Django之名称空间

由于name没有作用域，Django在反解URL时，会在项目全局顺序搜索，当查找到第一个name指定URL时，立即返回。

project/urls.py

urlpatterns = [
    path('admin/', admin.site.urls),
    path('app/', include('app.urls')),
    path('app2/', include('app2.urls')),
    path('app3/', include('app3.urls')),
]

app/urls.py

urlpatterns = [
    path('index/', views.index, name='index'),
]

app2/urls.py

urlpatterns = [
    path('index/', views.index, name='index'),
]

app3/urls.py

urlpatterns = [
    path('index/', views.index, name='index'),
]

在各自的函数中同时反解url

# app/views
def index(request):
    return HttpResponse(reverse('index'))

# app2/views
def index(request):
    return HttpResponse(reverse('index'))

# app3/views
def index(request):
    return HttpResponse(reverse('index'))

执行结果

http://127.0.0.1:8000/app/index/
/app3/index/

http://127.0.0.1:8000/app2/index/
/app3/index/

http://127.0.0.1:8000/app3/index/
/app3/index/

可以看到，当在不同的app的urls中定义相同的name时，最后反解出来的都是最后定义的一个URL，为了避免这种情况，Django引入了名称空间。

Django 2版本

project/urls.py

urlpatterns = [
    path('admin/', admin.site.urls),
    path('app/', include(('app.urls', 'app'))),  # include传入一个元组，第二个元素是app的名字
    path('app2/', include(('app2.urls', 'app2'))),
    path('app3/', include(('app3.urls', 'app3'))),
]

app/urls.py

urlpatterns = [
    path('index/', views.index, name='index'),
]

app2/urls.py

urlpatterns = [
    path('index/', views.index, name='index'),
]

app3/urls.py

urlpatterns = [
    path('index/', views.index, name='index'),
]

在各自的函数中同时反解url

# app/views
def index(request):
    return HttpResponse(reverse('app:index'))

# app2/views
def index(request):
    return HttpResponse(reverse('app2:index'))

# app3/views
def index(request):
    return HttpResponse(reverse('app3:index'))

运行结果

http://127.0.0.1:8000/app/index/
/app/index/

http://127.0.0.1:8000/app2/index/
/app2/index/

http://127.0.0.1:8000/app3/index/
/app3/index/

成功地避免反解出错的问题