add a dice rolling API view to the django app

dice/urls.py

@@ -0,0 +1,8 @@
+"""URL patterns for the dice views."""
+from django.urls import path
+
+from dice.views import rpc_roll_dice
+
+urlpatterns = [
+    path('rpc/roll/', rpc_roll_dice, name='dice_rpc_roll_dice'),
+]

dice/views.py

@@ -0,0 +1,36 @@
+"""Views for rolling dice."""
+import json
+import logging
+
+from rest_framework.authentication import BasicAuthentication
+from rest_framework.permissions import IsAuthenticated
+from rest_framework.response import Response
+from rest_framework.decorators import api_view, authentication_classes, permission_classes
+
+from dice.roller import DiceRoller
+
+logger = logging.getLogger(__name__)
+roller = DiceRoller()
+
+
+@api_view(['POST'])
+@authentication_classes((BasicAuthentication, ))
+@permission_classes((IsAuthenticated, ))
+def rpc_roll_dice(request):
+    """Get a dice string from the client, roll the dice, and give the result."""
+    if request.method != 'POST':
+        return Response({'detail': "Supported method: POST."}, status=405)
+
+    try:
+        roll_data = json.loads(request.body)
+        dice_str = roll_data['dice']
+    except (json.decoder.JSONDecodeError, KeyError):
+        return Response({'detail': "Request must be JSON with a 'dice' parameter."}, status=400)
+
+    try:
+        result_str = roller.do_roll(dice_str)
+        return Response({'dice': dice_str, 'result': result_str})
+    except AssertionError as aex:
+        return Response({'detail': f"Could not roll dice: {aex}"}, status=400)
+    except ValueError:
+        return Response({'detail': f"Could not parse requested dice '{dice_str}'."}, status=400)

dr_botzo/urls.py

@@ -13,6 +13,7 @@ admin.autodiscover()
 urlpatterns = [
     url(r'^$', TemplateView.as_view(template_name='index.html'), name='home'),
 
+    url(r'^dice/', include('dice.urls')),
     url(r'^dispatch/', include('dispatch.urls')),
     url(r'^itemsets/', include('facts.urls')),
     url(r'^karma/', include('karma.urls')),