Django pass URL parameter to custom FormMixin - django

Question

I have a page in my web app that can be accessed by the URL like this:
http://localhost:8000/organizations/list_student/?school_id=19
I'd like access to the school_id from the URL above for one of the form mixins, named PhoneNumberMixin (please see below). Could someone who's knowledgeable about Django tell me how I should pass that URL parameter into custom form mixin like PhoneNumberMixin? Thank you.
In models.py:
class Student(models.Model):
school = models.ForeignKey(School)
phone_number = models.CharField(max_length=15, blank=True)
In urls.py:
urlpatterns = patterns('',
# There are more, but to save space, only relevant part is included
url(r'^list_student/$', StudentListView.as_view(), name='list_student'),
)
In views.py for the page:
class StudentListView(LoginRequiredMixin, FormView):
form_class = SchoolAddStudentForm
template_name = 'organizations/list_student.html'
def get_success_url(self):
return reverse_lazy('organizations:list_student') + '?school_id=' + self.request.GET['school_id']
def get_form(self, form_class):
request = self.request
return form_class(request, **self.get_form_kwargs())
def get_context_data(self, **kwargs):
# add stuff to data to pass to HTML page here
return data
def form_valid(self, form):
data = form.cleaned_data
# save cleaned data to DB here
return HttpResponseRedirect(self.get_success_url())
In forms.py,
# Note PhoneNumberFormMixin below. It is used to clean phone numbers
# such duplicate checking against the existing numbers in the DB
class SchoolAddStudentForm(PhoneNumberFormMixin, forms.Form):
phone_numbers = forms.CharField(widget=forms.Textarea(attrs=form_attrs))
def __init__(self, request, *args, **kwargs):
super(SchoolAddStudentForm, self).__init__(*args, **kwargs)
self.fields['phone_numbers'].label = 'Step 1 (required): Add comma-separated list of phone numbers [E.g., 5856261234, 8613910912345]:'
In mixins.py:
class PhoneNumberFormMixin(object):
"""
Custom form mixin for validating phone numbers
"""
def clean_phone_numbers(self):
data = self.data
numbers = []
sid = #!!!! this is where I'd like to access school_id from the URL
qs = Student.objects.filter(school_id=sid)
# do something with the qs
return ','.join(numbers)

Answer 1

I'm not sure I have a full picture as you're missing views.py & urls.py. But generally, field cleaning methods should only check that an input is correctly formatted, and the actual application logic should be located in your view's form_valid() method. Form() methods don't have access to HTTP request information precisely because it is outside the scope of their functionality.
From your view, you can access the URL parameter with:
self.request.GET.get('school_id', None)
Read up on form_valid() -- this is where you should add code to modify an object + field values before it's saved, and / or create related objects if needed.

Answer 2

In my usecase I'm doing a search which displays a list of search results.
I ended up using this:
class SearchView(FormMixin, ListView):
def get_queryset(self):
qs = super().get_queryset()
# TODO implement filtering
return qs
def get_form_kwargs(self):
# use GET parameters as the data
kwargs = super().get_form_kwargs()
if self.request.method in ('GET'):
kwargs.update({
'data': self.request.GET,
})
return kwargs