add markov RPC method for generating a line from a context

markov/lib.py

@@ -164,6 +164,10 @@ def get_word_out_of_states(states, backwards=False):
     new_word = ''
     running = 0
     count_sum = states.aggregate(Sum('count'))['count__sum']
+    if not count_sum:
+        # this being None probably means there's no data for this context
+        raise ValueError("no markov states to generate from")
+
     hit = random.randint(0, count_sum)
 
     log.debug("sum: {0:d} hit: {1:d}".format(count_sum, hit))

markov/urls.py

@@ -1,11 +1,12 @@
 """URL patterns for markov stuff."""
-
-from django.conf.urls import url
+from django.urls import path
 from django.views.generic import TemplateView
 
-from markov.views import context_index
+from markov.views import context_index, rpc_generate_line_for_context
 
 urlpatterns = [
-    url(r'^$', TemplateView.as_view(template_name='index.html'), name='markov_index'),
-    url(r'^context/(?P<context_id>\d+)/$', context_index, name='markov_context_index'),
+    path('', TemplateView.as_view(template_name='index.html'), name='markov_index'),
+    path('context/<int:context_id>/', context_index, name='markov_context_index'),
+
+    path('rpc/context/<context>/generate/', rpc_generate_line_for_context, name='markov_rpc_generate_line'),
 ]

markov/views.py

@@ -1,16 +1,19 @@
 """Manipulate Markov data via the Django site."""
-
+import json
 import logging
 import time
 
 from django.http import HttpResponse
 from django.shortcuts import get_object_or_404, render
+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
 
 import markov.lib as markovlib
 from markov.models import MarkovContext
 
-
-log = logging.getLogger('markov.views')
+logger = logging.getLogger(__name__)
 
 
 def index(request):
@@ -28,3 +31,33 @@ def context_index(request, context_id):
     end_t = time.time()
 
     return render(request, 'markov/context.html', {'chain': chain, 'context': context, 'elapsed': end_t - start_t})
+
+
+@api_view(['POST'])
+@authentication_classes((BasicAuthentication, ))
+@permission_classes((IsAuthenticated, ))
+def rpc_generate_line_for_context(request, context):
+    """Generate a line from a given context, with optional topics included."""
+    if request.method != 'POST':
+        return Response({'detail': "Supported method: POST."}, status=405)
+
+    topics = None
+    try:
+        if request.body:
+            markov_data = json.loads(request.body)
+            topics = markov_data.get('topics', [])
+    except (json.decoder.JSONDecodeError, KeyError):
+        return Response({'detail': "Request body, if provided, must be JSON with an optional 'topics' parameter."},
+                        status=400)
+
+    context_id = markovlib.get_or_create_target_context(context)
+    try:
+        generated_words = markovlib.generate_line(context_id, topics)
+    except ValueError as vex:
+        return Response({'detail': f"Could not generate line: {vex}", 'context': context, 'topics': topics},
+                        status=400)
+    else:
+        return Response({
+            'context': context, 'topics': topics,
+            'generated_line': ' '.join(generated_words), 'generated_words': generated_words
+        })