Replace Signature in PDF in Python SDK

    import shutil
    import json
    import logging
    from pathlib import Path
    from asposepdfcloud import ApiClient, PdfApi, Signature, SignatureType, SignatureField, Rectangle

    # Configure logging
    logging.basicConfig(level=logging.INFO, format="%(asctime)s - %(levelname)s - %(message)s")


    class Config:
        """Configuration parameters."""
        CREDENTIALS_FILE = Path(r".../../../credentials.json")
        LOCAL_FOLDER = Path(r"C:\Samples")
        PDF_DOCUMENT_NAME = "sample.pdf"
        LOCAL_RESULT_DOCUMENT_NAME = "output_sample.pdf"
        LOCAL_SIGNATURE_PATH = Path(r"C:\Samples\Signatures\3")
        SIGNATURE_PFX = "signature.pfx"
        SIGNATURE_FORM_FIELD = 'Signature_1'
        SIGNATURE_PASSWORD='Password'
        SIGNATURE_CONTACT='Contact'
        SIGNATURE_LOCATION='Location'
        SIGNATURE_AUTHORITY='Issuer'
        SIGNATURE_DATE='04/19/2025 12:15:00.000 PM'
        SIGNATURE_RECT = Rectangle(100, 100, 500, 500)


    class PdfSignatures:
        """Class for managing PDF signatures using Aspose PDF Cloud API."""
        def __init__(self, credentials_file: Path = Config.CREDENTIALS_FILE):
            self.pdf_api = None
            self._init_api(credentials_file)

        def _init_api(self, credentials_file: Path):
            """Initialize the API client."""
            try:
                with credentials_file.open("r", encoding="utf-8") as file:
                    credentials = json.load(file)
                    api_key, app_id = credentials.get("key"), credentials.get("id")
                    if not api_key or not app_id:
                        raise ValueError("init_api(): Error: Missing API keys in the credentials file.")
                    self.pdf_api = PdfApi(ApiClient(api_key, app_id))
            except (FileNotFoundError, json.JSONDecodeError, ValueError) as e:
                logging.error(f"init_api(): Failed to load credentials: {e}")

        def upload_file(self, local_path: Path, fileName: str):
            """ Upload a local fileName to the Aspose Cloud server. """
            if self.pdf_api:
                file_path = local_path / fileName
                try:
                    self.pdf_api.upload_file(fileName, str(file_path))
                    logging.info(f"upload_file(): File '{fileName}' uploaded successfully.")
                except Exception as e:
                    logging.error(f"upload_document(): Failed to upload file: {e}")

        def upload_document(self):
            """ Upload a PDF document to the Aspose Cloud server. """
            self.upload_file(Config.LOCAL_FOLDER, Config.PDF_DOCUMENT_NAME)


        def download_result(self):
            """Download the processed PDF document from the Aspose Cloud server."""
            if self.pdf_api:
                try:
                    temp_file = self.pdf_api.download_file(Config.PDF_DOCUMENT_NAME)
                    local_path = Config.LOCAL_FOLDER / Config.LOCAL_RESULT_DOCUMENT_NAME
                    shutil.move(temp_file, str(local_path))
                    logging.info(f"download_result(): File successfully downloaded: {local_path}")
                except Exception as e:
                    logging.error(f"download_result(): Failed to download file: {e}")

        def replace_signature(self):
            """Append a new signature to the PDF document."""
            if self.pdf_api:
                
                signature = Signature(
                    signature_path=Config.SIGNATURE_PFX,
                    signature_type=SignatureType.PKCS7,
                    password=Config.SIGNATURE_PASSWORD,
                    contact=Config.SIGNATURE_CONTACT,
                    location=Config.SIGNATURE_LOCATION,
                    visible=True,
                    rectangle=Config.SIGNATURE_RECT,
                    form_field_name=Config.SIGNATURE_FORM_FIELD,
                    authority=Config.SIGNATURE_AUTHORITY,
                    date=Config.SIGNATURE_DATE,
                    show_properties=False)
                
                field = SignatureField(page_index=1)
                field.signature = signature
                field.partial_name = 'sign1'
                field.rect = Config.SIGNATURE_RECT

                try:
                    response = self.pdf_api.put_signature_field(Config.PDF_DOCUMENT_NAME, Config.SIGNATURE_FORM_FIELD, field)
                    if response.code == 200:
                        logging.info(f"append_signature(): Signature '{Config.SIGNATURE_CONTACT}' successfully added to the document.")
                    else:
                        logging.error(f"append_signature(): Failed to add signature to the document. Response code: {response.code}")
                except Exception as e:
                    logging.error(f"append_signature(): Error while adding signature: {e}")


    if __name__ == "__main__":
        pdf_sign = PdfSignatures()
        pdf_sign.upload_document()
        pdf_sign.upload_file(Config.LOCAL_SIGNATURE_PATH, Config.SIGNATURE_PFX)
        pdf_sign.replace_signature()
        pdf_sign.download_result()