… | |
… | |
37 | primary goal is to be I<correct> and its secondary goal is to be |
37 | primary goal is to be I<correct> and its secondary goal is to be |
38 | I<fast>. To reach the latter goal it was written in C. |
38 | I<fast>. To reach the latter goal it was written in C. |
39 | |
39 | |
40 | Beginning with version 2.0 of the JSON module, when both JSON and |
40 | Beginning with version 2.0 of the JSON module, when both JSON and |
41 | JSON::XS are installed, then JSON will fall back on JSON::XS (this can be |
41 | JSON::XS are installed, then JSON will fall back on JSON::XS (this can be |
42 | overriden) with no overhead due to emulation (by inheritign constructor |
42 | overridden) with no overhead due to emulation (by inheriting constructor |
43 | and methods). If JSON::XS is not available, it will fall back to the |
43 | and methods). If JSON::XS is not available, it will fall back to the |
44 | compatible JSON::PP module as backend, so using JSON instead of JSON::XS |
44 | compatible JSON::PP module as backend, so using JSON instead of JSON::XS |
45 | gives you a portable JSON API that can be fast when you need and doesn't |
45 | gives you a portable JSON API that can be fast when you need and doesn't |
46 | require a C compiler when that is a problem. |
46 | require a C compiler when that is a problem. |
47 | |
47 | |
… | |
… | |
65 | This module knows how to handle Unicode, documents how and when it does |
65 | This module knows how to handle Unicode, documents how and when it does |
66 | so, and even documents what "correct" means. |
66 | so, and even documents what "correct" means. |
67 | |
67 | |
68 | =item * round-trip integrity |
68 | =item * round-trip integrity |
69 | |
69 | |
70 | When you serialise a perl data structure using only datatypes supported |
70 | 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. |
71 | by JSON, the deserialised data structure is identical on the Perl level. |
72 | (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 |
73 | like a number). There minor I<are> exceptions to this, read the MAPPING |
73 | like a number). There minor I<are> exceptions to this, read the MAPPING |
74 | section below to learn about those. |
74 | section below to learn about those. |
75 | |
75 | |
… | |
… | |
84 | Compared to other JSON modules and other serialisers such as Storable, |
84 | Compared to other JSON modules and other serialisers such as Storable, |
85 | this module usually compares favourably in terms of speed, too. |
85 | this module usually compares favourably in terms of speed, too. |
86 | |
86 | |
87 | =item * simple to use |
87 | =item * simple to use |
88 | |
88 | |
89 | This module has both a simple functional interface as well as an objetc |
89 | This module has both a simple functional interface as well as an object |
90 | oriented interface interface. |
90 | oriented interface interface. |
91 | |
91 | |
92 | =item * reasonably versatile output formats |
92 | =item * reasonably versatile output formats |
93 | |
93 | |
94 | You can choose between the most compact guaranteed-single-line format |
94 | You can choose between the most compact guaranteed-single-line format |
95 | possible (nice for simple line-based protocols), a pure-ascii format |
95 | possible (nice for simple line-based protocols), a pure-ASCII format |
96 | (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 |
97 | 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 |
98 | 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. |
99 | |
99 | |
100 | =back |
100 | =back |
… | |
… | |
103 | |
103 | |
104 | package JSON::XS; |
104 | package JSON::XS; |
105 | |
105 | |
106 | use strict; |
106 | use strict; |
107 | |
107 | |
108 | our $VERSION = '2.2'; |
108 | our $VERSION = '2.22'; |
109 | our @ISA = qw(Exporter); |
109 | our @ISA = qw(Exporter); |
110 | |
110 | |
111 | our @EXPORT = qw(encode_json decode_json to_json from_json); |
111 | our @EXPORT = qw(encode_json decode_json to_json from_json); |
112 | |
112 | |
113 | sub to_json($) { |
113 | sub to_json($) { |
… | |
… | |
137 | |
137 | |
138 | This function call is functionally identical to: |
138 | This function call is functionally identical to: |
139 | |
139 | |
140 | $json_text = JSON::XS->new->utf8->encode ($perl_scalar) |
140 | $json_text = JSON::XS->new->utf8->encode ($perl_scalar) |
141 | |
141 | |
142 | except being faster. |
142 | Except being faster. |
143 | |
143 | |
144 | =item $perl_scalar = decode_json $json_text |
144 | =item $perl_scalar = decode_json $json_text |
145 | |
145 | |
146 | The opposite of C<encode_json>: expects an UTF-8 (binary) string and tries |
146 | The opposite of C<encode_json>: expects an UTF-8 (binary) string and tries |
147 | to parse that as an UTF-8 encoded JSON text, returning the resulting |
147 | to parse that as an UTF-8 encoded JSON text, returning the resulting |
… | |
… | |
149 | |
149 | |
150 | This function call is functionally identical to: |
150 | This function call is functionally identical to: |
151 | |
151 | |
152 | $perl_scalar = JSON::XS->new->utf8->decode ($json_text) |
152 | $perl_scalar = JSON::XS->new->utf8->decode ($json_text) |
153 | |
153 | |
154 | except being faster. |
154 | Except being faster. |
155 | |
155 | |
156 | =item $is_boolean = JSON::XS::is_bool $scalar |
156 | =item $is_boolean = JSON::XS::is_bool $scalar |
157 | |
157 | |
158 | Returns true if the passed scalar represents either JSON::XS::true or |
158 | Returns true if the passed scalar represents either JSON::XS::true or |
159 | JSON::XS::false, two constants that act like C<1> and C<0>, respectively |
159 | JSON::XS::false, two constants that act like C<1> and C<0>, respectively |
… | |
… | |
197 | |
197 | |
198 | If you didn't know about that flag, just the better, pretend it doesn't |
198 | If you didn't know about that flag, just the better, pretend it doesn't |
199 | exist. |
199 | exist. |
200 | |
200 | |
201 | =item 4. A "Unicode String" is simply a string where each character can be |
201 | =item 4. A "Unicode String" is simply a string where each character can be |
202 | validly interpreted as a Unicode codepoint. |
202 | validly interpreted as a Unicode code point. |
203 | |
203 | |
204 | If you have UTF-8 encoded data, it is no longer a Unicode string, but a |
204 | If you have UTF-8 encoded data, it is no longer a Unicode string, but a |
205 | Unicode string encoded in UTF-8, giving you a binary string. |
205 | Unicode string encoded in UTF-8, giving you a binary string. |
206 | |
206 | |
207 | =item 5. A string containing "high" (> 255) character values is I<not> a UTF-8 string. |
207 | =item 5. A string containing "high" (> 255) character values is I<not> a UTF-8 string. |
… | |
… | |
701 | =back |
701 | =back |
702 | |
702 | |
703 | |
703 | |
704 | =head1 INCREMENTAL PARSING |
704 | =head1 INCREMENTAL PARSING |
705 | |
705 | |
706 | [This section and the API it details is still EXPERIMENTAL] |
|
|
707 | |
|
|
708 | 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 |
709 | 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 |
710 | 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 |
711 | 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 |
712 | 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 |
713 | 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 |
714 | 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 |
715 | 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 |
716 | 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. |
717 | |
723 | |
718 | The following two methods deal with this. |
724 | The following methods implement this incremental parser. |
719 | |
725 | |
720 | =over 4 |
726 | =over 4 |
721 | |
727 | |
722 | =item [void, scalar or list context] = $json->incr_parse ([$string]) |
728 | =item [void, scalar or list context] = $json->incr_parse ([$string]) |
723 | |
729 | |
… | |
… | |
765 | |
771 | |
766 | 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 the |
767 | parsed text from the input buffer. This is useful after C<incr_parse> |
773 | parsed text from the input buffer. This is useful after C<incr_parse> |
768 | died, in which case the input buffer and incremental parser state is left |
774 | died, in which case the input buffer and incremental parser state is left |
769 | unchanged, to skip the text parsed so far and to reset the parse state. |
775 | unchanged, to skip the text parsed so far and to reset the parse state. |
|
|
776 | |
|
|
777 | =item $json->incr_reset |
|
|
778 | |
|
|
779 | This completely resets the incremental parser, that is, after this call, |
|
|
780 | it will be as if the parser had never parsed anything. |
|
|
781 | |
|
|
782 | This is useful if you want ot repeatedly parse JSON objects and want to |
|
|
783 | ignore any trailing data, which means you have to reset the parser after |
|
|
784 | each successful decode. |
770 | |
785 | |
771 | =back |
786 | =back |
772 | |
787 | |
773 | =head2 LIMITATIONS |
788 | =head2 LIMITATIONS |
774 | |
789 | |
… | |
… | |
1015 | Other unblessed references are generally not allowed and will cause an |
1030 | Other unblessed references are generally not allowed and will cause an |
1016 | exception to be thrown, except for references to the integers C<0> and |
1031 | exception to be thrown, except for references to the integers C<0> and |
1017 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
1032 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
1018 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
1033 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
1019 | |
1034 | |
1020 | encode_json [\0,JSON::XS::true] # yields [false,true] |
1035 | encode_json [\0, JSON::XS::true] # yields [false,true] |
1021 | |
1036 | |
1022 | =item JSON::XS::true, JSON::XS::false |
1037 | =item JSON::XS::true, JSON::XS::false |
1023 | |
1038 | |
1024 | These special values become JSON true and JSON false values, |
1039 | These special values become JSON true and JSON false values, |
1025 | respectively. You can also use C<\1> and C<\0> directly if you want. |
1040 | respectively. You can also use C<\1> and C<\0> directly if you want. |