Убрал ошибку с нахождением pk в форме создания урока. Доработал работу с файлом

source/portal/urls.py

 from django.contrib import admin
 from django.urls import path, include
+from django.conf import settings
+from django.conf.urls.static import static
+
 
 
 urlpatterns = [
     path('admin/', admin.site.urls),
     path('', include('webapp.urls')),
     path('accounts/', include('accounts.urls'))
-]
+] + static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)
\ No newline at end of file

source/webapp/models.py

@@ -38,6 +38,9 @@ class Class(models.Model):
     def __str__(self):
         return self.title
 
+    def get_absolute_url(self):
+        return reverse("webapp:course_detail", args=[str(self.id)])
+
     class Meta:
         verbose_name = "Class"
         verbose_name_plural = "Classes"

source/webapp/templates/classes/create.html

@@ -7,7 +7,7 @@
     <hr>
     <h1>Create new Class</h1>
     <div class='column-center'>
-        <form action="{% url "webapp:class_create" %}" method="POST">
+        <form action="{% url "webapp:class_create" course_pk %}" method="POST" enctype="multipart/form-data">
             {% include "partial/create_form.html" with button_text="Create new class" %}
         </form>
     </div>

source/webapp/templates/courses/courses_list.html

@@ -13,8 +13,9 @@
                     <a class="p-2" href="{% url 'webapp:course_delete' course.id %}"> <i class="fas fa-trash-alt"></i> </a>
                 </div>
                 <div class="card-body" style="height: 200px;">
+                <div class='topic-name' style="height: 50px;">
                     <a class="card-title" href="{% url 'webapp:course_detail' course.id %}"> <h5>{{course.title}}</h5> </a>
-                    <p class="card-text"> {{ course.description|truncatewords:30 }} </p>
+                </div>    
                     <p class="card-text"> <b>Teacher:</b> {{course.teacher}} </p>
                     <p class="card-text"> <b>Groups(s):</b>
                     {% for group in course.group.all %} {{group}} {% endfor %}

source/webapp/templates/courses/create.html

@@ -6,6 +6,7 @@
     <a href="{% url "webapp:courses_list" %}">Return to the main page..</a>
     <hr>
     <h1>Create new Course</h1>
+    {{course}}
     <div class='column-center'>
         <form action="{% url "webapp:course_create" %}" method="POST">
             {% include "partial/create_form.html" with button_text="Create new course" %}

source/webapp/templates/courses/detail.html

@@ -19,19 +19,19 @@
                 </blockquote>
             </div>
             <div style="width: 150px; height: 70px; margin: 20px;"> 
-                <a class='btn btn-primary' href="{% url "webapp:class_create" %}"> Create new week </a>
+                <a class='btn btn-primary' href="{% url "webapp:class_create" course.id %}"> Create new week </a>
             </div>
         </div>
     </div>
     {% for class in course.courses.all %}
-    <div class="card border-dark mb-3" style="max-width: 100%; height: 240px; margin: 15px auto;">
+    <div class="card border-dark mb-3" style="max-width: 100%; height: 260px; margin: 15px auto;">
         <div class="card-header"> 
             <h6 style="color: #3A63A7;"> Week #{{forloop.counter}} </h6>
         </div>
         <div class="card-body text-dark">
             <h5 class="card-title">Topic: {{ class.title }} </h5>
             <p class="card-text"> Description: {{ class.description }} </p>
-            {{ class.file }} 
+            <a href="{{ class.file.url }}"> See the lecture </a>
             <hr>
             <p> <b>Created at:</b> {{ class.created_at }} - <b>by:</b> {{ course.teacher }}</p>
         </div>

source/webapp/urls.py

@@ -10,5 +10,5 @@ urlpatterns = [
     path('course/new/', webapp_views.CourseCreateView.as_view(), name='course_create'), 
     path('course/<int:pk>/edit/', webapp_views.CourseEditView.as_view(), name='course_edit'),
 
-    path('courses/class/new', webapp_views.CreateClassView.as_view(), name='class_create')
+    path('course/<int:course_pk>/class/new', webapp_views.CreateClassView.as_view(), name='class_create')
 ]
\ No newline at end of file

source/webapp/views/classes_views.py

@@ -13,17 +13,17 @@ class CreateClassView(LoginRequiredMixin, PermissionRequiredMixin, CreateView):
     template_name = 'classes/create.html'
     permission_required = 'webapp.add_class'
     
+    def get_context_data(self,**kwargs):
+        kwargs['course_pk']=self.kwargs.get('course_pk')
+        return super().get_context_data(**kwargs)
+
     def form_valid(self, form):
-        course_pk = self.kwargs.get('pk')
+        course_pk = self.kwargs.get('course_pk')
         course = get_object_or_404(Course, pk=course_pk)
-        classweek = form.save(commit=False)
-        classweek.course = classweek
-        classweek.save()
+        classweek = form.save()
+        course.courses.add(classweek)
         return redirect("webapp:course_detail", course_pk=course.pk)
 
-    def get_success_url(self):
-        return reverse("webapp:course_detail", kwargs = {'project_pk': self.object.course.pk})
-
 
 class EditClassView(UpdateView):
     pass

source/webapp/views/courses_views.py

@@ -13,7 +13,7 @@ class CourseCreateView(LoginRequiredMixin, PermissionRequiredMixin, CreateView):
     template_name = 'courses/create.html'
     form_class = CourseForm
     model = Course 
-    pk_url_kwarg = 'project_pk'
+    pk_url_kwarg = 'course_pk'
     permission_required = 'webapp.add_course'
 
     def get_form(self, form_class=None):