Decode encoded php file

json_decode

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

Parameters

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 7159.

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

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

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

Version Description
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_ .

Examples

Example #1 json_decode() examples

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.

$obj = json_decode ( $json );
print $obj ->< 'foo-bar' >; // 12345

Example #3 common mistakes using json_decode()

// 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

// 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

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

User Contributed Notes 8 notes

JSON can be decoded to PHP arrays by using the $associative = true option. Be wary that associative arrays in PHP can be a «list» or «object» when converted to/from JSON, depending on the keys (of absence of them).

You would expect that recoding and re-encoding will always yield the same JSON string, but take this example:

$json = »;
$array = json_decode($json, true); // decode as associative hash
print json_encode($array) . PHP_EOL;

This will output a different JSON string than the original:

The object has turned into an array!

Similarly, a array that doesn’t have consecutive zero based numerical indexes, will be encoded to a JSON object instead of a list.

$array = [
‘first’,
‘second’,
‘third’,
];
print json_encode($array) . PHP_EOL;
// remove the second element
unset($array[1]);
print json_encode($array) . PHP_EOL;

The array has turned into an object!

In other words, decoding/encoding to/from PHP arrays is not always symmetrical, or might not always return what you expect!

On the other hand, decoding/encoding from/to stdClass objects (the default) is always symmetrical.

Arrays may be somewhat easier to work with/transform than objects. But especially if you need to decode, and re-encode json, it might be prudent to decode to objects and not arrays.

If you want to enforce an array to encode to a JSON list (all array keys will be discarded), use:

If you want to enforce an array to encode to a JSON object, use:

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