1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | JSON::XS - JSON serialising/deserialising, done correctly and fast |
3 | JSON::XS - JSON serialising/deserialising, done correctly and fast |
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4 | |
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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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6 | (http://fleur.hio.jp/perldoc/mix/lib/JSON/XS.html) |
4 | |
7 | |
5 | =head1 SYNOPSIS |
8 | =head1 SYNOPSIS |
6 | |
9 | |
7 | use JSON::XS; |
10 | use JSON::XS; |
8 | |
11 | |
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37 | |
40 | |
38 | =head2 FEATURES |
41 | =head2 FEATURES |
39 | |
42 | |
40 | =over 4 |
43 | =over 4 |
41 | |
44 | |
42 | =item * correct unicode handling |
45 | =item * correct Unicode handling |
43 | |
46 | |
44 | This module knows how to handle Unicode, and even documents how and when |
47 | This module knows how to handle Unicode, and even documents how and when |
45 | it does so. |
48 | it does so. |
46 | |
49 | |
47 | =item * round-trip integrity |
50 | =item * round-trip integrity |
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67 | This module has both a simple functional interface as well as an OO |
70 | This module has both a simple functional interface as well as an OO |
68 | interface. |
71 | interface. |
69 | |
72 | |
70 | =item * reasonably versatile output formats |
73 | =item * reasonably versatile output formats |
71 | |
74 | |
72 | You can choose between the most compact guarenteed single-line format |
75 | You can choose between the most compact guaranteed single-line format |
73 | possible (nice for simple line-based protocols), a pure-ascii format |
76 | possible (nice for simple line-based protocols), a pure-ascii format |
74 | (for when your transport is not 8-bit clean, still supports the whole |
77 | (for when your transport is not 8-bit clean, still supports the whole |
75 | unicode range), or a pretty-printed format (for when you want to read that |
78 | Unicode range), or a pretty-printed format (for when you want to read that |
76 | stuff). Or you can combine those features in whatever way you like. |
79 | stuff). Or you can combine those features in whatever way you like. |
77 | |
80 | |
78 | =back |
81 | =back |
79 | |
82 | |
80 | =cut |
83 | =cut |
81 | |
84 | |
82 | package JSON::XS; |
85 | package JSON::XS; |
83 | |
86 | |
84 | use strict; |
87 | use strict; |
85 | |
88 | |
86 | our $VERSION = '1.5'; |
89 | our $VERSION = '2.0'; |
87 | our @ISA = qw(Exporter); |
90 | our @ISA = qw(Exporter); |
88 | |
91 | |
89 | our @EXPORT = qw(to_json from_json); |
92 | our @EXPORT = qw(to_json from_json); |
90 | |
93 | |
91 | use Exporter; |
94 | use Exporter; |
92 | use XSLoader; |
95 | use XSLoader; |
93 | |
96 | |
94 | =head1 FUNCTIONAL INTERFACE |
97 | =head1 FUNCTIONAL INTERFACE |
95 | |
98 | |
96 | The following convinience methods are provided by this module. They are |
99 | The following convenience methods are provided by this module. They are |
97 | exported by default: |
100 | exported by default: |
98 | |
101 | |
99 | =over 4 |
102 | =over 4 |
100 | |
103 | |
101 | =item $json_text = to_json $perl_scalar |
104 | =item $json_text = to_json $perl_scalar |
102 | |
105 | |
103 | Converts the given Perl data structure (a simple scalar or a reference to |
106 | Converts the given Perl data structure to a UTF-8 encoded, binary string |
104 | a hash or array) to a UTF-8 encoded, binary string (that is, the string contains |
107 | (that is, the string contains octets only). Croaks on error. |
105 | octets only). Croaks on error. |
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106 | |
108 | |
107 | This function call is functionally identical to: |
109 | This function call is functionally identical to: |
108 | |
110 | |
109 | $json_text = JSON::XS->new->utf8->encode ($perl_scalar) |
111 | $json_text = JSON::XS->new->utf8->encode ($perl_scalar) |
110 | |
112 | |
111 | except being faster. |
113 | except being faster. |
112 | |
114 | |
113 | =item $perl_scalar = from_json $json_text |
115 | =item $perl_scalar = from_json $json_text |
114 | |
116 | |
115 | The opposite of C<to_json>: expects an UTF-8 (binary) string and tries to |
117 | The opposite of C<to_json>: expects an UTF-8 (binary) string and tries |
116 | parse that as an UTF-8 encoded JSON text, returning the resulting simple |
118 | to parse that as an UTF-8 encoded JSON text, returning the resulting |
117 | scalar or reference. Croaks on error. |
119 | reference. Croaks on error. |
118 | |
120 | |
119 | This function call is functionally identical to: |
121 | This function call is functionally identical to: |
120 | |
122 | |
121 | $perl_scalar = JSON::XS->new->utf8->decode ($json_text) |
123 | $perl_scalar = JSON::XS->new->utf8->decode ($json_text) |
122 | |
124 | |
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132 | Perl. |
134 | Perl. |
133 | |
135 | |
134 | =back |
136 | =back |
135 | |
137 | |
136 | |
138 | |
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139 | =head1 A FEW NOTES ON UNICODE AND PERL |
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140 | |
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141 | Since this often leads to confusion, here are a few very clear words on |
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142 | how Unicode works in Perl, modulo bugs. |
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143 | |
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144 | =over 4 |
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145 | |
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146 | =item 1. Perl strings can store characters with ordinal values > 255. |
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147 | |
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148 | This enables you to store Unicode characters as single characters in a |
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149 | Perl string - very natural. |
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150 | |
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151 | =item 2. Perl does I<not> associate an encoding with your strings. |
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152 | |
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153 | Unless you force it to, e.g. when matching it against a regex, or printing |
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154 | the scalar to a file, in which case Perl either interprets your string as |
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155 | locale-encoded text, octets/binary, or as Unicode, depending on various |
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156 | settings. In no case is an encoding stored together with your data, it is |
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157 | I<use> that decides encoding, not any magical metadata. |
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158 | |
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159 | =item 3. The internal utf-8 flag has no meaning with regards to the |
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160 | encoding of your string. |
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161 | |
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162 | Just ignore that flag unless you debug a Perl bug, a module written in |
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163 | XS or want to dive into the internals of perl. Otherwise it will only |
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164 | confuse you, as, despite the name, it says nothing about how your string |
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165 | is encoded. You can have Unicode strings with that flag set, with that |
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166 | flag clear, and you can have binary data with that flag set and that flag |
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167 | clear. Other possibilities exist, too. |
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168 | |
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169 | If you didn't know about that flag, just the better, pretend it doesn't |
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170 | exist. |
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171 | |
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172 | =item 4. A "Unicode String" is simply a string where each character can be |
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173 | validly interpreted as a Unicode codepoint. |
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174 | |
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175 | If you have UTF-8 encoded data, it is no longer a Unicode string, but a |
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176 | Unicode string encoded in UTF-8, giving you a binary string. |
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177 | |
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178 | =item 5. A string containing "high" (> 255) character values is I<not> a UTF-8 string. |
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179 | |
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180 | It's a fact. Learn to live with it. |
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181 | |
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182 | =back |
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183 | |
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184 | I hope this helps :) |
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185 | |
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186 | |
137 | =head1 OBJECT-ORIENTED INTERFACE |
187 | =head1 OBJECT-ORIENTED INTERFACE |
138 | |
188 | |
139 | The object oriented interface lets you configure your own encoding or |
189 | The object oriented interface lets you configure your own encoding or |
140 | decoding style, within the limits of supported formats. |
190 | decoding style, within the limits of supported formats. |
141 | |
191 | |
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152 | my $json = JSON::XS->new->utf8->space_after->encode ({a => [1,2]}) |
202 | my $json = JSON::XS->new->utf8->space_after->encode ({a => [1,2]}) |
153 | => {"a": [1, 2]} |
203 | => {"a": [1, 2]} |
154 | |
204 | |
155 | =item $json = $json->ascii ([$enable]) |
205 | =item $json = $json->ascii ([$enable]) |
156 | |
206 | |
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207 | =item $enabled = $json->get_ascii |
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208 | |
157 | If C<$enable> is true (or missing), then the C<encode> method will not |
209 | If C<$enable> is true (or missing), then the C<encode> method will not |
158 | generate characters outside the code range C<0..127> (which is ASCII). Any |
210 | generate characters outside the code range C<0..127> (which is ASCII). Any |
159 | unicode characters outside that range will be escaped using either a |
211 | Unicode characters outside that range will be escaped using either a |
160 | single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, |
212 | single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence, |
161 | as per RFC4627. The resulting encoded JSON text can be treated as a native |
213 | as per RFC4627. The resulting encoded JSON text can be treated as a native |
162 | unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string, |
214 | Unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string, |
163 | or any other superset of ASCII. |
215 | or any other superset of ASCII. |
164 | |
216 | |
165 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
217 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
166 | characters unless required by the JSON syntax or other flags. This results |
218 | characters unless required by the JSON syntax or other flags. This results |
167 | in a faster and more compact format. |
219 | in a faster and more compact format. |
… | |
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173 | JSON::XS->new->ascii (1)->encode ([chr 0x10401]) |
225 | JSON::XS->new->ascii (1)->encode ([chr 0x10401]) |
174 | => ["\ud801\udc01"] |
226 | => ["\ud801\udc01"] |
175 | |
227 | |
176 | =item $json = $json->latin1 ([$enable]) |
228 | =item $json = $json->latin1 ([$enable]) |
177 | |
229 | |
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230 | =item $enabled = $json->get_latin1 |
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231 | |
178 | If C<$enable> is true (or missing), then the C<encode> method will encode |
232 | If C<$enable> is true (or missing), then the C<encode> method will encode |
179 | the resulting JSON text as latin1 (or iso-8859-1), escaping any characters |
233 | the resulting JSON text as latin1 (or iso-8859-1), escaping any characters |
180 | outside the code range C<0..255>. The resulting string can be treated as a |
234 | outside the code range C<0..255>. The resulting string can be treated as a |
181 | latin1-encoded JSON text or a native unicode string. The C<decode> method |
235 | latin1-encoded JSON text or a native Unicode string. The C<decode> method |
182 | will not be affected in any way by this flag, as C<decode> by default |
236 | will not be affected in any way by this flag, as C<decode> by default |
183 | expects unicode, which is a strict superset of latin1. |
237 | expects Unicode, which is a strict superset of latin1. |
184 | |
238 | |
185 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
239 | If C<$enable> is false, then the C<encode> method will not escape Unicode |
186 | characters unless required by the JSON syntax or other flags. |
240 | characters unless required by the JSON syntax or other flags. |
187 | |
241 | |
188 | The main use for this flag is efficiently encoding binary data as JSON |
242 | The main use for this flag is efficiently encoding binary data as JSON |
189 | text, as most octets will not be escaped, resulting in a smaller encoded |
243 | text, as most octets will not be escaped, resulting in a smaller encoded |
190 | size. The disadvantage is that the resulting JSON text is encoded |
244 | size. The disadvantage is that the resulting JSON text is encoded |
191 | in latin1 (and must correctly be treated as such when storing and |
245 | in latin1 (and must correctly be treated as such when storing and |
192 | transfering), a rare encoding for JSON. It is therefore most useful when |
246 | transferring), a rare encoding for JSON. It is therefore most useful when |
193 | you want to store data structures known to contain binary data efficiently |
247 | you want to store data structures known to contain binary data efficiently |
194 | in files or databases, not when talking to other JSON encoders/decoders. |
248 | in files or databases, not when talking to other JSON encoders/decoders. |
195 | |
249 | |
196 | JSON::XS->new->latin1->encode (["\x{89}\x{abc}"] |
250 | JSON::XS->new->latin1->encode (["\x{89}\x{abc}"] |
197 | => ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not) |
251 | => ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not) |
198 | |
252 | |
199 | =item $json = $json->utf8 ([$enable]) |
253 | =item $json = $json->utf8 ([$enable]) |
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254 | |
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255 | =item $enabled = $json->get_utf8 |
200 | |
256 | |
201 | If C<$enable> is true (or missing), then the C<encode> method will encode |
257 | If C<$enable> is true (or missing), then the C<encode> method will encode |
202 | the JSON result into UTF-8, as required by many protocols, while the |
258 | the JSON result into UTF-8, as required by many protocols, while the |
203 | C<decode> method expects to be handled an UTF-8-encoded string. Please |
259 | C<decode> method expects to be handled an UTF-8-encoded string. Please |
204 | note that UTF-8-encoded strings do not contain any characters outside the |
260 | note that UTF-8-encoded strings do not contain any characters outside the |
205 | range C<0..255>, they are thus useful for bytewise/binary I/O. In future |
261 | range C<0..255>, they are thus useful for bytewise/binary I/O. In future |
206 | versions, enabling this option might enable autodetection of the UTF-16 |
262 | versions, enabling this option might enable autodetection of the UTF-16 |
207 | and UTF-32 encoding families, as described in RFC4627. |
263 | and UTF-32 encoding families, as described in RFC4627. |
208 | |
264 | |
209 | If C<$enable> is false, then the C<encode> method will return the JSON |
265 | If C<$enable> is false, then the C<encode> method will return the JSON |
210 | string as a (non-encoded) unicode string, while C<decode> expects thus a |
266 | string as a (non-encoded) Unicode string, while C<decode> expects thus a |
211 | unicode string. Any decoding or encoding (e.g. to UTF-8 or UTF-16) needs |
267 | Unicode string. Any decoding or encoding (e.g. to UTF-8 or UTF-16) needs |
212 | to be done yourself, e.g. using the Encode module. |
268 | to be done yourself, e.g. using the Encode module. |
213 | |
269 | |
214 | Example, output UTF-16BE-encoded JSON: |
270 | Example, output UTF-16BE-encoded JSON: |
215 | |
271 | |
216 | use Encode; |
272 | use Encode; |
… | |
… | |
238 | ] |
294 | ] |
239 | } |
295 | } |
240 | |
296 | |
241 | =item $json = $json->indent ([$enable]) |
297 | =item $json = $json->indent ([$enable]) |
242 | |
298 | |
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299 | =item $enabled = $json->get_indent |
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300 | |
243 | If C<$enable> is true (or missing), then the C<encode> method will use a multiline |
301 | If C<$enable> is true (or missing), then the C<encode> method will use a multiline |
244 | format as output, putting every array member or object/hash key-value pair |
302 | format as output, putting every array member or object/hash key-value pair |
245 | into its own line, identing them properly. |
303 | into its own line, indenting them properly. |
246 | |
304 | |
247 | If C<$enable> is false, no newlines or indenting will be produced, and the |
305 | If C<$enable> is false, no newlines or indenting will be produced, and the |
248 | resulting JSON text is guarenteed not to contain any C<newlines>. |
306 | resulting JSON text is guaranteed not to contain any C<newlines>. |
249 | |
307 | |
250 | This setting has no effect when decoding JSON texts. |
308 | This setting has no effect when decoding JSON texts. |
251 | |
309 | |
252 | =item $json = $json->space_before ([$enable]) |
310 | =item $json = $json->space_before ([$enable]) |
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311 | |
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312 | =item $enabled = $json->get_space_before |
253 | |
313 | |
254 | If C<$enable> is true (or missing), then the C<encode> method will add an extra |
314 | If C<$enable> is true (or missing), then the C<encode> method will add an extra |
255 | optional space before the C<:> separating keys from values in JSON objects. |
315 | optional space before the C<:> separating keys from values in JSON objects. |
256 | |
316 | |
257 | If C<$enable> is false, then the C<encode> method will not add any extra |
317 | If C<$enable> is false, then the C<encode> method will not add any extra |
… | |
… | |
263 | Example, space_before enabled, space_after and indent disabled: |
323 | Example, space_before enabled, space_after and indent disabled: |
264 | |
324 | |
265 | {"key" :"value"} |
325 | {"key" :"value"} |
266 | |
326 | |
267 | =item $json = $json->space_after ([$enable]) |
327 | =item $json = $json->space_after ([$enable]) |
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328 | |
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329 | =item $enabled = $json->get_space_after |
268 | |
330 | |
269 | If C<$enable> is true (or missing), then the C<encode> method will add an extra |
331 | If C<$enable> is true (or missing), then the C<encode> method will add an extra |
270 | optional space after the C<:> separating keys from values in JSON objects |
332 | optional space after the C<:> separating keys from values in JSON objects |
271 | and extra whitespace after the C<,> separating key-value pairs and array |
333 | and extra whitespace after the C<,> separating key-value pairs and array |
272 | members. |
334 | members. |
… | |
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279 | Example, space_before and indent disabled, space_after enabled: |
341 | Example, space_before and indent disabled, space_after enabled: |
280 | |
342 | |
281 | {"key": "value"} |
343 | {"key": "value"} |
282 | |
344 | |
283 | =item $json = $json->relaxed ([$enable]) |
345 | =item $json = $json->relaxed ([$enable]) |
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346 | |
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347 | =item $enabled = $json->get_relaxed |
284 | |
348 | |
285 | If C<$enable> is true (or missing), then C<decode> will accept some |
349 | If C<$enable> is true (or missing), then C<decode> will accept some |
286 | extensions to normal JSON syntax (see below). C<encode> will not be |
350 | extensions to normal JSON syntax (see below). C<encode> will not be |
287 | affected in anyway. I<Be aware that this option makes you accept invalid |
351 | affected in anyway. I<Be aware that this option makes you accept invalid |
288 | JSON texts as if they were valid!>. I suggest only to use this option to |
352 | JSON texts as if they were valid!>. I suggest only to use this option to |
… | |
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325 | |
389 | |
326 | =back |
390 | =back |
327 | |
391 | |
328 | =item $json = $json->canonical ([$enable]) |
392 | =item $json = $json->canonical ([$enable]) |
329 | |
393 | |
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394 | =item $enabled = $json->get_canonical |
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395 | |
330 | If C<$enable> is true (or missing), then the C<encode> method will output JSON objects |
396 | If C<$enable> is true (or missing), then the C<encode> method will output JSON objects |
331 | by sorting their keys. This is adding a comparatively high overhead. |
397 | by sorting their keys. This is adding a comparatively high overhead. |
332 | |
398 | |
333 | If C<$enable> is false, then the C<encode> method will output key-value |
399 | If C<$enable> is false, then the C<encode> method will output key-value |
334 | pairs in the order Perl stores them (which will likely change between runs |
400 | pairs in the order Perl stores them (which will likely change between runs |
335 | of the same script). |
401 | of the same script). |
336 | |
402 | |
337 | This option is useful if you want the same data structure to be encoded as |
403 | This option is useful if you want the same data structure to be encoded as |
338 | the same JSON text (given the same overall settings). If it is disabled, |
404 | the same JSON text (given the same overall settings). If it is disabled, |
339 | the same hash migh be encoded differently even if contains the same data, |
405 | the same hash might be encoded differently even if contains the same data, |
340 | as key-value pairs have no inherent ordering in Perl. |
406 | as key-value pairs have no inherent ordering in Perl. |
341 | |
407 | |
342 | This setting has no effect when decoding JSON texts. |
408 | This setting has no effect when decoding JSON texts. |
343 | |
409 | |
344 | =item $json = $json->allow_nonref ([$enable]) |
410 | =item $json = $json->allow_nonref ([$enable]) |
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411 | |
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412 | =item $enabled = $json->get_allow_nonref |
345 | |
413 | |
346 | If C<$enable> is true (or missing), then the C<encode> method can convert a |
414 | If C<$enable> is true (or missing), then the C<encode> method can convert a |
347 | non-reference into its corresponding string, number or null JSON value, |
415 | non-reference into its corresponding string, number or null JSON value, |
348 | which is an extension to RFC4627. Likewise, C<decode> will accept those JSON |
416 | which is an extension to RFC4627. Likewise, C<decode> will accept those JSON |
349 | values instead of croaking. |
417 | values instead of croaking. |
… | |
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359 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
427 | JSON::XS->new->allow_nonref->encode ("Hello, World!") |
360 | => "Hello, World!" |
428 | => "Hello, World!" |
361 | |
429 | |
362 | =item $json = $json->allow_blessed ([$enable]) |
430 | =item $json = $json->allow_blessed ([$enable]) |
363 | |
431 | |
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432 | =item $enabled = $json->get_allow_blessed |
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433 | |
364 | If C<$enable> is true (or missing), then the C<encode> method will not |
434 | If C<$enable> is true (or missing), then the C<encode> method will not |
365 | barf when it encounters a blessed reference. Instead, the value of the |
435 | barf when it encounters a blessed reference. Instead, the value of the |
366 | B<convert_blessed> option will decide wether C<null> (C<convert_blessed> |
436 | B<convert_blessed> option will decide whether C<null> (C<convert_blessed> |
367 | disabled or no C<to_json> method found) or a representation of the |
437 | disabled or no C<TO_JSON> method found) or a representation of the |
368 | object (C<convert_blessed> enabled and C<to_json> method found) is being |
438 | object (C<convert_blessed> enabled and C<TO_JSON> method found) is being |
369 | encoded. Has no effect on C<decode>. |
439 | encoded. Has no effect on C<decode>. |
370 | |
440 | |
371 | If C<$enable> is false (the default), then C<encode> will throw an |
441 | If C<$enable> is false (the default), then C<encode> will throw an |
372 | exception when it encounters a blessed object. |
442 | exception when it encounters a blessed object. |
373 | |
443 | |
374 | =item $json = $json->convert_blessed ([$enable]) |
444 | =item $json = $json->convert_blessed ([$enable]) |
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445 | |
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446 | =item $enabled = $json->get_convert_blessed |
375 | |
447 | |
376 | If C<$enable> is true (or missing), then C<encode>, upon encountering a |
448 | If C<$enable> is true (or missing), then C<encode>, upon encountering a |
377 | blessed object, will check for the availability of the C<TO_JSON> method |
449 | blessed object, will check for the availability of the C<TO_JSON> method |
378 | on the object's class. If found, it will be called in scalar context |
450 | on the object's class. If found, it will be called in scalar context |
379 | and the resulting scalar will be encoded instead of the object. If no |
451 | and the resulting scalar will be encoded instead of the object. If no |
… | |
… | |
436 | |
508 | |
437 | As this callback gets called less often then the C<filter_json_object> |
509 | As this callback gets called less often then the C<filter_json_object> |
438 | one, decoding speed will not usually suffer as much. Therefore, single-key |
510 | one, decoding speed will not usually suffer as much. Therefore, single-key |
439 | objects make excellent targets to serialise Perl objects into, especially |
511 | objects make excellent targets to serialise Perl objects into, especially |
440 | as single-key JSON objects are as close to the type-tagged value concept |
512 | as single-key JSON objects are as close to the type-tagged value concept |
441 | as JSON gets (its basically an ID/VALUE tuple). Of course, JSON does not |
513 | as JSON gets (it's basically an ID/VALUE tuple). Of course, JSON does not |
442 | support this in any way, so you need to make sure your data never looks |
514 | support this in any way, so you need to make sure your data never looks |
443 | like a serialised Perl hash. |
515 | like a serialised Perl hash. |
444 | |
516 | |
445 | Typical names for the single object key are C<__class_whatever__>, or |
517 | Typical names for the single object key are C<__class_whatever__>, or |
446 | C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even |
518 | C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even |
… | |
… | |
470 | |
542 | |
471 | { __widget__ => $self->{id} } |
543 | { __widget__ => $self->{id} } |
472 | } |
544 | } |
473 | |
545 | |
474 | =item $json = $json->shrink ([$enable]) |
546 | =item $json = $json->shrink ([$enable]) |
|
|
547 | |
|
|
548 | =item $enabled = $json->get_shrink |
475 | |
549 | |
476 | Perl usually over-allocates memory a bit when allocating space for |
550 | Perl usually over-allocates memory a bit when allocating space for |
477 | strings. This flag optionally resizes strings generated by either |
551 | strings. This flag optionally resizes strings generated by either |
478 | C<encode> or C<decode> to their minimum size possible. This can save |
552 | C<encode> or C<decode> to their minimum size possible. This can save |
479 | memory when your JSON texts are either very very long or you have many |
553 | memory when your JSON texts are either very very long or you have many |
… | |
… | |
497 | strings that look like integers or floats into integers or floats |
571 | strings that look like integers or floats into integers or floats |
498 | internally (there is no difference on the Perl level), saving space. |
572 | internally (there is no difference on the Perl level), saving space. |
499 | |
573 | |
500 | =item $json = $json->max_depth ([$maximum_nesting_depth]) |
574 | =item $json = $json->max_depth ([$maximum_nesting_depth]) |
501 | |
575 | |
|
|
576 | =item $max_depth = $json->get_max_depth |
|
|
577 | |
502 | Sets the maximum nesting level (default C<512>) accepted while encoding |
578 | Sets the maximum nesting level (default C<512>) accepted while encoding |
503 | or decoding. If the JSON text or Perl data structure has an equal or |
579 | or decoding. If the JSON text or Perl data structure has an equal or |
504 | higher nesting level then this limit, then the encoder and decoder will |
580 | higher nesting level then this limit, then the encoder and decoder will |
505 | stop and croak at that point. |
581 | stop and croak at that point. |
506 | |
582 | |
… | |
… | |
517 | used, which is rarely useful. |
593 | used, which is rarely useful. |
518 | |
594 | |
519 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
595 | See SECURITY CONSIDERATIONS, below, for more info on why this is useful. |
520 | |
596 | |
521 | =item $json = $json->max_size ([$maximum_string_size]) |
597 | =item $json = $json->max_size ([$maximum_string_size]) |
|
|
598 | |
|
|
599 | =item $max_size = $json->get_max_size |
522 | |
600 | |
523 | Set the maximum length a JSON text may have (in bytes) where decoding is |
601 | Set the maximum length a JSON text may have (in bytes) where decoding is |
524 | being attempted. The default is C<0>, meaning no limit. When C<decode> |
602 | being attempted. The default is C<0>, meaning no limit. When C<decode> |
525 | is called on a string longer then this number of characters it will not |
603 | is called on a string longer then this number of characters it will not |
526 | attempt to decode the string but throw an exception. This setting has no |
604 | attempt to decode the string but throw an exception. This setting has no |
… | |
… | |
573 | vice versa. These mappings are designed to "do the right thing" in most |
651 | vice versa. These mappings are designed to "do the right thing" in most |
574 | circumstances automatically, preserving round-tripping characteristics |
652 | circumstances automatically, preserving round-tripping characteristics |
575 | (what you put in comes out as something equivalent). |
653 | (what you put in comes out as something equivalent). |
576 | |
654 | |
577 | For the more enlightened: note that in the following descriptions, |
655 | For the more enlightened: note that in the following descriptions, |
578 | lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl> |
656 | lowercase I<perl> refers to the Perl interpreter, while uppercase I<Perl> |
579 | refers to the abstract Perl language itself. |
657 | refers to the abstract Perl language itself. |
580 | |
658 | |
581 | |
659 | |
582 | =head2 JSON -> PERL |
660 | =head2 JSON -> PERL |
583 | |
661 | |
584 | =over 4 |
662 | =over 4 |
585 | |
663 | |
586 | =item object |
664 | =item object |
587 | |
665 | |
588 | A JSON object becomes a reference to a hash in Perl. No ordering of object |
666 | A JSON object becomes a reference to a hash in Perl. No ordering of object |
589 | keys is preserved (JSON does not preserver object key ordering itself). |
667 | keys is preserved (JSON does not preserve object key ordering itself). |
590 | |
668 | |
591 | =item array |
669 | =item array |
592 | |
670 | |
593 | A JSON array becomes a reference to an array in Perl. |
671 | A JSON array becomes a reference to an array in Perl. |
594 | |
672 | |
… | |
… | |
620 | |
698 | |
621 | =item true, false |
699 | =item true, false |
622 | |
700 | |
623 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
701 | These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>, |
624 | respectively. They are overloaded to act almost exactly like the numbers |
702 | respectively. They are overloaded to act almost exactly like the numbers |
625 | C<1> and C<0>. You can check wether a scalar is a JSON boolean by using |
703 | C<1> and C<0>. You can check whether a scalar is a JSON boolean by using |
626 | the C<JSON::XS::is_bool> function. |
704 | the C<JSON::XS::is_bool> function. |
627 | |
705 | |
628 | =item null |
706 | =item null |
629 | |
707 | |
630 | A JSON null atom becomes C<undef> in Perl. |
708 | A JSON null atom becomes C<undef> in Perl. |
… | |
… | |
666 | to_json [\0,JSON::XS::true] # yields [false,true] |
744 | to_json [\0,JSON::XS::true] # yields [false,true] |
667 | |
745 | |
668 | =item JSON::XS::true, JSON::XS::false |
746 | =item JSON::XS::true, JSON::XS::false |
669 | |
747 | |
670 | These special values become JSON true and JSON false values, |
748 | These special values become JSON true and JSON false values, |
671 | respectively. You cna alos use C<\1> and C<\0> directly if you want. |
749 | respectively. You can also use C<\1> and C<\0> directly if you want. |
672 | |
750 | |
673 | =item blessed objects |
751 | =item blessed objects |
674 | |
752 | |
675 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
753 | Blessed objects are not allowed. JSON::XS currently tries to encode their |
676 | underlying representation (hash- or arrayref), but this behaviour might |
754 | underlying representation (hash- or arrayref), but this behaviour might |
… | |
… | |
693 | to_json [$value] # yields ["5"] |
771 | to_json [$value] # yields ["5"] |
694 | |
772 | |
695 | # undef becomes null |
773 | # undef becomes null |
696 | to_json [undef] # yields [null] |
774 | to_json [undef] # yields [null] |
697 | |
775 | |
698 | You can force the type to be a string by stringifying it: |
776 | You can force the type to be a JSON string by stringifying it: |
699 | |
777 | |
700 | my $x = 3.1; # some variable containing a number |
778 | my $x = 3.1; # some variable containing a number |
701 | "$x"; # stringified |
779 | "$x"; # stringified |
702 | $x .= ""; # another, more awkward way to stringify |
780 | $x .= ""; # another, more awkward way to stringify |
703 | print $x; # perl does it for you, too, quite often |
781 | print $x; # perl does it for you, too, quite often |
704 | |
782 | |
705 | You can force the type to be a number by numifying it: |
783 | You can force the type to be a JSON number by numifying it: |
706 | |
784 | |
707 | my $x = "3"; # some variable containing a string |
785 | my $x = "3"; # some variable containing a string |
708 | $x += 0; # numify it, ensuring it will be dumped as a number |
786 | $x += 0; # numify it, ensuring it will be dumped as a number |
709 | $x *= 1; # same thing, the choise is yours. |
787 | $x *= 1; # same thing, the choice is yours. |
710 | |
788 | |
711 | You can not currently output JSON booleans or force the type in other, |
789 | You can not currently force the type in other, less obscure, ways. Tell me |
712 | less obscure, ways. Tell me if you need this capability. |
790 | if you need this capability. |
713 | |
791 | |
714 | =back |
792 | =back |
715 | |
793 | |
716 | |
794 | |
717 | =head1 COMPARISON |
795 | =head1 COMPARISON |
… | |
… | |
726 | |
804 | |
727 | =item JSON 1.07 |
805 | =item JSON 1.07 |
728 | |
806 | |
729 | Slow (but very portable, as it is written in pure Perl). |
807 | Slow (but very portable, as it is written in pure Perl). |
730 | |
808 | |
731 | Undocumented/buggy Unicode handling (how JSON handles unicode values is |
809 | Undocumented/buggy Unicode handling (how JSON handles Unicode values is |
732 | undocumented. One can get far by feeding it unicode strings and doing |
810 | undocumented. One can get far by feeding it Unicode strings and doing |
733 | en-/decoding oneself, but unicode escapes are not working properly). |
811 | en-/decoding oneself, but Unicode escapes are not working properly). |
734 | |
812 | |
735 | No roundtripping (strings get clobbered if they look like numbers, e.g. |
813 | No round-tripping (strings get clobbered if they look like numbers, e.g. |
736 | the string C<2.0> will encode to C<2.0> instead of C<"2.0">, and that will |
814 | the string C<2.0> will encode to C<2.0> instead of C<"2.0">, and that will |
737 | decode into the number 2. |
815 | decode into the number 2. |
738 | |
816 | |
739 | =item JSON::PC 0.01 |
817 | =item JSON::PC 0.01 |
740 | |
818 | |
741 | Very fast. |
819 | Very fast. |
742 | |
820 | |
743 | Undocumented/buggy Unicode handling. |
821 | Undocumented/buggy Unicode handling. |
744 | |
822 | |
745 | No roundtripping. |
823 | No round-tripping. |
746 | |
824 | |
747 | Has problems handling many Perl values (e.g. regex results and other magic |
825 | Has problems handling many Perl values (e.g. regex results and other magic |
748 | values will make it croak). |
826 | values will make it croak). |
749 | |
827 | |
750 | Does not even generate valid JSON (C<{1,2}> gets converted to C<{1:2}> |
828 | Does not even generate valid JSON (C<{1,2}> gets converted to C<{1:2}> |
… | |
… | |
760 | Very inflexible (no human-readable format supported, format pretty much |
838 | Very inflexible (no human-readable format supported, format pretty much |
761 | undocumented. I need at least a format for easy reading by humans and a |
839 | undocumented. I need at least a format for easy reading by humans and a |
762 | single-line compact format for use in a protocol, and preferably a way to |
840 | single-line compact format for use in a protocol, and preferably a way to |
763 | generate ASCII-only JSON texts). |
841 | generate ASCII-only JSON texts). |
764 | |
842 | |
765 | Completely broken (and confusingly documented) Unicode handling (unicode |
843 | Completely broken (and confusingly documented) Unicode handling (Unicode |
766 | escapes are not working properly, you need to set ImplicitUnicode to |
844 | escapes are not working properly, you need to set ImplicitUnicode to |
767 | I<different> values on en- and decoding to get symmetric behaviour). |
845 | I<different> values on en- and decoding to get symmetric behaviour). |
768 | |
846 | |
769 | No roundtripping (simple cases work, but this depends on wether the scalar |
847 | No round-tripping (simple cases work, but this depends on whether the scalar |
770 | value was used in a numeric context or not). |
848 | value was used in a numeric context or not). |
771 | |
849 | |
772 | Dumping hashes may skip hash values depending on iterator state. |
850 | Dumping hashes may skip hash values depending on iterator state. |
773 | |
851 | |
774 | Unmaintained (maintainer unresponsive for many months, bugs are not |
852 | Unmaintained (maintainer unresponsive for many months, bugs are not |
775 | getting fixed). |
853 | getting fixed). |
776 | |
854 | |
777 | Does not check input for validity (i.e. will accept non-JSON input and |
855 | Does not check input for validity (i.e. will accept non-JSON input and |
778 | return "something" instead of raising an exception. This is a security |
856 | return "something" instead of raising an exception. This is a security |
779 | issue: imagine two banks transfering money between each other using |
857 | issue: imagine two banks transferring money between each other using |
780 | JSON. One bank might parse a given non-JSON request and deduct money, |
858 | JSON. One bank might parse a given non-JSON request and deduct money, |
781 | while the other might reject the transaction with a syntax error. While a |
859 | while the other might reject the transaction with a syntax error. While a |
782 | good protocol will at least recover, that is extra unnecessary work and |
860 | good protocol will at least recover, that is extra unnecessary work and |
783 | the transaction will still not succeed). |
861 | the transaction will still not succeed). |
784 | |
862 | |
785 | =item JSON::DWIW 0.04 |
863 | =item JSON::DWIW 0.04 |
786 | |
864 | |
787 | Very fast. Very natural. Very nice. |
865 | Very fast. Very natural. Very nice. |
788 | |
866 | |
789 | Undocumented unicode handling (but the best of the pack. Unicode escapes |
867 | Undocumented Unicode handling (but the best of the pack. Unicode escapes |
790 | still don't get parsed properly). |
868 | still don't get parsed properly). |
791 | |
869 | |
792 | Very inflexible. |
870 | Very inflexible. |
793 | |
871 | |
794 | No roundtripping. |
872 | No round-tripping. |
795 | |
873 | |
796 | Does not generate valid JSON texts (key strings are often unquoted, empty keys |
874 | Does not generate valid JSON texts (key strings are often unquoted, empty keys |
797 | result in nothing being output) |
875 | result in nothing being output) |
798 | |
876 | |
799 | Does not check input for validity. |
877 | Does not check input for validity. |
… | |
… | |
814 | my $yaml = $to_yaml->encode ($ref) . "\n"; |
892 | my $yaml = $to_yaml->encode ($ref) . "\n"; |
815 | |
893 | |
816 | This will usually generate JSON texts that also parse as valid |
894 | This will usually generate JSON texts that also parse as valid |
817 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
895 | YAML. Please note that YAML has hardcoded limits on (simple) object key |
818 | lengths that JSON doesn't have, so you should make sure that your hash |
896 | lengths that JSON doesn't have, so you should make sure that your hash |
819 | keys are noticably shorter than the 1024 characters YAML allows. |
897 | keys are noticeably shorter than the 1024 characters YAML allows. |
820 | |
898 | |
821 | There might be other incompatibilities that I am not aware of. In general |
899 | There might be other incompatibilities that I am not aware of. In general |
822 | you should not try to generate YAML with a JSON generator or vice versa, |
900 | you should not try to generate YAML with a JSON generator or vice versa, |
823 | or try to parse JSON with a YAML parser or vice versa: chances are high |
901 | or try to parse JSON with a YAML parser or vice versa: chances are high |
824 | that you will run into severe interoperability problems. |
902 | that you will run into severe interoperability problems. |
… | |
… | |
840 | It shows the number of encodes/decodes per second (JSON::XS uses |
918 | It shows the number of encodes/decodes per second (JSON::XS uses |
841 | the functional interface, while JSON::XS/2 uses the OO interface |
919 | the functional interface, while JSON::XS/2 uses the OO interface |
842 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
920 | with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables |
843 | shrink). Higher is better: |
921 | shrink). Higher is better: |
844 | |
922 | |
845 | Storable | 15779.925 | 14169.946 | |
|
|
846 | -----------+------------+------------+ |
|
|
847 | module | encode | decode | |
923 | module | encode | decode | |
848 | -----------|------------|------------| |
924 | -----------|------------|------------| |
849 | JSON | 4990.842 | 4088.813 | |
925 | JSON 1.x | 4990.842 | 4088.813 | |
850 | JSON::DWIW | 51653.990 | 71575.154 | |
926 | JSON::DWIW | 51653.990 | 71575.154 | |
851 | JSON::PC | 65948.176 | 74631.744 | |
927 | JSON::PC | 65948.176 | 74631.744 | |
852 | JSON::PP | 8931.652 | 3817.168 | |
928 | JSON::PP | 8931.652 | 3817.168 | |
853 | JSON::Syck | 24877.248 | 27776.848 | |
929 | JSON::Syck | 24877.248 | 27776.848 | |
854 | JSON::XS | 388361.481 | 227951.304 | |
930 | JSON::XS | 388361.481 | 227951.304 | |
… | |
… | |
856 | JSON::XS/3 | 338250.323 | 218453.333 | |
932 | JSON::XS/3 | 338250.323 | 218453.333 | |
857 | Storable | 16500.016 | 135300.129 | |
933 | Storable | 16500.016 | 135300.129 | |
858 | -----------+------------+------------+ |
934 | -----------+------------+------------+ |
859 | |
935 | |
860 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
936 | That is, JSON::XS is about five times faster than JSON::DWIW on encoding, |
861 | about three times faster on decoding, and over fourty times faster |
937 | about three times faster on decoding, and over forty times faster |
862 | than JSON, even with pretty-printing and key sorting. It also compares |
938 | than JSON, even with pretty-printing and key sorting. It also compares |
863 | favourably to Storable for small amounts of data. |
939 | favourably to Storable for small amounts of data. |
864 | |
940 | |
865 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
941 | Using a longer test string (roughly 18KB, generated from Yahoo! Locals |
866 | search API (http://nanoref.com/yahooapis/mgPdGg): |
942 | search API (http://nanoref.com/yahooapis/mgPdGg): |
867 | |
943 | |
868 | module | encode | decode | |
944 | module | encode | decode | |
869 | -----------|------------|------------| |
945 | -----------|------------|------------| |
870 | JSON | 55.260 | 34.971 | |
946 | JSON 1.x | 55.260 | 34.971 | |
871 | JSON::DWIW | 825.228 | 1082.513 | |
947 | JSON::DWIW | 825.228 | 1082.513 | |
872 | JSON::PC | 3571.444 | 2394.829 | |
948 | JSON::PC | 3571.444 | 2394.829 | |
873 | JSON::PP | 210.987 | 32.574 | |
949 | JSON::PP | 210.987 | 32.574 | |
874 | JSON::Syck | 552.551 | 787.544 | |
950 | JSON::Syck | 552.551 | 787.544 | |
875 | JSON::XS | 5780.463 | 4854.519 | |
951 | JSON::XS | 5780.463 | 4854.519 | |
… | |
… | |
879 | -----------+------------+------------+ |
955 | -----------+------------+------------+ |
880 | |
956 | |
881 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
957 | Again, JSON::XS leads by far (except for Storable which non-surprisingly |
882 | decodes faster). |
958 | decodes faster). |
883 | |
959 | |
884 | On large strings containing lots of high unicode characters, some modules |
960 | On large strings containing lots of high Unicode characters, some modules |
885 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
961 | (such as JSON::PC) seem to decode faster than JSON::XS, but the result |
886 | will be broken due to missing (or wrong) unicode handling. Others refuse |
962 | will be broken due to missing (or wrong) Unicode handling. Others refuse |
887 | to decode or encode properly, so it was impossible to prepare a fair |
963 | to decode or encode properly, so it was impossible to prepare a fair |
888 | comparison table for that case. |
964 | comparison table for that case. |
889 | |
965 | |
890 | |
966 | |
891 | =head1 SECURITY CONSIDERATIONS |
967 | =head1 SECURITY CONSIDERATIONS |
… | |
… | |
897 | any buffer overflows. Obviously, this module should ensure that and I am |
973 | any buffer overflows. Obviously, this module should ensure that and I am |
898 | trying hard on making that true, but you never know. |
974 | trying hard on making that true, but you never know. |
899 | |
975 | |
900 | Second, you need to avoid resource-starving attacks. That means you should |
976 | Second, you need to avoid resource-starving attacks. That means you should |
901 | limit the size of JSON texts you accept, or make sure then when your |
977 | limit the size of JSON texts you accept, or make sure then when your |
902 | resources run out, thats just fine (e.g. by using a separate process that |
978 | resources run out, that's just fine (e.g. by using a separate process that |
903 | can crash safely). The size of a JSON text in octets or characters is |
979 | can crash safely). The size of a JSON text in octets or characters is |
904 | usually a good indication of the size of the resources required to decode |
980 | usually a good indication of the size of the resources required to decode |
905 | it into a Perl structure. While JSON::XS can check the size of the JSON |
981 | it into a Perl structure. While JSON::XS can check the size of the JSON |
906 | text, it might be too late when you already have it in memory, so you |
982 | text, it might be too late when you already have it in memory, so you |
907 | might want to check the size before you accept the string. |
983 | might want to check the size before you accept the string. |
… | |
… | |
918 | And last but least, something else could bomb you that I forgot to think |
994 | And last but least, something else could bomb you that I forgot to think |
919 | of. In that case, you get to keep the pieces. I am always open for hints, |
995 | of. In that case, you get to keep the pieces. I am always open for hints, |
920 | though... |
996 | though... |
921 | |
997 | |
922 | If you are using JSON::XS to return packets to consumption |
998 | If you are using JSON::XS to return packets to consumption |
923 | by javascript scripts in a browser you should have a look at |
999 | by JavaScript scripts in a browser you should have a look at |
924 | L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether |
1000 | L<http://jpsykes.com/47/practical-csrf-and-json-security> to see whether |
925 | you are vulnerable to some common attack vectors (which really are browser |
1001 | you are vulnerable to some common attack vectors (which really are browser |
926 | design bugs, but it is still you who will have to deal with it, as major |
1002 | design bugs, but it is still you who will have to deal with it, as major |
927 | browser developers care only for features, not about doing security |
1003 | browser developers care only for features, not about doing security |
928 | right). |
1004 | right). |
929 | |
1005 | |
930 | |
1006 | |
|
|
1007 | =head1 THREADS |
|
|
1008 | |
|
|
1009 | This module is I<not> guaranteed to be thread safe and there are no |
|
|
1010 | plans to change this until Perl gets thread support (as opposed to the |
|
|
1011 | horribly slow so-called "threads" which are simply slow and bloated |
|
|
1012 | process simulations - use fork, its I<much> faster, cheaper, better). |
|
|
1013 | |
|
|
1014 | (It might actually work, but you have been warned). |
|
|
1015 | |
|
|
1016 | |
931 | =head1 BUGS |
1017 | =head1 BUGS |
932 | |
1018 | |
933 | While the goal of this module is to be correct, that unfortunately does |
1019 | While the goal of this module is to be correct, that unfortunately does |
934 | not mean its bug-free, only that I think its design is bug-free. It is |
1020 | not mean its bug-free, only that I think its design is bug-free. It is |
935 | still relatively early in its development. If you keep reporting bugs they |
1021 | still relatively early in its development. If you keep reporting bugs they |
936 | will be fixed swiftly, though. |
1022 | will be fixed swiftly, though. |
|
|
1023 | |
|
|
1024 | Please refrain from using rt.cpan.org or any other bug reporting |
|
|
1025 | service. I put the contact address into my modules for a reason. |
937 | |
1026 | |
938 | =cut |
1027 | =cut |
939 | |
1028 | |
940 | our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" }; |
1029 | our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" }; |
941 | our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" }; |
1030 | our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" }; |