Initial work to support multiple OAuth clients

pillar/auth/oauth.py

@@ -0,0 +1,72 @@
+import json
+
+from rauth import OAuth2Service
+from flask import current_app, url_for, request, redirect, session
+
+
+class OAuthSignIn(object):
+    providers = None
+
+    def __init__(self, provider_name):
+        self.provider_name = provider_name
+        credentials = current_app.config['OAUTH_CREDENTIALS'][provider_name]
+        self.consumer_id = credentials['id']
+        self.consumer_secret = credentials['secret']
+
+    def authorize(self):
+        pass
+
+    def callback(self):
+        pass
+
+    def get_callback_url(self):
+        return url_for('users.oauth_callback', provider=self.provider_name,
+                       _external=True)
+
+    @classmethod
+    def get_provider(cls, provider_name):
+        if cls.providers is None:
+            cls.providers = {}
+            for provider_class in cls.__subclasses__():
+                provider = provider_class()
+                cls.providers[provider.provider_name] = provider
+        return cls.providers[provider_name]
+
+
+class FacebookSignIn(OAuthSignIn):
+    def __init__(self):
+        super(FacebookSignIn, self).__init__('facebook')
+        self.service = OAuth2Service(
+            name='facebook',
+            client_id=self.consumer_id,
+            client_secret=self.consumer_secret,
+            authorize_url='https://graph.facebook.com/oauth/authorize',
+            access_token_url='https://graph.facebook.com/oauth/access_token',
+            base_url='https://graph.facebook.com/'
+        )
+
+    def authorize(self):
+        return redirect(self.service.get_authorize_url(
+            scope='email',
+            response_type='code',
+            redirect_uri=self.get_callback_url())
+        )
+
+    def callback(self):
+        def decode_json(payload):
+            return json.loads(payload.decode('utf-8'))
+
+        if 'code' not in request.args:
+            return None, None, None
+        oauth_session = self.service.get_auth_session(
+            data={'code': request.args['code'],
+                  'grant_type': 'authorization_code',
+                  'redirect_uri': self.get_callback_url()},
+            decoder=decode_json
+        )
+        me = oauth_session.get('me?fields=id,email').json()
+        # TODO handle case when user chooses not to disclose en email
+        return (
+            me['id'],
+            me.get('email'),
+        )