Reduce the number of database queries in the view.

home/forms.py

@@ -31,7 +31,7 @@ def make_choices(question: Question) -> list[tuple[str, str]]:
 
 
 class BaseSurveyForm(forms.Form):
-    def __init__(self, survey, user, *args, **kwargs):
+    def __init__(self, *args, survey, user, **kwargs):
         self.survey = survey
         self.user = user if user.is_authenticated else None
         self.field_names = []
@@ -138,6 +138,9 @@ def clean(self):
 
 
 class CreateUserSurveyResponseForm(BaseSurveyForm):
+    def __init__(self, *args, instance, user, **kwargs):
+        super().__init__(*args, survey=instance, user=user, *args, **kwargs)
+
     @transaction.atomic
     def save(self):
         cleaned_data = super().clean()
@@ -161,12 +164,10 @@ def save(self):
 
 
 class UserSurveyResponseForm(BaseSurveyForm):
-    def __init__(self, user_survey_response, *args, **kwargs):
-        self.survey = user_survey_response.survey
-        self.user_survey_response = user_survey_response
-        super().__init__(
-            survey=self.survey, user=user_survey_response.user, *args, **kwargs
-        )
+    def __init__(self, *args, instance, **kwargs):
+        self.survey = instance.survey
+        self.user_survey_response = instance
+        super().__init__(*args, survey=self.survey, user=instance.user, *args, **kwargs)
         self._set_initial_data()
 
     def _set_initial_data(self):

home/tests/test_forms.py

@@ -34,7 +34,7 @@ def setUpTestData(cls):
             cls.question_ids[type_field] = question.id
 
     def test_initialize_form(self):
-        form = CreateUserSurveyResponseForm(survey=self.survey, user=self.user)
+        form = CreateUserSurveyResponseForm(instance=self.survey, user=self.user)
         self.assertEqual(
             set(form.field_names),
             {f"field_survey_{value}" for value in self.question_ids.values()},
@@ -43,7 +43,7 @@ def test_initialize_form(self):
     def test_rating_validator_cannot_be_less_than_1(self):
         rating_field_name = f"field_survey_{self.question_ids['RATING']}"
         form = CreateUserSurveyResponseForm(
-            survey=self.survey,
+            instance=self.survey,
             user=self.user,
             data={rating_field_name: "0"},
         )
@@ -56,7 +56,7 @@ def test_rating_validator_cannot_be_less_than_1(self):
     def test_rating_validator_must_be_number(self):
         rating_field_name = f"field_survey_{self.question_ids['RATING']}"
         form = CreateUserSurveyResponseForm(
-            survey=self.survey,
+            instance=self.survey,
             user=self.user,
             data={rating_field_name: "H"},
         )
@@ -67,7 +67,7 @@ def test_rating_validator_must_be_number(self):
     def test_rating_validator_cannot_be_greater_than_max(self):
         rating_field_name = f"field_survey_{self.question_ids['RATING']}"
         form = CreateUserSurveyResponseForm(
-            survey=self.survey,
+            instance=self.survey,
             user=self.user,
             data={rating_field_name: "9"},
         )
@@ -80,7 +80,7 @@ def test_rating_validator_cannot_be_greater_than_max(self):
 
     def test_save_fields_required(self):
         form = CreateUserSurveyResponseForm(
-            survey=self.survey,
+            instance=self.survey,
             user=self.user,
             data={},
         )
@@ -93,7 +93,7 @@ def test_save_fields_required(self):
 
     def test_save_valid(self):
         form = CreateUserSurveyResponseForm(
-            survey=self.survey,
+            instance=self.survey,
             user=self.user,
             data={
                 f"field_survey_{self.question_ids['RADIO']}": "yes",

home/tests/test_user_survey_response_form_views.py

@@ -82,28 +82,40 @@ def setUpTestData(cls):
             name="Test Survey", description="This is a description of the survey!"
         )
         cls.user = UserFactory.create()
-        cls.question = QuestionFactory.create(
+        cls.question_1 = QuestionFactory.create(
             survey=cls.survey,
             label="How are you?",
         )
+        cls.question_2 = QuestionFactory.create(
+            survey=cls.survey,
+            label="What is your favourite food?",
+        )
         cls.survey_response = UserSurveyResponseFactory(
             survey=cls.survey, user=cls.user
         )
         UserQuestionResponseFactory(
             user_survey_response=cls.survey_response,
-            question=cls.question,
+            question=cls.question_1,
             value="Very good",
         )
+        UserQuestionResponseFactory(
+            user_survey_response=cls.survey_response,
+            question=cls.question_2,
+            value="Pizza",
+        )
         cls.url = reverse("user_survey_response", kwargs={"pk": cls.survey_response.id})
 
     def test_success_get(self):
         self.client.force_login(self.user)
-        response = self.client.get(self.url)
+        with self.assertNumQueries(2):
+            response = self.client.get(self.url)
         self.assertEqual(response.status_code, 200)
         self.assertContains(response, "Test Survey")
         self.assertContains(response, "This is a description of the survey!")
         self.assertContains(response, "How are you?")
         self.assertContains(response, "Very good")
+        self.assertContains(response, "What is your favourite food?")
+        self.assertContains(response, "Pizza")
         self.assertNotContains(response, "Submit")
 
     def test_cannot_view_others_survey_response(self):

home/views.py

@@ -5,17 +5,19 @@
 from django.contrib import messages
 from django.contrib.auth.mixins import LoginRequiredMixin
 from django.contrib.auth.mixins import UserPassesTestMixin
+from django.db.models import Prefetch
 from django.shortcuts import render
 from django.urls import reverse_lazy
 from django.views.generic.detail import DetailView
-from django.views.generic.edit import FormMixin
+from django.views.generic.edit import ModelFormMixin
 from django.views.generic.list import ListView
 
 from .forms import CreateUserSurveyResponseForm
 from .forms import UserSurveyResponseForm
 from .models import Event
 from .models import Session
 from .models import Survey
+from .models import UserQuestionResponse
 from .models import UserSurveyResponse
 
 
@@ -106,30 +108,29 @@ def get_queryset(self):
 
 
 class CreateUserSurveyResponseFormView(
-    LoginRequiredMixin, UserPassesTestMixin, FormMixin, DetailView
+    LoginRequiredMixin, UserPassesTestMixin, ModelFormMixin, DetailView
 ):
     model = Survey
-    object = None
     form_class = CreateUserSurveyResponseForm
     success_url = reverse_lazy("session_list")
     template_name = "home/surveys/form.html"
 
     def test_func(self):
-        survey = self.get_object()
         user = self.request.user
         return (
             user.profile.email_confirmed
-            and not UserSurveyResponse.objects.filter(survey=survey, user=user).exists()
+            and not UserSurveyResponse.objects.filter(
+                survey_id=self.kwargs.get(self.pk_url_kwarg), user=user
+            ).exists()
         )
 
     def get_form_kwargs(self):
         kwargs = super().get_form_kwargs()
-        kwargs["survey"] = self.get_object()
         kwargs["user"] = self.request.user
         return kwargs
 
     def get_context_data(self, **kwargs):
-        survey = self.get_object()
+        survey = self.object
         kwargs["title_page"] = survey.name
         kwargs["sub_title_page"] = survey.description
         return super().get_context_data(**kwargs)
@@ -147,25 +148,28 @@ def post(self, request, *args, **kwargs):
 
 
 class UserSurveyResponseView(
-    LoginRequiredMixin, UserPassesTestMixin, FormMixin, DetailView
+    LoginRequiredMixin, UserPassesTestMixin, ModelFormMixin, DetailView
 ):
     model = UserSurveyResponse
     form_class = UserSurveyResponseForm
     success_url = reverse_lazy("session_list")
     template_name = "home/surveys/form.html"
 
-    def test_func(self):
-        survey_response = self.get_object()
-        user = self.request.user
-        return user == survey_response.user
+    def get_queryset(self):
+        return UserSurveyResponse.objects.select_related("survey").prefetch_related(
+            Prefetch(
+                "userquestionresponse_set",
+                queryset=UserQuestionResponse.objects.select_related("question"),
+            )
+        )
 
-    def get_form_kwargs(self):
-        kwargs = super().get_form_kwargs()
-        kwargs["user_survey_response"] = self.get_object()
-        return kwargs
+    def test_func(self):
+        return UserSurveyResponse.objects.filter(
+            user=self.request.user, id=self.kwargs.get(self.pk_url_kwarg)
+        ).exists()
 
     def get_context_data(self, **kwargs):
-        survey = self.get_object().survey
+        survey = self.object.survey
         kwargs["title_page"] = survey.name
         kwargs["sub_title_page"] = survey.description
         kwargs["read_only"] = True