import contextlib
import OpenSSL.crypto
import os
import requests
import ssl
import tempfile

@contextlib.contextmanager
def pfx_to_pem(pfx_path, pfx_password):
    ''' Decrypts the .pfx file to be used with requests. '''
    with tempfile.NamedTemporaryFile(suffix='.pem') as t_pem:
        f_pem = open(t_pem.name, 'wb')
        pfx = open(pfx_path, 'rb').read()
        p12 = OpenSSL.crypto.load_pkcs12(pfx, pfx_password)
        f_pem.write(OpenSSL.crypto.dump_privatekey(OpenSSL.crypto.FILETYPE_PEM, p12.get_privatekey()))
        f_pem.write(OpenSSL.crypto.dump_certificate(OpenSSL.crypto.FILETYPE_PEM, p12.get_certificate()))
        ca = p12.get_ca_certificates()
        if ca is not None:
            for cert in ca:
                f_pem.write(OpenSSL.crypto.dump_certificate(OpenSSL.crypto.FILETYPE_PEM, cert))
        f_pem.close()
        yield t_pem.name

# HOW TO USE:
# with pfx_to_pem('foo.pem', 'bar') as cert:
#     requests.post(url, cert=cert, data=payload)