How does Django handle URL routing when

Using Django Forms & APIs
1
  1. We define a custom app_name in an app’s urls.py and use a different namespace in the include() method in urls.py of the base project?
  2. The app_name (or custom app_name) and the namespace are different or one of them matches the other?
  3. We have multiple apps where:
    Some apps have the same namespace defined in the base urls.py as one of the custom app_names.
    Some apps use entirely different app_name and namespace combinations.

How does Django resolve such URL routing scenarios, and does it prioritize namespace over app_name?

project/
    urls.py
    settings.py
    ...
    blog/
        urls.py
    blog_comments/
        urls.py
    posts/
        urls.py

from django.urls import path, include

urlpatterns = [
    # Blog app with custom app_name and namespace
    path('blog/', include(('blog.urls', 'blog'), namespace='blog_ns')),

    # Blog comments app with custom app_name and namespace
    path('comments/', include(('blog_comments.urls', 'comments_app'), namespace='blog')),

    # Posts app with default app_name and namespace
    path('posts/', include(('posts.urls', 'posts'), namespace='posts_post')),
]

from django.urls import path

# Define custom app_name
app_name = 'blog'

urlpatterns = [
    path('list/', lambda request: None, name='list'),
    path('detail/<int:id>/', lambda request: None, name='detail'),
]

from django.urls import path

# Define custom app_name
app_name = 'comments_app'

urlpatterns = [
    path('list/', lambda request: None, name='list'),
    path('add/', lambda request: None, name='add'),
]

from django.urls import path

# Default app_name aligned with the namespace
app_name = 'posts'

urlpatterns = [
    path('list/', lambda request: None, name='list'),
    path('detail/<int:id>/', lambda request: None, name='detail'),
]

What can happen when we used references: {% url 'blog:list" %} or {% url 'posts_pos:list' %}

Am not understanding the logic behind this. Is there anyone can explain it clearly?

2

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3

The precedence and resolution of namespaced urls is documented at URL namespaces.

Read the list at Reversing namespaced URLs to see what’s looked at first.

Also, quoting the second sentence of the first paragraph for the definition of instance namespace:

Instance namespaces should be unique across your entire project.

While Django may not throw an error in this situation, it’s probably not going to give you the result you expect, unless you’re working with nested namespaces.