How to Disable Methods in Django REST Framework ViewSets (Python, Django)

Context:

• Django REST Framework (DRF): A powerful toolkit for building web APIs in Django.
• ViewSet: A DRF class that provides a convenient way to handle multiple related API endpoints (like list, detail, create, update, delete) for a model.

Disabling Methods:

There are two main approaches to disable methods in a ViewSet:

1. http_method_names Attribute:

   • Inherit from ModelViewSet (or a custom ViewSet subclass).
   • Define the http_method_names attribute as a list containing the allowed HTTP methods (e.g., ['GET', 'POST']).

   from rest_framework.viewsets import ModelViewSet
   
   class MyViewSet(ModelViewSet):
       http_method_names = ['GET', 'POST']  # Disables PUT, PATCH, and DELETE
   

   • This approach is simple but inflexible. If you later need to enable a disabled method, you'll need to modify this list.

2. Raising MethodNotAllowed Exception:

   • Override the desired methods (e.g., put, patch, delete).
   • Inside the overridden method, raise a MethodNotAllowed exception with a clear error message.

   from rest_framework import status
   from rest_framework.exceptions import MethodNotAllowed
   
   class MyViewSet(ModelViewSet):
       def put(self, request, *args, **kwargs):
           raise MethodNotAllowed('PUT', 'This method is not allowed for this resource.')
   
       def patch(self, request, *args, **kwargs):
           raise MethodNotAllowed('PATCH', 'This method is not allowed for this resource.')
   
       # ... other methods (GET, POST, DELETE) as needed
   

   • This approach is more flexible as you can provide specific error messages for each disabled method.

Choosing the Right Approach:

• If you have a clear set of methods to permanently disable, http_method_names might suffice.
• If you need more control over disabling methods and providing informative error messages, the exception-raising approach is recommended.

Additional Considerations:

• Consider using custom permissions if you need to control access based on user roles or other criteria.
• If you're using a custom ViewSet subclass, ensure it correctly inherits from the appropriate DRF class (e.g., ModelViewSet, ReadOnlyViewSet).

By following these guidelines, you can effectively disable methods in your Django REST Framework ViewSets, ensuring your API endpoints behave as intended.

from rest_framework.viewsets import ModelViewSet

class MyViewSet(ModelViewSet):
    http_method_names = ['GET', 'POST']  # Disables PUT, PATCH, and DELETE

    # ... your viewset logic for GET and POST methods ...

This code defines a MyViewSet class that inherits from ModelViewSet. The http_method_names attribute restricts allowed methods to GET and POST, effectively disabling PUT, PATCH, and DELETE.

from rest_framework import status
from rest_framework.exceptions import MethodNotAllowed
from rest_framework.viewsets import ModelViewSet

class MyViewSet(ModelViewSet):
    def put(self, request, *args, **kwargs):
        raise MethodNotAllowed('PUT', 'Update operation (PUT) is not allowed for this resource.')

    def patch(self, request, *args, **kwargs):
        raise MethodNotAllowed('PATCH', 'Partial update operation (PATCH) is not allowed for this resource.')

    # ... your viewset logic for GET, POST, and DELETE methods (if applicable) ...

This code showcases a MyViewSet class that inherits from ModelViewSet. The put and patch methods are overridden to raise MethodNotAllowed exceptions with specific error messages explaining why these methods are disabled. You can include your actual viewset logic for the allowed methods (e.g., GET, POST, DELETE) in the placeholders.

• Use the http_method_names approach if you have a permanent set of methods to disable and don't need specific error messages.
• Use the exception-raising approach if you need more control over disabling methods and want to provide informative error messages for each disabled method.

Custom Permissions:

• Create a custom permission class that inherits from rest_framework.permissions.BasePermission.
• Override the has_permission method to check for the allowed HTTP method and return False for methods you want to disable.
• Apply this custom permission class to your ViewSet using the permission_classes attribute.

Example:

from rest_framework.permissions import BasePermission

class ReadOnlyPermission(BasePermission):
    """
    Custom permission to allow only GET requests.
    """

    def has_permission(self, request, view):
        return request.method in ('GET',)  # Allow only GET requests

class MyViewSet(ModelViewSet):
    permission_classes = [ReadOnlyPermission]

    # ... your viewset logic for GET methods ...

This approach offers finer control over access based on the request method and allows for potential reuse of the permission class across different ViewSets.

Mixins:

• Utilize Django REST Framework's built-in mixins like GenericAPIView or RetrieveAPIView for a more granular approach.
• These mixins define specific allowed methods, effectively disabling unwanted ones.

from rest_framework.generics import RetrieveAPIView

class MyReadOnlyViewSet(RetrieveAPIView):
    # ... your viewset logic for GET methods ...

This approach is useful when you only need specific methods (like GET) and want to keep the ViewSet class simpler.

The best approach depends on your specific needs:

• Clarity and simplicity: Use http_method_names for a straightforward way to disable methods.
• Flexibility and error messages: Opt for exception raising if you need more control and informative error messages.
• Reusable permissions: Employ custom permissions if you need method-based access control across multiple ViewSets.
• Granular control and simplicity: Utilize mixins for ViewSets with specific allowed methods.

Consider these alternatives along with the existing methods to tailor your Django REST Framework ViewSets to your API requirements.