[PHP8.3] 能够判断JSON是否正确

json_validate(string $json, int $depth = 512, int $flags = 0): bool

var_dump(json_validate('{ "test": { "foo": "bar" } }'));

var_dump(json_validate('{ "": "": "" } }'));

class JsonValidator extends ConstraintValidator

public function validateJson($attribute, $value)
{
    if (is_array($value)) {
        return false;
    }

    if (! is_scalar($value) && ! is_null($value) && ! method_exists($value, '__toString')) {
        return false;
    }

    json_decode($value);

    return json_last_error() === JSON_ERROR_NONE;
}

protected function isValidJsonValue($value)
{
    if (in_array($value, ['null', 'false', '0', '""', '[]'])
        || (json_decode($value) !== null && json_last_error() === JSON_ERROR_NONE)
    ) {
        return true;
    }
    //JSON last error reset
    json_encode([]);
    return false;
}

    public static function validateJson($value, $params)
    {
        return (bool) (@json_decode($value));
    }

final class Json extends AbstractRule
{
    /**
     * {@inheritDoc}
     */
    public function validate($input): bool
    {
        if (!is_string($input) || $input === '') {
            return false;
        }
 
        json_decode($input);
 
        return json_last_error() === JSON_ERROR_NONE;
    }
}

public static function isJson($string)
{
    json_decode($string);

    return json_last_error() == JSON_ERROR_NONE;
}

function is_json( $argument, $ignore_scalars = true ) {
    if ( ! is_string( $argument ) || '' === $argument ) {
        return false;
    }
 
    if ( $ignore_scalars && ! in_array( $argument[0], [ '{', '[' ], true ) ) {
        return false;
    }
 
    json_decode( $argument, $assoc = true );
 
    return json_last_error() === JSON_ERROR_NONE;
}

if (is_string($value)) {
    json_decode($value); //<------ HERE
 
    // Check if value is a valid JSON string.
    if ($value !== '' && json_last_error() !== JSON_ERROR_NONE) {
        /**
         * If the value is not empty and is not a valid JSON string,
         * it is most likely a custom field created in Joomla 3 and
         * the value is a string that contains the file name.
        */
        if (is_file(JPATH_ROOT . '/' . $value)) {
            $value = '{"imagefile":"' . $value . '","alt_text":""}';
        } else {
            $value = '';
        }
    }