basic json caching

anatomy/migrations/0004_auto_20201123_1619.py

@@ -0,0 +1,25 @@
+# Generated by Django 3.1.2 on 2020-11-23 16:19
+
+import anatomy.models
+import django.core.files.storage
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('anatomy', '0003_auto_20201119_1941'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='exam',
+            name='recreate_json',
+            field=models.BooleanField(default=False, help_text='If the json cache needs updating'),
+        ),
+        migrations.AlterField(
+            model_name='anatomyquestion',
+            name='image',
+            field=models.ImageField(storage=django.core.files.storage.FileSystemStorage(base_url='http://161.35.163.87//media/anatomy/', location='/home/ross/sites/rad/media//anatomy/'), upload_to=anatomy.models.image_directory_path),
+        ),
+    ]

anatomy/models.py

@@ -195,6 +195,9 @@ class Exam(models.Model):
     active = models.BooleanField(help_text="If an exam should be available",
                                  default=True)
 
+    recreate_json = models.BooleanField(help_text="If the json cache needs updating",
+                                 default=False)
+
     def __str__(self):
         return self.name
 

anatomy/templates/anatomy/exam_overview.html

@@ -12,6 +12,7 @@
 <li>{{ question }}</lid>
         {% endfor %}
 </ol>
+<a href="{% url 'anatomy:exam_json' pk=exam.pk %}">JSON</a>
 
 </div>
 {% endblock %}

anatomy/views.py

@@ -8,7 +8,8 @@ from django.contrib.auth.models import User
 
 from django.db.models.functions import Lower
 
-from django.http import Http404, JsonResponse
+from django.core.cache import cache
+
 
 from .forms import AnatomyAnswerForm, MarkAnatomyQuestionForm
 from .models import (
@@ -453,11 +454,18 @@ def active_exams(request):
 
 
 def exam_json(request, pk):
+
     exam = get_object_or_404(Exam, pk=pk)
 
     if not exam.active:
         raise Http404("No available exam")
 
+    exam_json_cache = cache.get("exam_json_{}".format(pk))
+
+    if exam_json_cache is not None and not exam.recreate_json:
+        return JsonResponse(exam_json)
+
+
     questions = exam.exam_questions.all()
 
     exam_questions = defaultdict(dict)
@@ -470,13 +478,18 @@ def exam_json(request, pk):
             "type": "anatomy",
         }
 
-        exam_json = {
-            "eid": exam.id,
-            "exam_type": "anatomy",
-            "exam_name": exam.name,
-            "exam_mode": True,
-            "questions": exam_questions,
-        }
+    exam_json = {
+        "eid": exam.id,
+        "exam_type": "anatomy",
+        "exam_name": exam.name,
+        "exam_mode": True,
+        "questions": exam_questions,
+    }
+
+    exam.recreate_json = False
+
+    cache.set("exam_json_{}".format(pk), exam_json, 3600)
+
     return JsonResponse(exam_json)