Add LTI 1.1 config on model

lti_consumer/admin.py

@@ -11,7 +11,7 @@ class LtiConfigurationAdmin(admin.ModelAdmin):
 
     Makes the location field read-only to avoid issues.
     """
-    readonly_fields = ('location', )
+    readonly_fields = ('location', 'config_id')
 
 
 admin.site.register(LtiConfiguration, LtiConfigurationAdmin)

lti_consumer/lti_1p1/consumer.py

@@ -68,10 +68,10 @@ def parse_result_json(json_str):
     """
     try:
         json_obj = json.loads(json_str)
-    except (ValueError, TypeError):
+    except (ValueError, TypeError) as err:
         msg = "Supplied JSON string in request body could not be decoded: {}".format(json_str)
         log.error("[LTI] %s", msg)
-        raise Lti1p1Error(msg)
+        raise Lti1p1Error(msg) from err
 
     # The JSON object must be a dict. If a non-empty list is passed in,
     # use the first element, but only if it is a dict
@@ -112,7 +112,7 @@ def parse_result_json(json_str):
         except (TypeError, ValueError) as err:
             msg = "Could not convert resultScore to float: {}".format(str(err))
             log.error("[LTI] %s", msg)
-            raise Lti1p1Error(msg)
+            raise Lti1p1Error(msg) from err
 
     return score, json_obj.get('comment', "")
 
@@ -387,4 +387,4 @@ class LtiConsumer1p1:
             return verify_oauth_body_signature(request, self.oauth_secret, outcome_service_url)
         except (ValueError, Lti1p1Error) as err:
             log.error("[LTI]: v2.0 result service -- OAuth body verification failed: %s", str(err))
-            raise Lti1p1Error(str(err))
+            raise Lti1p1Error(str(err)) from err

lti_consumer/lti_1p1/contrib/django.py

@@ -11,9 +11,6 @@ from ..consumer import LtiConsumer1p1
 def lti_embed(
         *,
         html_element_id,
-        lti_launch_url,
-        oauth_key,
-        oauth_secret,
         resource_link_id,
         user_id,
         roles,
@@ -21,6 +18,10 @@ def lti_embed(
         context_title,
         context_label,
         result_sourcedid,
+        lti_consumer=None,
+        lti_launch_url=None,
+        oauth_key=None,
+        oauth_secret=None,
         person_sourcedid=None,
         person_contact_email_primary=None,
         outcome_service_url=None,
@@ -49,9 +50,6 @@ def lti_embed(
 
     Arguments:
         html_element_id (string):  Value to use as the HTML element id in the HTML form
-        lti_launch_url (string):  The URL to send the LTI Launch request to
-        oauth_key (string):  The OAuth consumer key
-        oauth_secret (string):  The OAuth consumer secret
         resource_link_id (string):  Opaque identifier guaranteed to be unique
             for every placement of the link
         user_id (string):  Unique value identifying the user
@@ -62,6 +60,11 @@ def lti_embed(
         context_label (string):  Plain text label for the context
         result_sourcedid (string):  Indicates the LIS Result Identifier (if any)
             and uniquely identifies a row and column within the Tool Consumer gradebook
+        lti_consumer (LtiConsumer1p1): A pre-configured LtiConsumer1p1 object
+            as an alternative to providing the launch url, oauth key and oauth secret
+        lti_launch_url (string):  The URL to send the LTI Launch request to
+        oauth_key (string):  The OAuth consumer key
+        oauth_secret (string):  The OAuth consumer secret
         person_sourcedid (string):  LIS identifier for the user account performing the launch
         person_contact_email_primary (string):  Primary contact email address of the user
         outcome_service_url (string):  URL pointing to the outcome service. This
@@ -78,7 +81,10 @@ def lti_embed(
         unicode: HTML template with the form and JavaScript to automatically
             launch the LTI embedding
     """
-    lti_consumer = LtiConsumer1p1(lti_launch_url, oauth_key, oauth_secret)
+    if lti_consumer is None:
+        lti_consumer = LtiConsumer1p1(lti_launch_url, oauth_key, oauth_secret)
+    else:
+        lti_launch_url = lti_consumer.lti_launch_url
 
     # Set LTI parameters from kwargs
     lti_consumer.set_user_data(

lti_consumer/lti_1p1/contrib/tests/test_django.py

@@ -15,7 +15,7 @@ class TestLtiEmbed(TestCase):
     """
 
     def setUp(self):
-        super(TestLtiEmbed, self).setUp()
+        super().setUp()
         self.html_element_id = 'html_element_id'
         self.lti_launch_url = 'lti_launch_url'
         self.oauth_key = 'oauth_key'

lti_consumer/lti_1p1/oauth.py

@@ -56,8 +56,8 @@ def get_oauth_request_signature(key, secret, url, headers, body):
             body=body,
             headers=headers
         )
-    except ValueError:  # Scheme not in url.
-        raise Lti1p1Error("Failed to sign oauth request")
+    except ValueError as err:  # Scheme not in url.
+        raise Lti1p1Error("Failed to sign oauth request") from err
 
     return headers['Authorization']
 

lti_consumer/lti_1p1/tests/test_consumer.py

@@ -119,7 +119,7 @@ class TestLtiConsumer1p1(unittest.TestCase):
     """
 
     def setUp(self):
-        super(TestLtiConsumer1p1, self).setUp()
+        super().setUp()
         self.lti_launch_url = 'lti_launch_url'
         self.oauth_key = 'fake_consumer_key'
         self.oauth_secret = 'fake_signature'

lti_consumer/lti_1p3/consumer.py

@@ -404,8 +404,8 @@ class LtiConsumer1p3:
             assert response.get("state")
             assert response.get("client_id") == self.client_id
             assert response.get("redirect_uri") == self.launch_url
-        except AssertionError:
-            raise exceptions.PreflightRequestValidationFailure()
+        except AssertionError as err:
+            raise exceptions.PreflightRequestValidationFailure() from err
 
     def check_token(self, token, allowed_scopes=None):
         """
@@ -455,7 +455,7 @@ class LtiAdvantageConsumer(LtiConsumer1p3):
         """
         Override parent class and set up required LTI Advantage variables.
         """
-        super(LtiAdvantageConsumer, self).__init__(*args, **kwargs)
+        super().__init__(*args, **kwargs)
 
         # LTI AGS Variables
         self.ags = None

lti_consumer/lti_1p3/extensions/rest_framework/authentication.py

@@ -52,18 +52,18 @@ class Lti1p3ApiAuthentication(authentication.BaseAuthentication):
         try:
             lti_configuration = LtiConfiguration.objects.get(pk=lti_config_id)
             lti_consumer = lti_configuration.get_lti_consumer()
-        except Exception:
+        except Exception as err:
             msg = _('LTI configuration not found.')
-            raise exceptions.AuthenticationFailed(msg)
+            raise exceptions.AuthenticationFailed(msg) from err
 
         # Verify token validity
         # This doesn't validate specific permissions, just checks if the token
         # is valid or not.
         try:
             lti_consumer.check_token(auth[1])
-        except Exception:
+        except Exception as err:
             msg = _('Invalid token signature.')
-            raise exceptions.AuthenticationFailed(msg)
+            raise exceptions.AuthenticationFailed(msg) from err
 
         # Passing parameters back to the view through the request in order
         # to avoid implementing a separate authentication backend or

lti_consumer/lti_1p3/extensions/rest_framework/serializers.py

@@ -31,8 +31,8 @@ class UsageKeyField(serializers.Field):
         """
         try:
             return UsageKey.from_string(data)
-        except InvalidKeyError:
-            raise serializers.ValidationError("Invalid usage key: {}".format(data))
+        except InvalidKeyError as err:
+            raise serializers.ValidationError("Invalid usage key: {}".format(data)) from err
 
 
 class LtiAgsLineItemSerializer(serializers.ModelSerializer):

lti_consumer/lti_1p3/key_handlers.py

@@ -55,8 +55,8 @@ class ToolKeyHandler:
                 # Import Key and save to internal state
                 new_key.load_key(RSA.import_key(raw_key))
                 self.public_key = new_key
-            except ValueError:
-                raise exceptions.InvalidRsaKey()
+            except ValueError as err:
+                raise exceptions.InvalidRsaKey() from err
 
     def _get_keyset(self, kid=None):
         """
@@ -113,12 +113,12 @@ class ToolKeyHandler:
             # Else returns decoded message
             return message
 
-        except NoSuitableSigningKeys:
-            raise exceptions.NoSuitableKeys()
-        except BadSyntax:
-            raise exceptions.MalformedJwtToken()
-        except WrongNumberOfParts:
-            raise exceptions.MalformedJwtToken()
+        except NoSuitableSigningKeys as err:
+            raise exceptions.NoSuitableKeys() from err
+        except BadSyntax as err:
+            raise exceptions.MalformedJwtToken() from err
+        except WrongNumberOfParts as err:
+            raise exceptions.MalformedJwtToken() from err
 
 
 class PlatformKeyHandler:
@@ -145,8 +145,8 @@ class PlatformKeyHandler:
                     kid=kid,
                     key=RSA.import_key(key_pem)
                 )
-            except ValueError:
-                raise exceptions.InvalidRsaKey()
+            except ValueError as err:
+                raise exceptions.InvalidRsaKey() from err
 
     def encode_and_sign(self, message, expiration=None):
         """
@@ -211,7 +211,7 @@ class PlatformKeyHandler:
             # Else return token contents
             return message
 
-        except NoSuitableSigningKeys:
-            raise exceptions.NoSuitableKeys()
-        except BadSyntax:
-            raise exceptions.MalformedJwtToken()
+        except NoSuitableSigningKeys as err:
+            raise exceptions.NoSuitableKeys() from err
+        except BadSyntax as err:
+            raise exceptions.MalformedJwtToken() from err

lti_consumer/lti_1p3/tests/extensions/rest_framework/test_authentication.py

@@ -34,7 +34,7 @@ class TestLtiAuthentication(TestCase):
     Unit tests for Lti1p3ApiAuthentication class
     """
     def setUp(self):
-        super(TestLtiAuthentication, self).setUp()
+        super().setUp()
 
         # Set up consumer
         self.lti_consumer = LtiConsumer1p3(

lti_consumer/lti_1p3/tests/extensions/rest_framework/test_permissions.py

@@ -33,7 +33,7 @@ class TestLtiAuthentication(TestCase):
     Unit tests for Lti1p3ApiAuthentication class
     """
     def setUp(self):
-        super(TestLtiAuthentication, self).setUp()
+        super().setUp()
 
         # Set up consumer
         self.lti_consumer = LtiConsumer1p3(

lti_consumer/lti_1p3/tests/test_consumer.py

@@ -40,7 +40,7 @@ class TestLti1p3Consumer(TestCase):
     Unit tests for LtiConsumer1p3
     """
     def setUp(self):
-        super(TestLti1p3Consumer, self).setUp()
+        super().setUp()
 
         # Set up consumer
         self.lti_consumer = LtiConsumer1p3(
@@ -557,7 +557,7 @@ class TestLtiAdvantageConsumer(TestCase):
     Unit tests for LtiAdvantageConsumer
     """
     def setUp(self):
-        super(TestLtiAdvantageConsumer, self).setUp()
+        super().setUp()
 
         # Set up consumer
         self.lti_consumer = LtiAdvantageConsumer(

lti_consumer/lti_1p3/tests/test_key_handlers.py

@@ -24,7 +24,7 @@ class TestPlatformKeyHandler(TestCase):
     Unit tests for PlatformKeyHandler
     """
     def setUp(self):
-        super(TestPlatformKeyHandler, self).setUp()
+        super().setUp()
 
         self.rsa_key_id = "1"
         self.rsa_key = RSA.generate(2048).export_key('PEM')
@@ -187,7 +187,7 @@ class TestToolKeyHandler(TestCase):
     Unit tests for ToolKeyHandler
     """
     def setUp(self):
-        super(TestToolKeyHandler, self).setUp()
+        super().setUp()
 
         self.rsa_key_id = "1"
 

lti_consumer/lti_xblock.py

@@ -648,10 +648,10 @@ class LtiConsumerXBlock(StudioEditableXBlockMixin, XBlock):
                 if not key:
                     raise ValueError
                 key = ':'.join(key)
-            except ValueError:
+            except ValueError as err:
                 msg = 'Could not parse LTI passport: {lti_passport!r}. Should be "id:key:secret" string.'
                 msg = self.ugettext(msg).format(lti_passport=lti_passport)
-                raise LtiError(msg)
+                raise LtiError(msg) from err
 
             if lti_id == self.lti_id.strip():
                 return key, secret
@@ -783,11 +783,11 @@ class LtiConsumerXBlock(StudioEditableXBlockMixin, XBlock):
             for custom_parameter in self.custom_parameters:
                 try:
                     param_name, param_value = [p.strip() for p in custom_parameter.split('=', 1)]
-                except ValueError:
+                except ValueError as err:
                     _ = self.runtime.service(self, "i18n").ugettext
                     msg = 'Could not parse custom parameter: {custom_parameter!r}. Should be "x=y" string.'
                     msg = self.ugettext(msg).format(custom_parameter=custom_parameter)
-                    raise LtiError(msg)
+                    raise LtiError(msg) from err
 
                 # LTI specs: 'custom_' should be prepended before each custom parameter, as pointed in link above.
                 if param_name not in LTI_PARAMETERS:
@@ -870,7 +870,7 @@ class LtiConsumerXBlock(StudioEditableXBlockMixin, XBlock):
         Get Studio View fragment
         """
         loader = ResourceLoader(__name__)
-        fragment = super(LtiConsumerXBlock, self).studio_view(context)
+        fragment = super().studio_view(context)
 
         fragment.add_javascript(loader.load_unicode("static/js/xblock_studio_view.js"))
         fragment.initialize_js('LtiConsumerXBlockInitStudio')
@@ -929,7 +929,7 @@ class LtiConsumerXBlock(StudioEditableXBlockMixin, XBlock):
         return fragment
 
     @XBlock.handler
-    def lti_launch_handler(self, request, suffix=''):
+    def lti_launch_handler(self, request, suffix=''):  # pylint: disable=unused-argument
         """
         XBlock handler for launching LTI 1.1 tools.
 
@@ -984,7 +984,7 @@ class LtiConsumerXBlock(StudioEditableXBlockMixin, XBlock):
         return Response(template, content_type='text/html')
 
     @XBlock.handler
-    def lti_1p3_launch_handler(self, request, suffix=''):
+    def lti_1p3_launch_handler(self, request, suffix=''):  # pylint: disable=unused-argument
         """
         XBlock handler for launching the LTI 1.3 tools.
 
@@ -1010,7 +1010,7 @@ class LtiConsumerXBlock(StudioEditableXBlockMixin, XBlock):
         return Response(template, content_type='text/html')
 
     @XBlock.handler
-    def lti_1p3_launch_callback(self, request, suffix=''):
+    def lti_1p3_launch_callback(self, request, suffix=''):  # pylint: disable=unused-argument
         """
         XBlock handler for launching the LTI 1.3 tool.
 
@@ -1071,7 +1071,7 @@ class LtiConsumerXBlock(StudioEditableXBlockMixin, XBlock):
             return Response(template, status=400, content_type='text/html')
 
     @XBlock.handler
-    def lti_1p3_access_token(self, request, suffix=''):
+    def lti_1p3_access_token(self, request, suffix=''):  # pylint: disable=unused-argument
         """
         XBlock handler for creating access tokens for the LTI 1.3 tool.
 
@@ -1130,7 +1130,7 @@ class LtiConsumerXBlock(StudioEditableXBlockMixin, XBlock):
             )
 
     @XBlock.handler
-    def outcome_service_handler(self, request, suffix=''):
+    def outcome_service_handler(self, request, suffix=''):  # pylint: disable=unused-argument
         """
         XBlock handler for LTI Outcome Service requests.
 
@@ -1421,7 +1421,7 @@ class LtiConsumerXBlock(StudioEditableXBlockMixin, XBlock):
         # return key/value fields in a Python dict object
         # values may be numeric / string or dict
         # default implementation is an empty dict
-        xblock_body = super(LtiConsumerXBlock, self).index_dictionary()
+        xblock_body = super().index_dictionary()
 
         index_body = {
             "display_name": self.display_name,

lti_consumer/migrations/0006_add_on_model_config_for_lti_1p1.py

+# Generated by Django 2.2.17 on 2020-12-21 13:39
+
+from django.db import migrations, models
+import jsonfield.encoder
+import jsonfield.fields
+import uuid
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('lti_consumer', '0005_migrate_keyset_to_model'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='lticonfiguration',
+            name='config_id',
+            field=models.UUIDField(default=uuid.uuid4, editable=False, unique=True),
+        ),
+        migrations.AddField(
+            model_name='lticonfiguration',
+            name='lti_1p1_client_key',
+            field=models.CharField(blank=True, help_text='Client key provided by the LTI tool provider.', max_length=255),
+        ),
+        migrations.AddField(
+            model_name='lticonfiguration',
+            name='lti_1p1_client_secret',
+            field=models.CharField(blank=True, help_text='Client secret provided by the LTI tool provider.', max_length=255),
+        ),
+        migrations.AddField(
+            model_name='lticonfiguration',
+            name='lti_1p1_launch_url',
+            field=models.CharField(blank=True, help_text='The URL of the external tool that initiates the launch.', max_length=255),
+        ),
+        migrations.AddField(
+            model_name='lticonfiguration',
+            name='lti_config',
+            field=jsonfield.fields.JSONField(blank=True, default=dict, dump_kwargs={'cls': jsonfield.encoder.JSONEncoder, 'separators': (',', ':')}, help_text='LTI configuration data.', load_kwargs={}),
+        ),
+        migrations.AlterField(
+            model_name='lticonfiguration',
+            name='config_store',
+            field=models.CharField(choices=[('CONFIG_ON_XBLOCK', 'Configuration Stored on XBlock fields'), ('CONFIG_ON_DB', 'Configuration Stored on this model')], default='CONFIG_ON_XBLOCK', max_length=255),
+        ),
+    ]

lti_consumer/models.py

@@ -6,9 +6,11 @@ import json
 from django.db import models
 from django.core.validators import MinValueValidator
 from django.core.exceptions import ValidationError
+from django.utils.translation import ugettext_lazy as _
 
-from opaque_keys.edx.django.models import UsageKeyField
 from Cryptodome.PublicKey import RSA
+from opaque_keys.edx.django.models import UsageKeyField
+from jsonfield import JSONField
 
 # LTI 1.1
 from lti_consumer.lti_1p1.consumer import LtiConsumer1p1
@@ -60,8 +62,10 @@ class LtiConfiguration(models.Model):
     # stored on the block, but should be expanded to
     # enable storing LTI configuration in this model.
     CONFIG_ON_XBLOCK = 'CONFIG_ON_XBLOCK'
+    CONFIG_ON_DB = 'CONFIG_ON_DB'
     CONFIG_STORE_CHOICES = [
-        (CONFIG_ON_XBLOCK, 'Configuration Stored on XBlock fields'),
+        (CONFIG_ON_XBLOCK, _('Configuration Stored on XBlock fields')),
+        (CONFIG_ON_DB, _('Configuration Stored on this model')),
     ]
     config_store = models.CharField(
         max_length=255,
@@ -69,9 +73,10 @@ class LtiConfiguration(models.Model):
         default=CONFIG_ON_XBLOCK,
     )
 
+    # A secondary ID for this configuration that can be used in URLs without leaking primary id.
+    config_id = models.UUIDField(unique=True, default=uuid.uuid4, editable=False)
+
     # Block location where the configuration is stored.
-    # In the future, the LTI configuration will be
-    # stored in this model in a JSON field.
     location = UsageKeyField(
         max_length=255,
         db_index=True,
@@ -79,33 +84,71 @@ class LtiConfiguration(models.Model):
         blank=True,
     )
 
+    # This is where the configuration is stored in the model if stored on this model.
+    lti_config = JSONField(
+        null=False,
+        blank=True,
+        default=dict,
+        help_text=_("LTI configuration data.")
+    )
+
+    # LTI 1.1 Related variables
+    lti_1p1_launch_url = models.CharField(
+        max_length=255,
+        blank=True,
+        help_text=_("The URL of the external tool that initiates the launch.")
+    )
+    lti_1p1_client_key = models.CharField(
+        max_length=255,
+        blank=True,
+        help_text=_("Client key provided by the LTI tool provider.")
+    )
+
+    lti_1p1_client_secret = models.CharField(
+        max_length=255,
+        blank=True,
+        help_text=_("Client secret provided by the LTI tool provider.")
+    )
+
     # LTI 1.3 Related variables
     lti_1p3_internal_private_key = models.TextField(
         blank=True,
-        help_text="Platform's generated Private key. Keep this value secret.",
+        help_text=_("Platform's generated Private key. Keep this value secret."),
     )
 
     lti_1p3_internal_private_key_id = models.CharField(
         max_length=255,
         blank=True,
-        help_text="Platform's generated Private key ID",
+        help_text=_("Platform's generated Private key ID"),
     )
 
     lti_1p3_internal_public_jwk = models.TextField(
         blank=True,
-        help_text="Platform's generated JWK keyset.",
+        help_text=_("Platform's generated JWK keyset."),
     )
 
     lti_1p3_client_id = models.CharField(
         max_length=255,
         default=generate_client_id,
-        help_text="Client ID used by LTI tool",
+        help_text=_("Client ID used by LTI tool"),
     )
 
     # Empty variable that'll hold the block once it's retrieved
     # from the modulestore or preloaded
     _block = None
 
+    def clean(self):
+        if self.config_store == self.CONFIG_ON_XBLOCK and self.location is None:
+            raise ValidationError({
+                "config_store": _("LTI Configuration stores on XBlock needs a block location set."),
+            })
+        try:
+            consumer = self.get_lti_consumer()
+        except NotImplementedError:
+            consumer = None
+        if consumer is None:
+            raise ValidationError(_("Invalid LTI configuration."))
+
     @property
     def block(self):
         """
@@ -114,7 +157,7 @@ class LtiConfiguration(models.Model):
         block = getattr(self, '_block', None)
         if block is None:
             if self.location is None:
-                raise ValueError("Block location not set, it's not possible to retrieve the block.")
+                raise ValueError(_("Block location not set, it's not possible to retrieve the block."))
             block = self._block = compat.load_block_as_anonymous_user(self.location)
         return block
 
@@ -188,12 +231,13 @@ class LtiConfiguration(models.Model):
         # If LTI configuration is stored in the XBlock.
         if self.config_store == self.CONFIG_ON_XBLOCK:
             key, secret = self.block.lti_provider_key_secret
+            launch_url = self.block.launch_url
+        else:
+            key = self.lti_1p1_client_key
+            secret = self.lti_1p1_client_secret
+            launch_url = self.lti_1p1_launch_url
 
-            return LtiConsumer1p1(self.block.launch_url, key, secret)
-
-        # There's no configuration stored locally, so throw
-        # NotImplemented.
-        raise NotImplementedError
+        return LtiConsumer1p1(launch_url, key, secret)
 
     def _get_lti_1p3_consumer(self):
         """
@@ -399,7 +443,7 @@ class LtiAgsScore(models.Model):
         if self.score_given and self.score_maximum is None:
             raise ValidationError({'score_maximum': 'cannot be unset when score_given is set'})
 
-    def save(self, *args, **kwargs):  # pylint: disable=arguments-differ
+    def save(self, *args, **kwargs):  # pylint: disable=signature-differs
         self.full_clean()
         super().save(*args, **kwargs)
 

lti_consumer/outcomes.py

@@ -46,32 +46,32 @@ def parse_grade_xml_body(body):
         parser = etree.XMLParser(ns_clean=True, recover=True, encoding='utf-8')
         root = etree.fromstring(data, parser=parser)
     except etree.XMLSyntaxError as ex:
-        raise LtiError(str(ex) or 'Body is not valid XML')
+        raise LtiError(str(ex) or 'Body is not valid XML') from ex
 
     try:
         imsx_message_identifier = root.xpath("//def:imsx_messageIdentifier", namespaces=namespaces)[0].text or ''
-    except IndexError:
-        raise LtiError('Failed to parse imsx_messageIdentifier from XML request body')
+    except IndexError as ex:
+        raise LtiError('Failed to parse imsx_messageIdentifier from XML request body') from ex
 
     try:
         body = root.xpath("//def:imsx_POXBody", namespaces=namespaces)[0]
-    except IndexError:
-        raise LtiError('Failed to parse imsx_POXBody from XML request body')
+    except IndexError as ex:
+        raise LtiError('Failed to parse imsx_POXBody from XML request body') from ex
 
     try:
         action = body.getchildren()[0].tag.replace('{' + lti_spec_namespace + '}', '')
-    except IndexError:
-        raise LtiError('Failed to parse action from XML request body')
+    except IndexError as ex:
+        raise LtiError('Failed to parse action from XML request body') from ex
 
     try:
         sourced_id = root.xpath("//def:sourcedId", namespaces=namespaces)[0].text
-    except IndexError:
-        raise LtiError('Failed to parse sourcedId from XML request body')
+    except IndexError as ex:
+        raise LtiError('Failed to parse sourcedId from XML request body') from ex
 
     try:
         score = root.xpath("//def:textString", namespaces=namespaces)[0].text
-    except IndexError:
-        raise LtiError('Failed to parse score textString from XML request body')
+    except IndexError as ex:
+        raise LtiError('Failed to parse score textString from XML request body') from ex
 
     # Raise exception if score is not float or not in range 0.0-1.0 regarding spec.
     score = float(score)

lti_consumer/plugin/views.py

@@ -161,7 +161,7 @@ class LtiAgsLineItemViewset(viewsets.ModelViewSet):
         url_path='results/(?P<user_id>[^/.]+)?',
         renderer_classes=[LineItemResultsRenderer]
     )
-    def results(self, request, user_id=None, **kwargs):
+    def results(self, request, user_id=None, **kwargs):  # pylint: disable=unused-argument
         """
         Return a Result list for an LtiAgsLineItem
 
@@ -199,7 +199,7 @@ class LtiAgsLineItemViewset(viewsets.ModelViewSet):
         parser_classes=[LineItemScoreParser],
         renderer_classes=[LineItemScoreRenderer]
     )
-    def scores(self, request, *args, **kwargs):
+    def scores(self, request, *args, **kwargs):  # pylint: disable=unused-argument
         """
         Create a Score record for an LtiAgsLineItem
 

lti_consumer/tests/unit/plugin/test_views.py

@@ -16,7 +16,7 @@ class TestLti1p3KeysetEndpoint(TestCase):
     Test `public_keyset_endpoint` method.
     """
     def setUp(self):
-        super(TestLti1p3KeysetEndpoint, self).setUp()
+        super().setUp()
 
         self.location = 'block-v1:course+test+2020+type@problem+block@test'
         self.url = '/lti_consumer/v1/public_keysets/{}'.format(self.location)
@@ -70,7 +70,7 @@ class TestLti1p3LaunchGateEndpoint(TestCase):
     Test `launch_gate_endpoint` method.
     """
     def setUp(self):
-        super(TestLti1p3LaunchGateEndpoint, self).setUp()
+        super().setUp()
 
         self.location = 'block-v1:course+test+2020+type@problem+block@test'
         self.url = '/lti_consumer/v1/launch/'
@@ -113,7 +113,7 @@ class TestLti1p3AccessTokenEndpoint(TestCase):
     Test `access_token_endpoint` method.
     """
     def setUp(self):
-        super(TestLti1p3AccessTokenEndpoint, self).setUp()
+        super().setUp()
 
         self.location = 'block-v1:course+test+2020+type@problem+block@test'
         self.url = '/lti_consumer/v1/token/{}'.format(self.location)