✨(lti_toolbox) add LTIMessageType enum

Introduced a new enumeration encapsulating all LTI message types,
replacing hardcoded constants for improved code organization
and maintainability.

CHANGELOG.md

@@ -11,6 +11,7 @@ Versioning](https://semver.org/spec/v2.0.0.html).
 ### Added
 
 - Accept Content-Item selection request used in a deep linking context
+- Add an LTIMessageType enum
 
 ### Fixed
 

src/lti_toolbox/launch_params.py

@@ -4,13 +4,22 @@
 This is based on lti library (https://github.com/pylti/lti).
 """
 from collections.abc import MutableMapping
+from enum import Enum
 from typing import List, Set, Union
 from urllib.parse import urlencode
 
 from .exceptions import InvalidParamException, MissingParamException
 
 DEFAULT_LTI_VERSION = "LTI-1.0"
-SELECTION_PARAMS_MESSAGE_TYPE = "ContentItemSelectionRequest"
+
+
+class LTIMessageType(Enum):
+    """Enum describing all type of message received through LTI requests."""
+
+    LAUNCH_REQUEST = "basic-lti-launch-request"
+    SELECTION_REQUEST = "ContentItemSelectionRequest"
+    SELECTION_RESPONSE = "ContentItemSelection"
+
 
 LAUNCH_PARAMS_REQUIRED = {"lti_message_type", "lti_version", "resource_link_id"}
 

src/lti_toolbox/lti.py

@@ -6,12 +6,7 @@
 from oauthlib.oauth1 import SignatureOnlyEndpoint
 
 from .exceptions import LTIException, LTIRequestNotVerifiedException, ParamException
-from .launch_params import (
-    SELECTION_PARAMS_MESSAGE_TYPE,
-    LaunchParams,
-    ParamsMixins,
-    SelectionParams,
-)
+from .launch_params import LaunchParams, LTIMessageType, ParamsMixins, SelectionParams
 from .models import LTIConsumer, LTIPassport
 from .validator import LTIRequestValidator
 
@@ -37,8 +32,8 @@ def __init__(self, request):
     def _process_params(self) -> ParamsMixins:
         """Process LTI parameters based on request type."""
         is_selection_request = (
-                self.request.POST.get("lti_message_type")
-                == SELECTION_PARAMS_MESSAGE_TYPE
+            self.request.POST.get("lti_message_type")
+            == LTIMessageType.SELECTION_REQUEST.value
         )
         try:
             params = (

tests/lti_toolbox/test_launch_params.py

@@ -128,7 +128,6 @@ def test_invalid_parameter(self):
             )
 
 
-
 class SelectionParamTestCase(TestCase):
     """Test the SelectionParam class"""
 
@@ -144,7 +143,7 @@ def _selection_params(lti_parameters):
         url = "http://testserver/lti/launch"
         signed_parameters = sign_parameters(passport, lti_parameters, url)
         return SelectionParams(signed_parameters)
-    
+
     def test_only_required_parameters(self):
         """Test validation of a minimalistic LTI Content-Item
         Selection request with only required parameters.