Including other URLconfs

At any point, your urlpatterns can "include" other URLconf modules. This essentially "roots" a set of URLs

below other ones.

For example, here's an excerpt of the URLconf for the DjangoWeb site itself. It includes a number of other URLconfs:

from django.conf.urls import include, url

urlpatterns = [

# ... snip ...

url(r'^community/', include('django_website.aggregator.urls')),

url(r'^contact/', include('django_website.contact.urls')),

# ... snip ...

]

Note that the regular expressions in this example don't have a $ (end-of-string match character) but do include a trailing

slash. Whenever Django encounters include() (django.conf.urls.include()), it chops off whatever part

of the URL matched up to that point and sends the remaining string to the included URLconf for further processing.

Another possibility is to include additional URL patterns by using a list of url() instances. For example, consider

this URLconf:

from django.conf.urls import include, url

from apps.main import views as main_views

from credit import views as credit_views

extra_patterns = [

url(r'^reports/(?P<id>[0-9]+)/$', credit_views.report),

url(r'^charge/$', credit_views.charge),

]

urlpatterns = [

url(r'^$', main_views.homepage),

url(r'^help/', include('apps.help.urls')),

url(r'^credit/', include(extra_patterns)),

]

In this example, the /credit/reports/ URL will be handled by the credit.views.report() Django view.

This can be used to remove redundancy from URLconfs where a single pattern prefix is used repeatedly. For example,

consider this URLconf:

from django.conf.urls import url

from . import views

urlpatterns = [

url(r'^(?P<page_slug>\w+)-(?P<page_id>\w+)/history/$', views.history),

url(r'^(?P<page_slug>\w+)-(?P<page_id>\w+)/edit/$', views.edit),

url(r'^(?P<page_slug>\w+)-(?P<page_id>\w+)/discuss/$', views.discuss),

url(r'^(?P<page_slug>\w+)-(?P<page_id>\w+)/permissions/$', views.permissions),

]

We can improve this by stating the common path prefix only once and grouping the suffixes that differ:

from django.conf.urls import include, url

from . import views

urlpatterns = [

url(r'^(?P<page_slug>\w+)-(?P<page_id>\w+)/', include([

url(r'^history/$', views.history),

url(r'^edit/$', views.edit),

url(r'^discuss/$', views.discuss),

url(r'^permissions/$', views.permissions),

])),

]

Captured parameters

An included URLconf receives any captured parameters from parent URLconfs, so the following example is valid:

# In settings/urls/main.py

from django.conf.urls import include, url

urlpatterns = [

url(r'^(?P<username>\w+)/blog/', include('foo.urls.blog')),

]

# In foo/urls/blog.py

from django.conf.urls import url

from . import views

urlpatterns = [

url(r'^$', views.blog.index),

url(r'^archive/$', views.blog.archive),

]

In the above example, the captured "username" variable is passed to the included URLconf, as expected.

Passing extra options to view functions

URLconfs have a hook that lets you pass extra arguments to your view functions, as a Python dictionary.

The django.conf.urls.url() function can take an optional third argument which should be a dictionary of

extra keyword arguments to pass to the view function.

For example:

from django.conf.urls import url

from . import views

urlpatterns = [

url(r'^blog/(?P<year>[0-9]{4})/$', views.year_archive, {'foo': 'bar'}),

]

In this example, for a request to /blog/2005/, Django will call views.year_archive(request,

year='2005', foo='bar').

This technique is used in the syndication framework to pass metadata and options to views.

Dealing with conflicts

It's possible to have a URL pattern which captures named keyword arguments, and also passes arguments with the

same names in its dictionary of extra arguments. When this happens, the arguments in the dictionary will be used

instead of the arguments captured in the URL.

Passing extra options to include()

Similarly, you can pass extra options to include(). When you pass extra options to include(), each line in the

included URLconf will be passed the extra options.

For example, these two URLconf sets are functionally identical:

Set one:

# main.py

from django.conf.urls import include, url

urlpatterns = [

url(r'^blog/', include('inner'), {'blogid': 3}),

]

# inner.py

from django.conf.urls import url

from mysite import views

urlpatterns = [

url(r'^archive/$', views.archive),

url(r'^about/$', views.about),

]

Set two:

# main.py

from django.conf.urls import include, url

from mysite import views

urlpatterns = [

url(r'^blog/', include('inner')),

]

# inner.py

from django.conf.urls import url

urlpatterns = [

url(r'^archive/$', views.archive, {'blogid': 3}),

url(r'^about/$', views.about, {'blogid': 3}),

]

Note that extra options will always be passed to every line in the included URLconf, regardless of whether the line's

view actually accepts those options as valid. For this reason, this technique is only useful if you're certain that every

view in the included URLconf accepts the extra options you're passing.