refactor: Remove dependencies from edx-platform in extracted LTI block

- Defined constants for anonymous user ID and user role.
- Replaced HTML/Text helpers with markupsafe.

Author: ttqureshi

xblocks_contrib/lti/lti.py

@@ -59,6 +59,7 @@
 import datetime
 import hashlib
 import logging
+import markupsafe
 import textwrap
 from xml.sax.saxutils import escape
 from unittest import mock
@@ -81,13 +82,12 @@
     from xblockutils.resources import ResourceLoader
     from xblockutils.studio_editable import StudioEditableXBlockMixin
 
-from openedx.core.djangolib.markup import HTML, Text
 from .lti_2_util import LTI20BlockMixin, LTIError
 
-from common.djangoapps.xblock_django.constants import (
-    ATTR_KEY_ANONYMOUS_USER_ID,
-    ATTR_KEY_USER_ROLE,
-)
+# The anonymous user ID for the user in the course.
+ATTR_KEY_ANONYMOUS_USER_ID = 'edx-platform.anonymous_user_id'
+# The user's role in the course ('staff', 'instructor', or 'student').
+ATTR_KEY_USER_ROLE = 'edx-platform.user_role'
 
 resource_loader = ResourceLoader(__name__)
 
@@ -228,47 +228,47 @@ class LTIBlock(
 
     lti_id = String(
         display_name=_("LTI ID"),
-        help=Text(_(
+        help=markupsafe.escape(_(
             "Enter the LTI ID for the external LTI provider.  "
             "This value must be the same LTI ID that you entered in the "
             "LTI Passports setting on the Advanced Settings page."
             "{break_tag}See {docs_anchor_open}the edX LTI documentation{anchor_close} for more details on this setting."
         )).format(
-            break_tag=HTML(BREAK_TAG),
-            docs_anchor_open=HTML(DOCS_ANCHOR_TAG_OPEN),
-            anchor_close=HTML("</a>")
+            break_tag=markupsafe.Markup(BREAK_TAG),
+            docs_anchor_open=markupsafe.Markup(DOCS_ANCHOR_TAG_OPEN),
+            anchor_close=markupsafe.Markup("</a>")
         ),
         default='',
         scope=Scope.settings
     )
 
     launch_url = String(
         display_name=_("LTI URL"),
-        help=Text(_(
+        help=markupsafe.escape(_(
             "Enter the URL of the external tool that this component launches. "
             "This setting is only used when Hide External Tool is set to False."
             "{break_tag}See {docs_anchor_open}the edX LTI documentation{anchor_close} for more details on this setting."
         )).format(
-            break_tag=HTML(BREAK_TAG),
-            docs_anchor_open=HTML(DOCS_ANCHOR_TAG_OPEN),
-            anchor_close=HTML("</a>")
+            break_tag=markupsafe.Markup(BREAK_TAG),
+            docs_anchor_open=markupsafe.Markup(DOCS_ANCHOR_TAG_OPEN),
+            anchor_close=markupsafe.Markup("</a>")
         ),
         default='http://www.example.com',
         scope=Scope.settings)
-    
+
     custom_parameters = List(
         display_name=_("Custom Parameters"),
-        help=Text(_(
+        help=markupsafe.escape(_(
             "Add the key/value pair for any custom parameters, such as the page your e-book should open to or "
             "the background color for this component."
             "{break_tag}See {docs_anchor_open}the edX LTI documentation{anchor_close} for more details on this setting."
         )).format(
-            break_tag=HTML(BREAK_TAG),
-            docs_anchor_open=HTML(DOCS_ANCHOR_TAG_OPEN),
-            anchor_close=HTML("</a>")
+            break_tag=markupsafe.Markup(BREAK_TAG),
+            docs_anchor_open=markupsafe.Markup(DOCS_ANCHOR_TAG_OPEN),
+            anchor_close=markupsafe.Markup("</a>")
         ),
         scope=Scope.settings)
-    
+
     open_in_a_new_page = Boolean(
         display_name=_("Open in New Page"),
         help=_(
@@ -333,7 +333,7 @@ class LTIBlock(
         default=False,
         scope=Scope.settings
     )
-    
+
     ask_to_send_email = Boolean(
         display_name=_("Request user's email"),
         # Translators: This is used to request the user's email for a third party service.
@@ -367,7 +367,7 @@ class LTIBlock(
         default=True,
         scope=Scope.settings
     )
-    
+
     editable_fields = (
         "accept_grades_past_due", "button_text", "custom_parameters", "display_name",
         "hide_launch", "description", "lti_id", "launch_url", "open_in_a_new_page",
@@ -959,12 +959,12 @@ def verify_oauth_body_sign(self, request, content_type='application/x-www-form-u
 
         if (not signature.verify_hmac_sha1(mock_request_lti_1, client_secret) and not
                 signature.verify_hmac_sha1(mock_request_lti_2, client_secret)):
-            log.error("OAuth signature verification failed, for "
-                      "headers:{} url:{} method:{}".format(
-                          oauth_headers,
-                          self.get_outcome_service_url(),
-                          str(request.method)
-                      ))
+            log.error(
+                "OAuth signature verification failed, for "
+                "headers:{} url:{} method:{}".format(
+                    oauth_headers, self.get_outcome_service_url(), str(request.method)
+                )
+            )
             raise LTIError("OAuth signature verification has failed.")
 
     def get_client_key_secret(self):
@@ -996,4 +996,3 @@ def is_past_due(self):
         else:
             close_date = due_date
         return close_date is not None and datetime.datetime.now(UTC) > close_date
-

xblocks_contrib/lti/lti_2_util.py

@@ -8,6 +8,7 @@
 import hashlib
 import json
 import logging
+import math
 import re
 from unittest import mock
 from urllib import parse
@@ -17,8 +18,6 @@
 from webob import Response
 from xblock.core import XBlock
 
-from openedx.core.lib.grade_utils import round_away_from_zero
-
 log = logging.getLogger(__name__)
 
 LTI_2_0_REST_SUFFIX_PARSER = re.compile(r"^user/(?P<anon_id>\w+)", re.UNICODE)
@@ -154,6 +153,26 @@ def parse_lti_2_0_handler_suffix(self, suffix):
         log.info(f"[LTI]: {msg}")
         raise LTIError(msg)
 
+    def _round_away_from_zero(number, digits=0):
+        """
+        Round numbers using the 'away from zero' strategy as opposed to the
+        'Banker's rounding strategy.' The strategy refers to how we round when
+        a number is half way between two numbers.  eg. 0.5, 1.5, etc. In python 3
+        numbers round towards even. So 0.5 would round to 0 but 1.5 would round to 2.
+
+        See here for more on floating point rounding strategies:
+        https://en.wikipedia.org/wiki/IEEE_754#Rounding_rules
+
+        We want to continue to round away from zero so that student grades remain
+        consistent and don't suddenly change.
+        """
+        p = 10.0 ** digits
+
+        if number >= 0:
+            return float(math.floor((number * p) + 0.5)) / p
+        else:
+            return float(math.ceil((number * p) - 0.5)) / p
+
     def _lti_2_0_result_get_handler(self, request, real_user):
         """
         Helper request handler for GET requests to LTI 2.0 result endpoint
@@ -176,7 +195,7 @@ def _lti_2_0_result_get_handler(self, request, real_user):
             return Response(json.dumps(base_json_obj).encode('utf-8'), content_type=LTI_2_0_JSON_CONTENT_TYPE)
 
         # Fall through to returning grade and comment
-        base_json_obj['resultScore'] = round_away_from_zero(self.module_score, 2)
+        base_json_obj['resultScore'] = self._round_away_from_zero(self.module_score, 2)
         base_json_obj['comment'] = self.score_comment
         return Response(json.dumps(base_json_obj).encode('utf-8'), content_type=LTI_2_0_JSON_CONTENT_TYPE)