No ReverseMatch URL django - django

Question

I have a scenario that looks like this:
Models
from django.db import models
from django.core.urlresolvers import reverse_lazy, reverse
class State(models.Model):
short_name = models.CharField('Abbreviation', max_length=2)
state = models.SlugField('State Name', max_length=20)
def __str__(self):
return self.state
def get_absolute_url(self):
return reverse('state_list', kwargs={'state': self.state})
class City(models.Model):
state = models.ForeignKey(State)
city = models.CharField('City', max_length=100)
class Meta:
verbose_name = 'City'
verbose_name_plural = 'Cities'
def __str__(self):
return self.city
class School(models.Model):
name = models.CharField(max_length=69, default='')
def __str__(self):
return self.name
class Meta:
verbose_name = 'School'
verbose_name_plural = 'Schools'
Views
from django.shortcuts import get_object_or_404, render
from django.views.generic import ListView, DetailView, CreateView, UpdateView, DeleteView
from django.core.urlresolvers import reverse_lazy
from .models import School, City, State
def reviews_index(request):
state_list = State.objects.all()
context = {'states': state_list}
return render(request, 'reviews/reviews_index.html', context)
def state_detail(request, state=None):
city_list = City.objects.order_by('city')
context = {'cities': city_list}
return render(request, 'reviews/state_detail.html', context)
def city_detail(request, state=None, city=None):
school_list = School.objects.all()
context = {'schools': school_list}
return render(request, 'reviews/city_detail.html', context)
URLs
from django.conf.urls import url, include
from . import views
app_name = 'reviews'
urlpatterns = [
url(r'^$', views.reviews_index, name='reviews_index'),
url(r'^(?P<state>[a-z]+)/$', views.state_detail, name='state_detail'),
url(r'^(?P<state>[a-z]+)/(?P<city>[a-z]+)/$', views.city_detail, name='city_detail'),
]
However, when I try to create a link from the state_detail template to the city_detail template, I get this error:
NoReverseMatch at /reviews/alabama/
Reverse for 'city_detail' with arguments '('', 'Auburn')' and keyword arguments '{}' not found. 0 pattern(s) tried: []
This is how I am linking in the template:
{% block main_content %}
<div class="content">
<div class="row">
{% if cities %}
{% for city in cities %}
<div class="medium-3 column">
{{ city.city }}
</div>
{% endfor %}
{% endif %}
</div>
</div>
{% endblock %}
Can someone please tell me that I am doing wrong and help me fix it. Thanks in advance.

Answer 1

The city_detail url pattern includes the state.state, so you need to include the state in the template context.
In your view, you can use get_object_or_404 to fetch the state using the slug.
def state_detail(request, state=None):
state = get_object_or_404(State, state=state)
city_list = City.objects.filter(state=state).order_by('city')
context = {'cities': `city_list`, 'state': state}
return render(request, 'reviews/state_detail.html', context)
Note that I've changed city_list, so that it only displays cities in the state you are viewing.
It's not a great idea to use the same variable name state for the instance and the slug. It would be a good idea to rename one of them, e.g. to state_obj or state_slug. If you do this, you'll have to make sure you update your urls, views and templates to be consistent.