Details:
I have a Django application where I’m trying to create a dynamic view that displays a detail page for a model instance based on a URL parameter. I have set up the following:
Model Code:
<code>class Card(models.Model):
background_image_id = models.CharField(max_length=100)
border_id = models.CharField(max_length=100)
image = models.ImageField(upload_to='cards/')
number = models.IntegerField()
name = models.CharField(max_length=30)
subtitle = models.CharField(max_length=100)
title = models.CharField(max_length=200)
card_paragraph1 = models.TextField()
card_paragraph2 = models.TextField()
card_paragraph3 = models.TextField()
card_paragraph4 = models.TextField()
card_button_class = models.CharField(max_length=100)
card_detail_url = models.CharField(max_length=100, blank=True, null=True)
card_modal_class = models.CharField(max_length=100)
card_temple_url = models.CharField(max_length=100, blank=True, null=True)
quote = models.CharField(max_length=255)
background_modal_image_id = models.CharField(max_length=100)
modal_title = models.CharField(max_length=100)
</code>
<code>class Card(models.Model):
background_image_id = models.CharField(max_length=100)
border_id = models.CharField(max_length=100)
image = models.ImageField(upload_to='cards/')
number = models.IntegerField()
name = models.CharField(max_length=30)
subtitle = models.CharField(max_length=100)
title = models.CharField(max_length=200)
card_paragraph1 = models.TextField()
card_paragraph2 = models.TextField()
card_paragraph3 = models.TextField()
card_paragraph4 = models.TextField()
card_button_class = models.CharField(max_length=100)
card_detail_url = models.CharField(max_length=100, blank=True, null=True)
card_modal_class = models.CharField(max_length=100)
card_temple_url = models.CharField(max_length=100, blank=True, null=True)
quote = models.CharField(max_length=255)
background_modal_image_id = models.CharField(max_length=100)
modal_title = models.CharField(max_length=100)
</code>
class Card(models.Model):
background_image_id = models.CharField(max_length=100)
border_id = models.CharField(max_length=100)
image = models.ImageField(upload_to='cards/')
number = models.IntegerField()
name = models.CharField(max_length=30)
subtitle = models.CharField(max_length=100)
title = models.CharField(max_length=200)
card_paragraph1 = models.TextField()
card_paragraph2 = models.TextField()
card_paragraph3 = models.TextField()
card_paragraph4 = models.TextField()
card_button_class = models.CharField(max_length=100)
card_detail_url = models.CharField(max_length=100, blank=True, null=True)
card_modal_class = models.CharField(max_length=100)
card_temple_url = models.CharField(max_length=100, blank=True, null=True)
quote = models.CharField(max_length=255)
background_modal_image_id = models.CharField(max_length=100)
modal_title = models.CharField(max_length=100)
View Code:
<code>from django.shortcuts import render
from .models import Card
def card(request, name):
try:
# Attempt to retrieve the card with the given name
card = Card.objects.get(name=name)
except Card.DoesNotExist:
# If no card is found, render the placeholder template
return render(request, 'cards2/temples_placeholder.html')
else:
# If the card is found, render the card detail template
return render(request, 'cards2/card.html', {'card': card})
</code>
<code>from django.shortcuts import render
from .models import Card
def card(request, name):
try:
# Attempt to retrieve the card with the given name
card = Card.objects.get(name=name)
except Card.DoesNotExist:
# If no card is found, render the placeholder template
return render(request, 'cards2/temples_placeholder.html')
else:
# If the card is found, render the card detail template
return render(request, 'cards2/card.html', {'card': card})
</code>
from django.shortcuts import render
from .models import Card
def card(request, name):
try:
# Attempt to retrieve the card with the given name
card = Card.objects.get(name=name)
except Card.DoesNotExist:
# If no card is found, render the placeholder template
return render(request, 'cards2/temples_placeholder.html')
else:
# If the card is found, render the card detail template
return render(request, 'cards2/card.html', {'card': card})
URL Code:
<code>from django.urls import path
from . import views
urlpatterns = [
path('card/<str:name>/', views.card, name='card_detail'),
]
</code>
<code>from django.urls import path
from . import views
urlpatterns = [
path('card/<str:name>/', views.card, name='card_detail'),
]
</code>
from django.urls import path
from . import views
urlpatterns = [
path('card/<str:name>/', views.card, name='card_detail'),
]
Issue:
When I try to access a URL like http://127.0.0.1:8000/card/arepage/, I get a 404 error, indicating that the page cannot be found. (“arepage” being the name of my model instance)
I have confirmed that:
The Card model instance with name=’arepage’ exists in the database.
The URL pattern is correctly defined to match card/str:name/.
Questions:
Why might the URL not be matching the view, even though the model instance exists?
How can I debug or fix this issue to ensure that the page is found correctly?
2
I checked your project and understood that you didn’t provide your main urls.py in the question.
Because if you didn’t register your urls.py from app.py in main urls.py, in this case your url card/whatever/ is not registered and you should get 404.
I believe the name of the app folder is cards. To improve the situation, you should manually register your cards/urls.py in main urls.py:
<code># project_settings_folder/urls.py
# whole text, with admin etc.
...
# end of your file:
from django.urls import include
urlpatterns += [
path('', include('cards.urls')),
]
</code>
<code># project_settings_folder/urls.py
# whole text, with admin etc.
...
# end of your file:
from django.urls import include
urlpatterns += [
path('', include('cards.urls')),
]
</code>
# project_settings_folder/urls.py
# whole text, with admin etc.
...
# end of your file:
from django.urls import include
urlpatterns += [
path('', include('cards.urls')),
]
BTW, try to read about GCBV, it is much simplier and clear than FBV. More here: https://docs.djangoproject.com/en/5.1/topics/class-based-views/
2