generics.py

from rest_framework import mixins
from rest_framework.generics import SingleObjectAPIView
from yourapp.mixins import PartialUpdateModelMixin


class RetrievePartialUpdateDestroyAPIView(PartialUpdateModelMixin,
                                    mixins.RetrieveModelMixin,
                                    mixins.UpdateModelMixin,
                                    mixins.DestroyModelMixin,
                                    SingleObjectAPIView):
    @property
    def allowed_methods(self):
        """
        Return the list of allowed HTTP methods, uppercased.
        """
        self.http_method_names.append("patch")
        return [method.upper() for method in self.http_method_names
                if hasattr(self, method)]

    def get_serializer(self, instance=None, data=None, files=None, partial=False):
        """
        Return the serializer instance that should be used for validating and
        deserializing input, and for serializing output.
        """
        serializer_class = self.get_serializer_class()
        context = self.get_serializer_context()
        return serializer_class(instance, data=data, files=files, partial=partial, context=context)

    def patch(self, request, *args, **kwargs):
        return self.update_partial(request, *args, **kwargs)

    def get(self, request, *args, **kwargs):
        return self.retrieve(request, *args, **kwargs)

    def put(self, request, *args, **kwargs):
        return self.update(request, *args, **kwargs)

    def delete(self, request, *args, **kwargs):
        return self.destroy(request, *args, **kwargs)

mixins.py

from django.http import Http404
from rest_framework import status
from rest_framework.response import Response


class PartialUpdateModelMixin(object):
    """
    Update a model instance.
    Should be mixed in with `SingleObjectBaseView`.
    """
    def update_partial(self, request, *args, **kwargs):
        try:
            self.object = self.get_object()
            created = False
        except Http404:
            self.object = None
            created = True

        serializer = self.get_serializer(self.object, data=request.DATA, files=request.FILES, partial=True)

        if serializer.is_valid():
            self.pre_save(serializer.object)
            self.object = serializer.save()
            status_code = created and status.HTTP_201_CREATED or status.HTTP_200_OK
            return Response(serializer.data, status=status_code)

        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

views.py

# A Sample View to demonstrate how to use the PATCH method
from yourapp.generics import RetrievePartialUpdateDestroyAPIView
from yourapp.models import Project
from yourapp.serializers import ProjectSerializer

class ProjectDetail(RetrievePartialUpdateDestroyAPIView):
    model = Project
    permission_classes = (permissions.AllowAny,)
    serializer_class = ProjectSerializer


# your serializer class should not need to change.

xtesting

Some curl commands to help test:

Create:
curl -XPOST -H "Content-type: application/json" -d '{"project_name":"My Project", "project_description":"The original description"}' http://localhost:8000/projects/

Update:
curl -XPATCH -H "Content-type: application/json" -d '{"project_name":"A new name"}' http://localhost:8000/project/1/

OR

curl -XPUT -H "Content-type:application/json" -d '{"project_name":"A new name", "project_description":"The original description"}' http://localhost:8000/project/1/

Delete:
curl -XDELETE http://localhost:8000/project/1/