Django - Checkboxes & ManytoMany relationships in TemplateView - django

Question

I have a app where users can register their company and then select a number of settings from a list. Both the company and services are different models.
class Company(models.Model):
name = models.CharField(max_length=100)
(...)
class Service(models.Model):
name = models.CharField(max_length=100)
linked_companies = ManyToManyField(Company, blank=True)
What I want is to have a large list of services, with checkboxes behind their names, so the owner can quickly select the services that he wants to connect to his model. This used to be done through the admin interface, but due popular demand this feature is moved to 'the front'.
The problem is that I do not know how to fit this into the traditional (generic) view/form combinations that we' ve been using so far, since two different models are involved.
I am trying a more custom solution, but have hit a wall and I am wondering if you could help me. I have created a html page that should display both the list of services and a 'save' button.
<form action="." method="POST" class="post-form">{% csrf_token %}
<ul>
{% recursetree services %}
<li>
<label><input type="checkbox" name='service' value={{ node.pk }}><h3>{{ node.name }}</h3></label>
{% if not node.is_leaf_node %}
<ul class="children">
{{ children }}
</ul>
{% endif %}
</li>
{% endrecursetree %}
</ul>
<button type="submit" class="save btn btn-default">Add Selected
</button>
</form>
I am using the following ModelForm:
class FacetForm(forms.ModelForm):
class Meta:
model = Services
fields = ['linked_tenants', 'name']
widgets = {
'linked_tenants' : CheckboxSelectMultiple()
}
This HTML page seems to work as intended, showing a long list of services with checkboxes after their names.
However, I have trouble creating a function view. Together with a collegue the following view was created
class FacetList(TenantRootedMixin, TemplateView):
def get_context_data(self, **kwargs):
d = super(ServiceList, self).get_context_data(**kwargs)
d['services'] = Services.objects.all()
d['current_company'] = self.context.company.id
return d
def form_valid(self, *args, **kwargs):
return super(ServiceList, self).form_valid(*args, **kwargs)
This view works in the sense that it shows all of the relevant information (with the checkboxes). If I change the query to filter the services by 'company id'. the view works as desired as well.
The problems I have revolve around the fact that pressing 'save'. crashes the program, throwing the following error.
'super' object has no attribute 'post'
Our program works mostly through generic classbased views and modelforms, so we have relativly limited experience with creating our own custom solutions. By my own estimation the problem seems to be twofold:
The view is probably not configured right to process the 'post' data
It is questionable if the data will be processed to the database afterwards.
Though are 'sollution' is currently flawed, are we looking in the right direction? Are we on the right way to solve our problem?
Regards

Answer 1

I believe you are on the right track. What I would suggest is to not be afraid to move away from generic views and move toward a more custom solution (even if you are inexperienced with it.)
The first routine that comes to my mind would be as follows:
gather all the id's that were checked by the user into a list from request.POST
Update the appropriate object's M2M field to contain these new id's.
Save the fore-mentioned object.
[Edit]
One thing I have trouble with is gathering the ID' s from the request.POST. Could you provide me with an example on how to do this?
Sure, from your HTML file I see you are creating inputs with name=service. That leads me to believe you could do something like:
ids = request.POST.get('service')
but to teach you how to fish rather than giving you a fish, you should try to simply:
print request.POST.items()
This will return and print to the console everything that was posted from your form to your view function. Use this to find out if you are getting a list of id's from the template to the server. If not, you may have to re-evaluate how you are building your form in your template.

Answer 2

Your first point is correct: TemplateView has no "post" method defined and that is why you get the error message when you call super().form_valid. You must either define it yourself or use a CBV which has a post method that you can override (e.g. UpdateView)
And I also believe that your second point is correct.
You would need to use an UpdateView to use the built in functionality (or CreateView).
I had a similar problem to solve (selecting values from many-to-many fields in the front-end) and I ended up with doing it "by hand" because I could not get it to work with CBV. "by-hand" => parse the values from the form, update the database, return HttpResponse
You might want to look at ModelFormSets:
https://docs.djangoproject.com/en/1.11/topics/forms/modelforms/#model-formsets
Hope this helps!
Alex