Merge pull request #2 from AzureAD/client-credential-certificate

Merge as-is for now. More test cases will be added in future.

Author: rayluo

msal/application.py

@@ -1,4 +1,4 @@
-from . import request
+from .client_credential import ClientCredentialRequest
 
 
 class ClientApplication(object):
@@ -35,7 +35,7 @@ def __init__(self, client_id, client_credential, user_token_cache, **kwargs):
         self.app_token_cache = None  # TODO
 
     def acquire_token_for_client(self, scope, policy=''):
-        return request.ClientCredentialRequest(
+        return ClientCredentialRequest(
             client_id=self.client_id, client_credential=self.client_credential,
             scope=scope, policy=policy, authority=self.authority).run()
 

msal/client_credential.py

@@ -0,0 +1,56 @@
+import time
+import binascii
+import base64
+import uuid
+
+import jwt
+
+from .oauth2 import ClientCredentialGrant
+from .request import BaseRequest
+
+
+class ClientCredentialRequest(BaseRequest):
+    def __init__(self, **kwargs):
+        super(ClientCredentialRequest, self).__init__(**kwargs)
+        self.grant = ClientCredentialGrant(
+            self.client_id, token_endpoint=self.token_endpoint)
+
+    def get_token(self):
+        if isinstance(self.client_credential, dict):
+            return self.get_token_by_certificate(
+                self.client_credential['certificate'],
+                self.client_credential['thumbprint'])
+        else:
+            return self.get_token_by_secret(self.client_credential)
+
+    def get_token_by_secret(self, secret):
+        return self.grant.get_token(scope=self.scope, client_secret=secret)
+
+    def get_token_by_certificate(self, pem, thumbprint):
+        JWT_BEARER = 'urn:ietf:params:oauth:client-assertion-type:jwt-bearer'
+        assertion = create_jwt_assertion(
+            pem, thumbprint, self.grant.token_endpoint, self.client_id)
+        return self.grant.get_token(
+            client_assertion_type=JWT_BEARER, client_assertion=assertion,
+            scope=self.scope)
+
+
+def create_jwt_assertion(
+        private_pem, thumbprint, audience, issuer,
+        subject=None,  # If None is specified, the value of issuer will be used
+        not_valid_before=None,  # If None, the current time will be used
+        jwt_id=None):  # If None is specified, a UUID will be generated
+    assert '-----BEGIN PRIVATE KEY-----' in private_pem, "Need a standard PEM"
+    nbf = time.time() if not_valid_before is None else not_valid_before
+    payload = {  # key names are all from JWT standard names
+        'aud': audience,
+        'iss': issuer,
+        'sub': subject or issuer,
+        'nbf': nbf,
+        'exp': nbf + 10*60,  # 10 minutes
+        'jti': str(uuid.uuid4()) if jwt_id is None else jwt_id,
+        }
+    # Per http://self-issued.info/docs/draft-jones-json-web-token-01.html
+    h = {'x5t': base64.urlsafe_b64encode(binascii.a2b_hex(thumbprint)).decode()}
+    return jwt.encode(payload, private_pem, algorithm='RS256', headers=h)
+

msal/request.py

@@ -1,20 +1,31 @@
 import time
 
-from . import oauth2
 from .exceptions import MsalServiceError
 
 
 class BaseRequest(object):
-    TOKEN_ENDPOINT_PATH = 'oauth2/v2.0/token'
 
     def __init__(
-            self, authority=None, token_cache=None, scope=None, policy="",
+            self, authority=None, token_cache=None,
+	    scope=None, policy="",  # TBD: If scope and policy are paramters
+		# of both high level ClientApplication.acquire_token()
+                # and low level oauth2.*Grant.get_token(),
+		# shouldn't they be the parameters for run()?
             client_id=None, client_credential=None, authenticator=None,
             support_adfs=False, restrict_to_single_user=False):
         if not scope:
             raise ValueError("scope cannot be empty")
         self.__dict__.update(locals())
 
+        # TODO: Temporary solution here
+        self.token_endpoint = authority
+        if authority.startswith('https://login.microsoftonline.com/common/'):
+            self.token_endpoint += 'oauth2/v2.0/token'
+        elif authority.startswith('https://login.windows.net/'):  # AAD?
+            self.token_endpoint += 'oauth2/token'
+        if policy:
+            self.token_endpoint += '?policy={}'.format(policy)
+
     def run(self):
         """Returns a dictionary, which typically contains following keys:
 
@@ -55,12 +66,3 @@ def __timestamp(self, seconds_from_now=None):  # Returns timestamp IN SECOND
     def get_token(self):
         raise NotImplemented("Use proper sub-class instead")
 
-
-class ClientCredentialRequest(BaseRequest):
-    def get_token(self):
-        return oauth2.ClientCredentialGrant(
-            self.client_id,
-            token_endpoint="%s%s?policy=%s" % (
-                self.authority, self.TOKEN_ENDPOINT_PATH, self.policy),
-            ).get_token(scope=self.scope, client_secret=self.client_credential)
-

requirements.txt

@@ -1 +1,6 @@
 requests>=2,<3
+
+PyJWT>=1,<2
+#1.1.0 is the first that can be installed on windows
+cryptography>=1.1,<2
+