Newscoop\Gimme\Json::indent PHP Method

    public static function indent($json)
    {
        $result = '';
        $pos = 0;
        $strLen = strlen($json);
        $indentStr = '    ';
        $newLine = "\n";
        $prevChar = '';
        $outOfQuotes = true;
        for ($i = 0; $i <= $strLen; $i++) {
            // Grab the next character in the string.
            $char = substr($json, $i, 1);
            // Are we inside a quoted string?
            if ($char == '"' && $prevChar != '\\') {
                $outOfQuotes = !$outOfQuotes;
                // If this character is the end of an element,
                // output a new line and indent the next line.
            } else {
                if (($char == '}' || $char == ']') && $outOfQuotes) {
                    $result .= $newLine;
                    $pos--;
                    for ($j = 0; $j < $pos; $j++) {
                        $result .= $indentStr;
                    }
                }
            }
            // Add the character to the result string.
            $result .= $char;
            // If the last character was the beginning of an element,
            // output a new line and indent the next line.
            if (($char == ',' || $char == '{' || $char == '[') && $outOfQuotes) {
                $result .= $newLine;
                if ($char == '{' || $char == '[') {
                    $pos++;
                }
                for ($j = 0; $j < $pos; $j++) {
                    $result .= $indentStr;
                }
            }
            $prevChar = $char;
        }
        return $result;
    }

 public function onResponse(FilterResponseEvent $event)
 {
     if (HttpKernelInterface::MASTER_REQUEST !== $event->getRequestType()) {
         return;
     }
     $responseData = $event->getResponse()->getContent();
     $formatedJson = Json::indent($responseData);
     $newResponse = new Response($formatedJson);
     $event->setResponse($newResponse);
 }