1 | =encoding utf-8 |
|
|
2 | |
|
|
3 | =head1 NAME |
1 | =head1 NAME |
4 | |
2 | |
5 | JSON::XS - JSON serialising/deserialising, done correctly and fast |
3 | JSON::XS - JSON serialising/deserialising, done correctly and fast |
6 | |
4 | |
7 | JSON::XS - 正しくて高速な JSON シリアライザ/デシリアライザ |
5 | JSON::XS - 正しくて高速な JSON シリアライザ/デシリアライザ |
… | |
… | |
12 | use JSON::XS; |
10 | use JSON::XS; |
13 | |
11 | |
14 | # exported functions, they croak on error |
12 | # exported functions, they croak on error |
15 | # and expect/generate UTF-8 |
13 | # and expect/generate UTF-8 |
16 | |
14 | |
17 | $utf8_encoded_json_text = to_json $perl_hash_or_arrayref; |
15 | $utf8_encoded_json_text = encode_json $perl_hash_or_arrayref; |
18 | $perl_hash_or_arrayref = from_json $utf8_encoded_json_text; |
16 | $perl_hash_or_arrayref = decode_json $utf8_encoded_json_text; |
19 | |
17 | |
20 | # OO-interface |
18 | # OO-interface |
21 | |
19 | |
22 | $coder = JSON::XS->new->ascii->pretty->allow_nonref; |
20 | $coder = JSON::XS->new->ascii->pretty->allow_nonref; |
23 | $pretty_printed_unencoded = $coder->encode ($perl_scalar); |
21 | $pretty_printed_unencoded = $coder->encode ($perl_scalar); |
24 | $perl_scalar = $coder->decode ($unicode_json_text); |
22 | $perl_scalar = $coder->decode ($unicode_json_text); |
25 | |
23 | |
|
|
24 | # Note that JSON version 2.0 and above will automatically use JSON::XS |
|
|
25 | # if available, at virtually no speed overhead either, so you should |
|
|
26 | # be able to just: |
|
|
27 | |
|
|
28 | use JSON; |
|
|
29 | |
|
|
30 | # and do the same things, except that you have a pure-perl fallback now. |
|
|
31 | |
26 | =head1 DESCRIPTION |
32 | =head1 DESCRIPTION |
27 | |
33 | |
28 | This module converts Perl data structures to JSON and vice versa. Its |
34 | This module converts Perl data structures to JSON and vice versa. Its |
29 | primary goal is to be I<correct> and its secondary goal is to be |
35 | primary goal is to be I<correct> and its secondary goal is to be |
30 | I<fast>. To reach the latter goal it was written in C. |
36 | I<fast>. To reach the latter goal it was written in C. |
|
|
37 | |
|
|
38 | Beginning with version 2.0 of the JSON module, when both JSON and |
|
|
39 | JSON::XS are installed, then JSON will fall back on JSON::XS (this can be |
|
|
40 | overriden) with no overhead due to emulation (by inheritign constructor |
|
|
41 | and methods). If JSON::XS is not available, it will fall back to the |
|
|
42 | compatible JSON::PP module as backend, so using JSON instead of JSON::XS |
|
|
43 | gives you a portable JSON API that can be fast when you need and doesn't |
|
|
44 | require a C compiler when that is a problem. |
31 | |
45 | |
32 | As this is the n-th-something JSON module on CPAN, what was the reason |
46 | As this is the n-th-something JSON module on CPAN, what was the reason |
33 | to write yet another JSON module? While it seems there are many JSON |
47 | to write yet another JSON module? While it seems there are many JSON |
34 | modules, none of them correctly handle all corner cases, and in most cases |
48 | modules, none of them correctly handle all corner cases, and in most cases |
35 | their maintainers are unresponsive, gone missing, or not listening to bug |
49 | their maintainers are unresponsive, gone missing, or not listening to bug |
… | |
… | |
42 | |
56 | |
43 | =head2 FEATURES |
57 | =head2 FEATURES |
44 | |
58 | |
45 | =over 4 |
59 | =over 4 |
46 | |
60 | |
47 | =item * correct unicode handling |
61 | =item * correct Unicode handling |
48 | |
62 | |
49 | This module knows how to handle Unicode, and even documents how and when |
63 | This module knows how to handle Unicode, and even documents how and when |
50 | it does so. |
64 | it does so. |
51 | |
65 | |
52 | =item * round-trip integrity |
66 | =item * round-trip integrity |
… | |
… | |
72 | This module has both a simple functional interface as well as an OO |
86 | This module has both a simple functional interface as well as an OO |
73 | interface. |
87 | interface. |
74 | |
88 | |
75 | =item * reasonably versatile output formats |
89 | =item * reasonably versatile output formats |
76 | |
90 | |
77 | You can choose between the most compact guarenteed single-line format |
91 | You can choose between the most compact guaranteed single-line format |
78 | possible (nice for simple line-based protocols), a pure-ascii format |
92 | possible (nice for simple line-based protocols), a pure-ascii format |
79 | (for when your transport is not 8-bit clean, still supports the whole |
93 | (for when your transport is not 8-bit clean, still supports the whole |
80 | unicode range), or a pretty-printed format (for when you want to read that |
94 | Unicode range), or a pretty-printed format (for when you want to read that |
81 | stuff). Or you can combine those features in whatever way you like. |
95 | stuff). Or you can combine those features in whatever way you like. |
82 | |
96 | |
83 | =back |
97 | =back |
84 | |
98 | |
85 | =cut |
99 | =cut |
86 | |
100 | |
87 | package JSON::XS; |
101 | package JSON::XS; |
88 | |
102 | |
89 | use strict; |
103 | use strict; |
90 | |
104 | |
91 | our $VERSION = '1.5'; |
105 | our $VERSION = '2.01'; |
92 | our @ISA = qw(Exporter); |
106 | our @ISA = qw(Exporter); |
93 | |
107 | |
94 | our @EXPORT = qw(to_json from_json); |
108 | our @EXPORT = qw(encode_json decode_json to_json from_json); |
|
|
109 | |
|
|
110 | sub to_json($) { |
|
|
111 | require Carp; |
|
|
112 | Carp::croak ("JSON::XS::to_json has been renamed to encode_json, either downgrade to pre-2.0 versions of JSON::XS or rename the call"); |
|
|
113 | } |
|
|
114 | |
|
|
115 | sub from_json($) { |
|
|
116 | require Carp; |
|
|
117 | Carp::croak ("JSON::XS::from_json has been renamed to decode_json, either downgrade to pre-2.0 versions of JSON::XS or rename the call"); |
|
|
118 | } |
95 | |
119 | |
96 | use Exporter; |
120 | use Exporter; |
97 | use XSLoader; |
121 | use XSLoader; |
98 | |
122 | |
99 | =head1 FUNCTIONAL INTERFACE |
123 | =head1 FUNCTIONAL INTERFACE |
100 | |
124 | |
101 | The following convinience methods are provided by this module. They are |
125 | The following convenience methods are provided by this module. They are |
102 | exported by default: |
126 | exported by default: |
103 | |
127 | |
104 | =over 4 |
128 | =over 4 |
105 | |
129 | |
106 | =item $json_text = to_json $perl_scalar |
130 | =item $json_text = encode_json $perl_scalar |
107 | |
131 | |
108 | Converts the given Perl data structure to a UTF-8 encoded, binary string |
132 | Converts the given Perl data structure to a UTF-8 encoded, binary string |
109 | (that is, the string contains octets only). Croaks on error. |
133 | (that is, the string contains octets only). Croaks on error. |
110 | |
134 | |
111 | This function call is functionally identical to: |
135 | This function call is functionally identical to: |
112 | |
136 | |
113 | $json_text = JSON::XS->new->utf8->encode ($perl_scalar) |
137 | $json_text = JSON::XS->new->utf8->encode ($perl_scalar) |
114 | |
138 | |
115 | except being faster. |
139 | except being faster. |
116 | |
140 | |
117 | =item $perl_scalar = from_json $json_text |
141 | =item $perl_scalar = decode_json $json_text |
118 | |
142 | |
119 | The opposite of C<to_json>: expects an UTF-8 (binary) string and tries |
143 | The opposite of C<encode_json>: expects an UTF-8 (binary) string and tries |
120 | to parse that as an UTF-8 encoded JSON text, returning the resulting |
144 | to parse that as an UTF-8 encoded JSON text, returning the resulting |
121 | reference. Croaks on error. |
145 | reference. Croaks on error. |
122 | |
146 | |
123 | This function call is functionally identical to: |
147 | This function call is functionally identical to: |
124 | |
148 | |
… | |
… | |
145 | |
169 | |
146 | =over 4 |
170 | =over 4 |
147 | |
171 | |
148 | =item 1. Perl strings can store characters with ordinal values > 255. |
172 | =item 1. Perl strings can store characters with ordinal values > 255. |
149 | |
173 | |
150 | This enables you to store unicode characters as single characters in a |
174 | This enables you to store Unicode characters as single characters in a |
151 | Perl string - very natural. |
175 | Perl string - very natural. |
152 | |
176 | |
153 | =item 2. Perl does I<not> associate an encoding with your strings. |
177 | =item 2. Perl does I<not> associate an encoding with your strings. |
154 | |
178 | |
155 | Unless you force it to, e.g. when matching it against a regex, or printing |
179 | Unless you force it to, e.g. when matching it against a regex, or printing |
… | |
… | |
162 | encoding of your string. |
186 | encoding of your string. |
163 | |
187 | |
164 | Just ignore that flag unless you debug a Perl bug, a module written in |
188 | Just ignore that flag unless you debug a Perl bug, a module written in |
165 | XS or want to dive into the internals of perl. Otherwise it will only |
189 | XS or want to dive into the internals of perl. Otherwise it will only |
166 | confuse you, as, despite the name, it says nothing about how your string |
190 | confuse you, as, despite the name, it says nothing about how your string |
167 | is encoded. You can have unicode strings with that flag set, with that |
191 | is encoded. You can have Unicode strings with that flag set, with that |
168 | flag clear, and you can have binary data with that flag set and that flag |
192 | flag clear, and you can have binary data with that flag set and that flag |
169 | clear. Other possibilities exist, too. |
193 | clear. Other possibilities exist, too. |
170 | |
194 | |
171 | If you didn't know about that flag, just the better, pretend it doesn't |
195 | If you didn't know about that flag, just the better, pretend it doesn't |
172 | exist. |
196 | exist. |
… | |
… | |
177 | If you have UTF-8 encoded data, it is no longer a Unicode string, but a |
201 | If you have UTF-8 encoded data, it is no longer a Unicode string, but a |
178 | Unicode string encoded in UTF-8, giving you a binary string. |
202 | Unicode string encoded in UTF-8, giving you a binary string. |
179 | |
203 | |
180 | =item 5. A string containing "high" (> 255) character values is I<not> a UTF-8 string. |
204 | =item 5. A string containing "high" (> 255) character values is I<not> a UTF-8 string. |
181 | |
205 | |
182 | Its a fact. Learn to live with it. |
206 | It's a fact. Learn to live with it. |
183 | |
207 | |
184 | =back |
208 | =back |
185 | |
209 | |
186 | I hope this helps :) |
210 | I hope this helps :) |
187 | |
211 | |
… | |
… | |
204 | my $json = JSON::XS->new->utf8->space_after->encode ({a => [1,2]}) |
228 | my $json = JSON::XS->new->utf8->space_after->encode ({a => [1,2]}) |
205 | => {"a": [1, 2]} |
229 | => {"a": [1, 2]} |
206 | |
230 | |
207 | =item $json = $json->ascii ([$enable]) |
231 | =item $json = $json->ascii ([$enable]) |
208 | |
232 | |
|
|
233 | =item $enabled = $json->get_ascii |
|
|
234 | |
209 | If C<$enable> is true (or missing), then the C<encode> method will not |
235 | If C<$enable> is true (or missing), then the C<encode> method will not |
210 | generate characters outside the code range C<0..127> (which is ASCII). Any |
236 | generate characters outside the code range C<0..127> (which is ASCII). Any |
211 | unicode characters outside that range will be escaped using either a |
237 | Unicode characters outside that range will be escaped using either a |
212 | single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, |
238 | single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, |
213 | as per RFC4627. The resulting encoded JSON text can be treated as a native |
239 | as per RFC4627. The resulting encoded JSON text can be treated as a native |
214 | unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string, |
240 | Unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string, |
215 | or any other superset of ASCII. |
241 | or any other superset of ASCII. |
216 | |
242 | |
217 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
243 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
218 | characters unless required by the JSON syntax or other flags. This results |
244 | characters unless required by the JSON syntax or other flags. This results |
219 | in a faster and more compact format. |
245 | in a faster and more compact format. |
… | |
… | |
225 | JSON::XS->new->ascii (1)->encode ([chr 0x10401]) |
251 | JSON::XS->new->ascii (1)->encode ([chr 0x10401]) |
226 | => ["\ud801\udc01"] |
252 | => ["\ud801\udc01"] |
227 | |
253 | |
228 | =item $json = $json->latin1 ([$enable]) |
254 | =item $json = $json->latin1 ([$enable]) |
229 | |
255 | |
|
|
256 | =item $enabled = $json->get_latin1 |
|
|
257 | |
230 | If C<$enable> is true (or missing), then the C<encode> method will encode |
258 | If C<$enable> is true (or missing), then the C<encode> method will encode |
231 | the resulting JSON text as latin1 (or iso-8859-1), escaping any characters |
259 | the resulting JSON text as latin1 (or iso-8859-1), escaping any characters |
232 | outside the code range C<0..255>. The resulting string can be treated as a |
260 | outside the code range C<0..255>. The resulting string can be treated as a |
233 | latin1-encoded JSON text or a native unicode string. The C<decode> method |
261 | latin1-encoded JSON text or a native Unicode string. The C<decode> method |
234 | will not be affected in any way by this flag, as C<decode> by default |
262 | will not be affected in any way by this flag, as C<decode> by default |
235 | expects unicode, which is a strict superset of latin1. |
263 | expects Unicode, which is a strict superset of latin1. |
236 | |
264 | |
237 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
265 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
238 | characters unless required by the JSON syntax or other flags. |
266 | characters unless required by the JSON syntax or other flags. |
239 | |
267 | |
240 | The main use for this flag is efficiently encoding binary data as JSON |
268 | The main use for this flag is efficiently encoding binary data as JSON |
241 | text, as most octets will not be escaped, resulting in a smaller encoded |
269 | text, as most octets will not be escaped, resulting in a smaller encoded |
242 | size. The disadvantage is that the resulting JSON text is encoded |
270 | size. The disadvantage is that the resulting JSON text is encoded |
243 | in latin1 (and must correctly be treated as such when storing and |
271 | in latin1 (and must correctly be treated as such when storing and |
244 | transfering), a rare encoding for JSON. It is therefore most useful when |
272 | transferring), a rare encoding for JSON. It is therefore most useful when |
245 | you want to store data structures known to contain binary data efficiently |
273 | you want to store data structures known to contain binary data efficiently |
246 | in files or databases, not when talking to other JSON encoders/decoders. |
274 | in files or databases, not when talking to other JSON encoders/decoders. |
247 | |
275 | |
248 | JSON::XS->new->latin1->encode (["\x{89}\x{abc}"] |
276 | JSON::XS->new->latin1->encode (["\x{89}\x{abc}"] |
249 | => ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not) |
277 | => ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not) |
250 | |
278 | |
251 | =item $json = $json->utf8 ([$enable]) |
279 | =item $json = $json->utf8 ([$enable]) |
|
|
280 | |
|
|
281 | =item $enabled = $json->get_utf8 |
252 | |
282 | |
253 | If C<$enable> is true (or missing), then the C<encode> method will encode |
283 | If C<$enable> is true (or missing), then the C<encode> method will encode |
254 | the JSON result into UTF-8, as required by many protocols, while the |
284 | the JSON result into UTF-8, as required by many protocols, while the |
255 | C<decode> method expects to be handled an UTF-8-encoded string. Please |
285 | C<decode> method expects to be handled an UTF-8-encoded string. Please |
256 | note that UTF-8-encoded strings do not contain any characters outside the |
286 | note that UTF-8-encoded strings do not contain any characters outside the |
257 | range C<0..255>, they are thus useful for bytewise/binary I/O. In future |
287 | range C<0..255>, they are thus useful for bytewise/binary I/O. In future |
258 | versions, enabling this option might enable autodetection of the UTF-16 |
288 | versions, enabling this option might enable autodetection of the UTF-16 |
259 | and UTF-32 encoding families, as described in RFC4627. |
289 | and UTF-32 encoding families, as described in RFC4627. |
260 | |
290 | |
261 | If C<$enable> is false, then the C<encode> method will return the JSON |
291 | If C<$enable> is false, then the C<encode> method will return the JSON |
262 | string as a (non-encoded) unicode string, while C<decode> expects thus a |
292 | string as a (non-encoded) Unicode string, while C<decode> expects thus a |
263 | unicode string. Any decoding or encoding (e.g. to UTF-8 or UTF-16) needs |
293 | Unicode string. Any decoding or encoding (e.g. to UTF-8 or UTF-16) needs |
264 | to be done yourself, e.g. using the Encode module. |
294 | to be done yourself, e.g. using the Encode module. |
265 | |
295 | |
266 | Example, output UTF-16BE-encoded JSON: |
296 | Example, output UTF-16BE-encoded JSON: |
267 | |
297 | |
268 | use Encode; |
298 | use Encode; |
… | |
… | |
290 | ] |
320 | ] |
291 | } |
321 | } |
292 | |
322 | |
293 | =item $json = $json->indent ([$enable]) |
323 | =item $json = $json->indent ([$enable]) |
294 | |
324 | |
|
|
325 | =item $enabled = $json->get_indent |
|
|
326 | |
295 | If C<$enable> is true (or missing), then the C<encode> method will use a multiline |
327 | If C<$enable> is true (or missing), then the C<encode> method will use a multiline |
296 | format as output, putting every array member or object/hash key-value pair |
328 | format as output, putting every array member or object/hash key-value pair |
297 | into its own line, identing them properly. |
329 | into its own line, indenting them properly. |
298 | |
330 | |
299 | If C<$enable> is false, no newlines or indenting will be produced, and the |
331 | If C<$enable> is false, no newlines or indenting will be produced, and the |
300 | resulting JSON text is guarenteed not to contain any C<newlines>. |
332 | resulting JSON text is guaranteed not to contain any C<newlines>. |
301 | |
333 | |
302 | This setting has no effect when decoding JSON texts. |
334 | This setting has no effect when decoding JSON texts. |
303 | |
335 | |
304 | =item $json = $json->space_before ([$enable]) |
336 | =item $json = $json->space_before ([$enable]) |
|
|
337 | |
|
|
338 | =item $enabled = $json->get_space_before |
305 | |
339 | |
306 | If C<$enable> is true (or missing), then the C<encode> method will add an extra |
340 | If C<$enable> is true (or missing), then the C<encode> method will add an extra |
307 | optional space before the C<:> separating keys from values in JSON objects. |
341 | optional space before the C<:> separating keys from values in JSON objects. |
308 | |
342 | |
309 | If C<$enable> is false, then the C<encode> method will not add any extra |
343 | If C<$enable> is false, then the C<encode> method will not add any extra |
… | |
… | |
315 | Example, space_before enabled, space_after and indent disabled: |
349 | Example, space_before enabled, space_after and indent disabled: |
316 | |
350 | |
317 | {"key" :"value"} |
351 | {"key" :"value"} |
318 | |
352 | |
319 | =item $json = $json->space_after ([$enable]) |
353 | =item $json = $json->space_after ([$enable]) |
|
|
354 | |
|
|
355 | =item $enabled = $json->get_space_after |
320 | |
356 | |
321 | If C<$enable> is true (or missing), then the C<encode> method will add an extra |
357 | If C<$enable> is true (or missing), then the C<encode> method will add an extra |
322 | optional space after the C<:> separating keys from values in JSON objects |
358 | optional space after the C<:> separating keys from values in JSON objects |
323 | and extra whitespace after the C<,> separating key-value pairs and array |
359 | and extra whitespace after the C<,> separating key-value pairs and array |
324 | members. |
360 | members. |
… | |
… | |
331 | Example, space_before and indent disabled, space_after enabled: |
367 | Example, space_before and indent disabled, space_after enabled: |
332 | |
368 | |
333 | {"key": "value"} |
369 | {"key": "value"} |
334 | |
370 | |
335 | =item $json = $json->relaxed ([$enable]) |
371 | =item $json = $json->relaxed ([$enable]) |
|
|
372 | |
|
|
373 | =item $enabled = $json->get_relaxed |
336 | |
374 | |
337 | If C<$enable> is true (or missing), then C<decode> will accept some |
375 | If C<$enable> is true (or missing), then C<decode> will accept some |
338 | extensions to normal JSON syntax (see below). C<encode> will not be |
376 | extensions to normal JSON syntax (see below). C<encode> will not be |
339 | affected in anyway. I<Be aware that this option makes you accept invalid |
377 | affected in anyway. I<Be aware that this option makes you accept invalid |
340 | JSON texts as if they were valid!>. I suggest only to use this option to |
378 | JSON texts as if they were valid!>. I suggest only to use this option to |
… | |
… | |
377 | |
415 | |
378 | =back |
416 | =back |
379 | |
417 | |
380 | =item $json = $json->canonical ([$enable]) |
418 | =item $json = $json->canonical ([$enable]) |
381 | |
419 | |
|
|
420 | =item $enabled = $json->get_canonical |
|
|
421 | |
382 | If C<$enable> is true (or missing), then the C<encode> method will output JSON objects |
422 | If C<$enable> is true (or missing), then the C<encode> method will output JSON objects |
383 | by sorting their keys. This is adding a comparatively high overhead. |
423 | by sorting their keys. This is adding a comparatively high overhead. |
384 | |
424 | |
385 | If C<$enable> is false, then the C<encode> method will output key-value |
425 | If C<$enable> is false, then the C<encode> method will output key-value |
386 | pairs in the order Perl stores them (which will likely change between runs |
426 | pairs in the order Perl stores them (which will likely change between runs |
387 | of the same script). |
427 | of the same script). |
388 | |
428 | |
389 | This option is useful if you want the same data structure to be encoded as |
429 | This option is useful if you want the same data structure to be encoded as |
390 | the same JSON text (given the same overall settings). If it is disabled, |
430 | the same JSON text (given the same overall settings). If it is disabled, |
391 | the same hash migh be encoded differently even if contains the same data, |
431 | the same hash might be encoded differently even if contains the same data, |
392 | as key-value pairs have no inherent ordering in Perl. |
432 | as key-value pairs have no inherent ordering in Perl. |
393 | |
433 | |
394 | This setting has no effect when decoding JSON texts. |
434 | This setting has no effect when decoding JSON texts. |
395 | |
435 | |
396 | =item $json = $json->allow_nonref ([$enable]) |
436 | =item $json = $json->allow_nonref ([$enable]) |
|
|
437 | |
|
|
438 | =item $enabled = $json->get_allow_nonref |
397 | |
439 | |
398 | If C<$enable> is true (or missing), then the C<encode> method can convert a |
440 | If C<$enable> is true (or missing), then the C<encode> method can convert a |
399 | non-reference into its corresponding string, number or null JSON value, |
441 | non-reference into its corresponding string, number or null JSON value, |
400 | which is an extension to RFC4627. Likewise, C<decode> will accept those JSON |
442 | which is an extension to RFC4627. Likewise, C<decode> will accept those JSON |
401 | values instead of croaking. |
443 | values instead of croaking. |
… | |
… | |
411 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
453 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
412 | => "Hello, World!" |
454 | => "Hello, World!" |
413 | |
455 | |
414 | =item $json = $json->allow_blessed ([$enable]) |
456 | =item $json = $json->allow_blessed ([$enable]) |
415 | |
457 | |
|
|
458 | =item $enabled = $json->get_allow_blessed |
|
|
459 | |
416 | If C<$enable> is true (or missing), then the C<encode> method will not |
460 | If C<$enable> is true (or missing), then the C<encode> method will not |
417 | barf when it encounters a blessed reference. Instead, the value of the |
461 | barf when it encounters a blessed reference. Instead, the value of the |
418 | B<convert_blessed> option will decide wether C<null> (C<convert_blessed> |
462 | B<convert_blessed> option will decide whether C<null> (C<convert_blessed> |
419 | disabled or no C<to_json> method found) or a representation of the |
463 | disabled or no C<TO_JSON> method found) or a representation of the |
420 | object (C<convert_blessed> enabled and C<to_json> method found) is being |
464 | object (C<convert_blessed> enabled and C<TO_JSON> method found) is being |
421 | encoded. Has no effect on C<decode>. |
465 | encoded. Has no effect on C<decode>. |
422 | |
466 | |
423 | If C<$enable> is false (the default), then C<encode> will throw an |
467 | If C<$enable> is false (the default), then C<encode> will throw an |
424 | exception when it encounters a blessed object. |
468 | exception when it encounters a blessed object. |
425 | |
469 | |
426 | =item $json = $json->convert_blessed ([$enable]) |
470 | =item $json = $json->convert_blessed ([$enable]) |
|
|
471 | |
|
|
472 | =item $enabled = $json->get_convert_blessed |
427 | |
473 | |
428 | If C<$enable> is true (or missing), then C<encode>, upon encountering a |
474 | If C<$enable> is true (or missing), then C<encode>, upon encountering a |
429 | blessed object, will check for the availability of the C<TO_JSON> method |
475 | blessed object, will check for the availability of the C<TO_JSON> method |
430 | on the object's class. If found, it will be called in scalar context |
476 | on the object's class. If found, it will be called in scalar context |
431 | and the resulting scalar will be encoded instead of the object. If no |
477 | and the resulting scalar will be encoded instead of the object. If no |
… | |
… | |
435 | The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON> |
481 | The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON> |
436 | returns other blessed objects, those will be handled in the same |
482 | returns other blessed objects, those will be handled in the same |
437 | way. C<TO_JSON> must take care of not causing an endless recursion cycle |
483 | way. C<TO_JSON> must take care of not causing an endless recursion cycle |
438 | (== crash) in this case. The name of C<TO_JSON> was chosen because other |
484 | (== crash) in this case. The name of C<TO_JSON> was chosen because other |
439 | methods called by the Perl core (== not by the user of the object) are |
485 | methods called by the Perl core (== not by the user of the object) are |
440 | usually in upper case letters and to avoid collisions with the C<to_json> |
486 | usually in upper case letters and to avoid collisions with any C<to_json> |
441 | function. |
487 | function or method. |
442 | |
488 | |
443 | This setting does not yet influence C<decode> in any way, but in the |
489 | This setting does not yet influence C<decode> in any way, but in the |
444 | future, global hooks might get installed that influence C<decode> and are |
490 | future, global hooks might get installed that influence C<decode> and are |
445 | enabled by this setting. |
491 | enabled by this setting. |
446 | |
492 | |
… | |
… | |
488 | |
534 | |
489 | As this callback gets called less often then the C<filter_json_object> |
535 | As this callback gets called less often then the C<filter_json_object> |
490 | one, decoding speed will not usually suffer as much. Therefore, single-key |
536 | one, decoding speed will not usually suffer as much. Therefore, single-key |
491 | objects make excellent targets to serialise Perl objects into, especially |
537 | objects make excellent targets to serialise Perl objects into, especially |
492 | as single-key JSON objects are as close to the type-tagged value concept |
538 | as single-key JSON objects are as close to the type-tagged value concept |
493 | as JSON gets (its basically an ID/VALUE tuple). Of course, JSON does not |
539 | as JSON gets (it's basically an ID/VALUE tuple). Of course, JSON does not |
494 | support this in any way, so you need to make sure your data never looks |
540 | support this in any way, so you need to make sure your data never looks |
495 | like a serialised Perl hash. |
541 | like a serialised Perl hash. |
496 | |
542 | |
497 | Typical names for the single object key are C<__class_whatever__>, or |
543 | Typical names for the single object key are C<__class_whatever__>, or |
498 | C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even |
544 | C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even |
… | |
… | |
522 | |
568 | |
523 | { __widget__ => $self->{id} } |
569 | { __widget__ => $self->{id} } |
524 | } |
570 | } |
525 | |
571 | |
526 | =item $json = $json->shrink ([$enable]) |
572 | =item $json = $json->shrink ([$enable]) |
|
|
573 | |
|
|
574 | =item $enabled = $json->get_shrink |
527 | |
575 | |
528 | Perl usually over-allocates memory a bit when allocating space for |
576 | Perl usually over-allocates memory a bit when allocating space for |
529 | strings. This flag optionally resizes strings generated by either |
577 | strings. This flag optionally resizes strings generated by either |
530 | C<encode> or C<decode> to their minimum size possible. This can save |
578 | C<encode> or C<decode> to their minimum size possible. This can save |
531 | memory when your JSON texts are either very very long or you have many |
579 | memory when your JSON texts are either very very long or you have many |
… | |
… | |
549 | strings that look like integers or floats into integers or floats |
597 | strings that look like integers or floats into integers or floats |
550 | internally (there is no difference on the Perl level), saving space. |
598 | internally (there is no difference on the Perl level), saving space. |
551 | |
599 | |
552 | =item $json = $json->max_depth ([$maximum_nesting_depth]) |
600 | =item $json = $json->max_depth ([$maximum_nesting_depth]) |
553 | |
601 | |
|
|
602 | =item $max_depth = $json->get_max_depth |
|
|
603 | |
554 | Sets the maximum nesting level (default C<512>) accepted while encoding |
604 | Sets the maximum nesting level (default C<512>) accepted while encoding |
555 | or decoding. If the JSON text or Perl data structure has an equal or |
605 | or decoding. If the JSON text or Perl data structure has an equal or |
556 | higher nesting level then this limit, then the encoder and decoder will |
606 | higher nesting level then this limit, then the encoder and decoder will |
557 | stop and croak at that point. |
607 | stop and croak at that point. |
558 | |
608 | |
… | |
… | |
569 | used, which is rarely useful. |
619 | used, which is rarely useful. |
570 | |
620 | |
571 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
621 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
572 | |
622 | |
573 | =item $json = $json->max_size ([$maximum_string_size]) |
623 | =item $json = $json->max_size ([$maximum_string_size]) |
|
|
624 | |
|
|
625 | =item $max_size = $json->get_max_size |
574 | |
626 | |
575 | Set the maximum length a JSON text may have (in bytes) where decoding is |
627 | Set the maximum length a JSON text may have (in bytes) where decoding is |
576 | being attempted. The default is C<0>, meaning no limit. When C<decode> |
628 | being attempted. The default is C<0>, meaning no limit. When C<decode> |
577 | is called on a string longer then this number of characters it will not |
629 | is called on a string longer then this number of characters it will not |
578 | attempt to decode the string but throw an exception. This setting has no |
630 | attempt to decode the string but throw an exception. This setting has no |
… | |
… | |
625 | vice versa. These mappings are designed to "do the right thing" in most |
677 | vice versa. These mappings are designed to "do the right thing" in most |
626 | circumstances automatically, preserving round-tripping characteristics |
678 | circumstances automatically, preserving round-tripping characteristics |
627 | (what you put in comes out as something equivalent). |
679 | (what you put in comes out as something equivalent). |
628 | |
680 | |
629 | For the more enlightened: note that in the following descriptions, |
681 | For the more enlightened: note that in the following descriptions, |
630 | lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl> |
682 | lowercase I<perl> refers to the Perl interpreter, while uppercase I<Perl> |
631 | refers to the abstract Perl language itself. |
683 | refers to the abstract Perl language itself. |
632 | |
684 | |
633 | |
685 | |
634 | =head2 JSON -> PERL |
686 | =head2 JSON -> PERL |
635 | |
687 | |
636 | =over 4 |
688 | =over 4 |
637 | |
689 | |
638 | =item object |
690 | =item object |
639 | |
691 | |
640 | A JSON object becomes a reference to a hash in Perl. No ordering of object |
692 | A JSON object becomes a reference to a hash in Perl. No ordering of object |
641 | keys is preserved (JSON does not preserver object key ordering itself). |
693 | keys is preserved (JSON does not preserve object key ordering itself). |
642 | |
694 | |
643 | =item array |
695 | =item array |
644 | |
696 | |
645 | A JSON array becomes a reference to an array in Perl. |
697 | A JSON array becomes a reference to an array in Perl. |
646 | |
698 | |
… | |
… | |
672 | |
724 | |
673 | =item true, false |
725 | =item true, false |
674 | |
726 | |
675 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
727 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
676 | respectively. They are overloaded to act almost exactly like the numbers |
728 | respectively. They are overloaded to act almost exactly like the numbers |
677 | C<1> and C<0>. You can check wether a scalar is a JSON boolean by using |
729 | C<1> and C<0>. You can check whether a scalar is a JSON boolean by using |
678 | the C<JSON::XS::is_bool> function. |
730 | the C<JSON::XS::is_bool> function. |
679 | |
731 | |
680 | =item null |
732 | =item null |
681 | |
733 | |
682 | A JSON null atom becomes C<undef> in Perl. |
734 | A JSON null atom becomes C<undef> in Perl. |
… | |
… | |
713 | Other unblessed references are generally not allowed and will cause an |
765 | Other unblessed references are generally not allowed and will cause an |
714 | exception to be thrown, except for references to the integers C<0> and |
766 | exception to be thrown, except for references to the integers C<0> and |
715 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
767 | C<1>, which get turned into C<false> and C<true> atoms in JSON. You can |
716 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
768 | also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability. |
717 | |
769 | |
718 | to_json [\0,JSON::XS::true] # yields [false,true] |
770 | encode_json [\0,JSON::XS::true] # yields [false,true] |
719 | |
771 | |
720 | =item JSON::XS::true, JSON::XS::false |
772 | =item JSON::XS::true, JSON::XS::false |
721 | |
773 | |
722 | These special values become JSON true and JSON false values, |
774 | These special values become JSON true and JSON false values, |
723 | respectively. You can also use C<\1> and C<\0> directly if you want. |
775 | respectively. You can also use C<\1> and C<\0> directly if you want. |
724 | |
776 | |
725 | =item blessed objects |
777 | =item blessed objects |
726 | |
778 | |
727 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
779 | Blessed objects are not directly representable in JSON. See the |
728 | underlying representation (hash- or arrayref), but this behaviour might |
780 | C<allow_blessed> and C<convert_blessed> methods on various options on |
729 | change in future versions. |
781 | how to deal with this: basically, you can choose between throwing an |
|
|
782 | exception, encoding the reference as if it weren't blessed, or provide |
|
|
783 | your own serialiser method. |
730 | |
784 | |
731 | =item simple scalars |
785 | =item simple scalars |
732 | |
786 | |
733 | Simple Perl scalars (any scalar that is not a reference) are the most |
787 | Simple Perl scalars (any scalar that is not a reference) are the most |
734 | difficult objects to encode: JSON::XS will encode undefined scalars as |
788 | difficult objects to encode: JSON::XS will encode undefined scalars as |
735 | JSON null value, scalars that have last been used in a string context |
789 | JSON C<null> values, scalars that have last been used in a string context |
736 | before encoding as JSON strings and anything else as number value: |
790 | before encoding as JSON strings, and anything else as number value: |
737 | |
791 | |
738 | # dump as number |
792 | # dump as number |
739 | to_json [2] # yields [2] |
793 | encode_json [2] # yields [2] |
740 | to_json [-3.0e17] # yields [-3e+17] |
794 | encode_json [-3.0e17] # yields [-3e+17] |
741 | my $value = 5; to_json [$value] # yields [5] |
795 | my $value = 5; encode_json [$value] # yields [5] |
742 | |
796 | |
743 | # used as string, so dump as string |
797 | # used as string, so dump as string |
744 | print $value; |
798 | print $value; |
745 | to_json [$value] # yields ["5"] |
799 | encode_json [$value] # yields ["5"] |
746 | |
800 | |
747 | # undef becomes null |
801 | # undef becomes null |
748 | to_json [undef] # yields [null] |
802 | encode_json [undef] # yields [null] |
749 | |
803 | |
750 | You can force the type to be a string by stringifying it: |
804 | You can force the type to be a JSON string by stringifying it: |
751 | |
805 | |
752 | my $x = 3.1; # some variable containing a number |
806 | my $x = 3.1; # some variable containing a number |
753 | "$x"; # stringified |
807 | "$x"; # stringified |
754 | $x .= ""; # another, more awkward way to stringify |
808 | $x .= ""; # another, more awkward way to stringify |
755 | print $x; # perl does it for you, too, quite often |
809 | print $x; # perl does it for you, too, quite often |
756 | |
810 | |
757 | You can force the type to be a number by numifying it: |
811 | You can force the type to be a JSON number by numifying it: |
758 | |
812 | |
759 | my $x = "3"; # some variable containing a string |
813 | my $x = "3"; # some variable containing a string |
760 | $x += 0; # numify it, ensuring it will be dumped as a number |
814 | $x += 0; # numify it, ensuring it will be dumped as a number |
761 | $x *= 1; # same thing, the choise is yours. |
815 | $x *= 1; # same thing, the choice is yours. |
762 | |
816 | |
763 | You can not currently output JSON booleans or force the type in other, |
817 | You can not currently force the type in other, less obscure, ways. Tell me |
764 | less obscure, ways. Tell me if you need this capability. |
818 | if you need this capability (but don't forget to explain why its needed |
|
|
819 | :). |
765 | |
820 | |
766 | =back |
821 | =back |
767 | |
822 | |
768 | |
823 | |
769 | =head1 COMPARISON |
824 | =head1 COMPARISON |
… | |
… | |
778 | |
833 | |
779 | =item JSON 1.07 |
834 | =item JSON 1.07 |
780 | |
835 | |
781 | Slow (but very portable, as it is written in pure Perl). |
836 | Slow (but very portable, as it is written in pure Perl). |
782 | |
837 | |
783 | Undocumented/buggy Unicode handling (how JSON handles unicode values is |
838 | Undocumented/buggy Unicode handling (how JSON handles Unicode values is |
784 | undocumented. One can get far by feeding it unicode strings and doing |
839 | undocumented. One can get far by feeding it Unicode strings and doing |
785 | en-/decoding oneself, but unicode escapes are not working properly). |
840 | en-/decoding oneself, but Unicode escapes are not working properly). |
786 | |
841 | |
787 | No roundtripping (strings get clobbered if they look like numbers, e.g. |
842 | No round-tripping (strings get clobbered if they look like numbers, e.g. |
788 | the string C<2.0> will encode to C<2.0> instead of C<"2.0">, and that will |
843 | the string C<2.0> will encode to C<2.0> instead of C<"2.0">, and that will |
789 | decode into the number 2. |
844 | decode into the number 2. |
790 | |
845 | |
791 | =item JSON::PC 0.01 |
846 | =item JSON::PC 0.01 |
792 | |
847 | |
793 | Very fast. |
848 | Very fast. |
794 | |
849 | |
795 | Undocumented/buggy Unicode handling. |
850 | Undocumented/buggy Unicode handling. |
796 | |
851 | |
797 | No roundtripping. |
852 | No round-tripping. |
798 | |
853 | |
799 | Has problems handling many Perl values (e.g. regex results and other magic |
854 | Has problems handling many Perl values (e.g. regex results and other magic |
800 | values will make it croak). |
855 | values will make it croak). |
801 | |
856 | |
802 | Does not even generate valid JSON (C<{1,2}> gets converted to C<{1:2}> |
857 | Does not even generate valid JSON (C<{1,2}> gets converted to C<{1:2}> |
… | |
… | |
812 | Very inflexible (no human-readable format supported, format pretty much |
867 | Very inflexible (no human-readable format supported, format pretty much |
813 | undocumented. I need at least a format for easy reading by humans and a |
868 | undocumented. I need at least a format for easy reading by humans and a |
814 | single-line compact format for use in a protocol, and preferably a way to |
869 | single-line compact format for use in a protocol, and preferably a way to |
815 | generate ASCII-only JSON texts). |
870 | generate ASCII-only JSON texts). |
816 | |
871 | |
817 | Completely broken (and confusingly documented) Unicode handling (unicode |
872 | Completely broken (and confusingly documented) Unicode handling (Unicode |
818 | escapes are not working properly, you need to set ImplicitUnicode to |
873 | escapes are not working properly, you need to set ImplicitUnicode to |
819 | I<different> values on en- and decoding to get symmetric behaviour). |
874 | I<different> values on en- and decoding to get symmetric behaviour). |
820 | |
875 | |
821 | No roundtripping (simple cases work, but this depends on wether the scalar |
876 | No round-tripping (simple cases work, but this depends on whether the scalar |
822 | value was used in a numeric context or not). |
877 | value was used in a numeric context or not). |
823 | |
878 | |
824 | Dumping hashes may skip hash values depending on iterator state. |
879 | Dumping hashes may skip hash values depending on iterator state. |
825 | |
880 | |
826 | Unmaintained (maintainer unresponsive for many months, bugs are not |
881 | Unmaintained (maintainer unresponsive for many months, bugs are not |
827 | getting fixed). |
882 | getting fixed). |
828 | |
883 | |
829 | Does not check input for validity (i.e. will accept non-JSON input and |
884 | Does not check input for validity (i.e. will accept non-JSON input and |
830 | return "something" instead of raising an exception. This is a security |
885 | return "something" instead of raising an exception. This is a security |
831 | issue: imagine two banks transfering money between each other using |
886 | issue: imagine two banks transferring money between each other using |
832 | JSON. One bank might parse a given non-JSON request and deduct money, |
887 | JSON. One bank might parse a given non-JSON request and deduct money, |
833 | while the other might reject the transaction with a syntax error. While a |
888 | while the other might reject the transaction with a syntax error. While a |
834 | good protocol will at least recover, that is extra unnecessary work and |
889 | good protocol will at least recover, that is extra unnecessary work and |
835 | the transaction will still not succeed). |
890 | the transaction will still not succeed). |
836 | |
891 | |
837 | =item JSON::DWIW 0.04 |
892 | =item JSON::DWIW 0.04 |
838 | |
893 | |
839 | Very fast. Very natural. Very nice. |
894 | Very fast. Very natural. Very nice. |
840 | |
895 | |
841 | Undocumented unicode handling (but the best of the pack. Unicode escapes |
896 | Undocumented Unicode handling (but the best of the pack. Unicode escapes |
842 | still don't get parsed properly). |
897 | still don't get parsed properly). |
843 | |
898 | |
844 | Very inflexible. |
899 | Very inflexible. |
845 | |
900 | |
846 | No roundtripping. |
901 | No round-tripping. |
847 | |
902 | |
848 | Does not generate valid JSON texts (key strings are often unquoted, empty keys |
903 | Does not generate valid JSON texts (key strings are often unquoted, empty keys |
849 | result in nothing being output) |
904 | result in nothing being output) |
850 | |
905 | |
851 | Does not check input for validity. |
906 | Does not check input for validity. |
… | |
… | |
853 | =back |
908 | =back |
854 | |
909 | |
855 | |
910 | |
856 | =head2 JSON and YAML |
911 | =head2 JSON and YAML |
857 | |
912 | |
858 | You often hear that JSON is a subset (or a close subset) of YAML. This is, |
913 | You often hear that JSON is a subset of YAML. This is, however, a mass |
859 | however, a mass hysteria and very far from the truth. In general, there is |
914 | hysteria(*) and very far from the truth. In general, there is no way to |
860 | no way to configure JSON::XS to output a data structure as valid YAML. |
915 | configure JSON::XS to output a data structure as valid YAML that works for |
|
|
916 | all cases. |
861 | |
917 | |
862 | If you really must use JSON::XS to generate YAML, you should use this |
918 | If you really must use JSON::XS to generate YAML, you should use this |
863 | algorithm (subject to change in future versions): |
919 | algorithm (subject to change in future versions): |
864 | |
920 | |
865 | my $to_yaml = JSON::XS->new->utf8->space_after (1); |
921 | my $to_yaml = JSON::XS->new->utf8->space_after (1); |
866 | my $yaml = $to_yaml->encode ($ref) . "\n"; |
922 | my $yaml = $to_yaml->encode ($ref) . "\n"; |
867 | |
923 | |
868 | This will usually generate JSON texts that also parse as valid |
924 | This will I<usually> generate JSON texts that also parse as valid |
869 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
925 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
870 | lengths that JSON doesn't have, so you should make sure that your hash |
926 | lengths that JSON doesn't have and also has different and incompatible |
|
|
927 | unicode handling, so you should make sure that your hash keys are |
871 | keys are noticably shorter than the 1024 characters YAML allows. |
928 | noticeably shorter than the 1024 "stream characters" YAML allows and that |
|
|
929 | you do not have codepoints with values outside the Unicode BMP (basic |
|
|
930 | multilingual page). YAML also does not allow C<\/> sequences in strings |
|
|
931 | (which JSON::XS does not I<currently> generate). |
872 | |
932 | |
873 | There might be other incompatibilities that I am not aware of. In general |
933 | There might be other incompatibilities that I am not aware of (or the YAML |
|
|
934 | specification has been changed yet again - it does so quite often). In |
874 | you should not try to generate YAML with a JSON generator or vice versa, |
935 | general you should not try to generate YAML with a JSON generator or vice |
875 | or try to parse JSON with a YAML parser or vice versa: chances are high |
936 | versa, or try to parse JSON with a YAML parser or vice versa: chances are |
876 | that you will run into severe interoperability problems. |
937 | high that you will run into severe interoperability problems when you |
|
|
938 | least expect it. |
|
|
939 | |
|
|
940 | =over 4 |
|
|
941 | |
|
|
942 | =item (*) |
|
|
943 | |
|
|
944 | This is spread actively by the YAML team, however. For many years now they |
|
|
945 | claim YAML were a superset of JSON, even when proven otherwise. |
|
|
946 | |
|
|
947 | Even the author of this manpage was at some point accused of providing |
|
|
948 | "incorrect" information, despite the evidence presented (claims ranged |
|
|
949 | from "your documentation contains inaccurate and negative statements about |
|
|
950 | YAML" (the only negative comment is this footnote, and it didn't exist |
|
|
951 | back then; the question on which claims were inaccurate was never answered |
|
|
952 | etc.) to "the YAML spec is not up-to-date" (the *real* and supposedly |
|
|
953 | JSON-compatible spec is apparently not currently publicly available) |
|
|
954 | to actual requests to replace this section by *incorrect* information, |
|
|
955 | suppressing information about the real problem). |
|
|
956 | |
|
|
957 | So whenever you are told that YAML was a superset of JSON, first check |
|
|
958 | wether it is really true (it might be when you check it, but it certainly |
|
|
959 | was not true when this was written). I would much prefer if the YAML team |
|
|
960 | would spent their time on actually making JSON compatibility a truth |
|
|
961 | (JSON, after all, has a very small and simple specification) instead of |
|
|
962 | trying to lobby/force people into reporting untruths. |
|
|
963 | |
|
|
964 | =back |
877 | |
965 | |
878 | |
966 | |
879 | =head2 SPEED |
967 | =head2 SPEED |
880 | |
968 | |
881 | It seems that JSON::XS is surprisingly fast, as shown in the following |
969 | It seems that JSON::XS is surprisingly fast, as shown in the following |
… | |
… | |
892 | It shows the number of encodes/decodes per second (JSON::XS uses |
980 | It shows the number of encodes/decodes per second (JSON::XS uses |
893 | the functional interface, while JSON::XS/2 uses the OO interface |
981 | the functional interface, while JSON::XS/2 uses the OO interface |
894 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
982 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
895 | shrink). Higher is better: |
983 | shrink). Higher is better: |
896 | |
984 | |
897 | Storable | 15779.925 | 14169.946 | |
|
|
898 | -----------+------------+------------+ |
|
|
899 | module | encode | decode | |
985 | module | encode | decode | |
900 | -----------|------------|------------| |
986 | -----------|------------|------------| |
901 | JSON | 4990.842 | 4088.813 | |
987 | JSON 1.x | 4990.842 | 4088.813 | |
902 | JSON::DWIW | 51653.990 | 71575.154 | |
988 | JSON::DWIW | 51653.990 | 71575.154 | |
903 | JSON::PC | 65948.176 | 74631.744 | |
989 | JSON::PC | 65948.176 | 74631.744 | |
904 | JSON::PP | 8931.652 | 3817.168 | |
990 | JSON::PP | 8931.652 | 3817.168 | |
905 | JSON::Syck | 24877.248 | 27776.848 | |
991 | JSON::Syck | 24877.248 | 27776.848 | |
906 | JSON::XS | 388361.481 | 227951.304 | |
992 | JSON::XS | 388361.481 | 227951.304 | |
… | |
… | |
908 | JSON::XS/3 | 338250.323 | 218453.333 | |
994 | JSON::XS/3 | 338250.323 | 218453.333 | |
909 | Storable | 16500.016 | 135300.129 | |
995 | Storable | 16500.016 | 135300.129 | |
910 | -----------+------------+------------+ |
996 | -----------+------------+------------+ |
911 | |
997 | |
912 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
998 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
913 | about three times faster on decoding, and over fourty times faster |
999 | about three times faster on decoding, and over forty times faster |
914 | than JSON, even with pretty-printing and key sorting. It also compares |
1000 | than JSON, even with pretty-printing and key sorting. It also compares |
915 | favourably to Storable for small amounts of data. |
1001 | favourably to Storable for small amounts of data. |
916 | |
1002 | |
917 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
1003 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
918 | search API (http://nanoref.com/yahooapis/mgPdGg): |
1004 | search API (http://nanoref.com/yahooapis/mgPdGg): |
919 | |
1005 | |
920 | module | encode | decode | |
1006 | module | encode | decode | |
921 | -----------|------------|------------| |
1007 | -----------|------------|------------| |
922 | JSON | 55.260 | 34.971 | |
1008 | JSON 1.x | 55.260 | 34.971 | |
923 | JSON::DWIW | 825.228 | 1082.513 | |
1009 | JSON::DWIW | 825.228 | 1082.513 | |
924 | JSON::PC | 3571.444 | 2394.829 | |
1010 | JSON::PC | 3571.444 | 2394.829 | |
925 | JSON::PP | 210.987 | 32.574 | |
1011 | JSON::PP | 210.987 | 32.574 | |
926 | JSON::Syck | 552.551 | 787.544 | |
1012 | JSON::Syck | 552.551 | 787.544 | |
927 | JSON::XS | 5780.463 | 4854.519 | |
1013 | JSON::XS | 5780.463 | 4854.519 | |
… | |
… | |
931 | -----------+------------+------------+ |
1017 | -----------+------------+------------+ |
932 | |
1018 | |
933 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
1019 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
934 | decodes faster). |
1020 | decodes faster). |
935 | |
1021 | |
936 | On large strings containing lots of high unicode characters, some modules |
1022 | On large strings containing lots of high Unicode characters, some modules |
937 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
1023 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
938 | will be broken due to missing (or wrong) unicode handling. Others refuse |
1024 | will be broken due to missing (or wrong) Unicode handling. Others refuse |
939 | to decode or encode properly, so it was impossible to prepare a fair |
1025 | to decode or encode properly, so it was impossible to prepare a fair |
940 | comparison table for that case. |
1026 | comparison table for that case. |
941 | |
1027 | |
942 | |
1028 | |
943 | =head1 SECURITY CONSIDERATIONS |
1029 | =head1 SECURITY CONSIDERATIONS |
… | |
… | |
949 | any buffer overflows. Obviously, this module should ensure that and I am |
1035 | any buffer overflows. Obviously, this module should ensure that and I am |
950 | trying hard on making that true, but you never know. |
1036 | trying hard on making that true, but you never know. |
951 | |
1037 | |
952 | Second, you need to avoid resource-starving attacks. That means you should |
1038 | Second, you need to avoid resource-starving attacks. That means you should |
953 | limit the size of JSON texts you accept, or make sure then when your |
1039 | limit the size of JSON texts you accept, or make sure then when your |
954 | resources run out, thats just fine (e.g. by using a separate process that |
1040 | resources run out, that's just fine (e.g. by using a separate process that |
955 | can crash safely). The size of a JSON text in octets or characters is |
1041 | can crash safely). The size of a JSON text in octets or characters is |
956 | usually a good indication of the size of the resources required to decode |
1042 | usually a good indication of the size of the resources required to decode |
957 | it into a Perl structure. While JSON::XS can check the size of the JSON |
1043 | it into a Perl structure. While JSON::XS can check the size of the JSON |
958 | text, it might be too late when you already have it in memory, so you |
1044 | text, it might be too late when you already have it in memory, so you |
959 | might want to check the size before you accept the string. |
1045 | might want to check the size before you accept the string. |
960 | |
1046 | |
961 | Third, JSON::XS recurses using the C stack when decoding objects and |
1047 | Third, JSON::XS recurses using the C stack when decoding objects and |
962 | arrays. The C stack is a limited resource: for instance, on my amd64 |
1048 | arrays. The C stack is a limited resource: for instance, on my amd64 |
963 | machine with 8MB of stack size I can decode around 180k nested arrays but |
1049 | machine with 8MB of stack size I can decode around 180k nested arrays but |
964 | only 14k nested JSON objects (due to perl itself recursing deeply on croak |
1050 | only 14k nested JSON objects (due to perl itself recursing deeply on croak |
965 | to free the temporary). If that is exceeded, the program crashes. to be |
1051 | to free the temporary). If that is exceeded, the program crashes. To be |
966 | conservative, the default nesting limit is set to 512. If your process |
1052 | conservative, the default nesting limit is set to 512. If your process |
967 | has a smaller stack, you should adjust this setting accordingly with the |
1053 | has a smaller stack, you should adjust this setting accordingly with the |
968 | C<max_depth> method. |
1054 | C<max_depth> method. |
969 | |
1055 | |
970 | And last but least, something else could bomb you that I forgot to think |
1056 | And last but least, something else could bomb you that I forgot to think |
971 | of. In that case, you get to keep the pieces. I am always open for hints, |
1057 | of. In that case, you get to keep the pieces. I am always open for hints, |
972 | though... |
1058 | though... |
973 | |
1059 | |
974 | If you are using JSON::XS to return packets to consumption |
1060 | If you are using JSON::XS to return packets to consumption |
975 | by javascript scripts in a browser you should have a look at |
1061 | by JavaScript scripts in a browser you should have a look at |
976 | L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether |
1062 | L<http://jpsykes.com/47/practical-csrf-and-json-security> to see whether |
977 | you are vulnerable to some common attack vectors (which really are browser |
1063 | you are vulnerable to some common attack vectors (which really are browser |
978 | design bugs, but it is still you who will have to deal with it, as major |
1064 | design bugs, but it is still you who will have to deal with it, as major |
979 | browser developers care only for features, not about doing security |
1065 | browser developers care only for features, not about getting security |
980 | right). |
1066 | right). |
981 | |
1067 | |
982 | |
1068 | |
983 | =head1 THREADS |
1069 | =head1 THREADS |
984 | |
1070 | |
985 | This module is I<not> guarenteed to be thread safe and there are no |
1071 | This module is I<not> guaranteed to be thread safe and there are no |
986 | plans to change this until Perl gets thread support (as opposed to the |
1072 | plans to change this until Perl gets thread support (as opposed to the |
987 | horribly slow so-called "threads" which are simply slow and bloated |
1073 | horribly slow so-called "threads" which are simply slow and bloated |
988 | process simulations - use fork, its I<much> faster, cheaper, better). |
1074 | process simulations - use fork, its I<much> faster, cheaper, better). |
989 | |
1075 | |
990 | (It might actually work, but you ahve ben warned). |
1076 | (It might actually work, but you have been warned). |
991 | |
1077 | |
992 | |
1078 | |
993 | =head1 BUGS |
1079 | =head1 BUGS |
994 | |
1080 | |
995 | While the goal of this module is to be correct, that unfortunately does |
1081 | While the goal of this module is to be correct, that unfortunately does |