Obtener Firma de PDF en PHP SDK

    require __DIR__.'\..\..\vendor\autoload.php';

    use Aspose\PDF\Configuration;
    use Aspose\PDF\Api\PdfApi;

    $config = [
        'LOCAL_FOLDER' => "C:\\Samples\\",
        'PDF_DOCUMENT_NAME' => "sample-signed.pdf",
    ];

    class PdfSignatures {
        private $pdfApi;
        private $config;

        private function _create_rest_api() {
            $credentials = json_decode(file_get_contents("./Credentials/credentials.json"), true);

            $configAuth = new Configuration();
            $configAuth->setAppKey($credentials['key']);
            $configAuth->setAppSid($credentials['id']);

            $this->pdfApi = new PdfApi(null, $configAuth);
        }

        public function __construct($config) {
            $this->config = $config;
            $this->_create_rest_api();
        }

        public function uploadDocument() {
            $filePath = $this->config['LOCAL_FOLDER'] . $this->config['PDF_DOCUMENT_NAME'];
            $fileData = file_get_contents($filePath);

            $this->pdfApi->uploadFile($this->config['PDF_DOCUMENT_NAME'], $fileData);
            echo "File: '{$this->config['PDF_DOCUMENT_NAME']}' successfully uploaded.\n";
        }

        private function _showSignatureFieldsArray($fields): void {
            if (empty($fields->list)) {
                echo "Signature fields are empty!";
            } else {
                foreach ($fields->list as $item) {
                    echo "Signature field ID: '" . $item->signature->contact . "'";
                }
            }
        }

        public function getSignatureFields(): void {
            if ($this->pdfApi) {
                $response = $this->pdfApi->getDocumentSignatureFields($this->config['PDF_DOCUMENT_NAME']);
                if ($response->code === 200) {
                    echo "getSignatureFields(): Signature fields successfully extracted from '" . $this->config['PDF_DOCUMENT_NAME'] . "':";
                    $this->_showSignatureFieldsArray($response->fields);
                } else
                    echo "getSignatureFields(): Failed to extract signatures. Response code: " . $response->code;
            }
        }
    }

    try {
        $signatures = new PdfSignatures($pdfApi, $configParams);
        $signatures->uploadDocument();
        $signatures->getSignatureFields();
    } catch (Exception $e) {
        echo "Error: " . $e->getMessage() . "\n";
    }