how to check json data is correct or not in php code example

Example: php is json

function is_json($input_line) {
    if(is_string($input_line)){
        preg_match('/^\{(\s+|\n+)*(\"(.*)(\n+|\s+)*)*\}$|^\[(\s+|\n+)*\{(\s+|\n+)*(\"(.*)(\n+|\s+)*)*\}(\s+|\n)*\]$/', $input_line, $output_array);
        if (  isset($output_array) || !empty($output_array)) {
            return true;
        }
    }
    return false;
    }