Instantiating a ModelForm with initial values in CBVs - django

Question

I am a Django newbie working with Django CBVs and having difficulty setting initial values for my ModelForm. To give an overview, I am trying to learn by creating a simple messaging app.
Here is my code:
models.py
import datetime
from django.contrib.auth.models import User
from django.db import models
from django.utils.translation import ugettext_lazy as _
from django.utils import timezone
class Message(models.Model):
subject = models.CharField(_("Subject"), max_length=100)
body = models.TextField(_("Body"))
sender = models.ForeignKey(User, db_index=True, related_name='sent_messages')
recipient = models.ForeignKey(User, db_index=True, related_name='received_messages')
parent_msg = models.ForeignKey('self', related_name='next_messages', null=True, blank=True)
forms.py
from django.forms import ModelForm
from .models import Message
class MessageForm(ModelForm):
class Meta:
model = Message
exclude = ('sender', 'recipient', 'parent_msg',)
views.py
class MessageCreateView(CreateView):
form_class = MessageForm
model = Message
template_name = 'messages/compose.html'
def form_valid(self, form):
form.instance.sender = self.request.user
return super(MessageCreateView, self).form_valid(form)
urls.py
...
url(r'^compose/(?P<recipient>[\w.#+-]+)/$', MessageCreateView.as_view(), name='messages_compose_to'),
...
As you can see from the urls.py file, I am using the 'recipient' parameter as such: http://localhost:8000/members/compose/someusername
Now my problem is that I wish to open the compose message view, and initialize the recipient field by getting the username from the URL, then using the username from the url to get User with that particular username, and instantiate the form with it.
Where do I do this, in the view itself or in the form? Unless their is a better way of how to handle this.

Answer 1

You can add get_initial() method to return appropriate dict, something as below.
class MessageCreateView(CreateView):
...
def get_initial(self):
data = { 'recipient':
User.objects.get(username=self.kwargs.get('recipient'))
}
return data
Handle error appropriately.