python - Django 2.0 path error ?: (2_0.W001) has a route that contains '(?P<', begins with a '^', or ends with a '$'

64
votes

I'm new to Django and am trying to create the back end code for a music application on my website.

I have created the correct view in my views.py file (in the correct directory) as shown below:

def detail(request, album_id):
    return HttpResponse("<h1>Details for Album ID:" + str(album_id) + "</h1>")

however, when creating the url or path for this (shown below)

#/music/71/ (pk)
path(r'^(?P<album_id>[0-9])/$', views.detail, name='detail'),

I am experiencing a warning on my terminal stating:

?: (2_0.W001) Your URL pattern '^(?P<album_id>[0-9])/$' [name='detail'] has a route that contains '(?P<', begins with a '^', or ends with a '$'. This was likely an oversight when migrating to django.urls.path().

and whenever the /music/ (for which the path works) is followed by a number, such as /music/1 (which is what I want to be able to do) the page cannot be found and the terminal gives the above warning.

It may be a simple error and just me being stupid but I'm new to Django and python regex statements, so any help is appreciated.

7
pythondjangopython-3.xdjango-viewsdjango-urls
I think you either want to use re_path or don't use regex in the url pattern (path('music/<int:album_id>/', ....). - ayhan
You are mixing new and old urls syntax. Either change url to path('<int:album_id>/', views.detail, name='detail') or use re_path - Borut
It would be so nice if django would tell what to use instead. - Sören

7 Answers

127
votes

The new path() syntax in Django 2.0 does not use regular expressions. You want something like:

path('<int:album_id>/', views.detail, name='detail'),

If you want to use a regular expression, you can use re_path().

re_path(r'^(?P<album_id>[0-9])/$', views.detail, name='detail'),

The old url() still works and is now an alias to re_path, but it is likely to be deprecated in future.

url(r'^(?P<album_id>[0-9])/$', views.detail, name='detail'),
17
votes

Just to add to what @alasdair mentioned, I added re_path as part of the include and it works fine. Here is an example

Add re_path to your import (for django 2.0)

from django.urls import path, re_path

urlpatterns = [
    path('admin/', admin.site.urls),
    re_path(r'^$', home, name='home'),

]
8
votes

Instead of using 're_path' you can also use ''(empty string) as the first argument of your path(). I have used it and it worked for me.

urlpatterns = [
    path('admin/', admin.site.urls),
    path('',views.index,name='index'),
]
2
votes

If it doesn't work add this code to yoursite\urls.py inside urlpatterns:

path('music/<int:album_id>/', views.detail, name="detail"),
1
votes

Use an empty string '' instead of '/' or r'^$'. It works like a charm. Code is as below:

from django.urls import path, re_path

urlpatterns = [
    path('admin/', admin.site.urls),
    path('', home, name='home'),
]
0
votes

In django 2.0 version primary key write this way...

urls.py

from django.urls import path

from . import views


urlpatterns = [
    path('', views.course_list),
    path('<int:pk>/', views.course_detail),
]
0
votes

url() is deprecated in newer version of django. So instead of using url use re_path() in your urls file as follows:

from django.urls import path, re_path
from . import views

urlpatterns = [
    #url(r'^(?P<album_id>[0-9]+)/$', views.detail, name='detail'),
    path('', views.index, name='index'),
    re_path(r'^(?P<album_id>[0-9])/$', views.detail, name='detail'),
]