json_last_error

    (PHP 5 >= 5.3.0, PHP 7, PHP 8)

    json_last_error — Returns the last error occurred

    Description

    json_last_error(): int

    Returns the last error (if any) occurred during the last JSON encoding/decoding, which did not specify JSON_THROW_ON_ERROR.

    Parameters

    This function has no parameters.

    Return Values

    Returns an integer, the value can be one of the following constants:

    JSON error codes
    ConstantMeaningAvailability
    JSON_ERROR_NONENo error has occurred 
    JSON_ERROR_DEPTHThe maximum stack depth has been exceeded 
    JSON_ERROR_STATE_MISMATCHInvalid or malformed JSON 
    JSON_ERROR_CTRL_CHARControl character error, possibly incorrectly encoded 
    JSON_ERROR_SYNTAXSyntax error 
    JSON_ERROR_UTF8Malformed UTF-8 characters, possibly incorrectly encoded 
    JSON_ERROR_RECURSIONOne or more recursive references in the value to be encoded 
    JSON_ERROR_INF_OR_NAN One or more NAN or INF values in the value to be encoded  
    JSON_ERROR_UNSUPPORTED_TYPEA value of a type that cannot be encoded was given 
    JSON_ERROR_INVALID_PROPERTY_NAMEA property name that cannot be encoded was given 
    JSON_ERROR_UTF16Malformed UTF-16 characters, possibly incorrectly encoded 

    Examples

    Example #1 json_last_error() example

    <?php
    // A valid json string
    $json[] = '{"Organization": "PHP Documentation Team"}';

    // An invalid json string which will cause an syntax
    // error, in this case we used ' instead of " for quotation
    $json[] = "{'Organization': 'PHP Documentation Team'}";


    foreach (    $json as $string) {
    echo     'Decoding: ' . $string;
    json_decode($string);

    switch (    json_last_error()) {
    case     JSON_ERROR_NONE:
    echo     ' - No errors';
    break;
    case     JSON_ERROR_DEPTH:
    echo     ' - Maximum stack depth exceeded';
    break;
    case     JSON_ERROR_STATE_MISMATCH:
    echo     ' - Underflow or the modes mismatch';
    break;
    case     JSON_ERROR_CTRL_CHAR:
    echo     ' - Unexpected control character found';
    break;
    case     JSON_ERROR_SYNTAX:
    echo     ' - Syntax error, malformed JSON';
    break;
    case     JSON_ERROR_UTF8:
    echo     ' - Malformed UTF-8 characters, possibly incorrectly encoded';
    break;
    default:
    echo     ' - Unknown error';
    break;
    }

    echo     PHP_EOL;
    }
    ?>

    The above example will output:

    Decoding: {"Organization": "PHP Documentation Team"} - No errors Decoding: {'Organization': 'PHP Documentation Team'} - Syntax error, malformed JSON

    Example #2 json_last_error() with json_encode()

    <?php
    // An invalid UTF8 sequence
    $text = "\xB1\x31";

    $json = json_encode($text);
    $error = json_last_error();

    var_dump($json, $error === JSON_ERROR_UTF8);
    ?>

    The above example will output:

    string(4) "null" bool(true)

    Example #3 json_last_error() and JSON_THROW_ON_ERROR

    <?php
    // An invalid UTF8 sequence which causes JSON_ERROR_UTF8
    json_encode("\xB1\x31");

    // The following does not cause a JSON error
    json_encode('okay', JSON_THROW_ON_ERROR);

    // The global error state has not been changed by the former json_encode()
    var_dump(json_last_error() === JSON_ERROR_UTF8);
    ?>

    The above example will output:

    bool(true)

    See Also

    To Top