Add django-downloadview to the used packages. Add a Mayan generic sub class download view based on django-downloadviews' virtual download view class.

mayan/apps/common/generics.py

@@ -8,11 +8,15 @@ from django.utils.translation import ugettext_lazy as _
 from django.views.generic import (
     FormView as DjangoFormView, DetailView, TemplateView
 )
+from django.views.generic.base import ContextMixin
+from django.views.generic.detail import SingleObjectMixin
 from django.views.generic.edit import (
     CreateView, DeleteView, ModelFormMixin, UpdateView
 )
 from django.views.generic.list import ListView
 
+from django_downloadview import VirtualDownloadView
+from django_downloadview import VirtualFile
 from pure_pagination.mixins import PaginationMixin
 
 from .forms import ChoiceForm
@@ -344,6 +348,10 @@ class SingleObjectDetailView(ViewPermissionCheckMixin, ObjectPermissionCheckMixi
         return context
 
 
+class SingleObjectDownloadView(ViewPermissionCheckMixin, ObjectPermissionCheckMixin, VirtualDownloadView, SingleObjectMixin):
+    VirtualFile = VirtualFile
+
+
 class SingleObjectEditView(ObjectNameMixin, ViewPermissionCheckMixin, ObjectPermissionCheckMixin, ExtraContextMixin, RedirectionMixin, UpdateView):
     template_name = 'appearance/generic_form.html'