fabio fabio - 6 months ago 20
Python Question

Using additional fields of a through m2m on template

My

models.py
:

class Profile(models.Model):
name = models.CharField(max_length=32)
gender = models.CharField(max_length=1, choices=(('m', 'male'),
('f', 'female')), default='m')
addresses = models.ManyToManyField(City,
related_name='user_city', through='User_City')

class User_City(models.Model):
user = models.ForeignKey(Profile)
address = models.ForeignKey(City)
phone = models.CharField(max_length=32)

class Meta:
unique_together = ("user", "address")


My
view.py
:

def user_profile(request, city):
a=Profile.objects.filter(addresses=city)
context_dict['lista'] = a
###first alternative:
#b=User_City.objects.filter(user=request.user, address=city)
#context_dict['lista_address'] = b
###second alternative:
#for c in a:
#b=User_City.objects.filter(user=c, address=city)
#c.phone=b.phone
#context_dict['lista_address'] = c


My
template.html
:

{% for user in lista %}
{{ user.name }}
{{ user.gender}}
{{ user.phone }}
#{{ user.addresses.phone }}
#{{ user.addresses__phone }}
{% endfor %}


It read name and gender but not the phone...
I tried many solutions but to no avail.

I can add the lista_address context_dict but then I don't know how to use in the template (I should find the right user in the for cycle).

I could add some attribute in the view but it don't work (attribute don't exist).

Thank for the help

Answer

addresses is a ManyToManyField, so how is {{ user.addresses.phone }} (or the likes thereof) supposed to know which of the addresses (City instances) is meant there to look up phone.

Just loop directly over User_City objects, not Profiles:

# view.py
a = city.user_city_set.all()  # all through instances of city
# a = User_City.objects.filter(address=city)

# template.html
{% for u_c in lista %}
  {{ u_c.user.name }}
  {{ u_c.user.gender}}
  {{ u_c.phone }}
{% endfor %}

One more point: 'user_city' is a very bad related_name! It is the related manager's name used to access the Profile instances of a City:

city.user_city.all()  
# Bad: because this is a QuerySet of Profiles
# Better: related_name = 'users'