/
json-encode.xml
436 lines (412 loc) · 11.5 KB
/
json-encode.xml
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<refentry xml:id="function.json-encode" xmlns="http://docbook.org/ns/docbook">
<refnamediv>
<refname>json_encode</refname>
<refpurpose>Returns the JSON representation of a value</refpurpose>
</refnamediv>
<refsect1 role="description">
&reftitle.description;
<methodsynopsis>
<type>string</type><methodname>json_encode</methodname>
<methodparam><type>mixed</type><parameter>value</parameter></methodparam>
<methodparam choice="opt"><type>int</type><parameter>options</parameter><initializer>0</initializer></methodparam>
<methodparam choice="opt"><type>int</type><parameter>depth</parameter><initializer>512</initializer></methodparam>
</methodsynopsis>
<para>
Returns a string containing the JSON representation of the supplied
<parameter>value</parameter>.
</para>
<para>
The encoding is affected by the supplied <parameter>options</parameter>
and additionally the encoding of float values depends on the value of
<link linkend="ini.serialize-precision">serialize_precision</link>.
</para>
</refsect1>
<refsect1 role="parameters">
&reftitle.parameters;
<para>
<variablelist>
<varlistentry>
<term><parameter>value</parameter></term>
<listitem>
<para>
The <parameter>value</parameter> being encoded. Can be any type except
a <type>resource</type>.
</para>
<para>
All string data must be UTF-8 encoded.
</para>
&json.implementation.superset;
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>options</parameter></term>
<listitem>
<para>
Bitmask consisting of <constant>JSON_HEX_QUOT</constant>,
<constant>JSON_HEX_TAG</constant>,
<constant>JSON_HEX_AMP</constant>,
<constant>JSON_HEX_APOS</constant>,
<constant>JSON_NUMERIC_CHECK</constant>,
<constant>JSON_PRETTY_PRINT</constant>,
<constant>JSON_UNESCAPED_SLASHES</constant>,
<constant>JSON_FORCE_OBJECT</constant>,
<constant>JSON_PRESERVE_ZERO_FRACTION</constant>,
<constant>JSON_UNESCAPED_UNICODE</constant>,
<constant>JSON_PARTIAL_OUTPUT_ON_ERROR</constant>. The behaviour of these
constants is described on the
<link linkend="json.constants">JSON constants</link> page.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>depth</parameter></term>
<listitem>
<para>
Set the maximum depth. Must be greater than zero.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1 role="returnvalues">
&reftitle.returnvalues;
<para>
Returns a JSON encoded <type>string</type> on success &return.falseforfailure;.
</para>
</refsect1>
<refsect1 role="changelog">
&reftitle.changelog;
<para>
<informaltable>
<tgroup cols="2">
<thead>
<row>
<entry>&Version;</entry>
<entry>&Description;</entry>
</row>
</thead>
<tbody>
<row>
<entry>7.1.0</entry>
<entry>
<link linkend="ini.serialize-precision">serialize_precision</link> is
used instead of <link linkend="ini.precision">precision</link> when
encoding double values.
</entry>
</row>
<row>
<entry>5.6.6</entry>
<entry>
<constant>JSON_PRESERVE_ZERO_FRACTION</constant>
<parameter>option</parameter> was added.
</entry>
</row>
<row>
<entry>5.5.0</entry>
<entry>
<parameter>depth</parameter> parameter was added.
</entry>
</row>
<row>
<entry>5.5.0</entry>
<entry>
<constant>JSON_PARTIAL_OUTPUT_ON_ERROR</constant> option was added.
</entry>
</row>
<row>
<entry>5.5.0</entry>
<entry>
The return value on failure was changed from <literal>null</literal>
string to &false;.
</entry>
</row>
<row>
<entry>5.4.0</entry>
<entry>
<constant>JSON_PRETTY_PRINT</constant>,
<constant>JSON_UNESCAPED_SLASHES</constant>, and
<constant>JSON_UNESCAPED_UNICODE</constant>
<parameter>options</parameter> were added.
</entry>
</row>
<row>
<entry>5.3.3</entry>
<entry>
<constant>JSON_NUMERIC_CHECK</constant> <parameter>option</parameter> was added.
</entry>
</row>
<row>
<entry>5.3.0</entry>
<entry>
The <parameter>options</parameter> parameter was added.
</entry>
</row>
</tbody>
</tgroup>
</informaltable>
</para>
</refsect1>
<refsect1 role="examples">
&reftitle.examples;
<para>
<example>
<title>A <function>json_encode</function> example</title>
<programlisting role="php">
<![CDATA[
<?php
$arr = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 4, 'e' => 5);
echo json_encode($arr);
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
{"a":1,"b":2,"c":3,"d":4,"e":5}
]]>
</screen>
</example>
<example>
<title>
A <function>json_encode</function> example showing some options in use
</title>
<programlisting role="php">
<![CDATA[
<?php
$a = array('<foo>',"'bar'",'"baz"','&blong&', "\xc3\xa9");
echo "Normal: ", json_encode($a), "\n";
echo "Tags: ", json_encode($a, JSON_HEX_TAG), "\n";
echo "Apos: ", json_encode($a, JSON_HEX_APOS), "\n";
echo "Quot: ", json_encode($a, JSON_HEX_QUOT), "\n";
echo "Amp: ", json_encode($a, JSON_HEX_AMP), "\n";
echo "Unicode: ", json_encode($a, JSON_UNESCAPED_UNICODE), "\n";
echo "All: ", json_encode($a, JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_QUOT | JSON_HEX_AMP | JSON_UNESCAPED_UNICODE), "\n\n";
$b = array();
echo "Empty array output as array: ", json_encode($b), "\n";
echo "Empty array output as object: ", json_encode($b, JSON_FORCE_OBJECT), "\n\n";
$c = array(array(1,2,3));
echo "Non-associative array output as array: ", json_encode($c), "\n";
echo "Non-associative array output as object: ", json_encode($c, JSON_FORCE_OBJECT), "\n\n";
$d = array('foo' => 'bar', 'baz' => 'long');
echo "Associative array always output as object: ", json_encode($d), "\n";
echo "Associative array always output as object: ", json_encode($d, JSON_FORCE_OBJECT), "\n\n";
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
Normal: ["<foo>","'bar'","\"baz\"","&blong&","\u00e9"]
Tags: ["\u003Cfoo\u003E","'bar'","\"baz\"","&blong&","\u00e9"]
Apos: ["<foo>","\u0027bar\u0027","\"baz\"","&blong&","\u00e9"]
Quot: ["<foo>","'bar'","\u0022baz\u0022","&blong&","\u00e9"]
Amp: ["<foo>","'bar'","\"baz\"","\u0026blong\u0026","\u00e9"]
Unicode: ["<foo>","'bar'","\"baz\"","&blong&","é"]
All: ["\u003Cfoo\u003E","\u0027bar\u0027","\u0022baz\u0022","\u0026blong\u0026","é"]
Empty array output as array: []
Empty array output as object: {}
Non-associative array output as array: [[1,2,3]]
Non-associative array output as object: {"0":{"0":1,"1":2,"2":3}}
Associative array always output as object: {"foo":"bar","baz":"long"}
Associative array always output as object: {"foo":"bar","baz":"long"}
]]>
</screen>
</example>
<example>
<title>JSON_NUMERIC_CHECK option example</title>
<programlisting role="php">
<![CDATA[
<?php
echo "Strings representing numbers automatically turned into numbers".PHP_EOL;
$numbers = array('+123123', '-123123', '1.2e3', '0.00001');
var_dump(
$numbers,
json_encode($numbers, JSON_NUMERIC_CHECK)
);
echo "Strings containing improperly formatted numbers".PHP_EOL;
$strings = array('+a33123456789', 'a123');
var_dump(
$strings,
json_encode($strings, JSON_NUMERIC_CHECK)
);
?>
]]>
</programlisting>
&example.outputs.similar;
<screen>
<![CDATA[
Strings representing numbers automatically turned into numbers
array(4) {
[0]=>
string(7) "+123123"
[1]=>
string(7) "-123123"
[2]=>
string(5) "1.2e3"
[3]=>
string(7) "0.00001"
}
string(28) "[123123,-123123,1200,1.0e-5]"
Strings containing improperly formatted numbers
array(2) {
[0]=>
string(13) "+a33123456789"
[1]=>
string(4) "a123"
}
string(24) "["+a33123456789","a123"]"
]]>
</screen>
</example>
<example>
<title>Sequential versus non-sequential array example</title>
<programlisting role="php">
<![CDATA[
<?php
echo "Sequential array".PHP_EOL;
$sequential = array("foo", "bar", "baz", "blong");
var_dump(
$sequential,
json_encode($sequential)
);
echo PHP_EOL."Non-sequential array".PHP_EOL;
$nonsequential = array(1=>"foo", 2=>"bar", 3=>"baz", 4=>"blong");
var_dump(
$nonsequential,
json_encode($nonsequential)
);
echo PHP_EOL."Sequential array with one key unset".PHP_EOL;
unset($sequential[1]);
var_dump(
$sequential,
json_encode($sequential)
);
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
Sequential array
array(4) {
[0]=>
string(3) "foo"
[1]=>
string(3) "bar"
[2]=>
string(3) "baz"
[3]=>
string(5) "blong"
}
string(27) "["foo","bar","baz","blong"]"
Non-sequential array
array(4) {
[1]=>
string(3) "foo"
[2]=>
string(3) "bar"
[3]=>
string(3) "baz"
[4]=>
string(5) "blong"
}
string(43) "{"1":"foo","2":"bar","3":"baz","4":"blong"}"
Sequential array with one key unset
array(3) {
[0]=>
string(3) "foo"
[2]=>
string(3) "baz"
[3]=>
string(5) "blong"
}
string(33) "{"0":"foo","2":"baz","3":"blong"}"
]]>
</screen>
</example>
<example>
<title><constant>JSON_PRESERVE_ZERO_FRACTION</constant> option example</title>
<programlisting role="php">
<![CDATA[
<?php
var_dump(json_encode(12.0, JSON_PRESERVE_ZERO_FRACTION));
var_dump(json_encode(12.0));
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
string(4) "12.0"
string(2) "12"
]]>
</screen>
</example>
</para>
</refsect1>
<refsect1 role="notes">
&reftitle.notes;
<note>
<para>
In the event of a failure to encode, <function>json_last_error</function>
can be used to determine the exact nature of the error.
</para>
</note>
<note>
<para>
When encoding an array, if the keys are not a continuous numeric
sequence starting from 0, all keys are encoded as strings, and
specified explicitly for each key-value pair.
</para>
</note>
<note>
<para>
Like the reference JSON encoder, <function>json_encode</function> will
generate JSON that is a simple value (that is, neither an object nor an
array) if given a <type>string</type>, <type>integer</type>,
<type>float</type> or <type>boolean</type> as an input
<parameter>value</parameter>. While most decoders will accept these values
as valid JSON, some may not, as the specification is ambiguous on this
point.
</para>
<para>
To summarise, always test that your JSON decoder can handle the output you
generate from <function>json_encode</function>.
</para>
</note>
</refsect1>
<refsect1 role="seealso">
&reftitle.seealso;
<para>
<simplelist>
<member><interfacename>JsonSerializable</interfacename></member>
<member><function>json_decode</function></member>
<member><function>json_last_error</function></member>
<member><function>serialize</function></member>
</simplelist>
</para>
</refsect1>
</refentry>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
indent-tabs-mode:nil
sgml-parent-document:nil
sgml-default-dtd-file:"~/.phpdoc/manual.ced"
sgml-exposed-tags:nil
sgml-local-catalogs:nil
sgml-local-ecat-files:nil
End:
vim600: syn=xml fen fdm=syntax fdl=2 si
vim: et tw=78 syn=sgml
vi: ts=1 sw=1
-->