1 | =encoding utf-8 |
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2 | |
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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 |
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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 | |
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24 | # Note that JSON version 2.0 and above will automatically use JSON::XS |
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25 | # if available, at virtually no speed overhead either, so you should |
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26 | # be able to just: |
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27 | |
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28 | use JSON; |
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29 | |
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30 | # and do the same things, except that you have a pure-perl fallback now. |
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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. |
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37 | |
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38 | Beginning with version 2.0 of the JSON module, when both JSON and |
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39 | JSON::XS are installed, then JSON will fall back on JSON::XS (this can be |
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40 | overriden) with no overhead due to emulation (by inheritign constructor |
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41 | and methods). If JSON::XS is not available, it will fall back to the |
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42 | compatible JSON::PP module as backend, so using JSON instead of JSON::XS |
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43 | gives you a portable JSON API that can be fast when you need and doesn't |
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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 |
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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 |
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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 = '1.51'; |
105 | our $VERSION = '2.0'; |
92 | our @ISA = qw(Exporter); |
106 | our @ISA = qw(Exporter); |
93 | |
107 | |
94 | our @EXPORT = qw(to_json from_json); |
108 | our @EXPORT = qw(to_json from_json); |
95 | |
109 | |
96 | use Exporter; |
110 | use Exporter; |
97 | use XSLoader; |
111 | use XSLoader; |
98 | |
112 | |
99 | =head1 FUNCTIONAL INTERFACE |
113 | =head1 FUNCTIONAL INTERFACE |
100 | |
114 | |
101 | The following convinience methods are provided by this module. They are |
115 | The following convenience methods are provided by this module. They are |
102 | exported by default: |
116 | exported by default: |
103 | |
117 | |
104 | =over 4 |
118 | =over 4 |
105 | |
119 | |
106 | =item $json_text = to_json $perl_scalar |
120 | =item $json_text = to_json $perl_scalar |
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145 | |
159 | |
146 | =over 4 |
160 | =over 4 |
147 | |
161 | |
148 | =item 1. Perl strings can store characters with ordinal values > 255. |
162 | =item 1. Perl strings can store characters with ordinal values > 255. |
149 | |
163 | |
150 | This enables you to store unicode characters as single characters in a |
164 | This enables you to store Unicode characters as single characters in a |
151 | Perl string - very natural. |
165 | Perl string - very natural. |
152 | |
166 | |
153 | =item 2. Perl does I<not> associate an encoding with your strings. |
167 | =item 2. Perl does I<not> associate an encoding with your strings. |
154 | |
168 | |
155 | Unless you force it to, e.g. when matching it against a regex, or printing |
169 | Unless you force it to, e.g. when matching it against a regex, or printing |
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162 | encoding of your string. |
176 | encoding of your string. |
163 | |
177 | |
164 | Just ignore that flag unless you debug a Perl bug, a module written in |
178 | 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 |
179 | 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 |
180 | 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 |
181 | 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 |
182 | flag clear, and you can have binary data with that flag set and that flag |
169 | clear. Other possibilities exist, too. |
183 | clear. Other possibilities exist, too. |
170 | |
184 | |
171 | If you didn't know about that flag, just the better, pretend it doesn't |
185 | If you didn't know about that flag, just the better, pretend it doesn't |
172 | exist. |
186 | exist. |
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177 | If you have UTF-8 encoded data, it is no longer a Unicode string, but a |
191 | 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. |
192 | Unicode string encoded in UTF-8, giving you a binary string. |
179 | |
193 | |
180 | =item 5. A string containing "high" (> 255) character values is I<not> a UTF-8 string. |
194 | =item 5. A string containing "high" (> 255) character values is I<not> a UTF-8 string. |
181 | |
195 | |
182 | Its a fact. Learn to live with it. |
196 | It's a fact. Learn to live with it. |
183 | |
197 | |
184 | =back |
198 | =back |
185 | |
199 | |
186 | I hope this helps :) |
200 | I hope this helps :) |
187 | |
201 | |
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204 | my $json = JSON::XS->new->utf8->space_after->encode ({a => [1,2]}) |
218 | my $json = JSON::XS->new->utf8->space_after->encode ({a => [1,2]}) |
205 | => {"a": [1, 2]} |
219 | => {"a": [1, 2]} |
206 | |
220 | |
207 | =item $json = $json->ascii ([$enable]) |
221 | =item $json = $json->ascii ([$enable]) |
208 | |
222 | |
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223 | =item $enabled = $json->get_ascii |
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224 | |
209 | If C<$enable> is true (or missing), then the C<encode> method will not |
225 | If C<$enable> is true (or missing), then the C<encode> method will not |
210 | generate characters outside the code range C<0..127> (which is ASCII). Any |
226 | generate characters outside the code range C<0..127> (which is ASCII). Any |
211 | unicode characters outside that range will be escaped using either a |
227 | Unicode characters outside that range will be escaped using either a |
212 | single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, |
228 | single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, |
213 | as per RFC4627. The resulting encoded JSON text can be treated as a native |
229 | as per RFC4627. The resulting encoded JSON text can be treated as a native |
214 | unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string, |
230 | Unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string, |
215 | or any other superset of ASCII. |
231 | or any other superset of ASCII. |
216 | |
232 | |
217 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
233 | 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 |
234 | characters unless required by the JSON syntax or other flags. This results |
219 | in a faster and more compact format. |
235 | in a faster and more compact format. |
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225 | JSON::XS->new->ascii (1)->encode ([chr 0x10401]) |
241 | JSON::XS->new->ascii (1)->encode ([chr 0x10401]) |
226 | => ["\ud801\udc01"] |
242 | => ["\ud801\udc01"] |
227 | |
243 | |
228 | =item $json = $json->latin1 ([$enable]) |
244 | =item $json = $json->latin1 ([$enable]) |
229 | |
245 | |
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246 | =item $enabled = $json->get_latin1 |
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247 | |
230 | If C<$enable> is true (or missing), then the C<encode> method will encode |
248 | If C<$enable> is true (or missing), then the C<encode> method will encode |
231 | the resulting JSON text as latin1 (or iso-8859-1), escaping any characters |
249 | the resulting JSON text as latin1 (or iso-8859-1), escaping any characters |
232 | outside the code range C<0..255>. The resulting string can be treated as a |
250 | outside the code range C<0..255>. The resulting string can be treated as a |
233 | latin1-encoded JSON text or a native unicode string. The C<decode> method |
251 | latin1-encoded JSON text or a native Unicode string. The C<decode> method |
234 | will not be affected in any way by this flag, as C<decode> by default |
252 | will not be affected in any way by this flag, as C<decode> by default |
235 | expects unicode, which is a strict superset of latin1. |
253 | expects Unicode, which is a strict superset of latin1. |
236 | |
254 | |
237 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
255 | 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. |
256 | characters unless required by the JSON syntax or other flags. |
239 | |
257 | |
240 | The main use for this flag is efficiently encoding binary data as JSON |
258 | 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 |
259 | 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 |
260 | size. The disadvantage is that the resulting JSON text is encoded |
243 | in latin1 (and must correctly be treated as such when storing and |
261 | 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 |
262 | 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 |
263 | 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. |
264 | in files or databases, not when talking to other JSON encoders/decoders. |
247 | |
265 | |
248 | JSON::XS->new->latin1->encode (["\x{89}\x{abc}"] |
266 | JSON::XS->new->latin1->encode (["\x{89}\x{abc}"] |
249 | => ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not) |
267 | => ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not) |
250 | |
268 | |
251 | =item $json = $json->utf8 ([$enable]) |
269 | =item $json = $json->utf8 ([$enable]) |
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270 | |
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271 | =item $enabled = $json->get_utf8 |
252 | |
272 | |
253 | If C<$enable> is true (or missing), then the C<encode> method will encode |
273 | If C<$enable> is true (or missing), then the C<encode> method will encode |
254 | the JSON result into UTF-8, as required by many protocols, while the |
274 | the JSON result into UTF-8, as required by many protocols, while the |
255 | C<decode> method expects to be handled an UTF-8-encoded string. Please |
275 | C<decode> method expects to be handled an UTF-8-encoded string. Please |
256 | note that UTF-8-encoded strings do not contain any characters outside the |
276 | note that UTF-8-encoded strings do not contain any characters outside the |
257 | range C<0..255>, they are thus useful for bytewise/binary I/O. In future |
277 | range C<0..255>, they are thus useful for bytewise/binary I/O. In future |
258 | versions, enabling this option might enable autodetection of the UTF-16 |
278 | versions, enabling this option might enable autodetection of the UTF-16 |
259 | and UTF-32 encoding families, as described in RFC4627. |
279 | and UTF-32 encoding families, as described in RFC4627. |
260 | |
280 | |
261 | If C<$enable> is false, then the C<encode> method will return the JSON |
281 | 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 |
282 | 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 |
283 | 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. |
284 | to be done yourself, e.g. using the Encode module. |
265 | |
285 | |
266 | Example, output UTF-16BE-encoded JSON: |
286 | Example, output UTF-16BE-encoded JSON: |
267 | |
287 | |
268 | use Encode; |
288 | use Encode; |
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290 | ] |
310 | ] |
291 | } |
311 | } |
292 | |
312 | |
293 | =item $json = $json->indent ([$enable]) |
313 | =item $json = $json->indent ([$enable]) |
294 | |
314 | |
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315 | =item $enabled = $json->get_indent |
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316 | |
295 | If C<$enable> is true (or missing), then the C<encode> method will use a multiline |
317 | If C<$enable> is true (or missing), then the C<encode> method will use a multiline |
296 | format as output, putting every array member or object/hash key-value pair |
318 | format as output, putting every array member or object/hash key-value pair |
297 | into its own line, identing them properly. |
319 | into its own line, indenting them properly. |
298 | |
320 | |
299 | If C<$enable> is false, no newlines or indenting will be produced, and the |
321 | 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>. |
322 | resulting JSON text is guaranteed not to contain any C<newlines>. |
301 | |
323 | |
302 | This setting has no effect when decoding JSON texts. |
324 | This setting has no effect when decoding JSON texts. |
303 | |
325 | |
304 | =item $json = $json->space_before ([$enable]) |
326 | =item $json = $json->space_before ([$enable]) |
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327 | |
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328 | =item $enabled = $json->get_space_before |
305 | |
329 | |
306 | If C<$enable> is true (or missing), then the C<encode> method will add an extra |
330 | If C<$enable> is true (or missing), then the C<encode> method will add an extra |
307 | optional space before the C<:> separating keys from values in JSON objects. |
331 | optional space before the C<:> separating keys from values in JSON objects. |
308 | |
332 | |
309 | If C<$enable> is false, then the C<encode> method will not add any extra |
333 | If C<$enable> is false, then the C<encode> method will not add any extra |
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315 | Example, space_before enabled, space_after and indent disabled: |
339 | Example, space_before enabled, space_after and indent disabled: |
316 | |
340 | |
317 | {"key" :"value"} |
341 | {"key" :"value"} |
318 | |
342 | |
319 | =item $json = $json->space_after ([$enable]) |
343 | =item $json = $json->space_after ([$enable]) |
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344 | |
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345 | =item $enabled = $json->get_space_after |
320 | |
346 | |
321 | If C<$enable> is true (or missing), then the C<encode> method will add an extra |
347 | 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 |
348 | 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 |
349 | and extra whitespace after the C<,> separating key-value pairs and array |
324 | members. |
350 | members. |
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331 | Example, space_before and indent disabled, space_after enabled: |
357 | Example, space_before and indent disabled, space_after enabled: |
332 | |
358 | |
333 | {"key": "value"} |
359 | {"key": "value"} |
334 | |
360 | |
335 | =item $json = $json->relaxed ([$enable]) |
361 | =item $json = $json->relaxed ([$enable]) |
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362 | |
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363 | =item $enabled = $json->get_relaxed |
336 | |
364 | |
337 | If C<$enable> is true (or missing), then C<decode> will accept some |
365 | 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 |
366 | 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 |
367 | 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 |
368 | JSON texts as if they were valid!>. I suggest only to use this option to |
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377 | |
405 | |
378 | =back |
406 | =back |
379 | |
407 | |
380 | =item $json = $json->canonical ([$enable]) |
408 | =item $json = $json->canonical ([$enable]) |
381 | |
409 | |
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410 | =item $enabled = $json->get_canonical |
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411 | |
382 | If C<$enable> is true (or missing), then the C<encode> method will output JSON objects |
412 | If C<$enable> is true (or missing), then the C<encode> method will output JSON objects |
383 | by sorting their keys. This is adding a comparatively high overhead. |
413 | by sorting their keys. This is adding a comparatively high overhead. |
384 | |
414 | |
385 | If C<$enable> is false, then the C<encode> method will output key-value |
415 | 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 |
416 | pairs in the order Perl stores them (which will likely change between runs |
387 | of the same script). |
417 | of the same script). |
388 | |
418 | |
389 | This option is useful if you want the same data structure to be encoded as |
419 | 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, |
420 | 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, |
421 | the same hash might be encoded differently even if contains the same data, |
392 | as key-value pairs have no inherent ordering in Perl. |
422 | as key-value pairs have no inherent ordering in Perl. |
393 | |
423 | |
394 | This setting has no effect when decoding JSON texts. |
424 | This setting has no effect when decoding JSON texts. |
395 | |
425 | |
396 | =item $json = $json->allow_nonref ([$enable]) |
426 | =item $json = $json->allow_nonref ([$enable]) |
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427 | |
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428 | =item $enabled = $json->get_allow_nonref |
397 | |
429 | |
398 | If C<$enable> is true (or missing), then the C<encode> method can convert a |
430 | 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, |
431 | 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 |
432 | which is an extension to RFC4627. Likewise, C<decode> will accept those JSON |
401 | values instead of croaking. |
433 | values instead of croaking. |
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411 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
443 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
412 | => "Hello, World!" |
444 | => "Hello, World!" |
413 | |
445 | |
414 | =item $json = $json->allow_blessed ([$enable]) |
446 | =item $json = $json->allow_blessed ([$enable]) |
415 | |
447 | |
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448 | =item $enabled = $json->get_allow_blessed |
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449 | |
416 | If C<$enable> is true (or missing), then the C<encode> method will not |
450 | If C<$enable> is true (or missing), then the C<encode> method will not |
417 | barf when it encounters a blessed reference. Instead, the value of the |
451 | barf when it encounters a blessed reference. Instead, the value of the |
418 | B<convert_blessed> option will decide wether C<null> (C<convert_blessed> |
452 | B<convert_blessed> option will decide whether C<null> (C<convert_blessed> |
419 | disabled or no C<to_json> method found) or a representation of the |
453 | disabled or no C<TO_JSON> method found) or a representation of the |
420 | object (C<convert_blessed> enabled and C<to_json> method found) is being |
454 | object (C<convert_blessed> enabled and C<TO_JSON> method found) is being |
421 | encoded. Has no effect on C<decode>. |
455 | encoded. Has no effect on C<decode>. |
422 | |
456 | |
423 | If C<$enable> is false (the default), then C<encode> will throw an |
457 | If C<$enable> is false (the default), then C<encode> will throw an |
424 | exception when it encounters a blessed object. |
458 | exception when it encounters a blessed object. |
425 | |
459 | |
426 | =item $json = $json->convert_blessed ([$enable]) |
460 | =item $json = $json->convert_blessed ([$enable]) |
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461 | |
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462 | =item $enabled = $json->get_convert_blessed |
427 | |
463 | |
428 | If C<$enable> is true (or missing), then C<encode>, upon encountering a |
464 | If C<$enable> is true (or missing), then C<encode>, upon encountering a |
429 | blessed object, will check for the availability of the C<TO_JSON> method |
465 | blessed object, will check for the availability of the C<TO_JSON> method |
430 | on the object's class. If found, it will be called in scalar context |
466 | on the object's class. If found, it will be called in scalar context |
431 | and the resulting scalar will be encoded instead of the object. If no |
467 | and the resulting scalar will be encoded instead of the object. If no |
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488 | |
524 | |
489 | As this callback gets called less often then the C<filter_json_object> |
525 | As this callback gets called less often then the C<filter_json_object> |
490 | one, decoding speed will not usually suffer as much. Therefore, single-key |
526 | one, decoding speed will not usually suffer as much. Therefore, single-key |
491 | objects make excellent targets to serialise Perl objects into, especially |
527 | objects make excellent targets to serialise Perl objects into, especially |
492 | as single-key JSON objects are as close to the type-tagged value concept |
528 | as single-key JSON objects are as close to the type-tagged value concept |
493 | as JSON gets (its basically an ID/VALUE tuple). Of course, JSON does not |
529 | as JSON gets (it's basically an ID/VALUE tuple). Of course, JSON does not |
494 | support this in any way, so you need to make sure your data never looks |
530 | support this in any way, so you need to make sure your data never looks |
495 | like a serialised Perl hash. |
531 | like a serialised Perl hash. |
496 | |
532 | |
497 | Typical names for the single object key are C<__class_whatever__>, or |
533 | Typical names for the single object key are C<__class_whatever__>, or |
498 | C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even |
534 | C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even |
… | |
… | |
522 | |
558 | |
523 | { __widget__ => $self->{id} } |
559 | { __widget__ => $self->{id} } |
524 | } |
560 | } |
525 | |
561 | |
526 | =item $json = $json->shrink ([$enable]) |
562 | =item $json = $json->shrink ([$enable]) |
|
|
563 | |
|
|
564 | =item $enabled = $json->get_shrink |
527 | |
565 | |
528 | Perl usually over-allocates memory a bit when allocating space for |
566 | Perl usually over-allocates memory a bit when allocating space for |
529 | strings. This flag optionally resizes strings generated by either |
567 | strings. This flag optionally resizes strings generated by either |
530 | C<encode> or C<decode> to their minimum size possible. This can save |
568 | 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 |
569 | 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 |
587 | strings that look like integers or floats into integers or floats |
550 | internally (there is no difference on the Perl level), saving space. |
588 | internally (there is no difference on the Perl level), saving space. |
551 | |
589 | |
552 | =item $json = $json->max_depth ([$maximum_nesting_depth]) |
590 | =item $json = $json->max_depth ([$maximum_nesting_depth]) |
553 | |
591 | |
|
|
592 | =item $max_depth = $json->get_max_depth |
|
|
593 | |
554 | Sets the maximum nesting level (default C<512>) accepted while encoding |
594 | 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 |
595 | 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 |
596 | higher nesting level then this limit, then the encoder and decoder will |
557 | stop and croak at that point. |
597 | stop and croak at that point. |
558 | |
598 | |
… | |
… | |
569 | used, which is rarely useful. |
609 | used, which is rarely useful. |
570 | |
610 | |
571 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
611 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
572 | |
612 | |
573 | =item $json = $json->max_size ([$maximum_string_size]) |
613 | =item $json = $json->max_size ([$maximum_string_size]) |
|
|
614 | |
|
|
615 | =item $max_size = $json->get_max_size |
574 | |
616 | |
575 | Set the maximum length a JSON text may have (in bytes) where decoding is |
617 | 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> |
618 | 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 |
619 | 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 |
620 | 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 |
667 | vice versa. These mappings are designed to "do the right thing" in most |
626 | circumstances automatically, preserving round-tripping characteristics |
668 | circumstances automatically, preserving round-tripping characteristics |
627 | (what you put in comes out as something equivalent). |
669 | (what you put in comes out as something equivalent). |
628 | |
670 | |
629 | For the more enlightened: note that in the following descriptions, |
671 | For the more enlightened: note that in the following descriptions, |
630 | lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl> |
672 | lowercase I<perl> refers to the Perl interpreter, while uppercase I<Perl> |
631 | refers to the abstract Perl language itself. |
673 | refers to the abstract Perl language itself. |
632 | |
674 | |
633 | |
675 | |
634 | =head2 JSON -> PERL |
676 | =head2 JSON -> PERL |
635 | |
677 | |
636 | =over 4 |
678 | =over 4 |
637 | |
679 | |
638 | =item object |
680 | =item object |
639 | |
681 | |
640 | A JSON object becomes a reference to a hash in Perl. No ordering of object |
682 | 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). |
683 | keys is preserved (JSON does not preserve object key ordering itself). |
642 | |
684 | |
643 | =item array |
685 | =item array |
644 | |
686 | |
645 | A JSON array becomes a reference to an array in Perl. |
687 | A JSON array becomes a reference to an array in Perl. |
646 | |
688 | |
… | |
… | |
672 | |
714 | |
673 | =item true, false |
715 | =item true, false |
674 | |
716 | |
675 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
717 | 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 |
718 | 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 |
719 | 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. |
720 | the C<JSON::XS::is_bool> function. |
679 | |
721 | |
680 | =item null |
722 | =item null |
681 | |
723 | |
682 | A JSON null atom becomes C<undef> in Perl. |
724 | A JSON null atom becomes C<undef> in Perl. |
… | |
… | |
745 | to_json [$value] # yields ["5"] |
787 | to_json [$value] # yields ["5"] |
746 | |
788 | |
747 | # undef becomes null |
789 | # undef becomes null |
748 | to_json [undef] # yields [null] |
790 | to_json [undef] # yields [null] |
749 | |
791 | |
750 | You can force the type to be a string by stringifying it: |
792 | You can force the type to be a JSON string by stringifying it: |
751 | |
793 | |
752 | my $x = 3.1; # some variable containing a number |
794 | my $x = 3.1; # some variable containing a number |
753 | "$x"; # stringified |
795 | "$x"; # stringified |
754 | $x .= ""; # another, more awkward way to stringify |
796 | $x .= ""; # another, more awkward way to stringify |
755 | print $x; # perl does it for you, too, quite often |
797 | print $x; # perl does it for you, too, quite often |
756 | |
798 | |
757 | You can force the type to be a number by numifying it: |
799 | You can force the type to be a JSON number by numifying it: |
758 | |
800 | |
759 | my $x = "3"; # some variable containing a string |
801 | my $x = "3"; # some variable containing a string |
760 | $x += 0; # numify it, ensuring it will be dumped as a number |
802 | $x += 0; # numify it, ensuring it will be dumped as a number |
761 | $x *= 1; # same thing, the choise is yours. |
803 | $x *= 1; # same thing, the choice is yours. |
762 | |
804 | |
763 | You can not currently output JSON booleans or force the type in other, |
805 | 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. |
806 | if you need this capability. |
765 | |
807 | |
766 | =back |
808 | =back |
767 | |
809 | |
768 | |
810 | |
769 | =head1 COMPARISON |
811 | =head1 COMPARISON |
… | |
… | |
778 | |
820 | |
779 | =item JSON 1.07 |
821 | =item JSON 1.07 |
780 | |
822 | |
781 | Slow (but very portable, as it is written in pure Perl). |
823 | Slow (but very portable, as it is written in pure Perl). |
782 | |
824 | |
783 | Undocumented/buggy Unicode handling (how JSON handles unicode values is |
825 | Undocumented/buggy Unicode handling (how JSON handles Unicode values is |
784 | undocumented. One can get far by feeding it unicode strings and doing |
826 | undocumented. One can get far by feeding it Unicode strings and doing |
785 | en-/decoding oneself, but unicode escapes are not working properly). |
827 | en-/decoding oneself, but Unicode escapes are not working properly). |
786 | |
828 | |
787 | No roundtripping (strings get clobbered if they look like numbers, e.g. |
829 | 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 |
830 | 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. |
831 | decode into the number 2. |
790 | |
832 | |
791 | =item JSON::PC 0.01 |
833 | =item JSON::PC 0.01 |
792 | |
834 | |
793 | Very fast. |
835 | Very fast. |
794 | |
836 | |
795 | Undocumented/buggy Unicode handling. |
837 | Undocumented/buggy Unicode handling. |
796 | |
838 | |
797 | No roundtripping. |
839 | No round-tripping. |
798 | |
840 | |
799 | Has problems handling many Perl values (e.g. regex results and other magic |
841 | Has problems handling many Perl values (e.g. regex results and other magic |
800 | values will make it croak). |
842 | values will make it croak). |
801 | |
843 | |
802 | Does not even generate valid JSON (C<{1,2}> gets converted to C<{1:2}> |
844 | 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 |
854 | 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 |
855 | 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 |
856 | single-line compact format for use in a protocol, and preferably a way to |
815 | generate ASCII-only JSON texts). |
857 | generate ASCII-only JSON texts). |
816 | |
858 | |
817 | Completely broken (and confusingly documented) Unicode handling (unicode |
859 | Completely broken (and confusingly documented) Unicode handling (Unicode |
818 | escapes are not working properly, you need to set ImplicitUnicode to |
860 | escapes are not working properly, you need to set ImplicitUnicode to |
819 | I<different> values on en- and decoding to get symmetric behaviour). |
861 | I<different> values on en- and decoding to get symmetric behaviour). |
820 | |
862 | |
821 | No roundtripping (simple cases work, but this depends on wether the scalar |
863 | No round-tripping (simple cases work, but this depends on whether the scalar |
822 | value was used in a numeric context or not). |
864 | value was used in a numeric context or not). |
823 | |
865 | |
824 | Dumping hashes may skip hash values depending on iterator state. |
866 | Dumping hashes may skip hash values depending on iterator state. |
825 | |
867 | |
826 | Unmaintained (maintainer unresponsive for many months, bugs are not |
868 | Unmaintained (maintainer unresponsive for many months, bugs are not |
827 | getting fixed). |
869 | getting fixed). |
828 | |
870 | |
829 | Does not check input for validity (i.e. will accept non-JSON input and |
871 | 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 |
872 | return "something" instead of raising an exception. This is a security |
831 | issue: imagine two banks transfering money between each other using |
873 | issue: imagine two banks transferring money between each other using |
832 | JSON. One bank might parse a given non-JSON request and deduct money, |
874 | 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 |
875 | 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 |
876 | good protocol will at least recover, that is extra unnecessary work and |
835 | the transaction will still not succeed). |
877 | the transaction will still not succeed). |
836 | |
878 | |
837 | =item JSON::DWIW 0.04 |
879 | =item JSON::DWIW 0.04 |
838 | |
880 | |
839 | Very fast. Very natural. Very nice. |
881 | Very fast. Very natural. Very nice. |
840 | |
882 | |
841 | Undocumented unicode handling (but the best of the pack. Unicode escapes |
883 | Undocumented Unicode handling (but the best of the pack. Unicode escapes |
842 | still don't get parsed properly). |
884 | still don't get parsed properly). |
843 | |
885 | |
844 | Very inflexible. |
886 | Very inflexible. |
845 | |
887 | |
846 | No roundtripping. |
888 | No round-tripping. |
847 | |
889 | |
848 | Does not generate valid JSON texts (key strings are often unquoted, empty keys |
890 | Does not generate valid JSON texts (key strings are often unquoted, empty keys |
849 | result in nothing being output) |
891 | result in nothing being output) |
850 | |
892 | |
851 | Does not check input for validity. |
893 | Does not check input for validity. |
… | |
… | |
866 | my $yaml = $to_yaml->encode ($ref) . "\n"; |
908 | my $yaml = $to_yaml->encode ($ref) . "\n"; |
867 | |
909 | |
868 | This will usually generate JSON texts that also parse as valid |
910 | This will usually generate JSON texts that also parse as valid |
869 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
911 | 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 |
912 | lengths that JSON doesn't have, so you should make sure that your hash |
871 | keys are noticably shorter than the 1024 characters YAML allows. |
913 | keys are noticeably shorter than the 1024 characters YAML allows. |
872 | |
914 | |
873 | There might be other incompatibilities that I am not aware of. In general |
915 | There might be other incompatibilities that I am not aware of. In general |
874 | you should not try to generate YAML with a JSON generator or vice versa, |
916 | you should not try to generate YAML with a JSON generator or vice versa, |
875 | or try to parse JSON with a YAML parser or vice versa: chances are high |
917 | or try to parse JSON with a YAML parser or vice versa: chances are high |
876 | that you will run into severe interoperability problems. |
918 | that you will run into severe interoperability problems. |
… | |
… | |
892 | It shows the number of encodes/decodes per second (JSON::XS uses |
934 | It shows the number of encodes/decodes per second (JSON::XS uses |
893 | the functional interface, while JSON::XS/2 uses the OO interface |
935 | the functional interface, while JSON::XS/2 uses the OO interface |
894 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
936 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
895 | shrink). Higher is better: |
937 | shrink). Higher is better: |
896 | |
938 | |
897 | Storable | 15779.925 | 14169.946 | |
|
|
898 | -----------+------------+------------+ |
|
|
899 | module | encode | decode | |
939 | module | encode | decode | |
900 | -----------|------------|------------| |
940 | -----------|------------|------------| |
901 | JSON | 4990.842 | 4088.813 | |
941 | JSON 1.x | 4990.842 | 4088.813 | |
902 | JSON::DWIW | 51653.990 | 71575.154 | |
942 | JSON::DWIW | 51653.990 | 71575.154 | |
903 | JSON::PC | 65948.176 | 74631.744 | |
943 | JSON::PC | 65948.176 | 74631.744 | |
904 | JSON::PP | 8931.652 | 3817.168 | |
944 | JSON::PP | 8931.652 | 3817.168 | |
905 | JSON::Syck | 24877.248 | 27776.848 | |
945 | JSON::Syck | 24877.248 | 27776.848 | |
906 | JSON::XS | 388361.481 | 227951.304 | |
946 | JSON::XS | 388361.481 | 227951.304 | |
… | |
… | |
908 | JSON::XS/3 | 338250.323 | 218453.333 | |
948 | JSON::XS/3 | 338250.323 | 218453.333 | |
909 | Storable | 16500.016 | 135300.129 | |
949 | Storable | 16500.016 | 135300.129 | |
910 | -----------+------------+------------+ |
950 | -----------+------------+------------+ |
911 | |
951 | |
912 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
952 | 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 |
953 | about three times faster on decoding, and over forty times faster |
914 | than JSON, even with pretty-printing and key sorting. It also compares |
954 | than JSON, even with pretty-printing and key sorting. It also compares |
915 | favourably to Storable for small amounts of data. |
955 | favourably to Storable for small amounts of data. |
916 | |
956 | |
917 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
957 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
918 | search API (http://nanoref.com/yahooapis/mgPdGg): |
958 | search API (http://nanoref.com/yahooapis/mgPdGg): |
919 | |
959 | |
920 | module | encode | decode | |
960 | module | encode | decode | |
921 | -----------|------------|------------| |
961 | -----------|------------|------------| |
922 | JSON | 55.260 | 34.971 | |
962 | JSON 1.x | 55.260 | 34.971 | |
923 | JSON::DWIW | 825.228 | 1082.513 | |
963 | JSON::DWIW | 825.228 | 1082.513 | |
924 | JSON::PC | 3571.444 | 2394.829 | |
964 | JSON::PC | 3571.444 | 2394.829 | |
925 | JSON::PP | 210.987 | 32.574 | |
965 | JSON::PP | 210.987 | 32.574 | |
926 | JSON::Syck | 552.551 | 787.544 | |
966 | JSON::Syck | 552.551 | 787.544 | |
927 | JSON::XS | 5780.463 | 4854.519 | |
967 | JSON::XS | 5780.463 | 4854.519 | |
… | |
… | |
931 | -----------+------------+------------+ |
971 | -----------+------------+------------+ |
932 | |
972 | |
933 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
973 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
934 | decodes faster). |
974 | decodes faster). |
935 | |
975 | |
936 | On large strings containing lots of high unicode characters, some modules |
976 | 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 |
977 | (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 |
978 | 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 |
979 | to decode or encode properly, so it was impossible to prepare a fair |
940 | comparison table for that case. |
980 | comparison table for that case. |
941 | |
981 | |
942 | |
982 | |
943 | =head1 SECURITY CONSIDERATIONS |
983 | =head1 SECURITY CONSIDERATIONS |
… | |
… | |
949 | any buffer overflows. Obviously, this module should ensure that and I am |
989 | any buffer overflows. Obviously, this module should ensure that and I am |
950 | trying hard on making that true, but you never know. |
990 | trying hard on making that true, but you never know. |
951 | |
991 | |
952 | Second, you need to avoid resource-starving attacks. That means you should |
992 | 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 |
993 | 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 |
994 | 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 |
995 | 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 |
996 | 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 |
997 | 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 |
998 | 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. |
999 | might want to check the size before you accept the string. |
… | |
… | |
970 | And last but least, something else could bomb you that I forgot to think |
1010 | 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, |
1011 | of. In that case, you get to keep the pieces. I am always open for hints, |
972 | though... |
1012 | though... |
973 | |
1013 | |
974 | If you are using JSON::XS to return packets to consumption |
1014 | If you are using JSON::XS to return packets to consumption |
975 | by javascript scripts in a browser you should have a look at |
1015 | 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 |
1016 | 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 |
1017 | 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 |
1018 | 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 |
1019 | browser developers care only for features, not about doing security |
980 | right). |
1020 | right). |
981 | |
1021 | |
982 | |
1022 | |
983 | =head1 THREADS |
1023 | =head1 THREADS |
984 | |
1024 | |
985 | This module is I<not> guarenteed to be thread safe and there are no |
1025 | 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 |
1026 | 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 |
1027 | horribly slow so-called "threads" which are simply slow and bloated |
988 | process simulations - use fork, its I<much> faster, cheaper, better). |
1028 | process simulations - use fork, its I<much> faster, cheaper, better). |
989 | |
1029 | |
990 | (It might actually work, but you ahve ben warned). |
1030 | (It might actually work, but you have been warned). |
991 | |
1031 | |
992 | |
1032 | |
993 | =head1 BUGS |
1033 | =head1 BUGS |
994 | |
1034 | |
995 | While the goal of this module is to be correct, that unfortunately does |
1035 | While the goal of this module is to be correct, that unfortunately does |