Raising Exceptions in Django REST

Question

I'm trying to test the exceptions within the django rest framework. Based on http://www.django-rest-framework.org/api-guide/exceptions/ raising NotFound,

By default this exception results in a response with the HTTP status code "404 Not Found".

However when I issue a GET (to /example1) I get a 500 with ,

Request Method: GET
Request URL:    http://192.168.59.103:8002/example1
Django Version: 1.8.3
Exception Type: NotFound
Exception Value:    
not found
Exception Location: /home/djangoapp/testtools/api/views.py in example1, line 7
Python Executable:  /usr/bin/python

details below,

settings.py

REST_FRAMEWORK = {'EXCEPTION_HANDLER':'rest_framework.views.exception_handler'}

INSTALLED_APPS = (
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'rest_framework',
)

urls.py

from django.conf.urls import include, url
from api import views

urlpatterns = [
    url(r'example1', views.example1),
]

views.py

from rest_framework import status
from rest_framework.decorators import api_view
from rest_framework.response import Response
from rest_framework.exceptions import APIException,ParseError,NotFound

def example1(request):                                                                                                                               
    raise NotFound("not found")

Any ideas ?

Answer 1

from rest_framework.exceptions import NotFound

The class NotFound is extended from APIException. The default status code for APIException is 500 Internal Server Error, whereas for NotFound is 404.

So according to me here you are trying to throw a rest framework exception in a pure django view. I wrote a test case here to check what are the odds of getting the error raised. Guess what a simple django view trying to raise a rest framework exception is not recognized as an error to the view. But on providing the decorator and declaring it an API View it enters the exception_handler

So when you do:

from rest_framework.decorators import api_view

@api_view()
def example1(request):
    raise NotFound('not found')

This is now recognized as an exception thrown by the API which enters the default rest_framework EXCEPTION_HANDLER provided by you, where it returns the response for any given exception.

Its docstring says:

Returns the response that should be used for any given exception. By default we handle the REST framework APIException, and also Django's built-in ValidationError, Http404 and PermissionDenied exceptions. Any unhandled exceptions may return None, which will cause a 500 error to be raised.

Answer 2

I'm not sure why you are doing this. That's an internal exception used by DRF when it can't find a resource. But you're using it in a standard Django view, outside any of the DRF machinery. If you want to do that, you should use the standard Django exception:

from django.core.exceptions import Http404

def example1(request):
    raise Http404('not found')