1 files changed, 116 insertions, 0 deletions
diff --git a/rest_framework/mixins.py b/rest_framework/mixins.py
new file mode 100644
index 00000000..8873e4ae
--- /dev/null
+++ b/rest_framework/mixins.py
@@ -0,0 +1,116 @@
+"""
+Basic building blocks for generic class based views.
+
+We don't bind behaviour to http method handlers yet,
+which allows mixin classes to be composed in interesting ways.
+
+Eg. Use mixins to build a Resource class, and have a Router class
+    perform the binding of http methods to actions for us.
+"""
+from django.http import Http404
+from rest_framework import status
+from rest_framework.response import Response
+
+
+class CreateModelMixin(object):
+    """
+    Create a model instance.
+    Should be mixed in with any `BaseView`.
+    """
+    def create(self, request, *args, **kwargs):
+        serializer = self.get_serializer(data=request.DATA)
+        if serializer.is_valid():
+            self.pre_save(serializer.object)
+            self.object = serializer.save()
+            return Response(serializer.data, status=status.HTTP_201_CREATED)
+        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
+
+    def pre_save(self, obj):
+        pass
+
+
+class ListModelMixin(object):
+    """
+    List a queryset.
+    Should be mixed in with `MultipleObjectBaseView`.
+    """
+    empty_error = u"Empty list and '%(class_name)s.allow_empty' is False."
+
+    def list(self, request, *args, **kwargs):
+        self.object_list = self.get_queryset()
+
+        # Default is to allow empty querysets.  This can be altered by setting
+        # `.allow_empty = False`, to raise 404 errors on empty querysets.
+        allow_empty = self.get_allow_empty()
+        if not allow_empty and len(self.object_list) == 0:
+            error_args = {'class_name': self.__class__.__name__}
+            raise Http404(self.empty_error % error_args)
+
+        # Pagination size is set by the `.paginate_by` attribute,
+        # which may be `None` to disable pagination.
+        page_size = self.get_paginate_by(self.object_list)
+        if page_size:
+            packed = self.paginate_queryset(self.object_list, page_size)
+            paginator, page, queryset, is_paginated = packed
+            serializer = self.get_pagination_serializer(page)
+        else:
+            serializer = self.get_serializer(instance=self.object_list)
+
+        return Response(serializer.data)
+
+
+class RetrieveModelMixin(object):
+    """
+    Retrieve a model instance.
+    Should be mixed in with `SingleObjectBaseView`.
+    """
+    def retrieve(self, request, *args, **kwargs):
+        self.object = self.get_object()
+        serializer = self.get_serializer(instance=self.object)
+        return Response(serializer.data)
+
+
+class UpdateModelMixin(object):
+    """
+    Update a model instance.
+    Should be mixed in with `SingleObjectBaseView`.
+    """
+    def update(self, request, *args, **kwargs):
+        try:
+            self.object = self.get_object()
+        except Http404:
+            self.object = None
+
+        serializer = self.get_serializer(data=request.DATA, instance=self.object)
+
+        if serializer.is_valid():
+            self.pre_save(serializer.object)
+            self.object = serializer.save()
+            return Response(serializer.data)
+
+        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
+
+    def pre_save(self, obj):
+        """
+        Set any attributes on the object that are implicit in the request.
+        """
+        # pk and/or slug attributes are implicit in the URL.
+        pk = self.kwargs.get(self.pk_url_kwarg, None)
+        if pk:
+            setattr(obj, 'pk', pk)
+
+        slug = self.kwargs.get(self.slug_url_kwarg, None)
+        if slug:
+            slug_field = self.get_slug_field()
+            setattr(obj, slug_field, slug)
+
+
+class DestroyModelMixin(object):
+    """
+    Destroy a model instance.
+    Should be mixed in with `SingleObjectBaseView`.
+    """
+    def destroy(self, request, *args, **kwargs):
+        self.object = self.get_object()
+        self.object.delete()
+        return Response(status=status.HTTP_204_NO_CONTENT)