CODEWITHSUNDEEP
pythondjangodjango-rest-framework
Nathan
Nathan

Reputation: 509

How to modify error response in ModelViewSet class if detail not found for Django REST Framework?

I tried to implement this answer to create a custom base Response class for all my ModelViewSet classes. My problem is at the retrieve function. If the Id of instance I'm looking for not found, I can't seem to change the Response with my modified response_format. It still gives the default response. What should I change my if condition into?
views.py: 

class ResponseInfo(object):
    def __init__(self, **args):
        self.response = {
            "message": args.get('message', 'success'),
            "error": args.get('error', ),
            "data": args.get('data', []),
        }


class LanguageView(viewsets.ModelViewSet):
    def __init__(self, **kwargs):
        self.response_format = ResponseInfo().response
        super(LanguageView, self).__init__(**kwargs)

    permission_classes = [permissions.DjangoModelPermissions]
    queryset = Language.objects.all()
    serializer_class = LanguageSerializer

    def list(self, request, *args, **kwargs):
        # call the original 'list' to get the original response.
        response_data = super(LanguageView, self).list(request, *args, **kwargs)
        # customize the response data.
        self.response_format['data'] = response_data.data
        if not response_data.data:
            self.response_format['message'] = 'List is empty.'
            self.response_format['error'] = response_data.status_code
        return Response(self.response_format)

    def retrieve(self, request, *args, **kwargs):
        response_data = super(LanguageView, self).retrieve(request, *args, **kwargs)
        self.response_format['data'] = response_data.data
        if not response_data.data:
            self.response_format['message'] = 'Instance not found.'
            self.response_format['error'] = response_data.status_code
        return Response(self.response_format)

The JSON response when instance is found. E.g http://127.0.0.1:8000/languages/1/: 

{
    "message": "success",
    "error": null,
    "data": {
        "id": 1,
        "name": "English",
        "icon": "http://127.0.0.1:8000/media/language_icons/English.png",
        "xml": "http://127.0.0.1:8000/media/-",
        "abbreviation": "En"
    }
}

The JSON response when instance is not found. E.g URL: http://127.0.0.1:8000/languages/4/: 

{
    "detail": "Not found."
}

The response I'm hoping for: 

{  
    "message": "Instance not found.",  
    "error": "HTTP_404_NOT_FOUND",  
}

And is it possible to not show the "error" variable when there's no error? For this case when list is not empty and the searched instance is found.

Upvotes: 2

Views: 1952

Answers (1)

neverwalkaloner
neverwalkaloner

Reputation: 47364

You can implement custom exception handler:

from rest_framework.views import exception_handler

def custom_exception_handler(exc, context):
    # Call REST framework's default exception handler first,
    # to get the standard error response.
    response = exception_handler(exc, context)

    # Now add the HTTP status code to the response.
    if response is not None and response.status_code == 404:
        response.data = {  
            "message": "Instance not found.",  
            "error": "HTTP_404_NOT_FOUND",  
        }

    return response

To apply this handler for you project add it to REST_FRAMEWORK settings:

REST_FRAMEWORK = {
    'EXCEPTION_HANDLER': 'my_project.my_app.utils.custom_exception_handler'
}

Upvotes: 2

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