# WIP: OAuth draft implementation

* first working client implementation of oauth workflow for logging in users

konova/sub_settings/django_settings.py

@@ -49,7 +49,7 @@ CSRF_TRUSTED_ORIGINS = [
 ]
 
 # Authentication settings
-LOGIN_URL = "/login/"
+LOGIN_URL = "/oauth/login/"
 
 # Session settings
 SESSION_COOKIE_AGE = 60 * 60  # 60 minutes

konova/sub_settings/sso_settings.py

@@ -5,9 +5,18 @@ Contact: michel.peltriaux@sgdnord.rlp.de
 Created on: 31.01.22
 
 """
+import random
+import string
 
 # SSO settings
 SSO_SERVER_BASE = "http://127.0.0.1:8000/"
 SSO_SERVER = f"{SSO_SERVER_BASE}sso/"
-SSO_PRIVATE_KEY = "QuziFeih7U8DZvQQ1riPv2MXz0ZABupHED9wjoqZAqeMQaqkqTfxJDRXgSIyASwJ"
-SSO_PUBLIC_KEY = "AGGK7E8eT5X5u2GD38ygGG3GpAefmIldJiiWW7gldRPqCG1CzmUfGdvPSGDbEY2n"
+SSO_PRIVATE_KEY = "CHANGE_ME"
+SSO_PUBLIC_KEY = "CHANGE_ME"
+
+# OAuth
+OAUTH_CODE_VERIFIER = ''.join(
+    random.choice(
+        string.ascii_uppercase + string.digits
+    ) for _ in range(random.randint(43, 128))
+)

konova/urls.py

@@ -23,11 +23,14 @@ from konova.views.logout import LogoutView
 from konova.views.geometry import GeomParcelsView, GeomParcelsContentView
 from konova.views.home import HomeView
 from konova.views.map_proxy import ClientProxyParcelSearch, ClientProxyParcelWFS
+from konova.views.oauth import OAuthLoginView, OAuthCallbackView
 
 sso_client = KonovaSSOClient(SSO_SERVER, SSO_PUBLIC_KEY, SSO_PRIVATE_KEY)
 urlpatterns = [
     path('admin/', admin.site.urls),
     path('login/', include(sso_client.get_urls())),
+    path('oauth/callback/', OAuthCallbackView.as_view(), name="oauth-callback"),
+    path('oauth/login/', OAuthLoginView.as_view(), name="oauth-login"),
     path('logout/', LogoutView.as_view(), name="logout"),
     path('', HomeView.as_view(), name="home"),
     path('intervention/', include("intervention.urls")),

konova/views/oauth.py

@@ -0,0 +1,117 @@
+"""
+Author: Michel Peltriaux
+Organization: Struktur- und Genehmigungsdirektion Nord, Rhineland-Palatinate, Germany
+Contact: ksp-servicestelle@sgdnord.rlp.de
+Created on: 26.04.24
+
+"""
+import base64
+import hashlib
+import json
+from urllib.parse import urlencode
+
+import requests
+from django.contrib.auth import login
+from django.http import HttpRequest
+from django.shortcuts import redirect
+from django.urls import reverse
+from django.views import View
+
+from konova.sub_settings.sso_settings import SSO_SERVER_BASE, OAUTH_CODE_VERIFIER
+from user.models import User
+
+OAUTH_CLIENT_ID = "CHANGE_ME"
+OAUTH_CLIENT_SECRET = "CHANGE_ME"
+
+
+class OAuthCallbackView(View):
+    """
+    Callback view for a OAuth2.0 authentication token.
+    Authentication tokens need to be exchanged for the access token.
+    """
+
+    def get(self, request: HttpRequest, *args, **kwargs):
+        authentication_code = request.GET.get("code")
+        oauth_acces_token_url = f"{SSO_SERVER_BASE}o/token/"
+
+        next_callback_url = request.build_absolute_uri(
+            reverse(
+                "oauth-callback"
+            )
+        )
+
+        params = {
+            "grant_type": "authorization_code",
+            "code": authentication_code,
+            "redirect_uri": next_callback_url,
+            "code_verifier": OAUTH_CODE_VERIFIER,
+            "client_id": OAUTH_CLIENT_ID,
+            "client_secret": OAUTH_CLIENT_SECRET
+        }
+        access_code_response = requests.post(
+            oauth_acces_token_url,
+            data=params
+        )
+
+        access_code_response_body = access_code_response.content.decode("utf-8")
+        status_code_invalid = access_code_response.status_code != 200
+        if status_code_invalid:
+            raise RuntimeError(f"OAuth access token could not be fetched: {access_code_response.text}")
+
+        access_code_response_body = json.loads(access_code_response_body)
+        access_token = access_code_response_body.get("access_token")
+        if not access_token:
+            raise RuntimeError(f"Access token response contained no token: {access_code_response_body}")
+
+        user = User.oauth_get_user(access_token)
+        login(request, user)
+        return redirect("home")
+
+
+class OAuthLoginView(View):
+
+    def __create_code_challenge(self):
+        """
+        Creates a code verifier and code challenge for extra security.
+        See https://django-oauth-toolkit.readthedocs.io/en/latest/getting_started.html#authorization-code for further
+        information
+
+        Returns:
+
+        """
+        code_verifier = OAUTH_CODE_VERIFIER
+
+        code_challenge = hashlib.sha256(code_verifier.encode('utf-8')).digest()
+        code_challenge = base64.urlsafe_b64encode(code_challenge).decode('utf-8').replace('=', '')
+        return code_verifier, code_challenge
+
+    def get(self, request: HttpRequest, *args, **kwargs):
+        """ Redirects user to OAuth SSO webservice
+
+        Args:
+            request ():
+            *args ():
+            **kwargs ():
+
+        Returns:
+
+        """
+        oauth_authentication_code_url = f"{SSO_SERVER_BASE}o/authorize/"
+        code_verifier, code_challenge = self.__create_code_challenge()
+        print(code_verifier)
+
+        urlencode_params = urlencode(
+            {
+                "response_type": "code",
+                "code_challenge": code_challenge,
+                "code_challenge_method": "S256",
+                "client_id": OAUTH_CLIENT_ID,
+                "redirect_uri": request.build_absolute_uri(
+                    reverse(
+                        "oauth-callback"
+                    )
+                ),
+            }
+        )
+        url = f"{oauth_authentication_code_url}?{urlencode_params}"
+        return redirect(url)

user/models/user.py

@@ -5,12 +5,16 @@ Contact: michel.peltriaux@sgdnord.rlp.de
 Created on: 15.11.21
 
 """
+import json
+
+import requests
 from django.contrib.auth.models import AbstractUser
 
 from django.db import models
 
 from api.models import APIUserToken
 from konova.settings import ZB_GROUP, DEFAULT_GROUP, ETS_GROUP
+from konova.sub_settings.sso_settings import SSO_SERVER_BASE
 from konova.utils.mailer import Mailer
 from user.enums import UserNotificationEnum
 
@@ -214,4 +218,41 @@ class User(AbstractUser):
         shared_teams = self.teams.filter(
             deleted__isnull=True
         )
-        return shared_teams
+        return shared_teams
+
+    @staticmethod
+    def _oauth_update_user(user_data: dict):
+        username = user_data.get("username")
+        user, is_created = User.objects.get_or_create(
+            username=username
+        )
+        if is_created:
+            user.set_unusable_password()
+
+        user.first_name = user_data.get("first_name")
+        user.last_name = user_data.get("last_name")
+        user.email = user_data.get("email")
+
+        return user
+
+    @staticmethod
+    def oauth_get_user(oauth_access_token: str):
+        url = f"{SSO_SERVER_BASE}users/oauth/data"
+
+        response = requests.get(
+            url,
+            headers={
+                "Authorization":f"Bearer {oauth_access_token}",
+            }
+        )
+
+        is_response_code_invalid = response.status_code != 200
+        if is_response_code_invalid:
+            raise RuntimeError(f"OAuth user data fetching unsuccessful: {response.status_code}")
+
+        response_content = response.content.decode("utf-8")
+        response_content = json.loads(response_content)
+        user = User._oauth_update_user(response_content)
+
+        return user
+