wtv

lti/adapters.py

@@ -4,8 +4,10 @@ PyLTI1p3 Django adapters for MediaCMS
 Provides Django-specific implementations for PyLTI1p3 interfaces
 """
 
+import hashlib
 import json
 import time
+import uuid
 from typing import Any, Dict, Optional
 
 import jwt
@@ -192,8 +194,10 @@ class DjangoServiceConnector(ServiceConnector):
         self._access_token_expires = 0
 
     def get_access_token(self, scopes):
-        if self._access_token and time.time() < self._access_token_expires:
-            return self._access_token
+        cache_key = 'lti_access_token_' + self._registration.get_issuer() + '_' + hashlib.sha1(' '.join(scopes).encode('utf-8')).hexdigest()
+        token_data = cache.get(cache_key)
+        if token_data:
+            return token_data['access_token']
 
         key_obj = LTIToolKeys.get_or_create_keys()
         jwk_obj = jwk.JWK(**key_obj.private_key_jwk)
@@ -201,13 +205,17 @@ class DjangoServiceConnector(ServiceConnector):
         private_key = serialization.load_pem_private_key(pem_bytes, password=None, backend=default_backend())
 
         now = int(time.time())
+
+        # Moodle can be picky about audience. Including both token URL and issuer is safer.
+        audience = [self._registration.get_auth_token_url(), self._registration.get_issuer()]
+
         payload = {
             'iss': self._registration.get_client_id(),
             'sub': self._registration.get_client_id(),
-            'aud': self._registration.get_auth_token_url(),
+            'aud': audience,
             'iat': now,
             'exp': now + 300,
-            'jti': str(time.time()),
+            'jti': str(uuid.uuid4()),
         }
 
         client_assertion = jwt.encode(payload, private_key, algorithm='RS256', headers={'kid': key_obj.private_key_jwk['kid']})
@@ -220,15 +228,24 @@ class DjangoServiceConnector(ServiceConnector):
             'scope': ' '.join(scopes),
         }
 
+        print(f"LTI Service: Requesting access token from {token_url} with scopes: {scopes}")
         response = requests.post(token_url, data=data, timeout=10)
+
+        try:
             response.raise_for_status()
-
             token_data = response.json()
-        self._access_token = token_data['access_token']
-        expires_in = token_data.get('expires_in', 3600)
-        self._access_token_expires = time.time() + expires_in - 10
+            print(f"LTI Service: Successfully received access token. Expires in: {token_data.get('expires_in', 'N/A')}")
 
-        return self._access_token
+            expires_in = token_data.get('expires_in', 3600)
+            cache.set(cache_key, token_data, timeout=expires_in - 10)
+
+            return token_data['access_token']
+        except requests.exceptions.HTTPError as e:
+            print(f"LTI Service Error: Failed to get access token. Status: {e.response.status_code}, Response: {e.response.text}")
+            raise
+        except json.JSONDecodeError:
+            print(f"LTI Service Error: Failed to decode JSON from token endpoint. Response: {response.text}")
+            raise
 
     def make_service_request(self, scopes, url, is_post=False, data=None, **kwargs):
         access_token = self.get_access_token(scopes)

lti/views.py

@@ -158,11 +158,25 @@ class LaunchView(View):
 
             unverified = jwt.decode(id_token, options={"verify_signature": False})
             iss = unverified.get('iss')
-            aud = unverified.get('aud')
+            aud = unverified.get('aud')  # Can be a string or a list
+
+            platform = None
+            if isinstance(aud, list):
+                # If aud is a list, find a platform where the client_id is in the list
+                platforms = LTIPlatform.objects.filter(platform_id=iss, client_id__in=aud)
+                if platforms.count() == 1:
+                    platform = platforms.first()
+                elif platforms.count() > 1:
+                    raise LtiException(f"Multiple platforms found for issuer '{iss}' and client_ids '{aud}'")
+            else:
+                # If aud is a string, find it directly
                 try:
                     platform = LTIPlatform.objects.get(platform_id=iss, client_id=aud)
                 except LTIPlatform.DoesNotExist:
-                raise
+                    pass  # Platform will be None
+
+            if not platform:
+                raise LtiException(f"Platform not found for issuer '{iss}' and client_id(s) '{aud}'")
 
             tool_config = DjangoToolConfig.from_platform(platform)