Added Facebook authentication

README.md

@@ -17,5 +17,6 @@ Customs comes out of the box with the following strategies:
 - JWT
 - Google
 - Github
+- Facebook
 
 The list is growing, but if you still cannot find what you're looking for it is very easy to create a specific strategy for your purpose.

customs/strategies/__init__.py

@@ -8,6 +8,7 @@
 from customs.strategies.jwt_strategy import JWTStrategy
 from customs.strategies.google_strategy import GoogleStrategy
 from customs.strategies.github_strategy import GithubStrategy
+from customs.strategies.facebook_strategy import FacebookStrategy
 
 
-__all__ = ["LocalStrategy", "BasicStrategy", "JWTStrategy", "GoogleStrategy", "GithubStrategy"]
+__all__ = ["LocalStrategy", "BasicStrategy", "JWTStrategy", "GoogleStrategy", "GithubStrategy", "FacebookStrategy"]

customs/strategies/facebook_strategy.py

@@ -0,0 +1,61 @@
+from typing import Dict
+from customs.exceptions import UnauthorizedException
+from customs.strategies.oauth2_strategy import OAuth2Strategy
+
+from requests_oauthlib import OAuth2Session  # type: ignore
+from requests_oauthlib.compliance_fixes import facebook_compliance_fix  # type: ignore
+
+
+class FacebookStrategy(OAuth2Strategy):
+    """Authentication using Facebook as an OAuth2 provider."""
+
+    name = "facebook"
+    scopes = ["email", "public_profile"]
+    fields = ["id", "name", "first_name", "last_name", "picture", "email"]
+
+    authorization_base_url = "https://www.facebook.com/dialog/oauth"
+    token_url = "https://graph.facebook.com/oauth/access_token"
+    refresh_url = "https://graph.facebook.com/oauth/access_token"
+    user_profile_endpoint = "https://graph.facebook.com/me?"
+
+    def get_user_info(self) -> Dict:
+        """Method to get user info for the logged in user.
+
+        Raises:
+            UnauthorizedException: When the user is not authenticated
+
+        Returns:
+            Dict: The user profile
+        """
+
+        try:
+
+            # Get the token
+            token = self.token
+
+            # Helper method to update the token in the session
+            def token_updater(token):
+                self.token = token
+
+            # Get a session with auto-refresh of the token
+            client = OAuth2Session(
+                self.client_id,
+                token=token,
+                auto_refresh_kwargs={
+                    "client_id": self.client_id,
+                    "client_secret": self.client_secret,
+                },
+                auto_refresh_url=self.refresh_url,
+                token_updater=token_updater,
+            )
+
+            if self.name == "facebook":
+                facebook_compliance_fix(client)
+
+            # Return the user info
+            return client.get(
+                self.user_profile_endpoint + "fields=" + ",".join(self.fields)
+            ).json()
+
+        except Exception:
+            raise UnauthorizedException()

customs/strategies/jwt_strategy.py

@@ -69,7 +69,7 @@ def authenticate(self, request: Union[Request, FlaskRequest]) -> Any:
             decoded = jwt.decode(token, self.key)
             return self.deserialize_user(decoded)
 
-        except Exception as e:
+        except Exception:
             raise UnauthorizedException()
 
     def sign(self, user: Any) -> str:

customs/strategies/oauth2_strategy.py

@@ -13,6 +13,7 @@
 )
 from werkzeug.wrappers import Request
 from requests_oauthlib import OAuth2Session  # type: ignore
+from requests_oauthlib.compliance_fixes import facebook_compliance_fix  # type: ignore
 
 from customs.exceptions import UnauthorizedException
 from customs.strategies.base_strategy import BaseStrategy
@@ -170,6 +171,9 @@ def token_updater(token):
                 token_updater=token_updater,
             )
 
+            if self.name == "facebook":
+                facebook_compliance_fix(client)
+
             # Return the user info
             return client.get(self.user_profile_endpoint).json()
 
@@ -227,6 +231,10 @@ def login():
                 scope=self.scopes,
                 redirect_uri=url_for(".callback", _external=True),
             )
+
+            if self.name == "facebook":
+                facebook_compliance_fix(client)
+
             authorization_url, state = client.authorization_url(
                 self.authorization_base_url,
                 access_type="offline",
@@ -244,6 +252,10 @@ def callback():
                 state=session["oauth_state"],
                 redirect_uri=url_for(".callback", _external=True),
             )
+
+            if self.name == "facebook":
+                facebook_compliance_fix(client)
+
             self.token = client.fetch_token(
                 self.token_url,
                 client_secret=self.client_secret,

examples/facebook/main.py

@@ -0,0 +1,103 @@
+import os
+
+from typing import Any, Dict
+from flask import Flask
+from flask.templating import render_template
+
+from customs import Customs
+from customs.helpers import set_redirect_url
+from customs.strategies import FacebookStrategy
+from customs.exceptions import UnauthorizedException
+
+
+# App credentials for Facebook
+client_id = os.environ.get("FACEBOOK_CLIENT_ID")
+client_secret = os.environ.get("FACEBOOK_CLIENT_SECRET")
+
+# Create the Flask app
+app = Flask(__name__)
+app.secret_key = "d2cc6f0a-0d9e-414c-a3ca-6b75455d6332"
+
+# Create customs to protect the app, no need for sessions as we're using JWT tokens
+customs = Customs(app, unauthorized_redirect_url="/login")
+
+# Mock in-memory database (NOTE: Will forget everything on restart!)
+DATABASE: Dict[str, Dict] = {}
+
+
+# Create an implementation of the strategy (tell the strategy how to interact with our database for example)
+class FacebookAuthentication(FacebookStrategy):
+
+    scopes = ["email", "public_profile"]
+    fields = ["id", "name", "first_name", "last_name", "picture", "email"]  # Which fields to fetch from the users profile
+
+    def get_or_create_user(self, user: Dict) -> Dict:
+
+        user_id = str(user.get("id"))
+
+        # Create the user if not in the database (so registration is open to everyone)
+        if user_id not in DATABASE:
+            DATABASE[user_id] = user
+
+        # Return the user from the database
+        return DATABASE[user_id]
+
+    def serialize_user(self, user: Any) -> Dict:
+
+        # Keep only the user ID on the session for speed and safety
+        user_id = str(user.get("id"))
+        return {"id": user_id}
+
+    def deserialize_user(self, data: Dict) -> Any:
+
+        # Get the user ID from the session
+        user_id = str(data.get("id"))
+
+        # Conver the ID back to the user data from the database
+        if user_id is not None and user_id in DATABASE:
+            return {"id": str(data.get("id")), **DATABASE[str(data.get("id"))]}
+        else:
+            raise UnauthorizedException()
+
+
+# Create an instance of the strategy
+facebook = FacebookAuthentication(
+    client_id=client_id,
+    client_secret=client_secret,
+    enable_insecure=True,  # For testing purposes only, don't use in production!
+)
+
+# ----------------------- #
+# Define some open routes #
+# ----------------------- #
+
+
+# Open to everyone
+@app.route("/")
+def index():
+    return render_template("index.html")
+
+
+@app.route("/login")
+def login():
+
+    # Store the URL of the page that redirected here and store
+    # it so we can redirect to it after authentication
+    set_redirect_url()
+    return render_template("login.html")
+
+
+# ------------------------------ #
+# Define some (protected) routes #
+# ------------------------------ #
+
+
+@app.route("/profile")
+@customs.protect(strategies=[facebook])
+def profile(user: Dict):
+    print(user)
+    return render_template("profile.html", user=user)
+
+
+if __name__ == "__main__":
+    app.run()

examples/facebook/templates/index.html

@@ -0,0 +1,7 @@
+<html>
+    <body>
+        <h1>Home</h1>
+        <p><a href="/profile">Profile</a></p>
+        <p><a href="/auth/facebook/login">Facebook login</a></p>
+    </body>
+</html>

examples/facebook/templates/login.html

@@ -0,0 +1,6 @@
+<html>
+    <body>
+        <h1>Login</h1>
+        <a href="/auth/facebook/login">Facebook authentication</a>
+    </body>
+</html>

examples/facebook/templates/profile.html

@@ -0,0 +1,14 @@
+<html>
+    <body>
+        <h1>Profile</h1>
+        <table>
+            <tbody>
+                <tr>
+                    <td><img src="{{ user.picture.data.url }}"></td>
+                    <td>{{ user.name }}</td>
+                    <td>{{ user.email }}</td>
+                </tr>
+            </tbody>
+        </table>
+    </body>
+</html>