Filterig initial data in Django ManyToMany field

Question

I want to filter data in Django ManyToMany field.

The app creates Meetings that take place in some rooms which are located in some venues.

Many people can create Meetings, but a single person can just access to the venues and rooms that he created.

My models are (example):

class Room(models.Model):
    name = models.CharField(max_length=100)
    capacity = models.IntegerField()

    def __str__(self):
        return self.name

    def get_absolute_url(self):
        return reverse('venue:room_detail', kwargs={'pk':self.pk})

class Venue(models.Model):
    creator = models.ForeignKey(User)
    name = models.CharField(max_length=100)
    rooms = models.ManyToManyField(Room)

    def __str__(self):
        return self.name

    def get_absolute_url(self):
        return reverse('venue:venue_detail', kwargs={'pk':self.pk})

class Meeting(models.Model):
    name = models.CharField(max_length=100)
    venue = models.ForeignKey(Venue)
    room = models.ForeignKey(Room)

I'm using Django generic views in my application.

My question is, how can I filter only the specific rooms created by a user "User A" in the form of Meeting. "User A" cannot see rooms created by "User B"

In the same way, how can I select just the rooms created in a specific venue without all the rooms? I don't want to use JavaScript please.

Many thanks for your responses.

Answer 1

You can override the queryset from the form

#constructor from form
def __init__(self, *args, **kwargs):
    user = kwargs.pop('user', None)
    super(ObjectForm, self).__init__(*args, **kwargs)
    if user:
        self.fields['rooms'].queryset = Room.objects.filter(room__venue_creator=user)

You need to change ObjectForm with the name of your form

Something like that.

Answer 2

@angel

class Room(models.Model):
    name = models.CharField(max_length=100)

class Venue(models.Model):
    creator = models.ForeignKey(User)
    name = models.CharField(max_length=100)
    rooms = models.ManyToManyField(Room, through="VenueRooms")

class VenueRooms(models.Model):
    venue = models.ForeignKey(Venue)
    room = models.ForeignKey(Room)

class Meeting(models.Model):
    name = models.CharField(max_length=100)
    venue = models.ForeignKey(Venue)
    room = models.ForeignKey(Room)

class MeetingForm(ModelForm):
    class Meta:
        model = Meeting
        fields = ('name', 'venue', 'room',)

    def __init__(self, *args, **kwargs):
        user = kwargs.pop('user', None)
        print(user) # it prints None
        super(MeetingForm, self).__init__(*args, **kwargs)

That is the models and the ModelForm for MeetinfForm where I'm trying to get access to the queryset of rooms and venur created by a specific user. I suppose that user is refered to the autheticated user. It's like request.user; so by printing user un the shell, I should have the name of the authenticated user.