | an error occurs, an exception will be raised as in the scalar context |
753 | an error occurs, an exception will be raised as in the scalar context |
745 | case. Note that in this case, any previously-parsed JSON texts will be |
754 | case. Note that in this case, any previously-parsed JSON texts will be |
746 | lost. |
755 | lost. |
747 | |
756 | |
|
|
757 | Example: Parse some JSON arrays/objects in a given string and return |
|
|
758 | them. |
|
|
759 | |
|
|
760 | my @objs = JSON::XS->new->incr_parse ("[5][7][1,2]"); |
|
|
761 | |
748 | =item $lvalue_string = $json->incr_text |
762 | =item $lvalue_string = $json->incr_text |
749 | |
763 | |
750 | This method returns the currently stored JSON fragment as an lvalue, that |
764 | This method returns the currently stored JSON fragment as an lvalue, that |
751 | is, you can manipulate it. This I<only> works when a preceding call to |
765 | is, you can manipulate it. This I<only> works when a preceding call to |
752 | C<incr_parse> in I<scalar context> successfully returned an object. Under |
766 | C<incr_parse> in I<scalar context> successfully returned an object. Under |
… | |
… | |
759 | JSON object or b) parsing multiple JSON objects separated by non-JSON text |
773 | JSON object or b) parsing multiple JSON objects separated by non-JSON text |
760 | (such as commas). |
774 | (such as commas). |
761 | |
775 | |
762 | =item $json->incr_skip |
776 | =item $json->incr_skip |
763 | |
777 | |
764 | This will reset the state of the incremental parser and will remove the |
778 | 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> |
779 | 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 |
780 | 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. |
781 | state is left unchanged, to skip the text parsed so far and to reset the |
|
|
782 | parse state. |
|
|
783 | |
|
|
784 | The difference to C<incr_reset> is that only text until the parse error |
|
|
785 | occurred is removed. |
768 | |
786 | |
769 | =item $json->incr_reset |
787 | =item $json->incr_reset |
770 | |
788 | |
771 | This completely resets the incremental parser, that is, after this call, |
789 | This completely resets the incremental parser, that is, after this call, |
772 | it will be as if the parser had never parsed anything. |
790 | it will be as if the parser had never parsed anything. |
773 | |
791 | |
774 | This is useful if you want ot repeatedly parse JSON objects and want to |
792 | This is useful if you want to repeatedly parse JSON objects and want to |
775 | ignore any trailing data, which means you have to reset the parser after |
793 | ignore any trailing data, which means you have to reset the parser after |
776 | each successful decode. |
794 | each successful decode. |
777 | |
795 | |
778 | =back |
796 | =back |
779 | |
797 | |
… | |
… | |
970 | If the number consists of digits only, JSON::XS will try to represent |
988 | If the number consists of digits only, JSON::XS will try to represent |
971 | it as an integer value. If that fails, it will try to represent it as |
989 | it as an integer value. If that fails, it will try to represent it as |
972 | a numeric (floating point) value if that is possible without loss of |
990 | a numeric (floating point) value if that is possible without loss of |
973 | precision. Otherwise it will preserve the number as a string value (in |
991 | precision. Otherwise it will preserve the number as a string value (in |
974 | which case you lose roundtripping ability, as the JSON number will be |
992 | which case you lose roundtripping ability, as the JSON number will be |
975 | re-encoded toa JSON string). |
993 | re-encoded to a JSON string). |
976 | |
994 | |
977 | Numbers containing a fractional or exponential part will always be |
995 | Numbers containing a fractional or exponential part will always be |
978 | represented as numeric (floating point) values, possibly at a loss of |
996 | represented as numeric (floating point) values, possibly at a loss of |
979 | precision (in which case you might lose perfect roundtripping ability, but |
997 | precision (in which case you might lose perfect roundtripping ability, but |
980 | the JSON number will still be re-encoded as a JSON number). |
998 | the JSON number will still be re-encoded as a JSON number). |
|
|
999 | |
|
|
1000 | Note that precision is not accuracy - binary floating point values cannot |
|
|
1001 | represent most decimal fractions exactly, and when converting from and to |
|
|
1002 | floating point, JSON::XS only guarantees precision up to but not including |
|
|
1003 | the least significant bit. |
981 | |
1004 | |
982 | =item true, false |
1005 | =item true, false |
983 | |
1006 | |
984 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
1007 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
985 | respectively. They are overloaded to act almost exactly like the numbers |
1008 | respectively. They are overloaded to act almost exactly like the numbers |
… | |
… | |
1073 | |
1096 | |
1074 | You can not currently force the type in other, less obscure, ways. Tell me |
1097 | You can not currently force the type in other, less obscure, ways. Tell me |
1075 | if you need this capability (but don't forget to explain why it's needed |
1098 | if you need this capability (but don't forget to explain why it's needed |
1076 | :). |
1099 | :). |
1077 | |
1100 | |
|
|
1101 | Note that numerical precision has the same meaning as under Perl (so |
|
|
1102 | binary to decimal conversion follows the same rules as in Perl, which |
|
|
1103 | can differ to other languages). Also, your perl interpreter might expose |
|
|
1104 | extensions to the floating point numbers of your platform, such as |
|
|
1105 | infinities or NaN's - these cannot be represented in JSON, and it is an |
|
|
1106 | error to pass those in. |
|
|
1107 | |
1078 | =back |
1108 | =back |
1079 | |
1109 | |
1080 | |
1110 | |
1081 | =head1 ENCODING/CODESET FLAG NOTES |
1111 | =head1 ENCODING/CODESET FLAG NOTES |
1082 | |
1112 | |
… | |
… | |
1108 | =item C<utf8> flag disabled |
1138 | =item C<utf8> flag disabled |
1109 | |
1139 | |
1110 | When C<utf8> is disabled (the default), then C<encode>/C<decode> generate |
1140 | When C<utf8> is disabled (the default), then C<encode>/C<decode> generate |
1111 | and expect Unicode strings, that is, characters with high ordinal Unicode |
1141 | and expect Unicode strings, that is, characters with high ordinal Unicode |
1112 | values (> 255) will be encoded as such characters, and likewise such |
1142 | values (> 255) will be encoded as such characters, and likewise such |
1113 | characters are decoded as-is, no canges to them will be done, except |
1143 | characters are decoded as-is, no changes to them will be done, except |
1114 | "(re-)interpreting" them as Unicode codepoints or Unicode characters, |
1144 | "(re-)interpreting" them as Unicode codepoints or Unicode characters, |
1115 | respectively (to Perl, these are the same thing in strings unless you do |
1145 | respectively (to Perl, these are the same thing in strings unless you do |
1116 | funny/weird/dumb stuff). |
1146 | funny/weird/dumb stuff). |
1117 | |
1147 | |
1118 | This is useful when you want to do the encoding yourself (e.g. when you |
1148 | This is useful when you want to do the encoding yourself (e.g. when you |
… | |
… | |
1174 | proper subset of most 8-bit and multibyte encodings in use in the world. |
1204 | proper subset of most 8-bit and multibyte encodings in use in the world. |
1175 | |
1205 | |
1176 | =back |
1206 | =back |
1177 | |
1207 | |
1178 | |
1208 | |
|
|
1209 | =head2 JSON and ECMAscript |
|
|
1210 | |
|
|
1211 | JSON syntax is based on how literals are represented in javascript (the |
|
|
1212 | not-standardised predecessor of ECMAscript) which is presumably why it is |
|
|
1213 | called "JavaScript Object Notation". |
|
|
1214 | |
|
|
1215 | However, JSON is not a subset (and also not a superset of course) of |
|
|
1216 | ECMAscript (the standard) or javascript (whatever browsers actually |
|
|
1217 | implement). |
|
|
1218 | |
|
|
1219 | If you want to use javascript's C<eval> function to "parse" JSON, you |
|
|
1220 | might run into parse errors for valid JSON texts, or the resulting data |
|
|
1221 | structure might not be queryable: |
|
|
1222 | |
|
|
1223 | One of the problems is that U+2028 and U+2029 are valid characters inside |
|
|
1224 | JSON strings, but are not allowed in ECMAscript string literals, so the |
|
|
1225 | following Perl fragment will not output something that can be guaranteed |
|
|
1226 | to be parsable by javascript's C<eval>: |
|
|
1227 | |
|
|
1228 | use JSON::XS; |
|
|
1229 | |
|
|
1230 | print encode_json [chr 0x2028]; |
|
|
1231 | |
|
|
1232 | The right fix for this is to use a proper JSON parser in your javascript |
|
|
1233 | programs, and not rely on C<eval> (see for example Douglas Crockford's |
|
|
1234 | F<json2.js> parser). |
|
|
1235 | |
|
|
1236 | If this is not an option, you can, as a stop-gap measure, simply encode to |
|
|
1237 | ASCII-only JSON: |
|
|
1238 | |
|
|
1239 | use JSON::XS; |
|
|
1240 | |
|
|
1241 | print JSON::XS->new->ascii->encode ([chr 0x2028]); |
|
|
1242 | |
|
|
1243 | Note that this will enlarge the resulting JSON text quite a bit if you |
|
|
1244 | have many non-ASCII characters. You might be tempted to run some regexes |
|
|
1245 | to only escape U+2028 and U+2029, e.g.: |
|
|
1246 | |
|
|
1247 | # DO NOT USE THIS! |
|
|
1248 | my $json = JSON::XS->new->utf8->encode ([chr 0x2028]); |
|
|
1249 | $json =~ s/\xe2\x80\xa8/\\u2028/g; # escape U+2028 |
|
|
1250 | $json =~ s/\xe2\x80\xa9/\\u2029/g; # escape U+2029 |
|
|
1251 | print $json; |
|
|
1252 | |
|
|
1253 | Note that I<this is a bad idea>: the above only works for U+2028 and |
|
|
1254 | U+2029 and thus only for fully ECMAscript-compliant parsers. Many existing |
|
|
1255 | javascript implementations, however, have issues with other characters as |
|
|
1256 | well - using C<eval> naively simply I<will> cause problems. |
|
|
1257 | |
|
|
1258 | Another problem is that some javascript implementations reserve |
|
|
1259 | some property names for their own purposes (which probably makes |
|
|
1260 | them non-ECMAscript-compliant). For example, Iceweasel reserves the |
|
|
1261 | C<__proto__> property name for its own purposes. |
|
|
1262 | |
|
|
1263 | If that is a problem, you could parse try to filter the resulting JSON |
|
|
1264 | output for these property strings, e.g.: |
|
|
1265 | |
|
|
1266 | $json =~ s/"__proto__"\s*:/"__proto__renamed":/g; |
|
|
1267 | |
|
|
1268 | This works because C<__proto__> is not valid outside of strings, so every |
|
|
1269 | occurrence of C<"__proto__"\s*:> must be a string used as property name. |
|
|
1270 | |
|
|
1271 | If you know of other incompatibilities, please let me know. |
|
|
1272 | |
|
|
1273 | |
1179 | =head2 JSON and YAML |
1274 | =head2 JSON and YAML |
1180 | |
1275 | |
1181 | You often hear that JSON is a subset of YAML. This is, however, a mass |
1276 | You often hear that JSON is a subset of YAML. This is, however, a mass |
1182 | hysteria(*) and very far from the truth (as of the time of this writing), |
1277 | hysteria(*) and very far from the truth (as of the time of this writing), |
1183 | so let me state it clearly: I<in general, there is no way to configure |
1278 | so let me state it clearly: I<in general, there is no way to configure |
… | |
… | |
1191 | my $yaml = $to_yaml->encode ($ref) . "\n"; |
1286 | my $yaml = $to_yaml->encode ($ref) . "\n"; |
1192 | |
1287 | |
1193 | This will I<usually> generate JSON texts that also parse as valid |
1288 | This will I<usually> generate JSON texts that also parse as valid |
1194 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
1289 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
1195 | lengths that JSON doesn't have and also has different and incompatible |
1290 | lengths that JSON doesn't have and also has different and incompatible |
1196 | unicode handling, so you should make sure that your hash keys are |
1291 | unicode character escape syntax, so you should make sure that your hash |
1197 | noticeably shorter than the 1024 "stream characters" YAML allows and that |
1292 | keys are noticeably shorter than the 1024 "stream characters" YAML allows |
1198 | you do not have characters with codepoint values outside the Unicode BMP |
1293 | and that you do not have characters with codepoint values outside the |
1199 | (basic multilingual page). YAML also does not allow C<\/> sequences in |
1294 | Unicode BMP (basic multilingual page). YAML also does not allow C<\/> |
1200 | strings (which JSON::XS does not I<currently> generate, but other JSON |
1295 | sequences in strings (which JSON::XS does not I<currently> generate, but |
1201 | generators might). |
1296 | other JSON generators might). |
1202 | |
1297 | |
1203 | There might be other incompatibilities that I am not aware of (or the YAML |
1298 | There might be other incompatibilities that I am not aware of (or the YAML |
1204 | specification has been changed yet again - it does so quite often). In |
1299 | specification has been changed yet again - it does so quite often). In |
1205 | general you should not try to generate YAML with a JSON generator or vice |
1300 | general you should not try to generate YAML with a JSON generator or vice |
1206 | versa, or try to parse JSON with a YAML parser or vice versa: chances are |
1301 | versa, or try to parse JSON with a YAML parser or vice versa: chances are |
… | |
… | |
1225 | that difficult or long) and finally make YAML compatible to it, and |
1320 | that difficult or long) and finally make YAML compatible to it, and |
1226 | educating users about the changes, instead of spreading lies about the |
1321 | educating users about the changes, instead of spreading lies about the |
1227 | real compatibility for many I<years> and trying to silence people who |
1322 | real compatibility for many I<years> and trying to silence people who |
1228 | point out that it isn't true. |
1323 | point out that it isn't true. |
1229 | |
1324 | |
|
|
1325 | Addendum/2009: the YAML 1.2 spec is still incompatible with JSON, even |
|
|
1326 | though the incompatibilities have been documented (and are known to Brian) |
|
|
1327 | for many years and the spec makes explicit claims that YAML is a superset |
|
|
1328 | of JSON. It would be so easy to fix, but apparently, bullying people and |
|
|
1329 | corrupting userdata is so much easier. |
|
|
1330 | |
1230 | =back |
1331 | =back |
1231 | |
1332 | |
1232 | |
1333 | |
1233 | =head2 SPEED |
1334 | =head2 SPEED |
1234 | |
1335 | |
… | |
… | |
1241 | a very short single-line JSON string (also available at |
1342 | a very short single-line JSON string (also available at |
1242 | L<http://dist.schmorp.de/misc/json/short.json>). |
1343 | L<http://dist.schmorp.de/misc/json/short.json>). |
1243 | |
1344 | |
1244 | {"method": "handleMessage", "params": ["user1", |
1345 | {"method": "handleMessage", "params": ["user1", |
1245 | "we were just talking"], "id": null, "array":[1,11,234,-5,1e5,1e7, |
1346 | "we were just talking"], "id": null, "array":[1,11,234,-5,1e5,1e7, |
1246 | true, false]} |
1347 | 1, 0]} |
1247 | |
1348 | |
1248 | It shows the number of encodes/decodes per second (JSON::XS uses |
1349 | It shows the number of encodes/decodes per second (JSON::XS uses |
1249 | the functional interface, while JSON::XS/2 uses the OO interface |
1350 | the functional interface, while JSON::XS/2 uses the OO interface |
1250 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
1351 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
1251 | shrink). Higher is better: |
1352 | shrink. JSON::DWIW/DS uses the deserialise function, while JSON::DWIW::FJ |
|
|
1353 | uses the from_json method). Higher is better: |
1252 | |
1354 | |
1253 | module | encode | decode | |
1355 | module | encode | decode | |
1254 | -----------|------------|------------| |
1356 | --------------|------------|------------| |
1255 | JSON 1.x | 4990.842 | 4088.813 | |
1357 | JSON::DWIW/DS | 86302.551 | 102300.098 | |
1256 | JSON::DWIW | 51653.990 | 71575.154 | |
1358 | JSON::DWIW/FJ | 86302.551 | 75983.768 | |
1257 | JSON::PC | 65948.176 | 74631.744 | |
1359 | JSON::PP | 15827.562 | 6638.658 | |
1258 | JSON::PP | 8931.652 | 3817.168 | |
1360 | JSON::Syck | 63358.066 | 47662.545 | |
1259 | JSON::Syck | 24877.248 | 27776.848 | |
1361 | JSON::XS | 511500.488 | 511500.488 | |
1260 | JSON::XS | 388361.481 | 227951.304 | |
1362 | JSON::XS/2 | 291271.111 | 388361.481 | |
1261 | JSON::XS/2 | 227951.304 | 218453.333 | |
1363 | JSON::XS/3 | 361577.931 | 361577.931 | |
1262 | JSON::XS/3 | 338250.323 | 218453.333 | |
1364 | Storable | 66788.280 | 265462.278 | |
1263 | Storable | 16500.016 | 135300.129 | |
|
|
1264 | -----------+------------+------------+ |
1365 | --------------+------------+------------+ |
1265 | |
1366 | |
1266 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
1367 | That is, JSON::XS is almost six times faster than JSON::DWIW on encoding, |
1267 | about three times faster on decoding, and over forty times faster |
1368 | about five times faster on decoding, and over thirty to seventy times |
1268 | than JSON, even with pretty-printing and key sorting. It also compares |
1369 | faster than JSON's pure perl implementation. It also compares favourably |
1269 | favourably to Storable for small amounts of data. |
1370 | to Storable for small amounts of data. |
1270 | |
1371 | |
1271 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
1372 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
1272 | search API (L<http://dist.schmorp.de/misc/json/long.json>). |
1373 | search API (L<http://dist.schmorp.de/misc/json/long.json>). |
1273 | |
1374 | |
1274 | module | encode | decode | |
1375 | module | encode | decode | |
1275 | -----------|------------|------------| |
1376 | --------------|------------|------------| |
1276 | JSON 1.x | 55.260 | 34.971 | |
1377 | JSON::DWIW/DS | 1647.927 | 2673.916 | |
1277 | JSON::DWIW | 825.228 | 1082.513 | |
1378 | JSON::DWIW/FJ | 1630.249 | 2596.128 | |
1278 | JSON::PC | 3571.444 | 2394.829 | |
|
|
1279 | JSON::PP | 210.987 | 32.574 | |
1379 | JSON::PP | 400.640 | 62.311 | |
1280 | JSON::Syck | 552.551 | 787.544 | |
1380 | JSON::Syck | 1481.040 | 1524.869 | |
1281 | JSON::XS | 5780.463 | 4854.519 | |
1381 | JSON::XS | 20661.596 | 9541.183 | |
1282 | JSON::XS/2 | 3869.998 | 4798.975 | |
1382 | JSON::XS/2 | 10683.403 | 9416.938 | |
1283 | JSON::XS/3 | 5862.880 | 4798.975 | |
1383 | JSON::XS/3 | 20661.596 | 9400.054 | |
1284 | Storable | 4445.002 | 5235.027 | |
1384 | Storable | 19765.806 | 10000.725 | |
1285 | -----------+------------+------------+ |
1385 | --------------+------------+------------+ |
1286 | |
1386 | |
1287 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
1387 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
1288 | decodes faster). |
1388 | decodes a bit faster). |
1289 | |
1389 | |
1290 | On large strings containing lots of high Unicode characters, some modules |
1390 | On large strings containing lots of high Unicode characters, some modules |
1291 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
1391 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
1292 | will be broken due to missing (or wrong) Unicode handling. Others refuse |
1392 | will be broken due to missing (or wrong) Unicode handling. Others refuse |
1293 | to decode or encode properly, so it was impossible to prepare a fair |
1393 | to decode or encode properly, so it was impossible to prepare a fair |
… | |
… | |
1329 | information you might want to make sure that exceptions thrown by JSON::XS |
1429 | information you might want to make sure that exceptions thrown by JSON::XS |
1330 | will not end up in front of untrusted eyes. |
1430 | will not end up in front of untrusted eyes. |
1331 | |
1431 | |
1332 | If you are using JSON::XS to return packets to consumption |
1432 | If you are using JSON::XS to return packets to consumption |
1333 | by JavaScript scripts in a browser you should have a look at |
1433 | by JavaScript scripts in a browser you should have a look at |
1334 | L<http://jpsykes.com/47/practical-csrf-and-json-security> to see whether |
1434 | L<http://blog.archive.jpsykes.com/47/practical-csrf-and-json-security/> to |
1335 | you are vulnerable to some common attack vectors (which really are browser |
1435 | see whether you are vulnerable to some common attack vectors (which really |
1336 | design bugs, but it is still you who will have to deal with it, as major |
1436 | are browser design bugs, but it is still you who will have to deal with |
1337 | browser developers care only for features, not about getting security |
1437 | it, as major browser developers care only for features, not about getting |
1338 | right). |
1438 | security right). |
1339 | |
1439 | |
1340 | |
1440 | |
1341 | =head1 THREADS |
1441 | =head1 THREADS |
1342 | |
1442 | |
1343 | This module is I<not> guaranteed to be thread safe and there are no |
1443 | This module is I<not> guaranteed to be thread safe and there are no |
1344 | plans to change this until Perl gets thread support (as opposed to the |
1444 | plans to change this until Perl gets thread support (as opposed to the |
1345 | horribly slow so-called "threads" which are simply slow and bloated |
1445 | horribly slow so-called "threads" which are simply slow and bloated |
1346 | process simulations - use fork, it's I<much> faster, cheaper, better). |
1446 | process simulations - use fork, it's I<much> faster, cheaper, better). |
1347 | |
1447 | |
1348 | (It might actually work, but you have been warned). |
1448 | (It might actually work, but you have been warned). |
|
|
1449 | |
|
|
1450 | |
|
|
1451 | =head1 THE PERILS OF SETLOCALE |
|
|
1452 | |
|
|
1453 | Sometimes people avoid the Perl locale support and directly call the |
|
|
1454 | system's setlocale function with C<LC_ALL>. |
|
|
1455 | |
|
|
1456 | This breaks both perl and modules such as JSON::XS, as stringification of |
|
|
1457 | numbers no longer works correctly (e.g. C<$x = 0.1; print "$x"+1> might |
|
|
1458 | print C<1>, and JSON::XS might output illegal JSON as JSON::XS relies on |
|
|
1459 | perl to stringify numbers). |
|
|
1460 | |
|
|
1461 | The solution is simple: don't call C<setlocale>, or use it for only those |
|
|
1462 | categories you need, such as C<LC_MESSAGES> or C<LC_CTYPE>. |
|
|
1463 | |
|
|
1464 | If you need C<LC_NUMERIC>, you should enable it only around the code that |
|
|
1465 | actually needs it (avoiding stringification of numbers), and restore it |
|
|
1466 | afterwards. |
1349 | |
1467 | |
1350 | |
1468 | |
1351 | =head1 BUGS |
1469 | =head1 BUGS |
1352 | |
1470 | |
1353 | While the goal of this module is to be correct, that unfortunately does |
1471 | While the goal of this module is to be correct, that unfortunately does |