json_decode

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

    json_decode — Decodes a JSON string

    Description

    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.

    Parameters

    json

    The jsonstring being decoded.

    This function only works with UTF-8 encoded strings.

    Note:

    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.

    Return Values

    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.

    Errors/Exceptions

    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.

    Changelog

    VersionDescription
    7.3.0JSON_THROW_ON_ERRORflags was added.
    7.2.0associative is nullable now.
    7.2.0JSON_INVALID_UTF8_IGNORE, and JSON_INVALID_UTF8_SUBSTITUTEflags 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_.

    Examples

    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));

    ?>

    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()

    <?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;
    ?>

    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: 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));

    ?>

    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() can be used to determine the exact nature of the error.

    See Also

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