… | |
… | |
64 | so, and even documents what "correct" means. |
64 | so, and even documents what "correct" means. |
65 | |
65 | |
66 | =item * round-trip integrity |
66 | =item * round-trip integrity |
67 | |
67 | |
68 | 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 |
69 | 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 |
70 | (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 |
71 | 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 |
72 | section below to learn about those. |
72 | MAPPING section below to learn about those. |
73 | |
73 | |
74 | =item * strict checking of JSON correctness |
74 | =item * strict checking of JSON correctness |
75 | |
75 | |
76 | 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, |
77 | 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 |
… | |
… | |
101 | |
101 | |
102 | package JSON::XS; |
102 | package JSON::XS; |
103 | |
103 | |
104 | use common::sense; |
104 | use common::sense; |
105 | |
105 | |
106 | our $VERSION = '2.28'; |
106 | our $VERSION = 2.34; |
107 | our @ISA = qw(Exporter); |
107 | our @ISA = qw(Exporter); |
108 | |
108 | |
109 | our @EXPORT = qw(encode_json decode_json to_json from_json); |
109 | our @EXPORT = qw(encode_json decode_json to_json from_json); |
110 | |
110 | |
111 | sub to_json($) { |
111 | sub to_json($) { |
… | |
… | |
432 | If C<$enable> is true (or missing), then the C<encode> method will output JSON objects |
432 | If C<$enable> is true (or missing), then the C<encode> method will output JSON objects |
433 | by sorting their keys. This is adding a comparatively high overhead. |
433 | by sorting their keys. This is adding a comparatively high overhead. |
434 | |
434 | |
435 | If C<$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 |
436 | 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 |
437 | of the same script). |
437 | of the same script, and can change even within the same run from 5.18 |
|
|
438 | onwards). |
438 | |
439 | |
439 | 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 |
440 | 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, |
441 | 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, |
442 | as key-value pairs have no inherent ordering in Perl. |
443 | as key-value pairs have no inherent ordering in Perl. |
… | |
… | |
713 | calls). |
714 | calls). |
714 | |
715 | |
715 | JSON::XS will only attempt to parse the JSON text once it is sure it |
716 | JSON::XS will only attempt to parse the JSON text once it is sure it |
716 | has enough text to get a decisive result, using a very simple but |
717 | has enough text to get a decisive result, using a very simple but |
717 | truly incremental parser. This means that it sometimes won't stop as |
718 | 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 | early as the full parser, for example, it doesn't detect mismatched |
719 | mismatches. The only thing it guarantees is that it starts decoding as |
720 | parentheses. 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 | 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 | to set resource limits (e.g. C<max_size>) to ensure the parser will stop |
722 | parsing in the presence if syntax errors. |
723 | parsing in the presence if syntax errors. |
723 | |
724 | |
724 | The following methods implement this incremental parser. |
725 | The following methods implement this incremental parser. |
… | |
… | |
994 | Numbers containing a fractional or exponential part will always be |
995 | Numbers containing a fractional or exponential part will always be |
995 | represented as numeric (floating point) values, possibly at a loss of |
996 | represented as numeric (floating point) values, possibly at a loss of |
996 | precision (in which case you might lose perfect roundtripping ability, but |
997 | precision (in which case you might lose perfect roundtripping ability, but |
997 | 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). |
998 | |
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 leats significant bit. |
|
|
1004 | |
999 | =item true, false |
1005 | =item true, false |
1000 | |
1006 | |
1001 | 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>, |
1002 | respectively. They are overloaded to act almost exactly like the numbers |
1008 | respectively. They are overloaded to act almost exactly like the numbers |
1003 | C<1> and C<0>. You can check whether a scalar is a JSON boolean by using |
1009 | C<1> and C<0>. You can check whether a scalar is a JSON boolean by using |
… | |
… | |
1090 | |
1096 | |
1091 | 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 |
1092 | 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 |
1093 | :). |
1099 | :). |
1094 | |
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 | |
1095 | =back |
1108 | =back |
1096 | |
1109 | |
1097 | |
1110 | |
1098 | =head1 ENCODING/CODESET FLAG NOTES |
1111 | =head1 ENCODING/CODESET FLAG NOTES |
1099 | |
1112 | |
… | |
… | |
1243 | well - using C<eval> naively simply I<will> cause problems. |
1256 | well - using C<eval> naively simply I<will> cause problems. |
1244 | |
1257 | |
1245 | Another problem is that some javascript implementations reserve |
1258 | Another problem is that some javascript implementations reserve |
1246 | some property names for their own purposes (which probably makes |
1259 | some property names for their own purposes (which probably makes |
1247 | them non-ECMAscript-compliant). For example, Iceweasel reserves the |
1260 | them non-ECMAscript-compliant). For example, Iceweasel reserves the |
1248 | C<__proto__> property name for it's own purposes. |
1261 | C<__proto__> property name for its own purposes. |
1249 | |
1262 | |
1250 | If that is a problem, you could parse try to filter the resulting JSON |
1263 | If that is a problem, you could parse try to filter the resulting JSON |
1251 | output for these property strings, e.g.: |
1264 | output for these property strings, e.g.: |
1252 | |
1265 | |
1253 | $json =~ s/"__proto__"\s*:/"__proto__renamed":/g; |
1266 | $json =~ s/"__proto__"\s*:/"__proto__renamed":/g; |
… | |
… | |
1307 | 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 |
1308 | educating users about the changes, instead of spreading lies about the |
1321 | educating users about the changes, instead of spreading lies about the |
1309 | 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 |
1310 | point out that it isn't true. |
1323 | point out that it isn't true. |
1311 | |
1324 | |
1312 | Addendum/2009: the YAML 1.2 spec is still incomaptible with JSON, even |
1325 | Addendum/2009: the YAML 1.2 spec is still incompatible with JSON, even |
1313 | though the incompatibilities have been documented (and are known to |
1326 | though the incompatibilities have been documented (and are known to Brian) |
1314 | Brian) for many years and the spec makes explicit claims that YAML is a |
1327 | for many years and the spec makes explicit claims that YAML is a superset |
1315 | superset of JSON. It would be so easy to fix, but apparently, bullying and |
1328 | of JSON. It would be so easy to fix, but apparently, bullying people and |
1316 | corrupting userdata is so much easier. |
1329 | corrupting userdata is so much easier. |
1317 | |
1330 | |
1318 | =back |
1331 | =back |
1319 | |
1332 | |
1320 | |
1333 | |
… | |
… | |
1433 | process simulations - use fork, it's I<much> faster, cheaper, better). |
1446 | process simulations - use fork, it's I<much> faster, cheaper, better). |
1434 | |
1447 | |
1435 | (It might actually work, but you have been warned). |
1448 | (It might actually work, but you have been warned). |
1436 | |
1449 | |
1437 | |
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 correcly (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. |
|
|
1467 | |
|
|
1468 | |
1438 | =head1 BUGS |
1469 | =head1 BUGS |
1439 | |
1470 | |
1440 | 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 |
1441 | not mean it's bug-free, only that I think its design is bug-free. If you |
1472 | not mean it's bug-free, only that I think its design is bug-free. If you |
1442 | keep reporting bugs they will be fixed swiftly, though. |
1473 | keep reporting bugs they will be fixed swiftly, though. |