Passing a variable from views.py to models.py django

Question

I am still very new to programming.

My issue is this I have 2 models, one for Sale and one for Agent.

now to render each Agent and the sales they made(with different attributes) uniquely I needed to write model methods under my sale model to allow to me to call them in the template.

Now my issue is this, I want to be able to render that exact thing but by what dates the user chooses, I have tried manually doing this through my project files and it works, but I want to know is it possible to have those values moved from user into my method? What I mean is there is a basic form in the nav bar that allows the person to choose a from and to date, but those values I am not sure how to pass them into my models.py under the method where I need this date range applied.

I will show an example.

#this is my view that grabs relevant dates
def asearch_stats(request):
    if request.method == 'POST':
        from_date = request.POST['from']
        to_date = request.POST['to']
        return render(request,"Sales/salesfilter.html",{"flookup":flookup})


# this is my model with the methods I'm referring to below:
class SalesAgent(models.Model):
    user = models.OneToOneField(User,on_delete=models.SET_NULL,null=True,related_name="sauser")
    SA_name = models.CharField(max_length=40)
    role = models.CharField(choices=Roles,default="default",max_length=13)
    def __str__(self):
        return self.user.username

    #FILTERED SEARCH
# I need those dates on the below ones to be the variables like something like this
    def get_dates(request):
        if request.method == 'POST':
            from_date = request.POST['from']
            to_date = request.POST['to']

    def sfget_totals(self):
        return self.agent_sale.filter(Date_created__gte=(from_date),Date_created__lte=(to_date))
    def sfget_confirmed(self):
        return self.agent_sale.filter(State="Confirmed",Date_created__gte=('2022-03-01'),Date_created__lte=('2022-03-02'))
    def sfget_debi(self):
        return self.agent_sale.filter(AcknowledgeQA=True,State="Confirmed",Debi_status="Accepted",Date_created__gte=('2022-03-01'),Date_created__lte=('2022-03-02'))
    def sfget_requested(self):
        return self.agent_sale.filter(Debi_status="Requested",Date_created__gte=('2022-03-01'),Date_created__lte=('2022-03-02'))
    def sfget_cancelled(self):
        return self.agent_sale.filter(State="Cancelled",Date_created__gte=('2022-03-01'),Date_created__lte=('2022-03-02'))
    def sfget_pending(self):
        return self.agent_sale.filter(State="Pending",Date_created__gte=('2022-03-01'),Date_created__lte=('2022-03-02'))

Answer 1

You can't. Models encapsulate and abstract database tables. Views exist at a higher level. A model cannot refer to "its" view, because a model instance can exist without any view at all. For example, when you are working in a management command, or the shell, or a Celery task.

Maybe these methods should be (Class-based) view methods, not object methods. There's no reason you cannot pass the view to the template. The Class-based views do his by default (as context variable view )

If you wish to have model instance methods that depend on from and to dates from the nav bar, you have to pass them in.

class SalesAgent(models.Model):
...

    def method(self, from_date, to_date)

You will invoke this method from your view(s), where it will be something like

   agent = SalesAgent.objects.get( ...)
   agent.method( from_date = request.POST['from'], to_date = request.POST['to']  )

It's possible (if a little "hacky" to "stamp" an object in your view so that a whole bunch of methods don't need to be explicitly told about these dates

   agent = SalesAgent.objects.get( ...)
   agent._from_date = request.POST['from']
   agent._to_date   = request.POST['to']

Now, you have to make sure that your code which depends on these fields fails gracefully (or applies defaults): Things like

def method( self):
    from_date = getattr( self, '_from_date', datetime.date( 1900,1,1) )
    to_date = getattr( self, '_to_date', datetime.date.today() )

which default (sensibly? ) if the stamps have not been applied. Alternatively,

if not hasattr( self, '_to_date'):
    raise AttributeError (
        'SalesAgent object method "method" has been called in an invalid context: instance attribute "_to_date" is not yet set' )

I suppose it's always possible to attach the entire request or even the entire view to an object instance, if you really want to. Same caveat about defaulting or failing understandably.