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1 | =encoding utf-8 |
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2 | |
1 | =head1 NAME |
3 | =head1 NAME |
2 | |
4 | |
3 | JSON::XS - JSON serialising/deserialising, done correctly and fast |
5 | JSON::XS - JSON serialising/deserialising, done correctly and fast |
4 | |
6 | |
5 | JSON::XS - 正しくて高速な JSON シリアライザ/デシリアライザ |
7 | JSON::XS - 正しくて高速な JSON シリアライザ/デシリアライザ |
… | |
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58 | |
60 | |
59 | =over 4 |
61 | =over 4 |
60 | |
62 | |
61 | =item * correct Unicode handling |
63 | =item * correct Unicode handling |
62 | |
64 | |
63 | This module knows how to handle Unicode, and even documents how and when |
65 | This module knows how to handle Unicode, documents how and when it does |
64 | it does so. |
66 | so, and even documents what "correct" means. |
65 | |
67 | |
66 | =item * round-trip integrity |
68 | =item * round-trip integrity |
67 | |
69 | |
68 | When you serialise a perl data structure using only datatypes supported |
70 | When you serialise a perl data structure using only datatypes supported |
69 | by JSON, the deserialised data structure is identical on the Perl level. |
71 | by JSON, the deserialised data structure is identical on the Perl level. |
70 | (e.g. the string "2.0" doesn't suddenly become "2" just because it looks |
72 | (e.g. the string "2.0" doesn't suddenly become "2" just because it looks |
71 | like a number). |
73 | like a number). There minor I<are> exceptions to this, read the MAPPING |
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74 | section below to learn about those. |
72 | |
75 | |
73 | =item * strict checking of JSON correctness |
76 | =item * strict checking of JSON correctness |
74 | |
77 | |
75 | There is no guessing, no generating of illegal JSON texts by default, |
78 | There is no guessing, no generating of illegal JSON texts by default, |
76 | and only JSON is accepted as input by default (the latter is a security |
79 | and only JSON is accepted as input by default (the latter is a security |
77 | feature). |
80 | feature). |
78 | |
81 | |
79 | =item * fast |
82 | =item * fast |
80 | |
83 | |
81 | Compared to other JSON modules, this module compares favourably in terms |
84 | Compared to other JSON modules and other serialisers such as Storable, |
82 | of speed, too. |
85 | this module usually compares favourably in terms of speed, too. |
83 | |
86 | |
84 | =item * simple to use |
87 | =item * simple to use |
85 | |
88 | |
86 | This module has both a simple functional interface as well as an OO |
89 | This module has both a simple functional interface as well as an objetc |
87 | interface. |
90 | oriented interface interface. |
88 | |
91 | |
89 | =item * reasonably versatile output formats |
92 | =item * reasonably versatile output formats |
90 | |
93 | |
91 | You can choose between the most compact guaranteed single-line format |
94 | You can choose between the most compact guaranteed-single-line format |
92 | possible (nice for simple line-based protocols), a pure-ascii format |
95 | possible (nice for simple line-based protocols), a pure-ascii format |
93 | (for when your transport is not 8-bit clean, still supports the whole |
96 | (for when your transport is not 8-bit clean, still supports the whole |
94 | Unicode range), or a pretty-printed format (for when you want to read that |
97 | Unicode range), or a pretty-printed format (for when you want to read that |
95 | stuff). Or you can combine those features in whatever way you like. |
98 | stuff). Or you can combine those features in whatever way you like. |
96 | |
99 | |
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100 | |
103 | |
101 | package JSON::XS; |
104 | package JSON::XS; |
102 | |
105 | |
103 | use strict; |
106 | use strict; |
104 | |
107 | |
105 | our $VERSION = '2.01'; |
108 | our $VERSION = '2.1'; |
106 | our @ISA = qw(Exporter); |
109 | our @ISA = qw(Exporter); |
107 | |
110 | |
108 | our @EXPORT = qw(encode_json decode_json to_json from_json); |
111 | our @EXPORT = qw(encode_json decode_json to_json from_json); |
109 | |
112 | |
110 | sub to_json($) { |
113 | sub to_json($) { |
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174 | This enables you to store Unicode characters as single characters in a |
177 | This enables you to store Unicode characters as single characters in a |
175 | Perl string - very natural. |
178 | Perl string - very natural. |
176 | |
179 | |
177 | =item 2. Perl does I<not> associate an encoding with your strings. |
180 | =item 2. Perl does I<not> associate an encoding with your strings. |
178 | |
181 | |
179 | Unless you force it to, e.g. when matching it against a regex, or printing |
182 | ... until you force it to, e.g. when matching it against a regex, or |
180 | the scalar to a file, in which case Perl either interprets your string as |
183 | printing the scalar to a file, in which case Perl either interprets your |
181 | locale-encoded text, octets/binary, or as Unicode, depending on various |
184 | string as locale-encoded text, octets/binary, or as Unicode, depending |
182 | settings. In no case is an encoding stored together with your data, it is |
185 | on various settings. In no case is an encoding stored together with your |
183 | I<use> that decides encoding, not any magical metadata. |
186 | data, it is I<use> that decides encoding, not any magical meta data. |
184 | |
187 | |
185 | =item 3. The internal utf-8 flag has no meaning with regards to the |
188 | =item 3. The internal utf-8 flag has no meaning with regards to the |
186 | encoding of your string. |
189 | encoding of your string. |
187 | |
190 | |
188 | Just ignore that flag unless you debug a Perl bug, a module written in |
191 | Just ignore that flag unless you debug a Perl bug, a module written in |
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242 | |
245 | |
243 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
246 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
244 | characters unless required by the JSON syntax or other flags. This results |
247 | characters unless required by the JSON syntax or other flags. This results |
245 | in a faster and more compact format. |
248 | in a faster and more compact format. |
246 | |
249 | |
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250 | See also the section I<ENCODING/CODESET FLAG NOTES> later in this |
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251 | document. |
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252 | |
247 | The main use for this flag is to produce JSON texts that can be |
253 | The main use for this flag is to produce JSON texts that can be |
248 | transmitted over a 7-bit channel, as the encoded JSON texts will not |
254 | transmitted over a 7-bit channel, as the encoded JSON texts will not |
249 | contain any 8 bit characters. |
255 | contain any 8 bit characters. |
250 | |
256 | |
251 | JSON::XS->new->ascii (1)->encode ([chr 0x10401]) |
257 | JSON::XS->new->ascii (1)->encode ([chr 0x10401]) |
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262 | will not be affected in any way by this flag, as C<decode> by default |
268 | will not be affected in any way by this flag, as C<decode> by default |
263 | expects Unicode, which is a strict superset of latin1. |
269 | expects Unicode, which is a strict superset of latin1. |
264 | |
270 | |
265 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
271 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
266 | characters unless required by the JSON syntax or other flags. |
272 | characters unless required by the JSON syntax or other flags. |
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273 | |
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274 | See also the section I<ENCODING/CODESET FLAG NOTES> later in this |
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275 | document. |
267 | |
276 | |
268 | The main use for this flag is efficiently encoding binary data as JSON |
277 | The main use for this flag is efficiently encoding binary data as JSON |
269 | text, as most octets will not be escaped, resulting in a smaller encoded |
278 | text, as most octets will not be escaped, resulting in a smaller encoded |
270 | size. The disadvantage is that the resulting JSON text is encoded |
279 | size. The disadvantage is that the resulting JSON text is encoded |
271 | in latin1 (and must correctly be treated as such when storing and |
280 | in latin1 (and must correctly be treated as such when storing and |
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290 | |
299 | |
291 | If C<$enable> is false, then the C<encode> method will return the JSON |
300 | If C<$enable> is false, then the C<encode> method will return the JSON |
292 | string as a (non-encoded) Unicode string, while C<decode> expects thus a |
301 | string as a (non-encoded) Unicode string, while C<decode> expects thus a |
293 | Unicode string. Any decoding or encoding (e.g. to UTF-8 or UTF-16) needs |
302 | Unicode string. Any decoding or encoding (e.g. to UTF-8 or UTF-16) needs |
294 | to be done yourself, e.g. using the Encode module. |
303 | to be done yourself, e.g. using the Encode module. |
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304 | |
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305 | See also the section I<ENCODING/CODESET FLAG NOTES> later in this |
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306 | document. |
295 | |
307 | |
296 | Example, output UTF-16BE-encoded JSON: |
308 | Example, output UTF-16BE-encoded JSON: |
297 | |
309 | |
298 | use Encode; |
310 | use Encode; |
299 | $jsontext = encode "UTF-16BE", JSON::XS->new->encode ($object); |
311 | $jsontext = encode "UTF-16BE", JSON::XS->new->encode ($object); |
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706 | |
718 | |
707 | A JSON number becomes either an integer, numeric (floating point) or |
719 | A JSON number becomes either an integer, numeric (floating point) or |
708 | string scalar in perl, depending on its range and any fractional parts. On |
720 | string scalar in perl, depending on its range and any fractional parts. On |
709 | the Perl level, there is no difference between those as Perl handles all |
721 | the Perl level, there is no difference between those as Perl handles all |
710 | the conversion details, but an integer may take slightly less memory and |
722 | the conversion details, but an integer may take slightly less memory and |
711 | might represent more values exactly than (floating point) numbers. |
723 | might represent more values exactly than floating point numbers. |
712 | |
724 | |
713 | If the number consists of digits only, JSON::XS will try to represent |
725 | If the number consists of digits only, JSON::XS will try to represent |
714 | it as an integer value. If that fails, it will try to represent it as |
726 | it as an integer value. If that fails, it will try to represent it as |
715 | a numeric (floating point) value if that is possible without loss of |
727 | a numeric (floating point) value if that is possible without loss of |
716 | precision. Otherwise it will preserve the number as a string value. |
728 | precision. Otherwise it will preserve the number as a string value (in |
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729 | which case you lose roundtripping ability, as the JSON number will be |
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730 | re-encoded toa JSON string). |
717 | |
731 | |
718 | Numbers containing a fractional or exponential part will always be |
732 | Numbers containing a fractional or exponential part will always be |
719 | represented as numeric (floating point) values, possibly at a loss of |
733 | represented as numeric (floating point) values, possibly at a loss of |
720 | precision. |
734 | precision (in which case you might lose perfect roundtripping ability, but |
721 | |
735 | the JSON number will still be re-encoded as a JSON number). |
722 | This might create round-tripping problems as numbers might become strings, |
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723 | but as Perl is typeless there is no other way to do it. |
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724 | |
736 | |
725 | =item true, false |
737 | =item true, false |
726 | |
738 | |
727 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
739 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
728 | respectively. They are overloaded to act almost exactly like the numbers |
740 | respectively. They are overloaded to act almost exactly like the numbers |
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774 | These special values become JSON true and JSON false values, |
786 | These special values become JSON true and JSON false values, |
775 | respectively. You can also use C<\1> and C<\0> directly if you want. |
787 | respectively. You can also use C<\1> and C<\0> directly if you want. |
776 | |
788 | |
777 | =item blessed objects |
789 | =item blessed objects |
778 | |
790 | |
779 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
791 | Blessed objects are not directly representable in JSON. See the |
780 | underlying representation (hash- or arrayref), but this behaviour might |
792 | C<allow_blessed> and C<convert_blessed> methods on various options on |
781 | change in future versions. |
793 | how to deal with this: basically, you can choose between throwing an |
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794 | exception, encoding the reference as if it weren't blessed, or provide |
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795 | your own serialiser method. |
782 | |
796 | |
783 | =item simple scalars |
797 | =item simple scalars |
784 | |
798 | |
785 | Simple Perl scalars (any scalar that is not a reference) are the most |
799 | Simple Perl scalars (any scalar that is not a reference) are the most |
786 | difficult objects to encode: JSON::XS will encode undefined scalars as |
800 | difficult objects to encode: JSON::XS will encode undefined scalars as |
787 | JSON null value, scalars that have last been used in a string context |
801 | JSON C<null> values, scalars that have last been used in a string context |
788 | before encoding as JSON strings and anything else as number value: |
802 | before encoding as JSON strings, and anything else as number value: |
789 | |
803 | |
790 | # dump as number |
804 | # dump as number |
791 | encode_json [2] # yields [2] |
805 | encode_json [2] # yields [2] |
792 | encode_json [-3.0e17] # yields [-3e+17] |
806 | encode_json [-3.0e17] # yields [-3e+17] |
793 | my $value = 5; encode_json [$value] # yields [5] |
807 | my $value = 5; encode_json [$value] # yields [5] |
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811 | my $x = "3"; # some variable containing a string |
825 | my $x = "3"; # some variable containing a string |
812 | $x += 0; # numify it, ensuring it will be dumped as a number |
826 | $x += 0; # numify it, ensuring it will be dumped as a number |
813 | $x *= 1; # same thing, the choice is yours. |
827 | $x *= 1; # same thing, the choice is yours. |
814 | |
828 | |
815 | You can not currently force the type in other, less obscure, ways. Tell me |
829 | You can not currently force the type in other, less obscure, ways. Tell me |
816 | if you need this capability. |
830 | if you need this capability (but don't forget to explain why its needed |
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831 | :). |
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832 | |
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833 | =back |
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834 | |
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835 | |
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836 | =head1 ENCODING/CODESET FLAG NOTES |
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837 | |
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838 | The interested reader might have seen a number of flags that signify |
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839 | encodings or codesets - C<utf8>, C<latin1> and C<ascii>. There seems to be |
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840 | some confusion on what these do, so here is a short comparison: |
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841 | |
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842 | C<utf8> controls wether the JSON text created by C<encode> (and expected |
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843 | by C<decode>) is UTF-8 encoded or not, while C<latin1> and C<ascii> only |
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844 | control wether C<encode> escapes character values outside their respective |
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845 | codeset range. Neither of these flags conflict with each other, although |
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846 | some combinations make less sense than others. |
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847 | |
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848 | Care has been taken to make all flags symmetrical with respect to |
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849 | C<encode> and C<decode>, that is, texts encoded with any combination of |
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850 | these flag values will be correctly decoded when the same flags are used |
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851 | - in general, if you use different flag settings while encoding vs. when |
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852 | decoding you likely have a bug somewhere. |
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853 | |
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854 | Below comes a verbose discussion of these flags. Note that a "codeset" is |
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855 | simply an abstract set of character-codepoint pairs, while an encoding |
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856 | takes those codepoint numbers and I<encodes> them, in our case into |
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857 | octets. Unicode is (among other things) a codeset, UTF-8 is an encoding, |
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858 | and ISO-8859-1 (= latin 1) and ASCII are both codesets I<and> encodings at |
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859 | the same time, which can be confusing. |
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860 | |
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861 | =over 4 |
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862 | |
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863 | =item C<utf8> flag disabled |
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864 | |
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865 | When C<utf8> is disabled (the default), then C<encode>/C<decode> generate |
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866 | and expect Unicode strings, that is, characters with high ordinal Unicode |
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867 | values (> 255) will be encoded as such characters, and likewise such |
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868 | characters are decoded as-is, no canges to them will be done, except |
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869 | "(re-)interpreting" them as Unicode codepoints or Unicode characters, |
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870 | respectively (to Perl, these are the same thing in strings unless you do |
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871 | funny/weird/dumb stuff). |
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872 | |
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873 | This is useful when you want to do the encoding yourself (e.g. when you |
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874 | want to have UTF-16 encoded JSON texts) or when some other layer does |
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875 | the encoding for you (for example, when printing to a terminal using a |
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876 | filehandle that transparently encodes to UTF-8 you certainly do NOT want |
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877 | to UTF-8 encode your data first and have Perl encode it another time). |
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878 | |
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879 | =item C<utf8> flag enabled |
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880 | |
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881 | If the C<utf8>-flag is enabled, C<encode>/C<decode> will encode all |
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882 | characters using the corresponding UTF-8 multi-byte sequence, and will |
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883 | expect your input strings to be encoded as UTF-8, that is, no "character" |
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884 | of the input string must have any value > 255, as UTF-8 does not allow |
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885 | that. |
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886 | |
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887 | The C<utf8> flag therefore switches between two modes: disabled means you |
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888 | will get a Unicode string in Perl, enabled means you get an UTF-8 encoded |
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889 | octet/binary string in Perl. |
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890 | |
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891 | =item C<latin1> or C<ascii> flags enabled |
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892 | |
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893 | With C<latin1> (or C<ascii>) enabled, C<encode> will escape characters |
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894 | with ordinal values > 255 (> 127 with C<ascii>) and encode the remaining |
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895 | characters as specified by the C<utf8> flag. |
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896 | |
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897 | If C<utf8> is disabled, then the result is also correctly encoded in those |
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898 | character sets (as both are proper subsets of Unicode, meaning that a |
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899 | Unicode string with all character values < 256 is the same thing as a |
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900 | ISO-8859-1 string, and a Unicode string with all character values < 128 is |
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901 | the same thing as an ASCII string in Perl). |
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902 | |
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903 | If C<utf8> is enabled, you still get a correct UTF-8-encoded string, |
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904 | regardless of these flags, just some more characters will be escaped using |
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905 | C<\uXXXX> then before. |
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906 | |
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907 | Note that ISO-8859-1-I<encoded> strings are not compatible with UTF-8 |
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908 | encoding, while ASCII-encoded strings are. That is because the ISO-8859-1 |
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909 | encoding is NOT a subset of UTF-8 (despite the ISO-8859-1 I<codeset> being |
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910 | a subset of Unicode), while ASCII is. |
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911 | |
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912 | Surprisingly, C<decode> will ignore these flags and so treat all input |
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913 | values as governed by the C<utf8> flag. If it is disabled, this allows you |
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914 | to decode ISO-8859-1- and ASCII-encoded strings, as both strict subsets of |
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915 | Unicode. If it is enabled, you can correctly decode UTF-8 encoded strings. |
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916 | |
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917 | So neither C<latin1> nor C<ascii> are incompatible with the C<utf8> flag - |
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918 | they only govern when the JSON output engine escapes a character or not. |
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919 | |
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920 | The main use for C<latin1> is to relatively efficiently store binary data |
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921 | as JSON, at the expense of breaking compatibility with most JSON decoders. |
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922 | |
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923 | The main use for C<ascii> is to force the output to not contain characters |
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924 | with values > 127, which means you can interpret the resulting string |
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925 | as UTF-8, ISO-8859-1, ASCII, KOI8-R or most about any character set and |
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926 | 8-bit-encoding, and still get the same data structure back. This is useful |
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927 | when your channel for JSON transfer is not 8-bit clean or the encoding |
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928 | might be mangled in between (e.g. in mail), and works because ASCII is a |
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929 | proper subset of most 8-bit and multibyte encodings in use in the world. |
817 | |
930 | |
818 | =back |
931 | =back |
819 | |
932 | |
820 | |
933 | |
821 | =head1 COMPARISON |
934 | =head1 COMPARISON |
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825 | problems (or pleasures) I encountered with various existing JSON modules, |
938 | problems (or pleasures) I encountered with various existing JSON modules, |
826 | followed by some benchmark values. JSON::XS was designed not to suffer |
939 | followed by some benchmark values. JSON::XS was designed not to suffer |
827 | from any of these problems or limitations. |
940 | from any of these problems or limitations. |
828 | |
941 | |
829 | =over 4 |
942 | =over 4 |
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943 | |
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944 | =item JSON 2.xx |
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945 | |
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946 | A marvellous piece of engineering, this module either uses JSON::XS |
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947 | directly when available (so will be 100% compatible with it, including |
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948 | speed), or it uses JSON::PP, which is basically JSON::XS translated to |
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949 | Pure Perl, which should be 100% compatible with JSON::XS, just a bit |
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950 | slower. |
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951 | |
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952 | You cannot really lose by using this module, especially as it tries very |
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953 | hard to work even with ancient Perl versions, while JSON::XS does not. |
830 | |
954 | |
831 | =item JSON 1.07 |
955 | =item JSON 1.07 |
832 | |
956 | |
833 | Slow (but very portable, as it is written in pure Perl). |
957 | Slow (but very portable, as it is written in pure Perl). |
834 | |
958 | |
… | |
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906 | |
1030 | |
907 | |
1031 | |
908 | =head2 JSON and YAML |
1032 | =head2 JSON and YAML |
909 | |
1033 | |
910 | You often hear that JSON is a subset of YAML. This is, however, a mass |
1034 | You often hear that JSON is a subset of YAML. This is, however, a mass |
911 | hysteria and very far from the truth. In general, there is no way to |
1035 | hysteria(*) and very far from the truth (as of the time of this writing), |
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1036 | so let me state it clearly: I<in general, there is no way to configure |
912 | configure JSON::XS to output a data structure as valid YAML that works for |
1037 | JSON::XS to output a data structure as valid YAML> that works in all |
913 | all cases. |
1038 | cases. |
914 | |
1039 | |
915 | If you really must use JSON::XS to generate YAML, you should use this |
1040 | If you really must use JSON::XS to generate YAML, you should use this |
916 | algorithm (subject to change in future versions): |
1041 | algorithm (subject to change in future versions): |
917 | |
1042 | |
918 | my $to_yaml = JSON::XS->new->utf8->space_after (1); |
1043 | my $to_yaml = JSON::XS->new->utf8->space_after (1); |
919 | my $yaml = $to_yaml->encode ($ref) . "\n"; |
1044 | my $yaml = $to_yaml->encode ($ref) . "\n"; |
920 | |
1045 | |
921 | This will usually generate JSON texts that also parse as valid |
1046 | This will I<usually> generate JSON texts that also parse as valid |
922 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
1047 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
923 | lengths that JSON doesn't have and also has different and incompatible |
1048 | lengths that JSON doesn't have and also has different and incompatible |
924 | unicode handling, so you should make sure that your hash keys are |
1049 | unicode handling, so you should make sure that your hash keys are |
925 | noticeably shorter than the 1024 "stream characters" YAML allows and that |
1050 | noticeably shorter than the 1024 "stream characters" YAML allows and that |
926 | you do not have codepoints with values outside the Unicode BMP (basic |
1051 | you do not have characters with codepoint values outside the Unicode BMP |
927 | multilingual page). |
1052 | (basic multilingual page). YAML also does not allow C<\/> sequences in |
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1053 | strings (which JSON::XS does not I<currently> generate, but other JSON |
|
|
1054 | generators might). |
928 | |
1055 | |
929 | There might be other incompatibilities that I am not aware of. In general |
1056 | There might be other incompatibilities that I am not aware of (or the YAML |
|
|
1057 | specification has been changed yet again - it does so quite often). In |
930 | you should not try to generate YAML with a JSON generator or vice versa, |
1058 | general you should not try to generate YAML with a JSON generator or vice |
931 | or try to parse JSON with a YAML parser or vice versa: chances are high |
1059 | versa, or try to parse JSON with a YAML parser or vice versa: chances are |
932 | that you will run into severe interoperability problems when you least |
1060 | high that you will run into severe interoperability problems when you |
933 | expect it. |
1061 | least expect it. |
|
|
1062 | |
|
|
1063 | =over 4 |
|
|
1064 | |
|
|
1065 | =item (*) |
|
|
1066 | |
|
|
1067 | I have been pressured multiple times by Brian Ingerson (one of the |
|
|
1068 | authors of the YAML specification) to remove this paragraph, despite him |
|
|
1069 | acknowledging that the actual incompatibilities exist. As I was personally |
|
|
1070 | bitten by this "JSON is YAML" lie, I refused and said I will continue to |
|
|
1071 | educate people about these issues, so others do not run into the same |
|
|
1072 | problem again and again. After this, Brian called me a (quote)I<complete |
|
|
1073 | and worthless idiot>(unquote). |
|
|
1074 | |
|
|
1075 | In my opinion, instead of pressuring and insulting people who actually |
|
|
1076 | clarify issues with YAML and the wrong statements of some of its |
|
|
1077 | proponents, I would kindly suggest reading the JSON spec (which is not |
|
|
1078 | that difficult or long) and finally make YAML compatible to it, and |
|
|
1079 | educating users about the changes, instead of spreading lies about the |
|
|
1080 | real compatibility for many I<years> and trying to silence people who |
|
|
1081 | point out that it isn't true. |
|
|
1082 | |
|
|
1083 | =back |
934 | |
1084 | |
935 | |
1085 | |
936 | =head2 SPEED |
1086 | =head2 SPEED |
937 | |
1087 | |
938 | It seems that JSON::XS is surprisingly fast, as shown in the following |
1088 | It seems that JSON::XS is surprisingly fast, as shown in the following |
939 | tables. They have been generated with the help of the C<eg/bench> program |
1089 | tables. They have been generated with the help of the C<eg/bench> program |
940 | in the JSON::XS distribution, to make it easy to compare on your own |
1090 | in the JSON::XS distribution, to make it easy to compare on your own |
941 | system. |
1091 | system. |
942 | |
1092 | |
943 | First comes a comparison between various modules using a very short |
1093 | First comes a comparison between various modules using |
944 | single-line JSON string: |
1094 | a very short single-line JSON string (also available at |
|
|
1095 | L<http://dist.schmorp.de/misc/json/short.json>). |
945 | |
1096 | |
946 | {"method": "handleMessage", "params": ["user1", "we were just talking"], \ |
1097 | {"method": "handleMessage", "params": ["user1", "we were just talking"], \ |
947 | "id": null, "array":[1,11,234,-5,1e5,1e7, true, false]} |
1098 | "id": null, "array":[1,11,234,-5,1e5,1e7, true, false]} |
948 | |
1099 | |
949 | It shows the number of encodes/decodes per second (JSON::XS uses |
1100 | It shows the number of encodes/decodes per second (JSON::XS uses |
… | |
… | |
968 | about three times faster on decoding, and over forty times faster |
1119 | about three times faster on decoding, and over forty times faster |
969 | than JSON, even with pretty-printing and key sorting. It also compares |
1120 | than JSON, even with pretty-printing and key sorting. It also compares |
970 | favourably to Storable for small amounts of data. |
1121 | favourably to Storable for small amounts of data. |
971 | |
1122 | |
972 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
1123 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
973 | search API (http://nanoref.com/yahooapis/mgPdGg): |
1124 | search API (L<http://dist.schmorp.de/misc/json/long.json>). |
974 | |
1125 | |
975 | module | encode | decode | |
1126 | module | encode | decode | |
976 | -----------|------------|------------| |
1127 | -----------|------------|------------| |
977 | JSON 1.x | 55.260 | 34.971 | |
1128 | JSON 1.x | 55.260 | 34.971 | |
978 | JSON::DWIW | 825.228 | 1082.513 | |
1129 | JSON::DWIW | 825.228 | 1082.513 | |
… | |
… | |
1020 | to free the temporary). If that is exceeded, the program crashes. To be |
1171 | to free the temporary). If that is exceeded, the program crashes. To be |
1021 | conservative, the default nesting limit is set to 512. If your process |
1172 | conservative, the default nesting limit is set to 512. If your process |
1022 | has a smaller stack, you should adjust this setting accordingly with the |
1173 | has a smaller stack, you should adjust this setting accordingly with the |
1023 | C<max_depth> method. |
1174 | C<max_depth> method. |
1024 | |
1175 | |
1025 | And last but least, something else could bomb you that I forgot to think |
1176 | Something else could bomb you, too, that I forgot to think of. In that |
1026 | of. In that case, you get to keep the pieces. I am always open for hints, |
1177 | case, you get to keep the pieces. I am always open for hints, though... |
1027 | though... |
1178 | |
|
|
1179 | Also keep in mind that JSON::XS might leak contents of your Perl data |
|
|
1180 | structures in its error messages, so when you serialise sensitive |
|
|
1181 | information you might want to make sure that exceptions thrown by JSON::XS |
|
|
1182 | will not end up in front of untrusted eyes. |
1028 | |
1183 | |
1029 | If you are using JSON::XS to return packets to consumption |
1184 | If you are using JSON::XS to return packets to consumption |
1030 | by JavaScript scripts in a browser you should have a look at |
1185 | by JavaScript scripts in a browser you should have a look at |
1031 | L<http://jpsykes.com/47/practical-csrf-and-json-security> to see whether |
1186 | L<http://jpsykes.com/47/practical-csrf-and-json-security> to see whether |
1032 | you are vulnerable to some common attack vectors (which really are browser |
1187 | you are vulnerable to some common attack vectors (which really are browser |