PKCS#12 to PEM Converter Context

pkcs12_as_pem.py

class context:
    def __init__(self, pkcs12, password=None, separate_key=False):
        from OpenSSL.crypto import load_pkcs12
        from getpass import getpass
        from os.path import basename
        if not password:
            prompt = '{} Password: '.format(basename(pkcs12))
            password = getpass(prompt)
        with open(pkcs12, 'rb') as f:
            self.__p12 = load_pkcs12(f.read(), password)
        
        self.separate_key = separate_key

    def __enter__(self):
        from OpenSSL.crypto import dump_privatekey, dump_certificate
        from OpenSSL.crypto import FILETYPE_PEM
        from tempfile import NamedTemporaryFile
        
        # Write the Private Key.
        self._key = NamedTemporaryFile(suffix='.pem')
        self._key.write(dump_privatekey(FILETYPE_PEM,
                                        self.__p12.get_privatekey()))
        
        # Write the Cert and CA Chain (if available)
        crt_chain = [self.__p12.get_certificate()]
        if self.__p12.get_ca_certificates():
            crt_chain += list(self.__p12.get_ca_certificates())
        
        if self.separate_key:
            self._cert = NamedTemporaryFile(suffix='.pem')
        else:
            self._cert = self._key
        for crt in crt_chain:
            self._cert.write(dump_certificate(FILETYPE_PEM, crt))

        self._key.file.close()
        self._cert.file.close()
        return (self._cert.name, self._key.name) if self.separate_key else self._key.name

    def __exit__(self, type, value, traceback):
        self._key.close()
        if self.separate_key:
            self._cert.close()
        self._key, self._cert = (None, None)
        
class converter:
    def __init__(self, pkcs12, password=None):
        self.__ctxt = context(pkcs12, password, separate_key=True)
        self.pem_files = self.__ctxt.__enter__()
        
    def __delete__(self):
        self.__ctxt.__exit__()    
    
    def __len__(self):
        return len(self.pem_files)
    
    def __getitem__(self, i):
        return self.pem_files[i]

This is how to use the Context and Converter work...

from pkcs12_as_pem import context as pkcs12_as_pem_ctx
from pkcs12_as_pem import converter as p12_as_pem_conv
from os import path
import gc


p12_filepath="<path to pkcs#12>"


# Context Version
with pkcs12_as_pem_ctx(p12_filepath) as pem_path:
    assert(path.exists(pem_path))
assert(not path.exists(pem_path))


# Object Version
pem = p12_as_pem_conv(p12_filepath)

pem_path = pem.pem_file_path
assert(path.exists(pem_path))
del(pem)

#After GC collection Runs...
gc.collect()
assert(not path.exists(pem_path))