/**
     * Parse\Client::_request, internal method for communicating with Parse.
     *
     * @param string $method        HTTP Method for this request.
     * @param string $relativeUrl   REST API Path.
     * @param null   $sessionToken  Session Token.
     * @param null   $data          Data to provide with the request.
     * @param bool   $useMasterKey  Whether to use the Master Key.
     * @param bool   $appRequest    App request to create or modify a application
     * @param bool   $returnHeaders Returns response headers
     *
     * @throws \Exception
     *
     * @return mixed Result from Parse API Call.
     */
    public static function _request(
        $method,
        $relativeUrl,
        $sessionToken = null,
        $data = null,
        $useMasterKey = false,
        $appRequest = false,
        $returnHeaders = false
    ) {
        if ($data === '[]') {
            $data = '{}';
        }
        if ($appRequest) {
            self::assertAppInitialized();
            $headers = self::_getAppRequestHeaders();
        } else {
            self::assertParseInitialized();
            $headers = self::_getRequestHeaders($sessionToken, $useMasterKey);
        }

        $url = self::$serverURL.'/'.self::$mountPath.ltrim($relativeUrl, '/');
        if ($method === 'GET' && !empty($data)) {
            $url .= '?'.http_build_query($data);
        }
        $rest = curl_init();
        curl_setopt($rest, CURLOPT_URL, $url);
        curl_setopt($rest, CURLOPT_RETURNTRANSFER, 1);
        if ($method === 'POST') {
            $headers[] = 'Content-Type: application/json';
            curl_setopt($rest, CURLOPT_POST, 1);
            curl_setopt($rest, CURLOPT_POSTFIELDS, $data);
        }
        if ($method === 'PUT') {
            $headers[] = 'Content-Type: application/json';
            curl_setopt($rest, CURLOPT_CUSTOMREQUEST, $method);
            curl_setopt($rest, CURLOPT_POSTFIELDS, $data);
        }
        if ($method === 'DELETE') {
            curl_setopt($rest, CURLOPT_CUSTOMREQUEST, $method);
        }
        curl_setopt($rest, CURLOPT_HTTPHEADER, $headers);

        if (!is_null(self::$connectionTimeout)) {
            curl_setopt($rest, CURLOPT_CONNECTTIMEOUT, self::$connectionTimeout);
        }
        if (!is_null(self::$timeout)) {
            curl_setopt($rest, CURLOPT_TIMEOUT, self::$timeout);
        }

        if ($returnHeaders) {
            curl_setopt($rest, CURLOPT_HEADER, 1);
        }

        $response = curl_exec($rest);
        $status = curl_getinfo($rest, CURLINFO_HTTP_CODE);
        $contentType = curl_getinfo($rest, CURLINFO_CONTENT_TYPE);
        if (curl_errno($rest)) {
            if (self::$enableCurlExceptions) {
                throw new ParseException(curl_error($rest), curl_errno($rest));
            } else {
                return false;
            }
        }

        $headerData = [];

        if ($returnHeaders) {
            $headerSize = curl_getinfo($rest, CURLINFO_HEADER_SIZE);
            $headerContent = substr($response, 0, $headerSize);

            $headerData = self::parseCurlHeaders($headerContent);
            $response = substr($response, $headerSize);
        }

        curl_close($rest);
        if (strpos($contentType, 'text/html') !== false) {
            throw new ParseException('Bad Request', -1);
        }

        $decoded = json_decode($response, true);
        if (isset($decoded['error'])) {
            throw new ParseException(
                $decoded['error'],
                isset($decoded['code']) ? $decoded['code'] : 0
            );
        }

        $result = $decoded;

        if ($returnHeaders) {
            $result['_headers'] = $headerData;
        }

        return $result;
    }

    private static function parseCurlHeaders($headerContent)
    {
        $headers = [];
        $exploded = explode("\r\n", $headerContent);
        foreach ($exploded as $i => $line) {
            if (empty($line)) {
                continue;
            } elseif ($i === 0) {
                $headers['http_code'] = $line;
            } else {
                list ($headerName, $headerValue) = explode(': ', $line);
                $headers[$headerName] = $headerValue;
            }
        }

        return $headers;
    }