json_decode

(PHP 5 >= 5.2.0, PHP 7, PHP 8, PECL json >= 1.2.0)

json_decodeDecodes a JSON string

Descrizione

json_decode(
    string $json,
    ?bool $associative = null,
    int $depth = 512,
    int $flags = 0
): mixed

Takes a JSON encoded string and converts it into a PHP value.

Elenco dei parametri

json

The json string being decoded.

This function only works with UTF-8 encoded strings.

Nota:

PHP implements a superset of JSON as specified in the original » RFC 7159.

associative

When true, JSON objects will be returned as associative arrays; when false, JSON objects will be returned as objects. When null, JSON objects will be returned as associative arrays or objects depending on whether JSON_OBJECT_AS_ARRAY is set in the flags.

depth

Maximum nesting depth of the structure being decoded. The value must be greater than 0, and less than or equal to 2147483647.

flags

Bitmask of JSON_BIGINT_AS_STRING, JSON_INVALID_UTF8_IGNORE, JSON_INVALID_UTF8_SUBSTITUTE, JSON_OBJECT_AS_ARRAY, JSON_THROW_ON_ERROR. The behaviour of these constants is described on the JSON constants page.

Valori restituiti

Returns the value encoded in json as an appropriate PHP type. Unquoted 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 nesting limit.

Errori/Eccezioni

If depth is outside the allowed range, a ValueError is thrown as of PHP 8.0.0, while previously, an error of level E_WARNING was raised.

Log delle modifiche

Versione Descrizione
7.3.0 JSON_THROW_ON_ERROR flags was added.
7.2.0 associative is nullable now.
7.2.0 JSON_INVALID_UTF8_IGNORE, and JSON_INVALID_UTF8_SUBSTITUTE flags were added.
7.1.0 An empty JSON key ("") can be encoded to the empty object property instead of using a key with value _empty_.

Esempi

Example #1 json_decode() examples

<?php
$json
= '{"a":1,"b":2,"c":3,"d":4,"e":5}';

var_dump(json_decode($json));
var_dump(json_decode($json, true));

?>

Il precedente esempio visualizzerĂ :

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()

<?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 some data with a maximum depth of 4 (array -> array -> array -> string)
$json = json_encode(
array(
1 => array(
'English' => array(
'One',
'January'
),
'French' => array(
'Une',
'Janvier'
)
)
)
);

// Show the errors for different depths.
var_dump(json_decode($json, true, 4));
echo
'Last error: ', json_last_error_msg(), PHP_EOL, PHP_EOL;

var_dump(json_decode($json, true, 3));
echo
'Last error: ', json_last_error_msg(), PHP_EOL, PHP_EOL;
?>

Il precedente esempio visualizzerĂ :

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: No error

NULL
Last error: Maximum stack depth exceeded

Example #5 json_decode() of large integers

<?php
$json
= '{"number": 12345678901234567890}';

var_dump(json_decode($json));
var_dump(json_decode($json, false, 512, JSON_BIGINT_AS_STRING));

?>

Il precedente esempio visualizzerĂ :

object(stdClass)#1 (1) {
  ["number"]=>
  float(1.2345678901235E+19)
}
object(stdClass)#1 (1) {
  ["number"]=>
  string(20) "12345678901234567890"
}

Note

Nota:

The JSON spec is not JavaScript, but a subset of JavaScript.

Nota:

In the event of a failure to decode, json_last_error() can be used to determine the exact nature of the error.

Vedere anche:

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User Contributed Notes 4 notes

up
1
Alien426
2 years ago
Browsers don't choke on integers _starting_ with BigInt (64 bits), but before that (53 bits). The introduction of BigInt to modern browsers doesn't help much, when JSON handling functions do not support it. So I am trying to remedy that. My approach is to handle the decoded array before re-encoding it to a string:
<?php
function fix_large_int(&$value)
{
  if (
is_int($value) && $value > 9007199254740991)
   
$value = strval($value);
}
$json_str = '{"id":[1234567890123456789,12345678901234567890]}';
$json_arr = json_decode($json_str, flags: JSON_BIGINT_AS_STRING | JSON_OBJECT_AS_ARRAY);
echo(
json_encode($json_arr)); // {"id":[1234567890123456789,"12345678901234567890"]} (BigInt is already converted to a string here)
array_walk_recursive($json_arr, 'fix_large_int');
echo(
json_encode($json_arr)); // {"id":["1234567890123456789","12345678901234567890"]}
?>
up
0
greaties at ghvernuft dot nl
2 years ago
To load an object with data in json format:

function loadJSON($Obj, $json)
{
    $dcod = json_decode($json);
    $prop = get_object_vars ( $dcod );
    foreach($prop as $key => $lock)
    {
        if(property_exists ( $Obj ,  $key ))
        {
            if(is_object($dcod->$key))
            {
                loadJSON($Obj->$key, json_encode($dcod->$key));
            }
            else
            {
                $Obj->$key = $dcod->$key;
            }
        }
    }
}
up
0
cubefox at web dot NOSPAMPLEASE dot de
3 years ago
Warning: As the section "return values" mentions, the return value NULL is ambiguos. To repeat, it can mean three things:

* The input string had the value "null"
* There was an error while parsing the input data
* The encoded data was deeper than the recursion limit

To distinguish these cases, json_last_error() can be used.
up
-7
mattia
3 years ago
if you're using ajax to post, and your JavaScript code looks like this:

<code>
    var xhttp = new XMLHttpRequest();
    xhttp.open("POST", "something.php", true);
    xhttp.setRequestHeader("Content-Type", "application/json");
    xhttp.onreadystatechange = function() {
        if (this.readyState == 4 && this.status == 200) {
             // do something
        }
    };
    var data = {some: "thing"};
    xhttp.send(JSON.stringify(data));
</code>

then in <code>something.php</code> you can retrieve your json by doing

<?php
$data
= json_decode(file_get_contents("php://input"), true);
?>
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