src/OAuth/Services/OAuthService.php
private function buildRequestHeaders($body)
    {
        $credentials = $this->getConfig('credentials');
        $appId = $credentials->getAppId();
        $certId = $credentials->getCertId();

        $headers = [];

        $headers['Accept'] = 'application/json';
        $headers['Authorization'] = 'Basic '.base64_encode($appId.':'.$certId);
        $headers['Content-Type'] = 'application/x-www-form-urlencoded';
        $headers['Content-Length'] = strlen($body);

        return $headers;
    }
private function buildRequestHeaders($body)
    {
        $credentials = $this->getConfig('credentials');
        $appId = $credentials->getAppId();
        $certId = $credentials->getCertId();

        $headers = [];

        $headers['Accept'] = 'application/json';
        $headers['Authorization'] = 'Basic '.base64_encode($appId.':'.$certId);
        $headers['Content-Type'] = 'application/x-www-form-urlencoded';
        $headers['Content-Length'] = strlen($body);

        return $headers;
    }
Helper function that builds the HTTP request headers.

@param string $body The request body.

@return array An associative array of HTTP headers.