How to redirect an UpdateView upon success? - django

Question

I created a small Django application to manage data that fits a simple a model. For now I only need two views: one to list all records and another to edit a record with a generic form. Everything functions as expected, except the redirection from the edit view upon a successful update. In urls.py are the following contents:
from django.urls import path
from . import views
app_name = 'reqs'
urlpatterns = [
path('', views.IndexView.as_view(), name='index'),
path('<int:pk>/', views.ReqUpdateView.as_view(), name='update'),
]
In forms.py:
from django.forms import ModelForm
from .models import Requirement
class RequirementForm(ModelForm):
class Meta:
model = Requirement
fields = ['name', 'priority', 'source' , 'rationale']
And the templeate requirement_form.html:
<h1>{{ requirement.id }} - {{ requirement.name }}</h1>
<form method="post" novalidate>
{% csrf_token %}
<table>
{{ form.as_table }}
<tr><td></td><td><button type="submit">Save</button></td></tr>
</table>
</form>
{% if error_message %}<p><strong>{{ error_message }}</strong></p>{% endif %}
<br><br>
Back to list
Finally views.py, on a first attempt to redirect the update to the list:
from django.views.generic import ListView, UpdateView
from django.urls import reverse_lazy
from .models import Requirement
from .forms import RequirementForm
class IndexView(ListView):
template_name = 'reqs/index.html'
context_object_name = 'requirements_list'
def get_queryset(self):
return Requirement.objects.order_by('subject')
class ReqUpdateView(UpdateView):
model = Requirement
form_class = RequirementForm
success_url = reverse_lazy('/')
With this formulation the Save button produces this error:
Reverse for '/' not found. '/' is not a valid view function or pattern name.
I also tried an empty string as argument to reverse_lazy, as well as the path name index, but a similar error message is produced.
On a second attempt I tried to redirect to the same page, redefining the get_success_url method to do nothing:
class ReqUpdateView(UpdateView):
model = Requirement
form_class = RequirementForm
context_object_name = 'requirement_update'
def get_success_url(self):
pass #return the appropriate success url
This returns a 404 error trying to redirect the browser to /reqs/1/None.
A third attempt to redirect to the form with the same record:
class ReqUpdateView(UpdateView):
model = Requirement
form_class = RequirementForm
context_object_name = 'requirement_update'
def get_success_url(self):
pk = self.kwargs["pk"]
return reverse("update", kwargs={"pk": pk})
Which complains about not finding the view:
Reverse for 'update' not found. 'update' is not a valid view function or pattern name.
How can I redirect success to a valid URL? It can either be the items list or the item update view, as long as it works.

Answer 1

There are few misconception that you did
reverse parameter should be as documented
URL pattern name or the callable view object
You have set namespace but you are not reversing with namespace as documented
So in your case
def get_success_url(self):
pk = self.kwargs["pk"]
return reverse("reqs:update", kwargs={"pk": pk})

Answer 2

reverse / reverse_lazy are used to get the url using view name or pattern name. If you want to use a url directly just write:
success_url = '/'
For the case of return reverse("update", kwargs={"pk": pk}) not working since you set app_name = 'reqs' you should be using return reverse("reqs:update", kwargs={"pk": pk}) instead.