JSON_DECODE(3) 1 JSON_DECODE(3)
json_decode - Decodes a JSON string
SYNOPSIS
mixed json_decode (string $json, [bool $assoc = false], [int $depth = 512], [int $options])
DESCRIPTION
Takes a JSON encoded string and converts it into a PHP variable.
PARAMETERS
o $json
- The $json string being decoded. This function only works with UTF-8 encoded strings.
Note
PHP implements a superset of JSON as specified in the original RFC 4627 - it will also encode and decode scalar types and
NULL. RFC 4627 only supports these values when they are nested inside an array or an object.
Although this superset is consistent with the expanded definition of "JSON text" in the newer RFC 7159 (which aims to super-
sede RFC 4627) and ECMA-404, this may cause interoperability issues with older JSON parsers that adhere strictly to RFC 4627
when encoding a single scalar value.
o $assoc
- When TRUE, returned objects will be converted into associative arrays.
o $depth
- User specified recursion depth.
o $options
- Bitmask of JSON decode options. Currently only JSON_BIGINT_AS_STRING is supported (default is to cast large integers as floats)
RETURN VALUES
Returns the value encoded in $json in appropriate PHP type. Values true, false and null are returned as TRUE, FALSE and NULL respectively.
NULL is returned if the $json cannot be decoded or if the encoded data is deeper than the recursion limit.
EXAMPLES
Example #1
json_decode(3) examples
<?php
$json = '{"a":1,"b":2,"c":3,"d":4,"e":5}';
var_dump(json_decode($json));
var_dump(json_decode($json, true));
?>
The above example will output:
object(stdClass)#1(5) {
["a"] => int(1)
["b"] => int(2)
["c"] => int(3)
["d"] => int(4)
["e"] => int(5)
}
array(5) {
["a"] => int(1)
["b"] => int(2)
["c"] => int(3)
["d"] => int(4)
["e"] => int(5)
}
Example #2
Accessing invalid object properties
Accessing elements within an object that contain characters not permitted under PHP's naming convention (e.g. the hyphen) can be
accomplished by encapsulating the element name within braces and the apostrophe.
<?php
$json = '{"foo-bar": 12345}';
$obj = json_decode($json);
print $obj->{'foo-bar'}; // 12345
?>
Example #3
common mistakes using json_decode(3)
<?php
// the following strings are valid JavaScript but not valid JSON
// the name and value must be enclosed in double quotes
// single quotes are not valid
$bad_json = "{ 'bar': 'baz' }";
json_decode($bad_json); // null
// the name must be enclosed in double quotes
$bad_json = '{ bar: "baz" }';
json_decode($bad_json); // null
// trailing commas are not allowed
$bad_json = '{ bar: "baz", }';
json_decode($bad_json); // null
?>
Example #4
$depth errors
<?php
// Encode the data.
$json = json_encode(
array(
1 => array(
'English' => array(
'One',
'January'
),
'French' => array(
'Une',
'Janvier'
)
)
)
);
// Define the errors.
$constants = get_defined_constants(true);
$json_errors = array();
foreach ($constants["json"] as $name => $value) {
if (!strncmp($name, "JSON_ERROR_", 11)) {
$json_errors[$value] = $name;
}
}
// Show the errors for different depths.
foreach (range(4, 3, -1) as $depth) {
var_dump(json_decode($json, true, $depth));
echo 'Last error: ', $json_errors[json_last_error()], PHP_EOL, PHP_EOL;
}
?>
The above example will output:
array(1) {
[1]=>
array(2) {
["English"]=>
array(2) {
[0]=>
string(3) "One"
[1]=>
string(7) "January"
}
["French"]=>
array(2) {
[0]=>
string(3) "Une"
[1]=>
string(7) "Janvier"
}
}
}
Last error: JSON_ERROR_NONE
NULL
Last error: JSON_ERROR_DEPTH
Example #5
json_decode(3) of large integers
<?php
$json = '{"number": 12345678901234567890}';
var_dump(json_decode($json));
var_dump(json_decode($json, false, 512, JSON_BIGINT_AS_STRING));
?>
The above example will output:
object(stdClass)#1(1) {
["number"]=>
float(1.2345678901235E+19)
}
object(stdClass)#1(1) {
["number"]=>
string(20) "12345678901234567890"
}
NOTES
Note
The JSON spec is not JavaScript, but a subset of JavaScript.
Note
In the event of a failure to decode, json_last_error(3) can be used to determine the exact nature of the error.
CHANGELOG
+--------+---------------------------------------------------+
|Version | |
| | |
| | Description |
| | |
+--------+---------------------------------------------------+
| 5.6.0 | |
| | |
| | Invalid non-lowercased variants of the true, |
| | false and null literals are no longer accepted as |
| | valid input, and will generate warnings. |
| | |
| 5.4.0 | |
| | |
| | The $options parameter was added. |
| | |
| 5.3.0 | |
| | |
| | Added the optional $depth. The default recursion |
| | depth was increased from 128 to 512 |
| | |
| 5.2.3 | |
| | |
| | The nesting limit was increased from 20 to 128 |
| | |
| 5.2.1 | |
| | |
| | Added support for JSON decoding of basic types. |
| | |
+--------+---------------------------------------------------+
SEE ALSO
json_encode(3), json_last_error(3).
PHP Documentation Group JSON_DECODE(3)