[FIXED] Passing Parameters to Django CreateView

Issue

I am trying to implement an appointment-making application where users can create sessions that are associated with pre-existing classes. What I am trying to do is use a django CreateView to create a session without asking the user for an associated class, while under the hood assigning a class to the session. I am trying to do this by passing in the pk of the class in the url, so that I can look up the class within the CreateView and assign the class to the session.

What I can't figure out is how exactly to do this. I'm guessing that in the template I want to have something like <a href="{% url create_sessions %}?class={{ object.pk }}>Create Session</a> within a DetailView for the class, and a url in my urls.py file containing the line url(r'^create-sessions?class=(\d+)/$', CreateSessionsView.as_view(), name = 'create_sessions'), but I'm pretty new to django and don't exactly understand where this parameter is sent to my CBV (Class-Based View) and how to make use of it.

My plan for saving the class to the session is by overriding form_valid in my CBV to be:

def form_valid(self, form):
    form.instance.event = event
    return super(CreateSessionsView, self).form_valid(form)

If this is blatantly incorrect please let me know, as well.

Thank you!

Solution

GET parameters (those after ?) are not part of the URL and aren't matched in urls.py: you would get that from the request.GET dict. But it's much better to make that parameter part of the URL itself, so it would have the format "/create-sessions/1/".

So the urlconf would be:

url(r'^create-sessions/(?P<class>\d+)/$', CreateSessionsView.as_view(), name='create_sessions')

and the link can now be:

<a href="{% url create_sessions class=object.pk %}">Create Session</a>

and now in form_valid you can do:

event = Event.objects.get(pk=self.kwargs['class'])

Answered By - Daniel Roseman