Import OpenSSL Cryptography backend directly.

Author: keosak

flask_fastspring.py

@@ -2,7 +2,6 @@
 import requests
 
 from base64 import b64encode
-from cryptography.hazmat.backends import _available_backends
 from cryptography.hazmat.primitives.ciphers import Cipher
 from cryptography.hazmat.primitives.ciphers.algorithms import AES
 from cryptography.hazmat.primitives.ciphers.modes import ECB
@@ -56,7 +55,8 @@ def init_app(self, app):
             return
         private_key = app.config.get('FASTSPRING_PRIVATE_KEY')
         if private_key is not None:
-            self.openssl = openssl_backend()
+            from cryptography.hazmat.backends.openssl.backend import backend
+            self.openssl = backend
             with open(private_key, 'rb') as fp:
                 self.private_key = load_pem_private_key(
                     fp.read(), password=None, backend=self.openssl)
@@ -219,14 +219,6 @@ def __str__(self):
             self.response.text)
 
 
-def openssl_backend():
-    """Return OpenSSL cryptography backend or fail."""
-    for backend in _available_backends():
-        if backend.name == 'openssl':
-            return backend
-    raise Exception('Could not find OpenSSL cryptography backend')
-
-
 def openssl_private_encrypt(key, data, backend):
     """Encrypt data with RSA private key.