Clash Royale CLAN TAG#URR8PPP

router registration order influences output

I am facing a strange issue trying to implement a webservice using django rest frameworks. I have this two APIs - one for getting the list of news based on category(provided as URL parameter) and another to get the details of a news provided the news ID(provided as url parameter). Following is my app's urls.py code:

urls.py

from django.urls import path
from rest_framework import routers
...
router = routers.DefaultRouter()
router.register('news_contents', NewsContentViewSet)
router.register('news_infos', NewsInfoViewSet)
router.register('categories', CategoryViewSet)
router.register(r'^articles/(?P<category_name>[-w]+)', NewsItemViewSet, base_name="NewsInfo")
router.register(r'^articles/(?P<news_id>d+)/details', NewsDetailViewSet, base_name="NewsInfo")

urlpatterns = router.urls


The above code on calling:
http://localhost:8000/rest/articles/categoryname
returns the correct output, but calling:
http://localhost:8000/rest/articles/4057/details/
returns the following:

"detail":"Not found."


But when I change the order in which these two APIs are registered, both APIs start to work as expected.

Working urls.py:

urls.py

from django.urls import path
from rest_framework import routers
...
router = routers.DefaultRouter()
router.register('news_contents', NewsContentViewSet)
router.register('news_infos', NewsInfoViewSet)
router.register('categories', CategoryViewSet)
router.register(r'^articles/(?P<news_id>d+)/details', NewsDetailViewSet, base_name="NewsInfo") #brought to above the listing API
router.register(r'^articles/(?P<category_name>[-w]+)', NewsItemViewSet, base_name="NewsInfo")

urlpatterns = router.urls


Why is this happening? I am getting a feeling that as I add more APIs, whatever the reason behind this is going to get me stuck.

Another thing I noticed while debugging this was that, there are plenty of other endpoints which I don't want are automatically getting listed as available endpoints:

Using the URLconf defined in restnews.urls, Django tried these URL patterns, in this order:
rest/ ^news_contents/$ [name='newscontent-list']
rest/ ^news_contents.(?P<format>[a-z0-9]+)/?$ [name='newscontent-list']
rest/ ^news_contents/(?P<pk>[^/.]+)/$ [name='newscontent-detail']
rest/ ^news_contents/(?P<pk>[^/.]+).(?P<format>[a-z0-9]+)/?$ [name='newscontent-detail']
rest/ ^news_infos/$ [name='newsinfo-list']
rest/ ^news_infos.(?P<format>[a-z0-9]+)/?$ [name='newsinfo-list']
rest/ ^news_infos/(?P<pk>[^/.]+)/$ [name='newsinfo-detail']
rest/ ^news_infos/(?P<pk>[^/.]+).(?P<format>[a-z0-9]+)/?$ [name='newsinfo-detail']
rest/ ^^categories/$/$ [name='newsinfo-list']
rest/ ^^categories/$.(?P<format>[a-z0-9]+)/?$ [name='newsinfo-list']
rest/ ^^categories/$/(?P<pk>[^/.]+)/$ [name='newsinfo-detail']
rest/ ^^categories/$/(?P<pk>[^/.]+).(?P<format>[a-z0-9]+)/?$ [name='newsinfo-detail']
rest/ ^^articles/(?P<news_id>d+)/details/$ [name='NewsInfo-list']
rest/ ^^articles/(?P<news_id>d+)/details.(?P<format>[a-z0-9]+)/?$ [name='NewsInfo-list']
rest/ ^^articles/(?P<news_id>d+)/details/(?P<pk>[^/.]+)/$ [name='NewsInfo-detail']
rest/ ^^articles/(?P<news_id>d+)/details/(?P<pk>[^/.]+).(?P<format>[a-z0-9]+)/?$ [name='NewsInfo-detail']
rest/ ^^articles/(?P<category_name>[-w]+)/$ [name='NewsInfo-list']
rest/ ^^articles/(?P<category_name>[-w]+).(?P<format>[a-z0-9]+)/?$ [name='NewsInfo-list']
rest/ ^^articles/(?P<category_name>[-w]+)/(?P<pk>[^/.]+)/$ [name='NewsInfo-detail']
rest/ ^^articles/(?P<category_name>[-w]+)/(?P<pk>[^/.]+).(?P<format>[a-z0-9]+)/?$ [name='NewsInfo-detail']
rest/ ^$ [name='api-root']
rest/ ^.(?P<format>[a-z0-9]+)/?$ [name='api-root']


I have only provided 5 end points and all the remaining ones are not needed and hence need to be removed. Are these issues somehow connected? How can I solve these?

1 Answer
1

This is how the combination of ModelViewset and DefaultRouter class behave. From the DRF Doc, it provides a bunch of end-point by default
which is very very handy if you are doing CRUD Operations.


From your description, I understood that you are not dealing with CRUD operations, and hence you can't use the Magic of the DefaultRouter and ModelViewset.


So, What I suggest is, use rest_framework.views.APIView class for your purpose.


Example

CRUD

CRUD

DefaultRouter

ModelViewset

rest_framework.views.APIView

Example

views.py


from rest_framework.views import APIView
from rest_framework.response import Response


class MyViewClass(APIView):
def get(self, *args, **kwargs): # This fucntion will handle your "HTTP GET" requests
# put your logic here
return Response(data="mymsg": "this is my response")

def post(self, *args, **kwargs):
return Response("This is post method")

and in your urls.py

urls.py

from django.conf.urls import url

urlpatterns = [
url(r'mysample/', MyViewClass.as_view())

]

References

1. DRF Router

2. DRF viewset

3. DRF APIview


UPDATE-1

Read the Django document

How Django processes a request

When a user requests a page from your
Django-powered site, this is the algorithm the system follows to
determine which Python code to execute:

Router

CRUD

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