Source code for file.sign.swisscom_ais

from __future__ import annotations

import io
import os

from AIS import AIS, PDF
from contextlib import suppress
from onegov.file.sign.generic import SigningService


from typing import TYPE_CHECKING
if TYPE_CHECKING:
    from _typeshed import SupportsRead, SupportsWrite




class SwisscomAIS(SigningService, service_name='swisscom_ais'):
    """ Sign PDFs using Swisscom's All-In Signing Service. """

    def __init__(
        self,
        customer: str,
        key_static: str,
        cert_file: str,
        cert_key: str
    ):
        if not os.path.exists(cert_file):
            raise FileNotFoundError(cert_file)

        if not os.path.exists(cert_key):
            raise FileNotFoundError(cert_key)

        cert_file = os.path.abspath(cert_file)
        cert_key = os.path.abspath(cert_key)



        self.customer = customer



        self.client = AIS(customer, key_static, cert_file, cert_key)




    def sign(
        self,
        infile: SupportsRead[bytes],
        outfile: SupportsWrite[bytes]
    ) -> str:

        if hasattr(infile, 'seek'):
            with suppress(io.UnsupportedOperation):
                infile.seek(0)

        # NOTE: We gain nothing from a chunked read, since we need to
        #       keep the entire file in memory anyways.
        inout_stream = io.BytesIO(infile.read())

        pdf = PDF(inout_stream=inout_stream)
        self.client.sign_one_pdf(pdf)

        # NOTE: Same with the chunked write, the file is already in memory
        outfile.write(inout_stream.getvalue())

        return f'swisscom_ais/{self.customer}/{self.client.last_request_id}'